The majority of established model organisms belong to the supergroup Opisthokonta, which includes yeasts and animals. While enlightening, this focus has neglected protists, organisms that represent the bulk of eukaryotic diversity and are often regarded as primitive eukaryotes. One of these is the “supergroup” Excavata, which comprises unicellular flagellates of diverse lifestyles and contains species of medical importance, such as Trichomonas, Giardia, Naegleria, Trypanosoma and Leishmania. Excavata exhibits a continuum in mitochondrial forms, ranging from classical aerobic, cristae-bearing mitochondria to mitochondria-related organelles, such as hydrogenosomes and mitosomes, to the extreme case of a complete absence of the organelle. All forms of mitochondria house a machinery for the assembly of Fe–S clusters, ancient cofactors required in various biochemical activities needed to sustain every extant cell. In this review, we survey what is known about the Fe–S cluster assembly in the supergroup Excavata. We aim to bring attention to the diversity found in this group, ree fl cted in gene losses and gains that have shaped the Fe–S cluster biogenesis pathways. Keywords Fe–S cluster · Mitochondria · Excavata · Evolution Introduction (stramenopiles/alveolates/Rhizaria), photosynthetic algae, and Opisthokonta [1, 5]. Organelles of mitochondrial ori- The intimate relationship between eukaryotic cells and mito- gin, of which MROs form a part, have been classified into chondria, as endosymbiont-derived organelles, has taken bil- five types [ 5]: (1) “classical mitochondrion” with a complete lion of years to establish [1, 2]. It was initially accepted that electron transport chain, which is capable of using oxygen as the basis for the presence of mitochondria in virtually every an electron acceptor, and produces metabolic energy from eukaryotic cell had been the provision of energy from their such machinery; (2 and 3) organelles that bear a functional oxidative phosphorylation machinery, yet several lines of electron transport chain, yet use other electron acceptors evidence have proven otherwise . The description of vari- such as fumarate, and are capable of performing both sub- ous types of mitochondria and mitochondria-related orga- strate-level phosphorylation and may or may not produce H ; nelles (or MRO), many of which are found in a spectrum (4) double membrane-bound MROs called hydrogenosomes of unrelated protist clades, has brought into the spotlight that are capable of ATP production in anaerobic or micro- an enormous organellar diversity, or what is rather a con- aerophilic environments and excrete H as one of the end tinuum, ranging from a minimalistic MRO of Giardia to the products of substrate-level phosphorylation in an organelle highly complex mitochondria of trypanosomes . MROs lacking electron transport chain ; finally, (5) mitosomes have been found in eukaryotic supergroups Excavata, SAR represent a type of MRO incapable of energy production, as they lack the components of an active electron chain and mostly have lost their genome [1, 5]. The original version of this article was revised due to a Remarkably, the Fe–S cluster assembly pathway is the retrospective Open Access order. only known common denominator of this conglomerate of * Priscila Peña-Diaz organelles. Moreover, in one of the best-studied eukary- email@example.com otes, the yeast Saccharomyces cerevisiae, this pathway seems to be the only truly essential component of its mito- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic chondria [3, 7]. In this review, we revise what is known about the Fe–S cluster assembly pathways of the unicellular Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic Vol.:(0123456789) 1 3 522 JBIC Journal of Biological Inorganic Chemistry (2018) 23:521–541 supergroup Excavata and attempt to compare its inventory and NIF systems each bear a functional homolog of this with those described in other eukaryotes, but mostly in enzyme which, however, displays significant differences the Opisthokonta, the by far most studied supergroup that addressed below. (2) Assembly of an Fe–S cluster on a scaf- includes, not surprisingly, humans . fold protein; a Cys in the scaffold protein binds sulfur liber - Fe–S clusters are ancient cofactors found in the whole ated from the previous reaction, which physically interacts spectrum of life. In Archaea, Bacteria and Eukaryota, cells with the CD for the Fe–S assembly to occur. (3) Transfer have evolved different machineries for their Fe–S clusters of the Fe–S cluster from the CD–scaffold complex onto a assembly, namely the methanoarchaeal sulfur mobilization delivery protein, which will subsequently interact with the (SUF) machinery , the nitrogen fixation (NIF) pathway recipient proteins and install the cluster. , the cysteine sulfinate desulfinate (CSD) system [ 11], the iron–sulfur cluster assembly (ISC) pathway [12, 13] The ISC system and cytosolic iron–sulfur protein assembly (CIA) pathway [14–16]. The first one is present throughout bacteria and in The Fe–S cluster assembly by the ISC system involves the the chloroplasts of photosynthesizing organisms , while activity of at least five proteins. A cysteine desulfurase the NIF system was initially discovered in the maturation (IscS) provides the sulfur, while the formation of the cluster of nitrogenase in N -fixing bacteria . The CSD system takes place on the scaffold protein named IscU. Ferredoxin has been described in Escherichia coli as a partial func- (Fdx) likely acts as an electron donor in this reaction [31, tional homolog of the SUF system . The ISC pathway is 32]. Subsequently, IscU requires the assistance of the chap- associated with eubacteria and in eukaryotes located within erones HscA (heat shock cognate 66 kDa or Hsc66) and the mitochondria . Finally, the CIA machinery is found HscB (heat shock cognate 20 kDa or Hsc20). HscA is a in the cytosol of eukaryotes, where it assembles, with the member of the Hsp70/DnaK chaperone family and exhib- assistance of mitochondrial ISC, Fe–S clusters eventually its an intrinsic ATPase activity, while HscB belongs to the incorporated into proteins located in this cellular compart- Hsc20/DnaJ J-type co-chaperone family . The binding ment [14, 20]. It is now widely accepted that the latter path- of the chaperones, which is mediated by an LPPVK motif way was bequeathed from an endosymbiont to an ancestral found in IscU, occurs in an orderly fashion to release the eukaryote, while the plastid-bearing eukaryotes inherited nascent Fe–S cluster onto the delivery system in an ATP- their SUF machinery from an early cyanobacterium [17, dependent manner [34–37]. In this scenario, HscA binds 21, 22]. On the other hand, a lateral gene transfer has been IscU, enhanced by the presence of HscB, which increases the proposed to be behind the emergence of the SUF pathway ATPase activity of the former chaperone by approximately in some unicellular eukaryotes that either retain highly 400-fold [35, 38]. The binding model formulated based on diverged MROs, such as Blastocystis, Stygiella incarcerata the studies of the IscU mutants proposes that the chaperone and Pygsuia biforma, or lost the entire organelle, along with complex stabilizes IscU for the release of the cluster to the the ISC pathway, like in the case of Monocercomonoides receptor protein . IscU has also been observed to interact . In any case, the Fe–S cluster assembly represents a with both [2Fe–2S] and [4Fe–4S] clusters . This was hallmark that is always taken into account when analyzing further analyzed upon the binding of the scaffold protein to the evolution of divergent mitochondria-derived organelles Fdx, which has been proposed to mediate, at least partially [12, 24–28]. and in vitro, the reductive coupling of [2Fe–2S] clusters into [4Fe–4S] clusters . Once the Fe–S cluster has been assembled, it is transferred to the delivery system for further Fe–S cluster machineries: a brief overview insertion into apoproteins, a role carried out by the dedicated protein IscA. The bacterial frataxin, named CyaY, plays an Bacterial systems inhibitory role in the biogenesis of the Fe–S cluster assembly by binding to IscS in an iron-sensing regulatory role . The Fe–S cluster assembly machineries in bacteria can be subdivided into four systems mentioned above, their distri- The SUF system bution being species specific [18, 29, 30]. As an example, E. coli with the best-studied bacterial Fe–S assemblies exhibits The SUF system for the Fe–S cluster assembly is induced the ISC, the SUF and the CSD systems [18, 19]. These dis- by iron-depleted and oxidative stress conditions and mainly tinct systems share the main activities for the formation of involves the activity of two sub-complexes . Proteins a [2Fe–2S] cluster, which may be divided into three main SufE and SufS form the heterodimer SufSE, while a second stages: (1) Pyridoxal 5′-phosphate-dependent cysteine (Cys) sub-complex termed SufBCD is composed of SufB, SufC desulfuration with concomitant production of l -alanine, car- and SufD [43, 44]. SufS, which represents the CD and there- ried out by a cysteine desulfurase (CD). The ISC, SUF, CSD fore is an ortholog of IscS, collaborates with SufE, which 1 3 JBIC Journal of Biological Inorganic Chemistry (2018) 23:521–541 523 increases the desulfurase activity of the CD [43, 45, 46]. pneumoniae . The NIF system comprises a CD termed SufSE transfers the sulfur produced by the CD reaction, fol- NifS and a scaffold protein NifU. NifU is a functional lowing the interaction with the scaffold complex SufBCD, homolog of the scaffold protein IscU, yet it exhibits some which further enhances the desulfurase activity . SufB remarkable differences. On its N-terminus it bears cysteines has been defined as a scaffold, capable of interacting with intended for [2Fe–2S] cluster binding, while other cysteines SufD and the soluble ATPase SufC [45, 48, 49]. Moreover, found in its middle and its C-terminus seem to bind Fe–S this complex uses F ADH as a redox cofactor . SufD clusters in a non-transient manner . NifB is an S-adeno- shares substantial sequence similarity with SufB and has sylmethionine (SAM)-dependent enzyme involved in the for- been hypothesized to confer iron to the reaction [50, 51]. mation of an Fe–S cluster precursor of an iron–molybdenum The stoichiometry plays an important role in the structural cofactor (FeMo-co) required for the reconstitution of active dynamics of the SufBCD complex, with its various oligo- nitrogenase . Other proteins involved in the NIF system nif meric forms being capable of transferring in vitro the cluster are IscA , which likely functions as a scaffold for target to the receptor proteins [49, 50]. For in vitro maturation of apoproteins , and a O-acetylserine synthase denoted as Fdx, the SufBC D, SufB C and SufC D sub-complexes CysE1, whose activity has been proposed to increment the 2 2 2 2 2 interact with SufA, which has been proposed to act as a cysteine pool for the Fe–S assembly of nitrogenase . transfer protein for the nascent Fe–S cluster . However, it has also been established in vitro that the SufBCD complex The CSD system is capable of transferring clusters directly to apoproteins without the assistance of SufA . Once the Fe–S cluster is The CD of the CSD system is encoded by the csdA gene. assembled, it is ready to be targeted to the transfer proteins. It differs from SufA by substrate specificity, although both The SUF system exhibits an A-Type carrier protein termed proteins share substantial sequence similarity. CsdA is capa- SufA. . While SufA belongs to the suf operon and IscA ble of transferring sulfur from l -selenocysteine, l -seleno- to the isc operon, another transfer or carrier protein called cystine, l -cysteine, l -cystine and cysteine sulfinate . ErpA is independent of the Fe–S cluster assembly operons CsdE, a homolog of SufE, catalyzes the release of Se, SO . A-type carrier proteins were initially believed to act and S from l -selenocysteine (the most preferred substrate), as alternative scaffolds , but several lines of evidence l -cysteine sulfinate and l -cysteine (the least preferred sub- argued against this premise. It was observed that deletions strate) [70, 71]. Regardless of the CD activity observed of the type-A carrier produced no phenotypes, probably a in vitro for each pure protein, labeling assays confirmed that reflection of the fact that the nascent cluster can be trans- CsdA and CsdE may enhance each other’s activity twofold ferred directly from the scaffold protein . Moreover, the [11, 72]. In E. coli, the CsdAE complex has been observed in binding capacity of type-A carriers did not allow reversible unison with the SufSE and SufBCD sub-complexes. Under transfer of the Fe–S cluster from the scaffold, and their bind- specific nutritional deficiency stress, the CsdAE complex ing to CD was not as efficient as that of IscU . For these may also recruit CsdL, an E1-like protein found in ubiquitin- reasons, two possible roles in Fe–S assembly were consid- like systems . ered: they could either act as iron donors  or assist the process of transfer to the apoproteins once the Fe–S cluster Eukaryotic systems was assembled . Another protein belonging to the SUF system is the Zn- Eukaryotic cells exhibit the ISC system in the mitochon- dependent SufU , which is absent in the Gram-negative dria and the CIA pathway in the cytosol. The photosynthetic bacteria such as E. coli. SufU, a homolog of IscU, is able eukaryotes also carry the SUF system in their plastids . to complement SufE, as it happens in the case of Bacillus Moreover, the SUF system has been retained even in the subtillis, Enterococcus faecalis, Thermatoga maritima and non-photosynthetic apicoplast of the apicomplexan parasites various mycobacteria [58–61]. [74, 75], as well as in the cytosol of some parasitic and com- mensal amitochondriate protists . Finally, the NIF sys- The NIF system tem is rarely present in the mitochondria and cytosol (e.g., in Entamoeba histolytica and Mastigamoeba balamuthi) [76, The NIF system, initially described in nitrogen-fixing 77], while parts of the CSD system were found scattered in bacterium Azotobacter vinelandii, is a dedicated machin- some parasitic protozoan genomes . ery for the maturation of nitrogenase. Later on, it has also been found co-existing with one or more of the other three The mitochondrial ISC system Fe–S assembly systems in ε-proteobacteria, represented by Helicobacter pylori , as well as in the Gram-negative The best-studied mitochondrial ISC systems are those of γ-proteobacteria Dickeya dadantii [63, 64] and Klebsiella yeast, plants and mammalian cells. In this section, we will 1 3 524 JBIC Journal of Biological Inorganic Chemistry (2018) 23:521–541 base our description on the human model and therefore use NFS1–ISD11–ISCU complex, aided by the chaperone com- the nomenclature for the human ISC Fe–S cluster assembly, plex is capable of transferring Fe–S clusters, although these unless indicated otherwise. The ISC system from bacteria experiments were performed in the absence of GLRX5 . and eukaryotes exhibits the same general functional traits, Another piece of evidence to support this model comes from such as the sulfur acquisition from a donor cysteine and the in vitro experiments where GRX5 is capable of interaction assembly of a nascent Fe–S cluster on a scaffold protein, with transfer proteins ISCA1 and ISC2, and also mobilizes with the subsequent transfer to carrier proteins, which will their [2Fe–2S] clusters . Co-immunoprecipitations of in turn deliver the cluster to apoproteins. However, there GLRX5 in mice N2a and HeLa cells also detected an inter- are some important differences between the prokaryotic action with carrier proteins ISCU2 and IBA57 . Moreo- and eukaryotic ISCs. One of them is the ISD11 protein, ver, deletion of GRLX5 in humans is known to cause severe exclusive for eukaryotes . ISD11 is a small accessory microcytic-hypochromic anemia, related to Fe–S cluster protein that acts in concert with NFS1 [80–83], the scaf- biogenesis defects . Regardless, the model involving fold protein ISU2 and the acyl carrier protein ACP . GLRX5 also correlates with the formation and transfer of Within the NFS1–ISD11–ACP tripartite complex, ISD11 the [4Fe–4S] clusters (discussed in detail below), as the forms a dimeric association at its core, with ACP occupying ISD11–ISC2–HSC20–HSC9 complex may only answer for a hydrophobic pocket in each ISD11 monomer that stabilizes the assembly of [2Fe–2S] clusters into the respiratory com- the complex [85, 86]. The complex also binds to the scaf- plexes I through III . fold protein ISCU2 and to ferredoxin (FDX2) , which The LYR-based transfer model described in human cells acts as an electron donor aided by a ferredoxin reductase differs from the one proposed and demonstrated for yeast (FDXR) [88–90]. ISCU2 is the product of alternative splic- mitochondria . We understand these two models are ing of ISCU which also gives origin to ISCU1, also sug- complementary, but we intentionally describe them sepa- gested to play a role in the repair of the [4Fe–4S] clusters in rately, as they rely on different experimental setups. In yeast the cytosol . In humans, the binding is facilitated by the mitochondria, the chaperone Ssq1 binds to monothiol glu- interaction with a chaperone/co-chaperone complex formed taredoxin Grx5 prior to binding to the scaffold protein Isu1, by HSPA9 (also called GRP75 or PBP74) and HSC20 (or making use of two different binding sites for each protein HSCB) [92, 93], while in yeast this role is performed by . The binding of Ssq1 to Grx5 is ATP independent, mitochondrial Hsp70 protein, ATP-dependent Ssq1 and co- which entails that the ATP-dependent stage of Ssq1 activity chaperone Jac1 [94, 95]. Frataxin (FXN) has been proposed takes place in the reaction upstream, while binding to the 2+ to donate Fe for the reaction and/or act as an allosteric co-chaperone Jac1 (Fig. 1). Jac1 is then released from Ssq1 regulator of NFS1, stimulating its activity [96–98]. Moreo- prior to the binding to Grx5, a step that precedes the binding ver, FXN has also been suggested to bind to the chaper- to Isu1. The result is an efficient transfer of the newly formed one–ISCU2 complex . The binding of ISCU2 to the L(I) cluster from Isu1 to Grx5 . The model also implies the YR motif seems essential for the transfer of the cluster to a release of Grx5 bound to the cluster from the Ssq1–Isc1 specific recipient apoprotein . Studies using succinate complex, with the concerted activity of exchange nucleotide dehydrogenase complex (SDH) subunits in mammalian cells factor Mge1 . The integration of Mge1 into this model demonstrate that the clusters are transferred directly from comes from in vitro experiments, in which Mge1 is capable the chaperone complex to the subunits of SDH, achieving of releasing nucleotides bound to Ssq1 when the chaperone their maturation in this step; a similar result was observed is in contact with Isu1. Therefore, the release of the chap- for respiratory complexes I and III . Also a monothiol erone from the scaffold (though these experiments where glutaredoxin, GLRX5, has been observed to interact with made, in the absence of Grx5 and in presence of Jac1), HSC20, through binding to the same group of cysteines that allows the continuation of a new cycle of assembly . the chaperone uses to bind SDH . Hence, GLRX5 must Mutations in Grx5 in S. cerevisiae trigger a severe pheno- be released from the chaperone complex for it to bind to the type of iron accumulation and subsequent defects in the recipient respiratory complex unit. Consequently, it was pro- Fe–S cluster-bearing proteins . The interaction of Grx5 posed that GLRX5 acts as an alternative scaffold for delivery with the Isa1 and Isa2 proteins has also been documented of the Fe–S clusters to apoproteins . in the fission yeast Schizosaccharomyces pombe [ 105]. A An alternative model for the transfer of the cluster from yeast two-hybrid system provided additional evidence for the NFS1–ISD11–ACP–ISC2–FXN complex involves an the interaction between Grx5 and Isa1 in S. cerevisiae . interaction with GLRX5. This model implies that GLRX5 ISCA1 and ISCA2, along with IBA57, form the so-called requires a chaperone-assisted transfer of the Fe–S cluster ISA complex that has been proposed to act as a scaffold from the scaffold complex, which for most apoproteins involved in the assembly of [4Fe–4S] clusters into a range of cannot be bypassed . Mechanistic data for this model mitochondrial proteins, including lipoic acid synthase [89, have been obtained from the NMR spectra where the 107]. Depletion of ISCA1 and ISCA2 in HeLa cells resulted 1 3 JBIC Journal of Biological Inorganic Chemistry (2018) 23:521–541 525 Fig. 1 Schematic representation of the ISC and CIA pathways in ent proteins are depicted in white for ISC and blue for CIA. The CIA eukaryotic cells. The generic representation displays ISC compo- components reflect the complexes described for the mammalian cell nents (in light green) and CIA components (in dark green). Recipi- model in defects in the mitochondrial cristae formation, ultrastruc- [89, 107]. Interestingly, when ISCU2 alone was silenced, ture alterations and acidification of the growth media, which increased amount of ISCU1 was observed in HeLa cells and associates these proteins with the maturation of respiratory vice versa, which led to the suggestion that these proteins complexes and hence metabolic defects . However, in may have redundant functions . This is in partial agree- mouse cell lines, silencing of these proteins did not cause ment with human cases of leukodystrophy and hypergly- any morphological alterations, yet respiration measure- cemia associated with defects in ISCA2 accompanied by ments corroborated the metabolic defects . Silencing of a reduction in [4Fe–4S] clusters in respiratory complexes IBA57 failed to exert an effect on the activity of the Fe–S II and IV . Alternatively, overexpression of ISC2 in cluster-carrying mitochondrial aconitase, yet it decreased an ISCU1 knock-down background in mouse cells showed in the activity of SDH. Similarly, the depletion of ISCA1, that ISCA1, but not ISCA2, was essential for the [4Fe–4S] ISCA2 and IBA57 significantly lowered the activities of cluster assembly, since ISCU2 could not rescue the [4Fe–4S] pyruvate dehydrogenase, 2-oxoglutarate dehydrogenase, defect caused by silencing of ISCU1 . Regardless, the mitochondrial aconitase, the Rieske protein and other Fe–S two scaffold proteins in mouse and human interact with each cluster-containing mitochondrial proteins. The phenotype other in vitro [89, 109], although only ISCU2 was able to could be reversed by RNAi-resistant ectopic expression of bind IBA57 . the two transfer proteins, proving their involvement in the The counterparts of human ISCU1 and ISCU2 in yeast phenotype . However, [2Fe–2S] ferrochelatase was are Isa1 and Isa2, which also function as scaffold proteins unaffected by silencing of ISCU1 in mouse, and of ISCU1, [110–112]. Experiments replacing Isu1 with bacterial ISCU2 and IBA57 in human cells, corroborating their role A-type proteins in an Isu1 mutant background corroborated only in late-acting stages of the Fe–S cluster assembly that this protein, and not Isu2, is the functional ortholog of 1 3 526 JBIC Journal of Biological Inorganic Chemistry (2018) 23:521–541 the bacterial counterpart . Notably, Isu1 and Isu2 inter- three homologs in humans . Yeast BolA1 and BolA3 act unlike their counterparts in humans . Silencing of localize to the mitochondria, while BolA2 is present in the Isu1, Isu2 and Iba57 disrupts the activities of mitochondrial cytosol . BolA1 and BolA3 were shown to physically aconitase, biotin synthase and lipoic acid synthase, just like interact in vitro with human proteins NFU1 and GLRX5, in human cells [110, 111, 113]. Regardless of whether Isu1, respectively, providing further evidence that these proteins Isu2 and Iba57 are indeed directly involved in the [2Fe–2S] fulfill different functions. Indeed, bola1 and bola3 mutants cluster assembly in both humans and yeast [100, 109, 114], exhibit no growth phenotype, but the double bola1–bola3 there is a consensus that they all are late-acting components mutant displays a mild respiratory defect associated with in the Fe–S assembly, directly involved in [4Fe–4S] cluster decreased activities of enzymes related to the product of formation . lipoic acid synthase, all of which require 4Fe–4S clusters Another protein related to the Fe–S cluster assembly and . Previous findings in yeast regarding BolA2 indicate mitochondrial respiratory complexes is the P-loop ATPase that this cytosolic protein interacts with Grx3/4 as a chap- IND1. Silencing of IND1 caused a severe decrease of the erone . Fe–S cluster-carrying complex I subunits, namely NDUFS1, A very important finding that defined the extent of the NDUFV1, NDUFS3 and NDUFA13, leading to a defect in mitochondrial Fe–S assembly machinery was that of Atm1. the assembly of the peripheral arm of the complex . A mutant strain for a mitochondrial ABC transporter in yeast Depletion of Ind1 in the yeast Yarrowia lipolytica also exhibited iron accumulation in mitochondria, respiration causes a defect in complex I assembly . defects and increased concentrations of glutathione . The transfer of the Fe–S clusters to apoproteins involves Labeled iron assays in a mutant for Atm1 indicated that the mobilization of the recently formed cluster to transfer this protein did not affect the assembly of Fe–S clusters in proteins or assembly factors (called carrier proteins in bac- mitochondria, yet it decreased the levels of the Fe–S cluster teria), which will subsequently pass on the cluster to the protein Leu1 in cytosol . The transporter is located in recipient protein. In bacteria, this process has been defined the inner mitochondrial membrane, with its ABC domains to work in a “one-way” mode, i.e., is irreversible [19, 49]. facing the mitochondrial matrix, which implies an export The transfer protein NFU1 (or Nfu in yeast) is known to activity mode . This transporter likely transfers a sulfur form homodimers and functions in mitochondria, cytosol derivative compound across the mitochondrial membrane, and plastids [118–122], although in vitro experiments of the which is essential in cytosol. bacterial protein in A. vinelandii has been recorded form- ing heteromers . The exact role of NFU1 in humans The CIA pathway remains unclear, although defects in NFU1 have been related to multiple mitochondria dysfunction syndrome [124–126]. Impairment of the mitochondrial Fe–S cluster assembly In this syndrome, the lack of lipoic acid, due to the defective affects maturation of the Fe–S proteins in the cytosol of activity of lipoic synthase, causes the subsequent impair- yeast and humans . Indeed, the mitochondrial machin- ment in lipoid acid-dependent enzymes, such as PDH and ery is involved in the formation of a glutathione-based com- KDH . In vitro assays have determined that the pro- pound that is translocated to the cytosol to be integrated into tein interacts with ISCA1  and BOL3 in humans . the cytosolic Fe–S cluster assembly through the ABC trans- Similar assays performed with yeast Nfu detected associa- porter Atm1 (Fig. 1) [131, 134, 135]. The maturation of the tions with Isa1 and Isa2, as well as with the [4Fe–4S] cluster Fe–S cluster proteins in the cytosol is performed by a differ - proteins, Aco1, Aco2, lipoic synthase, biotin synthase and ent machinery from that of the ISC system that depends on homoaconitase (Lys4) . Yeast cells defective in Nfu substrates that must be exported out of the mitochondrion. displayed a relatively mild respiration impairment . The cytosolic and nuclear de novo formation of [4Fe–4S] Yeast triple mutant bola1–bola3–nfu exhibited an enhanced Fe–S clusters requires the heterodimeric association of pro- phenotype unlike any of the individual mutants. Comple- teins Cfd1 and Nbp35, which share signic fi ant sequence sim - mentation experiments using human NFU1 or BOLA1 ilarity [136–138]. The latter also shares homology with its partially recovered the phenotype of the mutant, but not bacterial and archaeal counterpart ApbC, both being classi- BOLA3, which indicates that a concerted activity of NFU1 fied as P-loop-containing nucleoside triphosphate hydrolases and BOLA3 is necessary to recover the phenotype . . The ApbC/Nbp35 proteins were the first Fe–S cluster Moreover, the overexpression of Nfu in a bola3 mutant assembly proteins described in the Archaea . Nbp35 recovered the respiratory defect phenotype, which indicates exhibits an N-terminal Fdx-like domain, an ATP-binding overlapping functions . motif and C-terminal cysteine residues . The forma- The obvious connection between Nfu and BolA assembly tion of the stable heterodimer depends on a shared [4Fe–4S] factors places them in similar, yet non-overlapping roles. C-terminal cluster, labeled as bridging cluster, while both BolA is a recently described protein of bacterial origin with Nbp35 and Cfd1 each bear another [4Fe–4S] cluster in their 1 3 JBIC Journal of Biological Inorganic Chemistry (2018) 23:521–541 527 N-termini [137, 140] (Fig. 1). Of importance is the fact that cluster of Nbp35, yet has no effect on Cfd1 . In human the N-terminal Fe–S cluster of Nbp35 is oxygen stable, cells, CIAPIN1 has been found to interact with GLRX3, a unlike the bridging cluster [138, 140, 141]. Consequently, cytosolic monothiol glutaredoxin [129, 147, 149] described the N-terminal truncations render the protein unable to bear below. Indeed, in vitro assays captured the transfer of a a cluster . The Cfd1–Nbp35 conformation results in [2Fe–2S] cluster from the N-terminus of GLRX3 to the a heterotetrameric association capable of functioning as a N-terminus of CIAPIN1. This result led to propose that the scaffold for the assembly of an Fe–S cluster . Remarka- glutaredoxin feeds the [2Fe–S] cluster to CIAPIN1 . bly, Cfd1 and Nbp35 are not targets of the de novo assembly However, this observation is in disagreement with the previ- factors of the CIA pathway, despite the fact that they them- ously mentioned results from yeast, where the C-terminus selves carry clusters. Their assembly and insertion depend of Dre2 is key for cluster binding . Another piece of on the early steps of the pathway . Importantly, the evidence postulates that the maturation of the [2Fe–S] clus- Cfd1–Nbp35 heterotetramer formation does not take place ter in CIAPIN1 is not dependent on GLRX3, regardless of in plants and certain anaerobic protists due to the absence their physical interaction . of Cfd1 from their genomes [142, 143]. In humans, abla- The transient assembly of the Fe–S cluster on the tion of NBP35 causes an impairment in the iron-regulatory Cfd1–Nbp35 scaffold is followed by the interaction of the protein IRP1, which in turn affects the levels of ferritin and heterotetrameric complex with the iron-only dehydroge- increases the levels of transferrin uptake by a concomitant nase Nar1, which receives the cluster to further pass it on increase of transferrin receptor levels in the cell. This effect to the targeting complex that will install the cluster into the on iron homeostasis involves the CIA machinery in a regu- apotargets . Nar1 also bears an Fdx-like domain on its lation role in mammals that is not observed in yeast . N-terminus and a cysteine domain on its C-terminus typical The answer to which factors feed the stable Fe–S clusters of iron-only hydrogenases (for binding of the H-cluster). to the scaffold protein Nbp35 came about with the char - Since Nar1 is itself an Fe–S cluster protein, its maturation acterization of Dre2 in yeast . The deletion of Dre2 depends on its association with the Cfd1–Nbp35 complex was lethal when combined with those of the mitochondrial . carrier proteins Mrs3 and Mrs4 under iron-depleted condi- The following proteins constitute the CIA targeting com- tions. The rationale behind this experiment was to identify plex in humans: the WD-40-type protein CIA1 (also called protein(s) that provide a compound(s) for the cytosolic Fe–S CIAO), which functions as a scaffold; MMS19 (Met18 in cluster assembly, and resemble the phenotypes of CIA pro- yeast), CIA2A (or FAM96A) and CIA2B (or FAM96B), tein mutants known at the time . Interestingly, although whose role is targeting recipient apoproteins [15, 150–153]. described as a cytosolic protein, low amount of Dre2 was The cytosolic iron–sulfur protein 1 (CIA1) belongs to also found either in the mitochondria and/or bound to the the family of WD-40 proteins, which are known for their cytosolic side of the outer mitochondrial membrane [145, β-propeller structure repeats . It was initially charac- 146]. Dre2 is the yeast counterpart of anamorsin (or CIA- terized in yeast, where its depletion affected the maturation PIN1, cytokine-induced apoptosis inducer 1) in humans, as of the cytosolic and nuclear Fe–S proteins, yet it had no proven by a complementation assay in yeast with the human impact on the levels of Nbp35. Moreover, Cia1 was found to gene [144, 145, 147]. The protein exhibits an N-terminal interact with Nar1, the iron-only hydrogenase that receives SAM methyltransferase-like domain, and on its C-terminus the clusters from the Cfd1–Nbp35 scaffold. Similarly, Fe two motifs named I and II, which display cysteines required incorporation in the Cia1 mutant affected apoproteins, such to bind the clusters . In vitro experiments with overex- as Leu1 and Rli1, but had no significant impact on Nbp35, pressed protein show that maturation of Dre2, which bears Nar1 and mitochondrial Fe–S proteins . Complementa- a [2Fe–2S] and a [4Fe–4S] cluster, is independent of the tion assays of the Cia1 mutant with the human CIAO protein CIA factors, but requires the presence of Nfs1, positioning it recovered the phenotype, confirming their functional redun- functionally upstream of the Cfd1–Nbp35 scaffold step [144, dancy. Moreover, a structural analysis of Cia1 determined 148]. Further analyses revealed that Dre2 interacts and func- that it exhibits a conserved propeller axis structure . tions in association with a diflavin reductase Tah18, which Hence, it was concluded that in the maturation of cytosolic transfers electrons from NADPH to Dre2 (Fig. 1) . Fe–S cluster proteins, Cia1 performs a role downstream of At the same time, the human homolog of Tah18, NDOR, Nar1 . rescues the phenotype of tah18 yeast mutants and cooper- MMS19 was initially discovered in yeast, in mutants ates with Dre2, which further strengthens the relationship with an increased sensitivity to methyl methasulfonate, between Dre2 and Tah18 . However, in this model as reflected by its name . Fe incorporation in cells Dre2 is incapable of transferring clusters to apoproteins, but depleted for Mms19 affected apoproteins in a fashion similar seems indirectly involved, together with Tah18, in the trans- to that described for the Cia1 mutant . Importantly, the fer of electrons for the formation of the [4Fe–4S] N-terminal downregulation of MMS19 influenced proteins involved in 1 3 528 JBIC Journal of Biological Inorganic Chemistry (2018) 23:521–541 the DNA metabolism, such as Rad3 helicase and XPD. In homeostasis . Yeast mutants Grx3/4 exhibit reduced line with this finding, DNA helicase Dna2 and Rli1 were activities of respiratory complexes II and IV, as well as found interacting with MMS19, and the same applies to those of the mitochondrial ISC assembly scaffold proteins components of the CIA complex, namely CIA1, CIA2A and Aco1, Leu1 and Isu1. Moreover, the mutants display up to CIA2B [151, 152, 156]. Combined, these results provide tenfold decrease of iron incorporation into the CIA com- evidence for the role of MMS19 downstream of CIA1, tar- ponents that themselves carry Fe–S clusters, namely Dre2, geting a specific set of proteins, many of which are involved Nar1 and their target protein Rli1, and the same applies in DNA maintenance [151, 152]. for Isu1, biotin synthase, dihydroxyacid dehydratase and Further characterization of proteins that were found to heme-containing catalase [158, 159]. These results point interact with MMS19 revealed their involvement in the late to an overall effect on iron supply, which was markedly stages of the CIA pathway. Interestingly, CIA2A and CIA2B more severe in the cytosol than in the mitochondria . were found to interact in a mutually exclusive fashion with The regulation of iron concentration in yeast is directed CIA1 . Specific associations of these proteins seem to by the transcription factors Aft1 and Aft2, which manage be necessary for the maturation of certain proteins. CIA2A the transport of iron into the cell . In iron-replete is directly involved in the maturation of IRP1, which plays conditions, Aft1 is a cytosolic protein, yet when iron con- a role in cellular iron homeostasis . CIA2B in associa- centration is low, it is mobilized to the nucleus, where it tion with CIA1 and MMS19 is responsible for the assembly activates the transcription of the iron regulon [160–162]. of the Fe–S cluster of DYPD, an enzyme involved in the It has been suggested that this activation is incited by the detoxification of pyrimidine derivatives . Moreover, for failure of the mitochondrial iron supply directed toward the maturation of GPAT, an enzyme of the purine nucleotide the Fe–S cluster assembly, yet the deletion of components synthesis pathway, and POLD, only CIA1 and CIA2B were of the CIA pathway does not induce the same response required [15, 153]. [163, 164]. Mutants that activate the iron regulon by stim- MMS19 exhibits nine HEAT repeats, known to facilitate ulating the activity of the high-affinity iron transport sys- protein–protein interactions, which are distributed through- tem of multicopper oxidase Fet3 led to the discovery of six out the whole protein . Mutations in the C-terminal proteins involved in this role [160, 165]. These are Nfs1, HEAT repeats of MMS19 prove that they are responsible Isu1, Gsh2 , mitochondrial carrier Mtm1, an interac- for the binding of CIA2B. Moreover, the absence of MMS19 tor of the multiprotein regulator complex (which in turns renders CIA2B subject to proteosomal degradation . regulates RNA polymerase II), Sin4,  and Fra1 (Fe Since the binding of CIA2B to MMS19 was often accom- repressor of activation-1), the yeast homolog of bacterial panied by the presence of CIA1, it was proposed that at least BolA . These findings confirm earlier observations, two distinct types of associations, namely CIA1–CIA2A and in which the deletion of Grx3 and Grx4 induced the iron CIA1–MMS19–CIA2B, perform the maturation of differ - regulon when iron concentrations were normal [161, 162]. ent subsets of proteins (Fig. 1). In this model, CIA1 with Fra1 interacts with Fra2, Grx3 and Grx4, interactions that CIA2A act in an iron-regulation/sensing role, as depicted took place regardless of the iron conditions in which the by their specific interaction with IRP1 and IRP2, whereas cells were maintained . It was also described that CIA1 with MMS19 and CIA2B supply DNA metabolism- Grx3 and Grx4 interact with Aft1 . Deletion of the related proteins . gene fra1 does not specifically activate the iron regulon, while that of fra2 does . Fra2 binds Grx3 through Iron sensing and regulation and the relationship a specific interaction mediated via a histidine residue, with the CIA pathway which is critical for modulation of the iron regulon via Aft1 . Based on this finding, Fra1 and Fra2 seem to Iron sensing as a regulatory mechanism differs between interpret the iron conditions of the Fe–S cluster assembly. mammals and yeast. In mammals, the iron-responsive They are related to mitochondrial Fe–S cluster assembly protein 1 (IRP1) exhibits aconitase activity when bound and the iron regulon is induced when their concentration to Fe–S clusters; once the cluster is lost, IRP binds to decreases . iron-responsive elements on mRNAs that specify proteins In humans, only GLRX3 (also called PICOT) is found known to regulate iron homeostasis . In yeast, aco- in the cytosol where it interacts with the cytosolic form nitase does not exhibit mRNA binding activity. However, of the BOLA family in humans, BOLA2 [129, 169]. This two important players related to the cytosolic Fe–S cluster interaction is iron concentration dependent. Moreover, assembly and iron homeostasis are the Grx3/4 proteins. mutation of the GLRX3 cysteines in the motifs GrxA and They affect CIA proteins, their target apoproteins and GrxB, which are involved in binding of the [2Fe–2S] Fe–S some mitochondrial Fe–S assembly proteins, and there- cluster, almost completely disrupts the interaction with fore their involvement in cytosolic and mitochondrial iron BOLA2 . 1 3 JBIC Journal of Biological Inorganic Chemistry (2018) 23:521–541 529 these parasitic groups exhibit a classical cytosolic Fe–S Fe–S clusters in the supergroup Excavata assembly, from the genomic information available to us we predict that similarly conserved situation occurs in Euglenozoa diplonemids and euglenids (our unpubl. data). The Fe–S cluster assembly was systematically stud- Excavata is a eukaryotic “supergroup” that brings together ied only in the model species Trypanosoma brucei, which a diverse array of protists [8, 170, 171], with just a few expresses all components of the ISC and CIA pathways in its studied so far from the perspective of the Fe–S cluster mitochondrion and cytosol (Fig. 2) [172, 174]. Upon deple- assembly. The best-described one is that of the kineto- tion, most of these proteins are essential for both studied plastid flagellates, which are responsible for a range of life cycle stages, namely the bloodstream stage found in the diseases in humans and other vertebrates . The blood of mammals and the procyclic stage that is confined to only information available for the other two euglenozoan the tsetse fly vector. Moreover, rescues by human homologs clades, the euglenids and diplonemids, can be derived or expression of the T. brucei proteins in the corresponding from their genomes which are, however, not yet publicly yeast mutants confirmed sequence-based homology predic- available. All these protists display a single, usually exten- tions [20, 175–185], Tonini et al., resubmitted]. Only FdxB sively reticulated, cristae-bearing mitochondrion, with an , selenocysteine lyase  and TbCia2A (Tonini et al. active and complex electron transport chain. Kinetoplas- 2018, resubmitted) were found to be dispensable for T. bru- tids that belong to the genera Trypanosoma and Leishma- cei. A homolog of the Grx-interacting protein, BolA, has nia are capable of aerobic fermentation, as they excrete also been detected in the genome of T. brucei, although its metabolites from both glucose and amino acid metabo- role and localization have not been studied yet. lisms, but use O as an electron acceptor . Since both Fig. 2 Distribution of ISC (black letters), CIA (white letters), NIF incarcerata*, Naegleria gruberi**, Spironucleus salmonicida§, (light blue letters), CSD (purple letters) and SUF (in dark blue, gene Monocercomonoides sp., Trichomonas vaginalis and Giardia intesti- fusions in red) components in metazoans and representative species nalis. Data presented here should not be assumed for the whole gen- of Excavata. Representative species denoted in the figure are Stygiella era, but only for representative species 1 3 530 JBIC Journal of Biological Inorganic Chemistry (2018) 23:521–541 A number of gene duplications likely took place, as have been found in a wide range of environmental condi- several components of this pathway are supernumerary. In tions such as extreme heat, cold, high altitudes, extreme pH particular, Nfu is represented by three paralogs, which are and hypersaline concentrations [192–197]. We know most expressed in the mitochondrion and the cytosol in T. bru- about the genus Naegleria, as it includes the brain-infect- cei, while four paralogs are found in the related Leishmania ing amoeba N. fowlerii, and the related Paravahlkampfia spp., although these remain unstudied . Moreover, in T. francinae, also responsible for amoebic meningoencephalitis brucei two ferredoxins (FdxA, FdxB) are present and tran- . Both species possess classical mitochondria. On the scribed , Mms19 is found in two genomic loci and Cia2 other hand, a group of heteloboseids, such as Sawyeria mar- has been duplicated into Cia2A and Cia2B  [Tonini ylandensis [199, 200], Psalteriomonas lanterna [201–203], et al., resubmitted], just like in humans . The presence Monopylocystis visvesvarai  and Creneis carolina of supernumerary components is not unique, since f.e. in the , are found mostly in low oxygen conditions and carry plant Arabidopsis thaliana five Nfu homologs are present in the MROs. Other heteroloboseids including the halophilic various subcellular compartments . In some instances, Pleurostomum flabellatum and Vahlkampfia anaerobica the complexity took the path of alternatively spliced versions have been described to harbor cristae-devoid mitochondria, targeted at different locations, as was described in humans although their genomes and metabolisms have not yet been . The finding that all three Nfu proteins are essential thoroughly studied [193, 205]. for T. brucei suggests that they are likely involved in the Naegleria possesses classical ATP-producing mitochon- maturation of different sets of proteins . dria and displays components of the ISC pathway IscS, IscU Several aspects of the Fe–S cluster assembly and Fe–S and Isd11, as well as two putative Fdxs, Isa, Grx, Atm1 and cluster-carrying proteins have also been studied in the a BolA-like protein (Fig. 2). Moreover, the hydrogenosome trypanosomatid parasite Leishmania spp., which unlike T. of Sawyeria marylandensis contains paralogs of IscS and brucei prefers an intracellular niche that requires a range IscU, as well as Fxn and Fdx . of specific metabolic adaptations . Leishmania seems to use several Fe–S clusters containing proteins for redox Jakobids sensing . Trypanosoma cruzi, T. brucei and Leishmania spp. encode three 1-C-Grx genes in their genomes . Mitochondrial genomes of jakobids belong to the most Monothiol (1-C-Grx) and dithiol (2-C-Grx) glutaredoxins bacterial-like genomes known to date, though this premise exhibit distinct active sites motifs, CxxS and CxxC, respec- has been challenged by the plausibility of extensive lateral tively, which differentiate them . It has been observed gene transfer into the mitochondrial genomes [206–208]. in vitro that in T. brucei three 1-C-Grxs proteins are capa- Regardless, the organelle of jakobids contains the most ble of using glutathione and trypanothione as cofactors in gene-rich mitochondrial genomes, with the most extreme the mitochondrial [2Fe–2S] cluster transfer . This is a case represented by Andalucia godoyi, which displays 66 striking difference from the system described in yeast, where protein-coding genes and 29 tRNA genes . The orga- the glutaredoxin-bearing domain of Grx5 uses glutathione nelle of Stygiella incarcerata, originally considered to be a as a sulfur donor . Even more remarkable is the fact mitochondrion devoid of the cristae, is now known to be a that in T. brucei only 1-C-Grx1, but not 1-C-Grx2 and 3, is DNA-lacking hydrogenosome [207, 210]. capable of partially rescuing the deleterious phenotype of Interestingly, the hydrogenosome of S. incarcerata the Grx5 yeast mutant . All other components of the retains a complete Fe–S cluster assembly machinery, which ISC pathway, as well as most proteins known to participate includes IscS, IscU, Isa1 and Isa2, Fxn, Fdx, Grx5, Ssq1 in the CIA pathway, have also been detected in the Leish- chaperone and Nfu (Fig. 2, Table 1) . The ABC trans- mania genome . porter Atm1 is also expressed, suggesting this organism dis- plays a mitochondrion-dependent, cytosol-localized Fe–S Heteroloboseids cluster assembly. At the same time, a SufCB fusion seems to lack the mitochondrial targeting signal, implying its highly This clade brings together amoebic, amoeboflagellated likely cytosolic localization . However, it has been and cyst-forming protists found in both oxic and anoxic documented in other MRO-bearing organisms such as Blas- (or microaerophilic) environments, most of which remain tocystis, Entamoeba and Trichomonas that the hydrogenoso- understudied . Approximately, 150 species are known mal proteins may not require a dedicated targeting signal to to belong to this clade and, though it is not species rich, this be translocated into the organelle [28, 211–213]. The assem- group gathers a high morphological variability and a broad bly of SufBCD in bacteria studied both in vitro and in vivo ecological distribution. Some of its members may transit demonstrated its role in the maturation of [2Fe–2S] Fdx, through the flagellated and amoeba life stages, while others aided by SufA in the transfer of the cluster [48–50]. The have retained either the former or the latter stage . They SufCB fusion, most likely obtained from bacteria, has been 1 3 JBIC Journal of Biological Inorganic Chemistry (2018) 23:521–541 531 Table 1 Presence/absence of ISC, CIA, SUF, NIF and CSD components in different excavates and breviate Pygsuia a a a a a Organism T. brucei L.donovani Naegleria Sawyeria Stygiella Giardia Spironucleus Trichomonas Monocer- Pygsuia como- noides ISC IscS ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ IscU ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ Isd11 ✓ ✓ ✓ ✓ ✓ ✓ Isa1 ✓ ✓ Isa2 ✓ ✓ ✓ Fdx ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ Fnx ✓ ✓ ✓ ✓ ✓ ✓ ✓ Nfu ✓ ✓ ✓ ✓ ✓ ✓ ✓ Iba57 ✓ Ind1 ✓ ✓ ✓ Atm1 ✓ ✓ ✓ ✓ ✓ CIA Cfd1 ✓ ✓ ✓ ? ✓ ? ✓ ✓ Nbp35 ✓ ✓ ✓ ? ? ✓ ✓ ✓ ✓ ✓ Dre2 ✓ ✓ ✓ ? ? ? Tah18 ✓ ✓ ✓ ? ? ? Nar1 ✓ ✓ ? ? ✓ ✓ ? ✓ ✓ Cia1 ✓ ✓ ✓ ? ? ✓ ✓ ✓ ✓ ✓ Cia2 ✓ ✓ ✓ ? ? ✓ ✓ ✓ ✓ ✓ Mms19 ✓ ✓ ? ? ? ✓ SUF SufS ✓ SufU SufB ✓ ✓ ✓ SufC ✓ NIF NifS CSD CsdA ✓ The data corresponds to representative species (should not be assumed for the whole genera): Sawyeria marylandensis, Stygiella incarcerata, Giardia intestinalis, Spironucleus salmonicida, Trichomonas vaginalis, Monocercomonoides sp. ✓ indicates presence; ? denotes the gene/protein has not been found, but may be present; blank indicates absence documented only in the cytosol of the anaerobic pathogen Giardia mitosomes lack DNA and are unable to generate Blastocystis , in the MRO lumen of Pygsuia biforma or export ATP into the cytosol . Nevertheless, they pos-  and Stygiella . The other bacterial machinery, the sess classic ISC components, such as IscS, IscU, Isa, Nfu NIF pathway, has been observed replacing the ISC system and Grx [216–221]. Although incomplete, most of the CIA of Entamoeba histolytica  and Mastigamoeba balamuthi pathway of Giardia is localized in the cytosol, with three . homologs of Nbp35 (Nbp35-1, Nbp35-2 and Nbp35-3), while Dre2, Tah18 and Mms19 seem to be absent (Table 1) Metamonada . Moreover, the ortholog of Cia2 exhibits dual locali- zation in the intermembrane space of the mitosome and the This group consists of anaerobic or microaerophilic protists cytosol, while Npb35 seems to be associated with the cyto- and is formed by three main lineages: (1) Fornicata (or the solic side of the outer mitosomal membrane . It was diplomonad/retortemonad/carpediemonad clade), repre- rather unexpected to find the CIA pathway in a cell lacking sented in this review by the mitosome-bearing Giardia intes- Atm1 and its cytosolic interactor, the Tah18/Dre2 complex, tinalis and Spironucleus salmonicida ; (2) Parabasalia, as it is widely accepted that the CIA pathway depends on a with the flag species Trichomonas vaginalis, bearer of the sulfur-containing molecule transported from the mitochon- first-described hydrogenosome ; (3) Preaxostyla, denoted drial matrix into the cytosol via Atm1. Therefore, it has been by Monocercomonoides  and the free-living Paratrimas- hypothesized that the dual localization of Cia2 aids in the tix . In all of Excavata, Metamonada exhibits the great- transport of the sulfur-containing molecule necessary for est functional diversity of MROs . the cytosolic assembly, in the apparent absence of the ABC 1 3 532 JBIC Journal of Biological Inorganic Chemistry (2018) 23:521–541 transporter Atm1 . The conspicuous absence of these while it expresses orthologs of Cfd1, Nbp35, Nar1, Cia1 proteins has also been observed in flagellates where the SUF and Cia2 (Table 1) . or the NIF system has replaced the ISC pathway, such as Various other metamonads, namely Carpediemonas Pygsuia and Blastocystis [13, 22]. membranifera, Chilomastix cuspidata, Dysnectes brevis, Spironucleus salmonicida encodes an unusually high Ergobibamus cyprinoides, Spironucleus vortens and Trepo- number of cysteine-rich proteins and evolved an extended monas PC1, for which no complete genomes but expressed system for counteracting oxygen stress . This diplo- sequence tags are available, bear IscS and IscU . Moreo- monad exhibits a standard hydrogenosome with a classical ver, they all seem to express Nbp35 of the CIA pathway, MRO-type ISC pathway [222, 223]. All of its components, while Cfd1 is mostly absent in this group, with the excep- namely IscS, IscU, Nfu, Fxn, two Fdxs and Jac1, have been tion of C. membranifera and C. cuspidata . Cia1 was localized to the organelle and bear MRO targeting signals found in all these protists, except S. vortens. Like in a range . Moreover, a selenocysteine lyase has been detected of metamonads, the Tah18/Dre2 complex and Mms19 are in this parasite, although neither its expression nor its absent. However, it has been suggested that the remaining localization has been confirmed; still, a sequence of a fused CIA components may be present in the genomes, but missed selenophosphate synthetase–NifS is present in its genome, in the available datasets . similar to the one found in T. brucei [78, 214]. Putative com- Finally, the oxymonad Monocercomonoides, the only ponents of the CIA pathway are also found in the S. salmo- genuine “amitochondriate” known so far, is also the most nicida genome, such as Cfd1, Nbp35, Tah18, Nar1, Cia1, extreme example of the Fe–S cluster machinery reduction Mms19 and Cia2 (Fig. 2, Table 1). . With several CIA pathway components complemented The human parasite T. vaginalis is a microaerophile, by the expression of SufB, SufC and the SufS–U fusion, it which exhibits a very strong iron-regulatable gene expres- is the only known eukaryote that completely lacks the mito- sion that allows it to modulate virulence factors and its abil- chondrial ISC machinery and instead acquired the bacterial- ity to adapt to microenvironments upon infection [224–227]. type SUF components. None of these components seem to Changes in the iron concentrations of its environment result bear a MRO targeting signal, as they translocate neither in fold changes in the expression of Fe–S clusters assembly into the hydrogenosome of T. vaginalis nor the mitochon- components [224, 225]. The DNA-lacking hydrogenosome dria of S. cerevisiae . The CIA pathway components of of T. vaginalis  harbors the ISC-type Fe–S cluster Monocercomonoides identified so far are Nbp35, Nar1, Cia1 assembly and makes use of a supernumerary machinery and Cia2A and Cia2B (Table 1). Its composition implies that of components: IscU, two IscS, Isd11s and Fxns, seven the de novo formation of clusters uses the bacterial SufS–U [2Fe–2S] Fdxs, three Isa2, four Nfus, four Ind1s (Table 1), CD-scaffold on SufB and SufC, and was apparently obtained as well as two homologs of the chaperone Hsc20 [24, 225, by a lateral gene transfer. This event likely took place before 229–231]. Upon iron depletion, most of these components the loss of the mitochondrion in Monocercomonoides, as become upregulated at least twofold. An example of this sit- gathered from its closest relative, Paratrimastix pyriformis, uation is Fdx, which in this flagellate exhibits six orthologs, which also possesses homologs of the SUF machinery and of which half is upregulated and half is down-regulated bears an MRO [23, 235]. during low iron conditions. This led to the assumption that the expression levels would relate them to their putatively different function, namely a role in the Fe–S cluster assem- Presence vs functionality: the requirement bly of the upregulated members, whereas those with low for mechanistic data to complement expression are likely involved in metabolic activities . phylogenomic analyses Trichomonas vaginalis is the only member of Excavata and the only other eukaryote apart from Entamoeba histo- The expansion of genomic analysis tools has given rise to lytica to express a homolog of the bacterial-type iron–sul- a high number of publicly available genomes. Studies of fur flavoprotein (Isf) . This hydrogenosomal protein is the evolution of mitochondria and MROs have unraveled involved in ROS detoxification and protection from the oxy - a wide variety of adaptations in the Fe–S cluster assembly gen-rich environmental changes. Moreover, it seems to be machineries that could provide explanations for the substan- present only in methane-synthesizing archaea and bacteria tial differences observed even among the model organisms [233, 234]. Isf is able to reduce oxygen and has a detoxifying from the supergroup Opisthokonta. The mechanisms behind activity against the drugs metronidazole and chlorampheni- the presence or absence of components of the ISC, SUF and col, used to treat anaerobic infections like those caused by T. CIA pathway in these clades, however, are mostly unknown, vaginalis . Isf is able to receive in vitro electrons from basically due to lack of mechanistic data. Fdx and NADH . Like other metamonads, T. vaginalis One of the prevalent differences observed between the also lacks the Tah18/Dre2 complex, along with Mms19, few above-mentioned species and the Opisthokonta model 1 3 JBIC Journal of Biological Inorganic Chemistry (2018) 23:521–541 533 species is the absence of Isd11 in organisms bearing ISC. systems . Its wide distribution among the aerobic and This feature points out to an acquisition of IscS/IscU from anaerobic organisms led to the proposal that it evolved prior bacterial lineages. Regardless, in Excavata IscS is always to oxygenation of the biosphere and adopted mechanisms accompanied by IscU, which confirms the findings of several for counteracting oxidizing conditions . Though the groups on the requirement of the CD for its specific scaffold SUF and ISC systems coexist in various bacterial lineages, to perform desulfuration of cysteine . The presence of the complementation with SUF components in the absence Isd11 in T. vaginalis has been suggested as a unique acquisi- of specific ISC components has not been possible . It tion, from a endosymbiotic event that gave origin to MROs has been well established that in proteobacteria the Fe–S . However, this hypothesis leaves out the fact that the cluster assembly by the SUF pathway is highly regulated protein is also absent in protists described recently as bear- by protein–protein interactions [55, 236, 243]. A study that ing similar organelles. reported the complementation of the SUF system of E. coli The dispersed distribution of the scaffold-type proteins, with that of E. faecalis also conveyed that the SUF machin- particularly those characterized as the carrier or transfer pro- ery of the Gram-positive bacteria could replace IscS neither teins, is important for the determination of the mechanistic in E. coli nor in A. vinelandii . These features pin- specificity of the Fe–S cluster assembly systems. CsdE is point to a specificity of activities, which may explain why a CD incapable of complementing the assembly of Fe–S in the protist systems with the SUF fusions IscS or IscU are clusters on the IscU scaffold, despite the wide range of sub- absent. The presence of the SUF systems in eukaryotes is strates this CD is able to metabolize [46, 71, 73, 236]. This documented in plastids, which also lack ISC . How- is, however, not exactly the same for the transfer proteins, ever, this system displays functional differences from that which to deliver the clusters also require a physical interac- of bacteria. The observation that SufB in A. thaliana has an tion with their recipient apoproteins. Unlike the CDs with ATPase activity, unlike its counterpart in bacteria, denotes U-type scaffolds, the carrier or transfer proteins seem to that in eukaryotes the SUF system has acquired unique fea- be, to a certain extent, interchangeable in bacteria . For tures [245, 246]. example, the deletion of IscA or SufA in E. coli does not The hypothesis mentioned above gives a mechanistic affect survival; however, this is not true for the absence of answer for the characteristic presence of the SUF system ErpA [237, 238]. A similar situation was observed for S. in protists. However, there is no explanation as to why the cerevisiae . However, in the presence of oxygen, Azo- SUF system, rather than the ISC or the NIF systems, was tobacter vinelandii cannot survive mutation of IscA in the obtained. It has been reported that the relationship between presence of oxygen . The distinct phenotypes following the SUF and ISC systems involves regulation of the com- the deletions or mutations of carrier proteins in bacteria indi- plete pathways based on environmental conditions. Such is cate their functional specificity in vivo [53, 237]. This means the case of the SUF operon in E. coli, which is overexpressed that the recipient proteins that require maturation by specific on low-iron conditions and oxidative stress, at the same time transfer proteins may or may not be structurally recognized that the ISC operon is rendered inactive by transcriptional by a given system component . These cellular require- regulation of IscR. In Pseudomonas aeruginosa, IscR regu- ments cannot be bypassed by the apparent overall functional lates cellular iron homeostasis by sensing Fe–S concentra- redundancy of the Fe–S assembly systems. The case of Pyg- tions . T. vaginalis is an example of adaptation of the suia is a notable exception to these observations. Breviate Fe–S cluster machinery to match specific cellular require- Pygsuia exhibits a SufB–C fusion, yet it also harbors a copy ments. This anaerobic parasite displays supernumerary com- of IscS, with no obvious presence of IscU. Therefore, this ponents of various components of the ISC pathway, which fusion scaffold may be capable of providing the structural are up- or down-regulated in response to the changing iron functionality for IscS. . concentrations in its environment . A scaffold protein that has been conserved throughout Therefore, to characterize the regulatory capacity of a evolution is Nbp35. Although the CIA pathway displays the system, one has to determine the expression of its com- characteristics of a relatively new eukaryotic acquisition, the ponents. However, this type of data may be obtained only almost universal presence of this protein conveys how the by analyzing the Fe–S cluster assembly as a whole, a field Fe–S cluster assembly can repurpose a pre-existing protein where microbiologists take the lead when compared with for a new function. On the other hand, the partner of Nbp35, what is known about eukaryotic systems. This should not Cfd1, has a rather patchy distribution in the protist groups. be confused with analytical methods, which are rich in stud- Originally from Archaea, most ApbC homologs in bacteria ies of the Fe–S cluster assembly in Opisthokonta. Still, the and archaea lack the Fdx motif present in Nbp35 . limited set of model organisms restricts our overall picture. Another interesting finding is the gene fusion of various While it is challenging to establish the methodology for a SUF components present in metamonads and jakobids. The new eukaryotic model organism, this has to be overcome. SUF system is the most ancient of all Fe–S cluster assembly The establishment of evolutionary relationships based 1 3 534 JBIC Journal of Biological Inorganic Chemistry (2018) 23:521–541 7. Lill R, Kispal G (2000) Maturation of cellular Fe–S proteins: on proven experimental models nicely complements the an essential function of mitochondria. Trends Biochem Sci increasing available genomic data, providing elegant mecha- 25:352–356 nistic explanations for changing phylogenomic models [248, 8. Adl SM, Simpson AGB, Lane CE et al (2012) The revised clas- 249]. sification of eukaryotes. J Eukaryot Microbiol 59:429–514. https ://doi.org/10.1111/j.1550-7408.2012.00644 .x 9. Takahashi Y, Tokumoto U (2002) A third bacterial system for the assembly of iron–sulfur clusters with homologs in archaea and Closing remarks plastids. J Biol Chem 277:28380–28383. https://doi.or g/10.1074/ jbc.C2003 65200 10. Jacobson MR, Cash VL, Weiss MC et al (1989) Biochemical and The reduction of mitochondria has seen the relocation of genetic analysis of the nifUSVWZM cluster from Azotobacter the Fe–S cluster assembly to about elsewhere in the cell or vinelandii. Mol Gen Genet 219:49–57 a general replacement of its components with paralogs from 11. Loiseau L, Ollagnier de Choudens S, Lascoux D et al (2005) Analysis of the heteromeric CsdA–CsdE cysteine desulfurase, diverse proteobacterial lineages. The notion that the ISC has assisting Fe–S cluster biogenesis in Escherichia coli. J Biol been lost from MROs does not translate into the same fate Chem 280:26760–26769. https ://doi.or g/10.1074/jbc.M5040 for the mechanism in question, in this case the Fe–S cluster assembly. It translates into an adaptation to maintain the 12. Stairs CW, Leger MM, Roger AJ (2015) Diversity and origins of anaerobic metabolism in mitochondria and related organelles. entire mechanism, more than to strictly conserve a given set Philos Trans R Soc Lond B Biol Sci 370:20140326. https ://doi. of genes of certain origin. It will require functional analy- org/10.1098/rstb.2014.0326 sis of the pathway in some of the protists mentioned above 13. Stairs CW, Eme L, Brown MW et al (2014) A SUF Fe–S cluster to define the flexibility and limits of simplification and/or biogenesis system in the mitochondrion-related organelles of the anaerobic protist Pygsuia. Curr Biol 24:1176–1186. https ://doi. patching of the Fe–S cluster assembly, which from all we org/10.1016/j.cub.2014.04.033 know is an indispensable component of all extant life. 14. Lill R, Dutkiewicz R, Freibert SA et al (2015) The role of mito- chondria and the CIA machinery in the maturation of cytosolic Acknowledgements We are grateful to Dr. Vladimír Hampl (BIOCEV, and nuclear iron–sulfur proteins. Eur J Cell Biol 94:280–291. Charles University, Prague) for critical reading of the manuscript. We https ://doi.org/10.1016/j.ejcb.2015.05.002 would also like to acknowledge the immense amount of guidance from 15. Stehling O, Mascarenhas J, Vashisht AA et al (2013) Human the reviewers of the final manuscript. Support from the Czech Grant CIA2A-FAM96A and CIA2B-FAM96B integrate iron homeo- Agency 16-18699S, ERC CZ LL1601, and the ERD Funds, Project stasis and maturation of different subsets of cytosolic-nuclear OPVVV 16_019/0000759 to JL are kindly acknowledged. This article iron–sulfur proteins. Cell Metab 18:187–198. https ://doi. is based upon work from COST action CA15133, supported by COST org/10.1016/j.cmet.2013.06.015 (European Cooperation in Science and Technology). 16. Paul VD, Lill R (2015) Biogenesis of cytosolic and nuclear iron–sulfur proteins and their role in genome stability. BBA- Open Access This article is distributed under the terms of the Crea- Mol Cell Res 1853:1528–1539. https://doi.or g/10.1016/j.bbamc tive Commons Attribution 4.0 International License (http://creat iveco r.2014.12.018 mmons .org/licen ses/by/4.0/), which permits use, duplication, adapta- 17. Balk J, Pilon M (2011) Ancient and essential: the assembly of tion, distribution and reproduction in any medium or format, as long iron–sulfur clusters in plants. Trends Plant Sci 16:218–226. https as you give appropriate credit to the original author(s) and the source, ://doi.org/10.1016/j.tplan ts.2010.12.006 provide a link to the Creative Commons license and indicate if changes 18. Barras F, Loiseau L, Py B (2005) How Escherichia coli and Sac- were made. charomyces cerevisiae build Fe/S proteins. Adv Microb Physiol 50:41–101. https ://doi.org/10.1016/S0065 -2911(05)50002 -X 19. Roche B, Aussel L, Ezraty B et al (2013) Iron/sulfur proteins biogenesis in prokaryotes: formation, regulation and diversity. References Biochim Biophys Acta 1827:455–469. https://doi.or g/10.1016/j. bbabi o.2012.12.010 20. Basu S, Netz DJ, Haindrich AC et al (2014) Cytosolic iron–sul- 1. Roger AJ, Muñoz-Gómez SA, Kamikawa R (2017) The origin phur protein assembly is functionally conserved and essential in and diversification of mitochondria. Curr Biol 27:R1177–R1192. procyclic and bloodstream Trypanosoma brucei. Mol Microbiol https ://doi.org/10.1016/j.cub.2017.09.015 93:897–910. https ://doi.org/10.1111/mmi.12706 2. Maguire F, Richards TA (2014) Organelle evolution: a mosaic 21. Iwasaki T (2010) Iron–sulfur world in aerobic and hyperther- of “mitochondrial” functions. Curr Biol 24:R518–R520. https:// moacidophilic archaea Sulfolobus. Archaea 2010:1–14. https :// doi.org/10.1016/j.cub.2014.03.075 doi.org/10.1155/2010/84263 9 3. Lill R (2009) Function and biogenesis of iron–sulphur proteins. 22. Tsaousis AD, Ollagnier de Choudens S, Gentekaki E et al (2012) Nature 460:831–838. https ://doi.org/10.1038/natur e0830 1 Evolution of Fe/S cluster biogenesis in the anaerobic parasite 4. Verner Z, Basu S, Benz C et al (2015) Malleable mitochondrion Blastocystis. Proc Natl Acad Sci USA 109:10426–10431. https of Trypanosoma brucei. Int Rev Cell Mol Biol 315:73–151. https ://doi.org/10.1073/pnas.11160 67109 ://doi.org/10.1016/bs.ircmb .2014.11.001 23. Karnkowska A, Vacek V, Zubácová Z et al (2016) A eukaryote 5. Müller M, Mentel M, van Hellemond JJ et al (2012) Biochemis- without a mitochondrial organelle. Curr Biol 26:1274–1284. try and evolution of anaerobic energy metabolism in eukaryotes. https ://doi.org/10.1016/j.cub.2016.03.053 Microbiol Mol Biol Rev 76:444–495. https ://doi.org/10.1128/ 24. Tachezy J, Sánchez LB, Müller M (2001) Mitochondrial type MMBR.05024 -11 iron–sulfur cluster assembly in the amitochondriate eukaryotes 6. Müller M (1993) The hydrogenosome. J Gen Microbiol Trichomonas vaginalis and Giardia intestinalis, as indicated 139:2879–2889 1 3 JBIC Journal of Biological Inorganic Chemistry (2018) 23:521–541 535 by the phylogeny of IscS. Mol Biol Evol 18:1919–1928. https 41. Chandramouli K, Unciuleac M-C, Naik S et al (2007) Forma- ://doi.org/10.1093/oxfor djour nals.molbe v.a0037 32 tion and properties of [4Fe–4S] clusters on the IscU scaffold 25. Freibert SA, Goldberg AV, Hacker C et al (2016) Evolution- protein. Biochemistry 46:6804–6811. https://doi.or g/10.1021/ ary conservation and in vitro reconstitution of microsporidian bi602 6659 iron–sulfur cluster biosynthesis. Nat Commun 8:1–12. https:// 42. Adinolfi S, Iannuzzi C, Prischi F et al (2009) Bacterial frataxin doi.org/10.1038/ncomm s1393 2 CyaY is the gatekeeper of iron–sulfur cluster formation cata- 26. Dellibovi-Ragheb TA, Gisselberg JE, Prigge ST (2013) Para- lyzed by IscS. Nat Struct Mol Biol 16:390–396. https ://doi. sites FeS up: iron–sulfur cluster biogenesis in eukaryotic path- org/10.1038/nsmb.1579 ogens. PLoS Pathog 9:e1003227. https://doi.or g/10.1371/journ 43. Loiseau L, Ollagnier de Choudens S, Nachin L et al (2003) al.ppat.10032 27 Biogenesis of Fe–S cluster by the bacterial Suf system: SufS 27. Hjort K, Goldberg AV, Tsaousis AD et al (2010) Diversity and and SufE form a new type of cysteine desulfurase. J Biol Chem reductive evolution of mitochondria among microbial eukary- 278:38352–38359. https ://doi.org/10.1074/jbc.M3059 53200 otes. Philos Trans R Soc Lond B Biol Sci 365:713–727. https 44. Outten FW, Djaman O, Storz G (2004) A suf operon require- ://doi.org/10.1073/pnas.90.7.2754 ment for Fe–S cluster assembly during iron starvation in Escheri- 28. Leger MM, Kolísko M, Kamikawa R et al (2017) Organelles chia coli. Mol Microbiol 52:861–872. https ://doi.or g/10.111 that illuminate the origins of Trichomonas hydrogenosomes 1/j.1365-2958.2004.04025 .x and Giardia mitosomes. Nat Ecol Evol 1:0092. https ://doi. 45. Outten FW, Wood MJ, Muñoz FM, Storz G (2003) The SufE org/10.1038/s4155 9-017-0092 protein and the SufBCD complex enhance SufS cysteine desul- 29. Yan R, Konarev PV, Iannuzzi C et al (2013) Ferredoxin com- furase activity as part of a sulfur transfer pathway for Fe–S clus- petes with bacterial frataxin in binding to the desulfurase IscS. ter assembly in Escherichia coli. J Biol Chem 278:45713–45719. J Biol Chem 288:24777–24787. https ://doi.org/10.1074/jbc.https ://doi.org/10.1074/jbc.M3080 04200 M113.48032 7 46. Mihara H, Esaki N (2002) Bacterial cysteine desulfurases: their 30. Ayala-Castro C, Saini A, Outten FW (2008) Fe–S clus- function and mechanisms. Appl Microbiol Biotechnol 60:12–23. ter assembly pathways in bacteria. Microbiol Mol Biol Rev https ://doi.org/10.1007/s0025 3-002-1107-4 72:110–125. https://doi.or g/10.1128/mmbr.00034-07 (table of 47. Layer G, Gaddam SA, Ayala-Castro CN et al (2007) SufE trans- contents) fers sulfur from SufS to SufB for iron–sulfur cluster assembly. 31. Ollagnier-de-Choudens S, Mattioli T, Takahashi Y, Fonte- J Biol Chem 282:13342–13350. https ://doi.or g/10.1074/jbc. cave M (2001) Iron–sulfur cluster assembly: characterization M6085 55200 of IscA and evidence for a specific and functional complex 48. Wollers S, Layer G, Garcia Serres R et al (2010) Iron–sulfur with ferredoxin. J Biol Chem 276:22604–22607. https ://doi. (Fe–S) cluster assembly: the SufBCD complex is a new type org/10.1074/jbc.M1029 02200 of Fe–S scaffold with a flavin redox cofactor. J Biol Chem 32. Krebs C, Agar JN, Smith AD et al (2001) IscA, an alternate 285:23331–23341. https ://doi.org/10.1074/jbc.M110.12744 9 scaffold for Fe–S cluster biosynthesis. Biochemistry 40:14069– 49. Chahal HK, Outten FW (2012) Separate FeS scaffold and car - 14080. https ://doi.org/10.1021/bi015 656z rier functions for SufB C and SufA during in vitro maturation 2 2 33. Vickery LE, Cupp-Vickery JR (2008) Molecular chaperones of [2Fe2S] Fdx. J Inorg Biochem 116:126–134. https ://doi. HscA/Ssq1 and HscB/Jac1 and their roles in iron–sulfur pro-org/10.1016/j.jinor gbio.2012.06.008 tein maturation. Crit Rev Biochem Mol Biol 42:95–111. https 50. Saini A, Mapolelo DT, Chahal HK et al (2010) SufD and SufC ://doi.org/10.1080/10409 23070 13222 98 ATPase activity are required for iron acquisition during in vivo 34. Silberg JJ, Tapley TL, Hoff KG, Vickery LE (2004) Regulation Fe–S cluster formation on SufB. Biochemistry 49:9402–9412. of the HscA ATPase reaction cycle by the co-chaperone HscB https ://doi.org/10.1021/bi101 1546 and the iron–sulfur cluster assembly protein IscU. J Biol Chem 51. Nachin L, Loiseau L, Expert D, Barras F (2003) SufC: an unor- 279:53924–53931. https ://doi.org/10.1074/jbc.M4101 17200 thodox cytoplasmic ABC/ATPase required for [Fe–S] biogen- 35. Reyda MR, Fugate CJ, Jarrett JT (2009) A complex between esis under oxidative stress. EMBO J 22:427–437. https ://doi. biotin synthase and the iron–sulfur cluster assembly chaperone org/10.1093/emboj /cdg06 1 HscA that enhances in vivo cluster assembly. Biochemistry 52. Hirabayashi K, Yuda E, Tanaka N et al (2015) Functional dynam- 48:10782–10792. https ://doi.org/10.1021/bi901 393t ics revealed by the structure of the SufBCD complex, a novel 36. Bonomi F, Iametti S, Morleo A et al (2008) Studies on the ATP-binding cassette (ABC) protein that serves as a scaffold for mechanism of catalysis of iron–sulfur cluster transfer from iron–sulfur cluster biogenesis. J Biol Chem 290:29717–29731. IscU[2Fe2S] by HscA/HscB chaperones. Biochemistry https ://doi.org/10.1074/jbc.M115.68093 4 47:12795–12801. https ://doi.org/10.1021/bi801 565j 53. Vinella D, Brochier-Armanet C, Loiseau L et al (2009) Iron– 37. Chandramouli K, Johnson MK (2006) HscA and HscB stimu- sulfur (Fe/S) protein biogenesis: phylogenomic and genetic late [2Fe–2S] cluster transfer from IscU to apoferredoxin in an studies of A-type carriers. PLoS Genet 5:e1000497. https ://doi. ATP-dependent reaction. Biochemistry 45:11087–11095. https org/10.1371/journ al.pgen.10004 97 ://doi.org/10.1021/bi061 237w 54. Chahal HK, Dai Y, Saini A et al (2009) The SufBCD Fe–S scaf- 38. Hoff KG, Silberg JJ, Vickery LE (2000) Interaction of the fold complex interacts with SufA for Fe–S cluster transfer. Bio- iron–sulfur cluster assembly protein IscU with the Hsc66/ chemistry 48:10644–10653. https ://doi.org/10.1021/bi901 518y Hsc20 molecular chaperone system of Escherichia coli. Proc 55. Outten FW (2015) Recent advances in the Suf Fe–S cluster bio- Natl Acad Sci USA 97:7790–7795. https ://doi.org/10.1073/ genesis pathway: beyond the Proteobacteria. BBA Mol Cell Res pnas.13020 1997 1853:1464–1469. https://doi.or g/10.1016/j.bbamcr .2014.11.001 39. Bonomi F, Iametti S, Morleo A et al (2011) Facilitated transfer of 56. Yang J, Bitoun JP, Ding H (2006) Interplay of IscA and IscU IscU-[2Fe2S] clusters by chaperone-mediated ligand exchange. in biogenesis of iron–sulfur clusters. J Biol Chem 281:27956– Biochemistry 50:9641–9650. https: //doi.org/10.1021/bi20112 3z 27963. https ://doi.org/10.1074/jbc.M6013 56200 40. Agar JN, Krebs C, Frazzon J et al (2000) IscU as a scaffold for 57. Selbach BP, Chung AH, Scott AD et al (2013) Fe–S cluster iron–sulfur cluster biosynthesis: sequential assembly of [2Fe–2S] biogenesis in Gram-positive bacteria: SufU is a zinc-dependent and [4Fe–4S] clusters in IscU. Biochemistry 39:7856–7862. https sulfur transfer protein. Biochemistry 53:152–160. https ://doi. ://doi.org/10.1021/bi000 931norg/10.1021/bi401 1978 1 3 536 JBIC Journal of Biological Inorganic Chemistry (2018) 23:521–541 58. Albrecht AG, Netz DJA, Miethke M et al (2010) SufU is an pathway by recruiting CsdL (ex-YgdL), a ubiquitin-modifying- essential iron–sulfur cluster scaffold protein in Bacillus subtilis. like protein. Mol Microbiol 74:1527–1542. https ://doi.org/10.1 J Bacteriol 192:1643–1651. https://doi.or g/10.1128/JB.01536-09 111/j.1365-2958.2009.06954 .x 59. Riboldi GP, de Oliveira JS, Frazzon J (2011) Enterococcus fae- 74. Ali V, Nozaki T (2013) Iron–sulphur clusters, their biosynthesis, calis SufU scaffold protein enhances SufS desulfurase activity and biological functions in protozoan parasites. Adv Parasitol by acquiring sulfur from its cysteine-153. BBA Proteins Proteom 83:1–92. https://doi.or g/10.1016/B978-0-12-407705-8.00001 -X 1814:1910–1918. https://doi.or g/10.1016/j.bbapap.2011.06.016 75. Kumar B, Chaubey S, Shah P et al (2011) Interaction between 60. Mansy SS, Wu G, Surerus KK, Cowan JA (2002) Iron–sulfur sulphur mobilisation proteins SufB and SufC: evidence for an cluster biosynthesis. Thermatoga maritima IscU is a structured iron–sulphur cluster biogenesis pathway in the apicoplast of iron–sulfur cluster assembly protein. J Biol Chem 277:21397– Plasmodium falciparum. Int J Parasitol 41:991–999. https ://doi. 21404. https ://doi.org/10.1074/jbc.M2014 39200 org/10.1016/j.ijpar a.2011.05.006 61. Huet G, Daffe M, Saves I (2005) Identification of the Mycobacte- 76. Nývltová E, Sutak R, Harant K et al (2013) NIF-type iron–sul- rium tuberculosis SUF machinery as the exclusive mycobacterial fur cluster assembly system is duplicated and distributed in the system of [Fe–S] cluster assembly: evidence for its implication mitochondria and cytosol of Mastigamoeba balamuthi. Proc in the pathogen’s survival. J Bacteriol 187:6137–6146. https :// Natl Acad Sci USA 110:7371–7376. https ://doi.org/10.1073/ doi.org/10.1128/JB.187.17.6137-6146.2005pnas.12195 90110 62. Olson JW, Agar JN, Johnson MK, Maier RJ (2000) Characteriza- 77. Ali V, Shigeta Y, Tokumoto U et al (2004) An intestinal parasitic tion of the NifU and NifS Fe–S cluster formation proteins essen- protist, Entamoeba histolytica, possesses a non-redundant nitro- tial for viability in Helicobacter pylori. Biochemistry 39:16213– gen fixation-like system for iron–sulfur cluster assembly under 16219. https ://doi.org/10.1021/bi001 744s anaerobic conditions. J Biol Chem 279:16863–16874. https://doi. 63. Rincon-Enriquez G, Crété P, Barras F, Py B (2008) Biogen-org/10.1074/jbc.M3133 14200 esis of Fe/S proteins and pathogenicity: IscR plays a key role 78. Poliak P, Van Hoewyk D, Oborník M et al (2009) Functions and in allowing Erwinia chrysanthemi to adapt to hostile condi- cellular localization of cysteine desulfurase and selenocysteine tions. Mol Microbiol 67:1257–1273. https ://doi.or g/10.111 lyase in Trypanosoma brucei. FEBS J 277:383–393. https :// 1/j.1365-2958.2008.06118 .xdoi.org/10.1111/j.1742-4658.2009.07489 .x 64. Glasner JD, Yang C-H, Reverchon S et al (2011) Genome 79. Richards TA, van der Giezen M (2006) Evolution of the Isd11– sequence of the plant-pathogenic bacterium Dickeya dadan- IscS complex reveals a single alpha-proteobacterial endosymbio- tii 3937. J Bacteriol 193:2076–2077. https ://doi.org/10.1128/ sis for all eukaryotes. Mol Biol Evol 23:1341–1344. https ://doi. JB.01513 -10org/10.1093/molbe v/msl00 1 65. Arnold W, Rump A, Klipp W et al (1988) Nucleotide sequence 80. Wiedemann N, Urzica E, Guiard B et al (2006) Essential role of a 24,206-base-pair DNA fragment carrying the entire nitro- of Isd11 in mitochondrial iron–sulfur cluster synthesis on Isu gen fixation gene cluster of Klebsiella pneumoniae. J Mol Biol scaffold proteins. EMBO J 25:184–195. https://doi.or g/10.1038/ 203:715–738sj.emboj .76009 06 66. Frazzon J, Dean DR (2003) Formation of iron–sulfur clusters 81. Shi Y, Ghosh MC, Tong W-H, Rouault TA (2009) Human ISD11 in bacteria: an emerging field in bioinorganic chemistry. Curr is essential for both iron–sulfur cluster assembly and mainte- Opin Chem Biol 7:166–173. https ://doi.or g/10.1016/S1367 nance of normal cellular iron homeostasis. Hum Mol Gen -5931(03)00021 -8 18:3014–3025. https ://doi.org/10.1093/hmg/ddp23 9 67. Curatti L, Ludden PW, Rubio LM (2006) NifB-dependent in vitro 82. Friemel M, Marelja Z, Li K, Leimkühler S (2017) The N-termi- synthesis of the iron–molybdenum cofactor of nitrogenase. Proc nus of iron–sulfur cluster assembly factor ISD11 is crucial for Natl Acad Sci USA 103:5297–5301. https ://doi.org/10.1073/ subcellular targeting and interaction with l -cysteine desulfurase pnas.06011 15103 NFS1. Biochemistry 56:1797–1808. https://doi.or g/10.1021/acs. 68. Evans DJ, Jones R, Woodley PR et al (1991) Nucleotide sequence bioch em.6b012 39 and genetic analysis of the Azotobacter chroococcum nifUS- 83. Biederbick A, Stehling O, Rösser R et al (2006) Role of human VWZM gene cluster, including a new gene (nifP) which encodes mitochondrial Nfs1 in cytosolic iron–sulfur protein biogenesis a serine acetyltransferase. J Bacteriol 173:5457–5469 and iron regulation. Mol Cell Biol 26:5675–5687. https ://doi. 69. Mihara H, Kurihara T, Yoshimura T et al (1997) Cysteine sulfi-org/10.1128/MCB.00112 -06 nate desulfinase, a NIFS-like protein of Escherichia coli with 84. Van Vranken JG, Jeong M-Y, Wei P et al (2016) The mitochon- selenocysteine lyase and cysteine desulfurase activities. Gene drial acyl carrier protein (ACP) coordinates mitochondrial fatty cloning, purification, and characterization of a novel pyridoxal acid synthesis with iron sulfur cluster biogenesis. Elife. https :// enzyme. J Biol Chem 272:22417–22424doi.org/10.7554/eLife .17828 70. Mihara H, Maeda M, Fujii T et al (1999) A nifS-like gene, 85. Cory SA, Van Vranken JG, Brignole EJ et al (2017) Structure of csdB, encodes an Escherichia coli counterpart of mammalian human Fe–S assembly subcomplex reveals unexpected cysteine selenocysteine lyase. Gene cloning, purification, characteriza- desulfurase architecture and acyl-ACP–ISD11 interactions. Proc tion and preliminary X-ray crystallographic studies. J Biol Chem Natl Acad Sci USA 114:E5325–E5334. https://doi.or g/10.1073/ 274:14768–14772pnas.17028 49114 71. Mihara H, Kurihara T, Yoshimura T, Esaki N (2000) Kinetic 86. Boniecki MT, Freibert SA, Mühlenhoff U et al (2017) Structure and mutational studies of three NifS homologs from Escherichia and functional dynamics of the mitochondrial Fe/S cluster syn- coli: mechanistic difference between l -cysteine desulfurase and thesis complex. Nat Commun 8:1287. https ://doi.org/10.1038/ l -selenocysteine lyase reactions. J Biochem 127:559–567s4146 7-017-01497 -1 72. Fontecave M, Ollagnier de Choudens S (2008) Iron–sulfur clus- 87. Sheftel AD, Stehling O, Pierik AJ et al (2010) Humans pos- ter biosynthesis in bacteria: mechanisms of cluster assembly sess two mitochondrial ferredoxins, Fdx1 and Fdx2, with dis- and transfer. Arch Biochem Biophys 474:226–237. https ://doi. tinct roles in steroidogenesis, heme, and Fe/S cluster biosyn- org/10.1016/j.abb.2007.12.014 thesis. Proc Natl Acad Sci USA 107:11775–11780. https ://doi. 73. Trotter V, Vinella D, Loiseau L et al (2009) The CsdA org/10.1073/pnas.10042 50107 cysteine desulphurase promotes Fe/S biogenesis by recruit- 88. Shan Y, Cortopassi G (2012) HSC20 interacts with frataxin and is ing Suf components and participates to a new sulphur transfer involved in iron–sulfur cluster biogenesis and iron homeostasis. 1 3 JBIC Journal of Biological Inorganic Chemistry (2018) 23:521–541 537 Hum Mol Gen 21:1457–1469. https ://doi.or g/10.1093/hmg/ddr58 104. Rodríguez-Manzaneque MT, Tamarit J, Bellí G et al (2002) 2 Grx5 is a mitochondrial glutaredoxin required for the activity 89. Beilschmidt LK, Ollagnier de Choudens S, Fournier M et al of iron/sulfur enzymes. Mol Biol Cell 13:1109–1121. https :// (2017) ISCA1 is essential for mitochondrial Fe S biogenesis doi.org/10.1091/mbc.01-10-0517 4 4 in vivo. Nat Commun 8:15124. https ://doi.org/10.1038/ncomm 105. Kim K-D, Chung W-H, Kim H-J et al (2010) Monothiol glu- s1512 4 taredoxin Grx5 interacts with Fe–S scaffold proteins Isa1 90. Ciofi-Baffoni S, Nasta V, Banci L (2018) Protein networks in the and Isa2 and supports Fe–S assembly and DNA integrity in maturation of human iron–sulfur proteins. Metallomics 10:49– mitochondria of fission yeast. Biochem Biophys Res Commun 72. https ://doi.org/10.1039/c7mt0 0269f 392:467–472. https ://doi.org/10.1016/j.bbrc.2010.01.051 91. Tong W-H, Rouault T (2000) Distinct iron–sulfur cluster assem- 106. Vilella F, Alves R, Rodríguez-Manzaneque MT et al (2004) bly complexes exist in the cytosol and mitochondria of human Evolution and cellular function of monothiol glutaredoxins: cells. EMBO J 19:5692–5700. https ://doi.org/10.1093/emboj involvement in iron–sulphur cluster assembly. Comp Funct /19.21.5692 Genomics 5:328–341. https ://doi.org/10.1002/cfg.406 92. Uhrigshardt H, Singh A, Kovtunovych G et al (2010) Charac- 107. Sheftel AD, Wilbrecht C, Stehling O et al (2012) The human terization of the human HSC20, an unusual DnaJ type III pro- mitochondrial ISCA1, ISCA2, and IBA57 proteins are required tein, involved in iron–sulfur cluster biogenesis. Hum Mol Gen for [4Fe–4S] protein maturation. Mol Biol Cell 23:1157–1166. 19:3816–3834. https ://doi.org/10.1093/hmg/ddq30 1https ://doi.org/10.1091/mbc.E11-09-0772 93. Uhrigshardt H, Rouault TA, Missirlis F (2013) Insertion mutants 108. Alaimo JT, Besse A, Alston CL et al (2018) Loss-of-function in Drosophila melanogaster Hsc20 halt larval growth and lead mutations in ISCA2 disrupt 4Fe–4S cluster machinery and to reduced iron–sulfur cluster enzyme activities and impaired cause a fatal leukodystrophy with hyperglycinemia and mtDNA iron homeostasis. J Biol Inorg Chem 18:441–449. https ://doi. depletion. Hum Mutat 39:537–549. https ://doi.org/10.1002/ org/10.1007/s0077 5-013-0988-2 humu.23396 94. Schilke B, Williams B, Knieszner H et al (2006) Evolution 109. Brancaccio D, Gallo A, Mikolajczyk M et al (2014) Formation of mitochondrial chaperones utilized in Fe–S cluster bio- of [4Fe–4S] clusters in the mitochondrial iron–sulfur cluster genesis. Curr Biol 16:1660–1665. https ://doi.or g/10.1016/j. assembly machinery. J Am Chem Soc 136:16240–16250. https cub.2006.06.069://doi.org/10.1021/ja507 822j 95. Maio N, Singh A, Uhrigshardt H et al (2014) Cochaperone 110. Mühlenhoff U, Gerl MJ, Flauger B et al (2007) The ISC pro- binding to LYR motifs confers specificity of iron sulfur clus- teins Isa1 and Isa2 are required for the function but not for the ter delivery. Cell Metab 19:445–457. https ://doi.org/10.1016/j. de novo synthesis of the Fe/S clusters of biotin synthase in cmet.2014.01.015 Saccharomyces cerevisiae. Eukaryot Cell 6:495–504. https :// 96. Bridwell-Rabb J, Iannuzzi C, Pastore A, Barondeau DP (2012) doi.org/10.1128/EC.00191 -06 Effector role reversal during evolution: the case of Frataxin in 111. Mühlenhoff U, Richter N, Pines O et al (2011) Specialized Fe–S cluster biosynthesis. Biochemistry 51:2506–2514. https :// function of yeast Isa1 and Isa2 proteins in the maturation of doi.org/10.1021/bi201 628j mitochondrial [4Fe–4S] proteins. J Biol Chem 286:41205– 97. Bridwell-Rabb J, Fox NG, Tsai C-L et al (2014) Human Frataxin 41216. https ://doi.org/10.1074/jbc.M111.29615 2 activates Fe–S cluster biosynthesis by facilitating sulfur transfer 112. Kaut A, Lange H, Diekert K et al (2000) Isa1p is a compo- chemistry. Biochemistry 53:4904–4913. https: //doi.org/10.1021/ nent of the mitochondrial machinery for maturation of cellu- bi500 532e lar iron–sulfur proteins and requires conserved cysteine resi- 98. Schmucker S, Martelli A, Colin F et al (2011) Mammalian dues for function. J Biol Chem 275:15955–15961. https ://doi. frataxin: an essential function for cellular viability through an org/10.1074/jbc.M9095 02199 interaction with a preformed ISCU/NFS1/ISD11 iron–sulfur 113. Gelling C, Dawes IW, Richhardt N et al (2008) Mitochondrial assembly complex. PLoS One 6:e16199. https://doi.or g/10.1371/ Iba57p is required for Fe/S cluster formation on aconitase and journ al.pone.00161 99 activation of radical SAM enzymes. Mol Cell Biol 28:1851– 99. Cai K, Frederick RO, Kim JH et al (2013) Human mitochon- 1861. https ://doi.org/10.1128/MCB.01963 -07 drial chaperone (mtHSP70) and cysteine desulfurase (NFS1) 114. Sánchez LA, Gomez-Gallardo M, Díaz-Pérez AL et al (2018) bind preferentially to the disordered conformation, whereas Iba57p participates in maturation of a [2Fe–2S]-cluster Rieske co-chaperone (HSC20) binds to the structured conformation protein and in formation of supercomplexes III/IV of Saccha- of the iron–sulfur cluster scaffold protein (ISCU). J Biol Chem romyces cerevisiae electron transport chain. Mitochondrion. 288:28755–28770. https ://doi.org/10.1074/jbc.M113.48204 2https ://doi.org/10.1016/j.mito.2018.01.003 100. Banci L, Brancaccio D, Ciofi-Baffoni S et al (2014) [2Fe–2S] 115. Braymer JJ, Lill R (2017) Iron–sulfur cluster biogenesis and cluster transfer in iron–sulfur protein biogenesis. Proc Natl Acad trafficking in mitochondria. J Biol Chem 292:12754–12763. Sci USA 111:6203–6208. https ://doi.org/10.1073/pnas.14001 https ://doi.org/10.1074/jbc.R117.78710 1 02111 116. Sheftel AD, Stehling O, Pierik AJ et al (2009) Human Ind1, 101. Camaschella C, Campanella A, De Falco L et al (2007) The an iron–sulfur cluster assembly factor for respiratory com- human counterpart of zebrafish shiraz shows sideroblastic-like plex I. Mol Cell Biol 29:6059–6073. https ://doi.org/10.1128/ microcytic anemia and iron overload. Blood 110:1353–1358. MCB.00817 -09 https ://doi.org/10.1182/blood -2007-02-07252 0 117. Bych K, Kerscher S, Netz DJA et al (2008) The iron–sulphur 102. Uzarska MA, Dutkiewicz R, Freibert S-A et al (2013) The protein Ind1 is required for effective complex I assembly. EMBO mitochondrial Hsp70 chaperone Ssq1 facilitates Fe/S cluster J 27:1736–1746. https ://doi.org/10.1038/emboj .2008.98 transfer from Isu1 to Grx5 by complex formation. Mol Biol Cell 118. Tong W-H, Jameson GNL, Huynh BH, Rouault TA (2003) Sub- 24:1830–1841. https ://doi.org/10.1091/mbc.E12-09-0644 cellular compartmentalization of human Nfu, an iron–sulfur 103. Dutkiewicz R, Schilke B, Knieszner H et al (2003) Ssq1, a mito- cluster scaffold protein, and its ability to assemble a [4Fe–4S] chondrial Hsp70 involved in iron–sulfur (Fe/S) center biogen- cluster. Proc Natl Acad Sci USA 100:9762–9767. https ://doi. esis. Similarities to and differences from its bacterial counter -org/10.1073/pnas.17325 41100 part. J Biol Chem 278:29719–29727. https://doi.or g/10.1074/jbc. 119. Léon S, Touraine B, Ribot C et al (2003) Iron–sulphur cluster M3035 27200 assembly in plants: distinct NFU proteins in mitochondria and 1 3 538 JBIC Journal of Biological Inorganic Chemistry (2018) 23:521–541 plastids from Arabidopsis thaliana. Biochem J 371:823–830. 136. Roy A, Solodovnikova N, Nicholson T et al (2003) A novel https ://doi.org/10.1042/BJ200 21946 eukaryotic factor for cytosolic Fe–S cluster assembly. EMBO J 120. Melber A, Na U, Vashisht A et al (2016) Role of Nfu1 and Bol3 22:4826–4835. https ://doi.org/10.1093/emboj /cdg45 5 in iron–sulfur cluster transfer to mitochondrial clients. Elife 137. Hausmann A, Aguilar Netz DJ, Balk J et al (2005) The eukary- 5:186. https ://doi.org/10.7554/eLife .15991 otic P loop NTPase Nbp35: an essential component of the cyto- 121. Gao H, Subramanian S, Couturier J et al (2013) Arabidopsis solic and nuclear iron–sulfur protein assembly machinery. Proc thaliana Nfu2 accommodates [2Fe–2S] or [4Fe–4S] clusters and Natl Acad Sci USA 102:3266–3271. https ://doi.org/10.1073/ is competent for in vitro maturation of chloroplast [2Fe–2S] and pnas.04064 47102 [4Fe–4S] cluster-containing proteins. Biochemistry 52:6633– 138. Netz DJA, Pierik AJ, Stümpfig M et al (2007) The Cfd1–Nbp35 6645. https ://doi.org/10.1021/bi400 7622 complex acts as a scao ff ld for iron–sulfur protein assembly in the 122. Wachnowsky C, Fidai I, Cowan JA (2016) Iron–sulfur clus- yeast cytosol. Nat Chem Biol 3:278–286. https://doi.or g/10.1038/ ter exchange reactions mediated by the human Nfu protein. J nchem bio87 2 Biol Inorg Chem 21:825–836. https ://doi.or g/10.1007/s0077 139. Boyd JM, Drevland RM, Downs DM, Graham DE (2009) 5-016-1381-8 Archaeal ApbC/Nbp35 homologs function as iron–sulfur clus- 123. Benoit SL, Holland AA, Johnson MK, Maier RJ (2018) Iron–sul- ter carrier proteins. J Bacteriol 191:1490–1497. https ://doi. fur protein maturation in Helicobacter pylori: identifying a Nfu-org/10.1128/JB.01469 -08 type cluster carrier protein and its iron–sulfur protein targets. 140. Netz DJA, Pierik AJ, Stumpfig M et al (2012) A bridging Mol Microbiol. https ://doi.org/10.1111/mmi.13942 [4Fe–4S] cluster and nucleotide binding are essential for func- 124. Tonduti D, Dorboz I, Imbard A et al (2015) New spastic paraple- tion of the Cfd1–Nbp35 complex as a scaffold in iron–sulfur gia phenotype associated to mutation of NFU1. Orphanet J Rare protein maturation. J Biol Chem 287:12365–12378. https ://doi. Dis 10:13. https ://doi.org/10.1186/s1302 3-015-0237-6org/10.1074/jbc.M111.32891 4 125. Navarro-Sastre A, Tort F, Stehling O et al (2011) A fatal mito- 141. Stehling O, Netz DJA, Niggemeyer B et al (2008) Human Nbp35 chondrial disease is associated with defective NFU1 function is essential for both cytosolic iron–sulfur protein assembly and in the maturation of a subset of mitochondrial Fe–S proteins. iron homeostasis. Mol Cell Biol 28:5517–5528. https ://doi. Am J Hum Genet 89:656–667. https ://doi.or g/10.1016/j.org/10.1128/MCB.00545 -08 ajhg.2011.10.005 142. Bych K, Netz DJA, Vigani G et al (2008) The essential cytosolic 126. Cameron JM, Janer A, Levandovskiy V et al (2011) Mutations iron–sulfur protein Nbp35 acts without Cfd1 partner in the green in iron–sulfur cluster scaffold genes NFU1 and BOLA3 cause lineage. J Biol Chem 283:35797–35804. https://doi.or g/10.1074/ a fatal deficiency of multiple respiratory chain and 2-oxoacid jbc.M8073 03200 dehydrogenase enzymes. Am J Hum Genet 89:486–495. https :// 143. Pyrih J, Pyrihová E, Kolísko M et al (2016) Minimal cytosolic doi.org/10.1016/j.ajhg.2011.08.011 iron–sulfur cluster assembly machinery of Giardia intestinalis 127. Uzarska MA, Nasta V, Weiler BD et al (2016) Mitochondrial is partially associated with mitosomes. Mol Microbiol 102:701– Bol1 and Bol3 function as assembly factors for specific iron–sul- 714. https ://doi.org/10.1111/mmi.13487 fur proteins. Elife 5:e16673. https://doi.or g/10.7554/eLife.16673 144. Netz DJA, Stümpfig M, Doré C et al (2010) Tah18 transfers elec- 128. Willems P, Wanschers BFJ, Esseling J et al (2013) BOLA1 Is trons to Dre2 in cytosolic iron–sulfur protein biogenesis. Nat an aerobic protein that prevents mitochondrial morphology Chem Biol 6:758–765. https ://doi.org/10.1038/nchem bio.432 changes induced by glutathione depletion. Antioxid Redox Sig- 145. Zhang Y, Lyver ER, Nakamaru-Ogiso E et al (2008) Dre2, a nal 18:129–138. https ://doi.org/10.1089/ars.2011.4253 conserved eukaryotic Fe/S cluster protein, functions in cytosolic 129. Frey AG, Palenchar DJ, Wildemann JD, Philpott CC (2016) A Fe/S protein biogenesis. Mol Cell Biol 28:5569–5582. https :// glutaredoxin BolA complex serves as an iron–sulfur cluster chap-doi.org/10.1128/MCB.00642 -08 erone for the cytosolic cluster assembly machinery. J Biol Chem 146. Peleh V, Riemer J, Dancis A, Herrmann JM (2014) Protein oxi- 291:22344–22356. https ://doi.org/10.1074/jbc.M116.74494 6 dation in the intermembrane space of mitochondria is substrate- 130. Sipos K, Lange H, Fekete Z et al (2002) Maturation of cyto- specific rather than general. Microb Cell 1:81–93. https ://doi. solic iron–sulfur proteins requires glutathione. J Biol Chem org/10.15698 /mic20 14.01.130 277:26944–26949. https ://doi.org/10.1074/jbc.M2006 77200 147. Banci L, Bertini I, Ciofi-Baffoni S et al (2011) Anamorsin is a 131. Kispal G, Csere P, Prohl C, Lill R (1999) The mitochondrial pro- [2Fe–2S] cluster-containing substrate of the Mia40-dependent teins Atm1p and Nfs1p are essential for biogenesis of cytosolic mitochondrial protein trapping machinery. Chem Biol 18:794– Fe/S proteins. EMBO J 18:3981–3989. https ://doi.org/10.1093/ 804. https ://doi.org/10.1016/j.chemb iol.2011.03.015 emboj /18.14.3981 148. Netz DJA, Genau HM, Weiler BD et al (2016) The conserved 132. Leighton J, Schatz G (1995) An ABC transporter in the mito- protein Dre2 uses essential [2Fe–2S] and [4Fe–4S] clusters for chondrial inner membrane is required for normal growth of yeast. its function in cytosolic iron–sulfur protein assembly. Biochem EMBO J 14:188–195 J 473:2073–2085. https ://doi.org/10.1042/BCJ20 16041 6 133. Balk J, Pierik AJ, Netz DJA et al (2004) The hydrogenase- 149. Banci L, Ciofi-Baffoni S, Gajda K et al (2015) N-terminal like Nar1p is essential for maturation of cytosolic and nuclear domains mediate [2Fe–2S] cluster transfer from glutaredoxin-3 to iron–sulphur proteins. EMBO J 23:2105–2115. https ://doi. anamorsin. Nat Chem Biol 11:772–778. https://doi.or g/10.1038/ org/10.1038/sj.emboj .76002 16nchem bio.1892 134. Stehling O, Lill R (2013) The role of mitochondria in cellular 150. Balk J, Aguilar Netz DJ, Tepper K et al (2005) The essential iron–sulfur protein biogenesis: mechanisms, connected pro- WD40 protein Cia1 is involved in a late step of cytosolic and cesses, and diseases. Cold Spring Harb Perspect Biol 5:a011312. nuclear iron–sulfur protein assembly. Mol Cell Biol 25:10833– https ://doi.org/10.1101/cshpe rspec t.a0113 12 10841. https ://doi.org/10.1128/MCB.25.24.10833 -10841 .2005 135. Srinivasan V, Pierik AJ, Lill R (2014) Crystal structures of nucle- 151. Stehling O, Vashisht AA, Mascarenhas J et al (2012) MMS19 otide-free and glutathione-bound mitochondrial ABC transporter assembles iron–sulfur proteins required for DNA metabolism and Atm1. Science 343:1137–1140. https ://doi.org/10.1126/scien genomic integrity. Science 337:195–199. https://doi.or g/10.1126/ ce.12467 29scien ce.12197 23 152. Gari K, Ortiz AML, Borel V et al (2012) MMS19 links cyto- plasmic iron–sulfur cluster assembly to DNA metabolism. 1 3 JBIC Journal of Biological Inorganic Chemistry (2018) 23:521–541 539 Science 337:243–245. https ://doi.org/10.1126/scien ce.12196 169. Haunhorst P, Berndt C, Eitner S et al (2010) Characterization 64 of the human monothiol glutaredoxin 3 (PICOT) as iron–sulfur 153. Odermatt DC, Gari K (2017) The CIA targeting complex is protein. Biochem Biophys Res Commun 394:372–376. https :// highly regulated and provides two distinct binding sites for cli- doi.org/10.1016/j.bbrc.2010.03.016 ent iron–sulfur proteins. Cell Rep 18:1434–1443. https ://doi. 170. Hampl V, Hug L, Leigh JW et al (2009) Phylogenomic analyses org/10.1016/j.celre p.2017.01.037 support the monophyly of Excavata and resolve relationships 154. Srinivasan V, Netz DJA, Webert H et al (2007) Structure of the among eukaryotic “supergroups”. Proc Natl Acad Sci USA yeast WD40 domain protein Cia1, a component acting late in 106:3859–3864. https ://doi.org/10.1073/pnas.08078 80106 iron–sulfur protein biogenesis. Structure 15:1246–1257. https:// 171. Derelle R, Torruella G, Klimeš V et al (2015) Bacterial pro- doi.org/10.1016/j.str.2007.08.009 teins pinpoint a single eukaryotic root. Proc Natl Acad Sci USA 155. Prakash L, Prakash S (1979) Three additional genes involved in 112:E693–E699. https ://doi.org/10.1073/pnas.14206 57112 pyrimidine dimer removal in Saccharomyces cerevisiae: RAD7, 172. Lukeš J, Basu S (2015) Fe/S protein biogenesis in trypano- RAD14 and MMS19. Mol Gen Genet 176:351–359. https ://doi. somes—a review. Biochim Biophys Acta 1853:1481–1492. https org/10.1007/BF003 33097 ://doi.org/10.1016/j.bbamc r.2014.08.015 156. Li F, Martienssen R, Cande WZ (2011) Coordination of DNA 173. Hannaert V, Bringaud F, Opperdoes FR, Michels PA (2003) replication and histone modification by the Rik1–Dos2 complex. Evolution of energy metabolism and its compartmentation Nature 475:244–248. https ://doi.org/10.1038/natur e1016 1 in Kinetoplastida. Kinetoplastid Biol Dis 2:11. https ://doi. 157. Eisenstein RS (2000) Iron regulatory proteins and the molecular org/10.1186/1475-9292-2-11 control of mammalian iron metabolism. Annu Rev Nutr 20:627– 174. Basu S, Horáková E, Lukeš J (2016) Iron-associated biology of 662. https ://doi.org/10.1146/annur ev.nutr.20.1.627 Trypanosoma brucei. BBA Gen Subjects 1860:363–370. https:// 158. Mühlenhoff U, Molik S, Godoy JR et al (2010) Cytosolic doi.org/10.1016/j.bbage n.2015.10.027 monothiol glutaredoxins function in intracellular iron sensing 175. Smíd O, Horáková E, Vilímová V et al (2006) Knock-downs and trafficking via their bound iron–sulfur cluster. Cell Metab of iron–sulfur cluster assembly proteins IscS and IscU down- 12:373–385. https ://doi.org/10.1016/j.cmet.2010.08.001 regulate the active mitochondrion of procyclic Trypanosoma 159. Yarunin A, Panse VG, Petfalski E et al (2005) Functional link brucei. J Biol Chem 281:28679–28686. https://doi.or g/10.1074/ between ribosome formation and biogenesis of iron–sulfur pro-jbc.M5137 81200 teins. EMBO J 24:580–588. https ://doi.org/10.1038/sj.emboj 176. Paris Z, Changmai P, Rubio MAT et al (2010) The Fe/S clus- .76005 40 ter assembly protein Isd11 is essential for tRNA thiolation in 160. Van Ho A, Ward DM, Kaplan J (2002) Transition metal trans- Trypanosoma brucei. J Biol Chem 285:22394–22402. https :// port in yeast. Annu Rev Microbiol 56:237–261. https ://doi.doi.org/10.1074/jbc.M109.08377 4 org/10.1146/annur ev.micro .56.01230 2.16084 7 177. Changmai P, Horáková E, Long S et al (2013) Both human 161. Ojeda L, Keller G, Mühlenhoff U et al (2006) Role of glutar - ferredoxins equally efficiently rescue ferredoxin deficiency in edoxin-3 and glutaredoxin-4 in the iron regulation of the Aft1 Trypanosoma brucei. Mol Microbiol 89:135–151. https ://doi. transcriptional activator in Saccharomyces cerevisiae. J Biol org/10.1111/mmi.12264 Chem 281:17661–17669. https ://doi.or g/10.1074/jbc.M6021 178. Comini MA, Rettig J, Dirdjaja N et al (2008) Monothiol glutar- 65200 edoxin-1 is an essential iron–sulfur protein in the mitochondrion 162. Pujol-Carrion N, Bellí G, Herrero E et al (2006) Glutaredoxins of african trypanosomes. J Biol Chem 283:27785–27798. https Grx3 and Grx4 regulate nuclear localisation of Aft1 and the oxi-://doi.org/10.1074/jbc.M8020 10200 dative stress response in Saccharomyces cerevisiae. J Cell Sci 179. Long S, Jirků M, Ayala FJ, Lukeš J (2008) Mitochondrial locali- 119:4554–4564. https ://doi.org/10.1242/jcs.03229 zation of human frataxin is necessary but processing is not for 163. Chen OS, Crisp RJ, Valachovic M et al (2004) Transcription of rescuing frataxin deficiency in Trypanosoma brucei. Proc Natl the yeast iron regulon does not respond directly to iron but rather Acad Sci USA 105:13468–13473. https ://doi.or g/10.1073/ to iron–sulfur cluster biosynthesis. J Biol Chem 279:29513–pnas.08067 62105 29518. https ://doi.org/10.1074/jbc.M4032 09200 180. Long S, Changmai P, Tsaousis AD et al (2011) Stage-specific 164. Rutherford JC, Ojeda L, Balk J et al (2005) Activation of the iron requirement for Isa1 and Isa2 proteins in the mitochondrion of regulon by the yeast Aft1/Aft2 transcription factors depends on Trypanosoma brucei and heterologous rescue by human and mitochondrial but not cytosolic iron–sulfur protein biogenesis. Blastocystis orthologues. Mol Microbiol 81:1403–1418. https:// J Biol Chem 280:10135–10140. https ://doi.or g/10.1074/jbc.doi.org/10.1111/j.1365-2958.2011.07769 .x M4137 31200 181. Horáková E, Changmai P, Paris Z et al (2015) Simultaneous 165. Kumánovics A, Chen OS, Li L et al (2008) Identification of depletion of Atm and Mdl rebalances cytosolic Fe–S cluster FRA1 and FRA2 as genes involved in regulating the yeast iron assembly but not heme import into the mitochondrion of Trypa- regulon in response to decreased mitochondrial iron–sulfur nosoma brucei. FEBS J 282:4157–4175. https://doi.or g/10.1111/ cluster synthesis. J Biol Chem 283:10276–10286. https ://doi. febs.13411 org/10.1074/jbc.M8011 60200 182. Basu S, Leonard JC, Desai N et al (2013) Divergence of Erv1- 166. Li Y (1995) Yeast global transcriptional regulators Sin4 and Rgr1 associated mitochondrial import and export pathways in trypa- are components of mediator complex/RNA polymerase II holo- nosomes and anaerobic protists. Eukaryot Cell 12:343–355. https enzyme. Proc Natl Acad Sci USA 92:10864–10868. https ://doi.://doi.org/10.1128/EC.00304 -12 org/10.1073/pnas.17143 41115 183. Haindrich AC, Boudová M, Vancová M et al (2017) The inter- 167. Aldea M, Hernández-Chico C, la Campa de AG et al (1988) Iden- membrane space protein Erv1 of Trypanosoma brucei is essential tification, cloning, and expression of bolA, an ftsZ-dependent for mitochondrial Fe–S cluster assembly and operates alone. Mol morphogene of Escherichia coli. J Bacteriol 170:5169–5176. Biochem Parasitol 214:47–51. https ://doi.org/10.1016/j.molbi https ://doi.org/10.1128/jb.170.11.5169-5176.1988opara .2017.03.009 168. Li H, Mapolelo DT, Dingra NN et al (2011) Histidine 103 in 184. Kovářová J, Horáková E, Changmai P et al (2014) Mitochon- Fra2 is an iron–sulfur cluster ligand in the [2Fe–2S] Fra2-Grx3 drial and nucleolar localization of cysteine desulfurase Nfs and the scaffold protein Isu in Trypanosoma brucei. Eukaryot Cell complex and is required for in vivo iron signaling in yeast. J Biol 13:353–362. https ://doi.org/10.1128/EC.00235 -13 Chem 286:867–876. https ://doi.org/10.1074/jbc.M110.18417 6 1 3 540 JBIC Journal of Biological Inorganic Chemistry (2018) 23:521–541 185. Benz C, Kovářová J, Králová-Hromadová I et al (2016) Roles 201. Broers CA, Stumm CK, Vogels GD, Brugerolle G (1990) Psalte- of the Nfu Fe–S targeting factors in the trypanosome mitochon- riomonas lanterna gen. nov., sp. nov., a free-living amoeboflagel- drion. Int J Parasitol 46:641–651. https ://doi.org/10.1016/j.ijpar late isolated from freshwater anaerobic sediments. Eur J Protistol a.2016.04.006 25:369–380. https ://doi.org/10.1016/S0932 -4739(11)80130 -6 186. Saunders EC, Ng WW, Kloehn J et al (2014) Induction of a 202. de Graaf RM, Duarte I, van Alen TA et al (2009) The hydrogeno- stringent metabolic response in intracellular stages of Leishma- somes of Psalteriomonas lanterna. BMC Evol Biol 9:287. https nia mexicana leads to increased dependence on mitochondrial ://doi.org/10.1186/1471-2148-9-287 metabolism. PLoS Pathog 10:e1003888. https://doi.or g/10.1371/ 203. Pánek T, Silberman JD, Yubuki N et al (2012) Diversity, evo- journ al.ppat.10038 88 lution and molecular systematics of the Psalteriomonadidae, 187. Pratap Singh K, Zaidi A, Anwar S et al (2014) Reactive oxygen the main lineage of anaerobic/microaerophilic heterolobo- species regulates expression of iron–sulfur cluster assembly pro- seans (excavata: discoba). Protist 163:807–831. https ://doi. tein IscS of Leishmania donovani. Free Radic Biol Med 75:195–org/10.1016/j.proti s.2011.11.002 209. https ://doi.org/10.1016/j.freer adbio med.2014.07.017 204. Pánek T, Simpson AGB, Hampl V, Čepička I (2014) Creneis 188. Filser M, Comini MA, Molina-Navarro MM et al (2008) Cloning, carolina gen. et sp. nov. (Heterolobosea), a novel marine anaero- functional analysis, and mitochondrial localization of Trypano- bic protist with strikingly derived morphology and life cycle. soma brucei monothiol glutaredoxin-1. Biol Chem 389:21–32. Ann Anat. https ://doi.org/10.1016/j.proti s.2014.05.005 https ://doi.org/10.1515/BC.2007.147 205. Smirnov AV, Fenchel T (1996) Vahlkampfia anaerobica n. sp. 189. Comini MA, Krauth-Siegel RL, Bellanda M (2013) Mono- and and Vannella peregrinia n. sp. (Rhizopoda)—anaerobic amoebae dithiol glutaredoxins in the trypanothione-based redox metab- from a marine sediment. Arch Protistenkd 147:189–198. https:// olism of pathogenic trypanosomes. Antioxid Redox Signal doi.org/10.1016/S0003 -9365(96)80033 -9 19:708–722. https ://doi.org/10.1089/ars.2012.4932 206. Lang BF, Burger G, O’Kelly CJ et al (1997) An ancestral mito- 190. Manta B, Pavan C, Sturlese M et al (2013) Iron–sulfur cluster chondrial DNA resembling a eubacterial genome in miniature. binding by mitochondrial monothiol glutaredoxin-1 of Trypa- Nature 387:493–497. https ://doi.org/10.1038/38749 3a0 nosoma brucei: molecular basis of iron–sulfur cluster coordina- 207. Lara E, Chatzinotas A, Simpson AGB (2006) Andalucia (n. tion and relevance for parasite infectivity. Antioxid Redox Signal gen.)-the deepest branch within jakobids (Jakobida; Excavata), 19:665–682. https ://doi.org/10.1089/ars.2012.4859 based on morphological and molecular study of a new flagellate 191. Pánek T, Čepička I (2012) Diversity of heterolobosea. Genet from soil. J Eukaryot Microbiol 53:112–120. https ://doi.org/10. Divers Microorg. https ://doi.org/10.5772/35333 1111/j.1550-7408.2005.00081 .x 192. De Jonckheere JF, Baumgartner M, Opperdoes FR, Stetter KO 208. He D, Fu C-J, Baldauf SL (2015) Multiple origins of eukaryotic (2009) Marinamoeba thermophila, a new marine heterolobosean cox15 suggest horizontal gene transfer from bacteria to jakobid amoeba growing at 50 °C. Eur J Protistol 45:231–236. https :// mitochondrial DNA. Mol Biol Evol 33:122–133. https ://doi. doi.org/10.1016/j.ejop.2009.01.001org/10.1093/molbe v/msv20 1 193. Park JS, Simpson AGB, Lee WJ, Cho BC (2007) Ultrastructure 209. Burger G, Gray MW, Forget L, Lang BF (2013) Strikingly bacte- and phylogenetic placement within Heterolobosea of the previ- ria-like and gene-rich mitochondrial genomes throughout jakobid ously unclassified, extremely halophilic heterotrophic flagellate protists. Genome Biol Evol 5:418–438. https ://doi.org/10.1093/ Pleurostomum flabellatum (Ruinen 1938). Ann Anat 158:397–gbe/evt00 8 413. https ://doi.org/10.1016/j.proti s.2007.03.004 210. Leger MM, Eme L, Hug LA, Roger AJ (2016) Novel hydrogeno- 194. De Jonckheere JF (2006) Isolation and molecular identification somes in the microaerophilic jakobid Stygiella incarcerata. Mol of free-living amoebae of the genus Naegleria from Arctic and Biol Evol MSW. https ://doi.org/10.1093/molbe v/msw10 3 sub-Antarctic regions. Eur J Protistol 42:115–123. https ://doi. 211. Dolezal P, Dagley MJ, Kono M et al (2010) The essentials of org/10.1016/j.ejop.2006.02.001 protein import in the degenerate mitochondrion of Entamoeba 195. Park JS, Simpson AGB (2015) Diversity of heterotrophic protists histolytica. PLoS Pathog 6:e1000812. https ://doi.org/10.1371/ from extremely hypersaline habitats. Ann Anat 166:422–437. journ al.ppat.10008 12 https ://doi.org/10.1016/j.proti s.2015.06.001 212. Rada P, Makki AR, Zimorski V et al (2015) N-terminal pre- 196. Geisen S, Bonkowski M, Zhang J, De Jonckheere JF (2015) sequence-independent import of phosphofructokinase into Heterogeneity in the genus Allovahlkampfia and the description hydrogenosomes of Trichomonas vaginalis. Eukaryot Cell of the new genus Parafumarolamoeba (Vahlkampfiidae; Heter - 14:1264–1275. https ://doi.org/10.1128/EC.00104 -15 olobosea). Eur J Protistol 51:335–349. https://doi.or g/10.1016/j. 213. Garg S, Stölting J, Zimorski V et al (2015) Conservation of tran- ejop.2015.05.003 sit peptide-independent protein import into the mitochondrial and 197. Baumgartner M, Eberhardt S, De Jonckheere JF, Stetter KO hydrogenosomal matrix. Genome Biol Evol 7:2716–2726. https (2009) Tetramitus thermacidophilus n. sp., an amoeboflagellate ://doi.org/10.1093/gbe/evv17 5 from acidic hot springs. J Eukaryot Microbiol 56:201–206. https 214. Xu F, Jerlström-Hultqvist J, Einarsson E et al (2014) The genome ://doi.org/10.1111/j.1550-7408.2009.00390 .x of Spironucleus salmonicida highlights a fish pathogen adapted 198. Visvesvara GS, Sriram R, Qvarnstrom Y et al (2009) Paravahl- to fluctuating environments. PLoS Genet 10:e1004053. https :// kampfia francinae n. sp. masquerading as an agent of primary doi.org/10.1371/journ al.pgen.10040 53 amoebic meningoencephalitis. J Eukaryot Microbiol 56:357– 215. Zhang Q, Táborský P, Silberman JD et al (2015) Marine iso- 366. https ://doi.org/10.1111/j.1550-7408.2009.00410 .x lates of Trimastix marina form a plesiomorphic deep-branching 199. O’Kelly CJ, Silberman JD, Amaral Zettler LA et al (2003) Mono- lineage within Preaxostyla, separate from other known trimas- pylocystis visvesvarai n. gen., n. sp. and Sawyeria marylandensis tigids (Paratrimastix n. gen.). Protist 166:468–491. https ://doi. n. gen., n. sp.: two new amitochondrial heterolobosean amoebae org/10.1016/j.proti s.2015.07.003 from anoxic environments. Ann Anat 154:281–290. https ://doi. 216. Tovar J, León-Avila G, Sánchez LB et al (2003) Mitochondrial org/10.1078/14344 61033 22166 563 remnant organelles of Giardia function in iron–sulphur protein 200. Barbera MJ, Ruiz-Trillo I, Tufts JYA et al (2010) Sawyeria mar- maturation. Nature 426:172–176. https ://doi.org/10.1038/natur ylandensis (Heterolobosea) has a hydrogenosome with novel e0194 5 217. Rada P, Smid O, Sutak R et al (2009) The monothiol single- metabolic properties. Eukaryot Cell 9:1913–1924. https://d oi. domain glutaredoxin is conserved in the highly reduced org/10.1128/EC.00122 -10 1 3 JBIC Journal of Biological Inorganic Chemistry (2018) 23:521–541 541 mitochondria of Giardia intestinalis. Eukaryot Cell 8:1584– hydrogenosomes. Antimicrob Agents Chemother 58:3224–3232. 1591. https ://doi.org/10.1128/EC.00181 -09https ://doi.org/10.1128/AAC.02320 -13 218. Dolezal P, Šmid O, Rada P et al (2005) Giardia mitosomes and 233. Ferry JG (1997) Enzymology of the fermentation of acetate to trichomonad hydrogenosomes share a common mode of protein methane by Methanosarcina thermophila. BioFactors 6:25–35 targeting. Proc Natl Acad Sci USA 102:10924–10929. https :// 234. Zhao T, Cruz F, Ferry JG (2001) Iron–sulfur flavoprotein (Isf) doi.org/10.1073/pnas.05003 49102 from Methanosarcina thermophila is the prototype of a widely 219. Jedelský PL, Dolezal P, Rada P et al (2011) The minimal distributed family. J Bacteriol 183:6225–6233. https ://doi. proteome in the reduced mitochondrion of the parasitic pro- org/10.1128/JB.183.21.6225-6233.2001 tist Giardia intestinalis. PLoS One 6:e17285. https ://doi. 235. Hampl V, Silberman JD, Stechmann A et al (2008) Genetic evi- org/10.1371/journ al.pone.00172 85 dence for a mitochondriate ancestry in the “amitochondriate” 220. Rout S, Zumthor JP, Schraner EM et al (2016) An interactome- flagellate Trimastix pyriformis. PLoS One 3:e1383. https ://doi. centered protein discovery approach reveals novel components org/10.1371/journ al.pone.00013 83 involved in mitosome function and homeostasis in Giardia lam- 236. Kurihara T, Mihara H, Kato S-I et al (2003) Assembly of iron– blia. PLoS Pathog 12:e1006036. https ://doi.org/10.1371/journ sulfur clusters mediated by cysteine desulfurases, IscS, CsdB and al.ppat.10060 36 CSD, from Escherichia coli. Biochim Biophys Acta 1647:303– 221. Regoes A, Zourmpanou D, León-Avila G et al (2005) Protein 309. https ://doi.org/10.1016/S1570 -9639(03)00078 -5 import, replication, and inheritance of a vestigial mitochondrion. 237. Loiseau L, Gerez C, Bekker M et al (2007) ErpA, an iron sulfur J Biol Chem 280:30557–30563. https ://doi.or g/10.1074/jbc. (Fe S) protein of the A-type essential for respiratory metabolism M5007 87200 in Escherichia coli. Proc Natl Acad Sci USA 104:13626–13631. 222. Jerlström-Hultqvist J, Einarsson E, Xu F et al (2013) Hydrogeno-https ://doi.org/10.1073/pnas.07058 29104 somes in the diplomonad Spironucleus salmonicida. Nat Com- 238. Lu J, Yang J, Tan G, Ding H (2008) Complementary roles of mun 4:2493. https ://doi.org/10.1038/ncomm s3493 SufA and IscA in the biogenesis of iron–sulfur clusters in Escher- 223. Millet COM, Cable J, Lloyd D (2010) The diplomonad ichia coli. Biochem J 409:535–543. h tt p s : // d oi .o r g / 10 . 10 42 / fish parasite Spironucleus vortens produces hydrogen. J BJ200 71166 Eukaryot Microbiol 57:400–404. https ://doi.or g/10.111 239. Jensen LT, Culotta VC (2000) Role of Saccharomyces cerevisiae 1/j.1550-7408.2010.00499 .x ISA1 and ISA2 in iron homeostasis. Mol Cell Biol 20:3918–3927 224. Horváthová L, Šafaříková L, Basler M et al (2012) Transcrip- 240. Johnson DC, Unciuleac MC, Dean DR (2006) Controlled tomic identification of iron-regulated and iron-independent expression and functional analysis of iron–sulfur cluster biosyn- gene copies within the heavily duplicated Trichomonas vagi- thetic components within Azotobacter vinelandii. J Bacteriol nalis genome. Genome Biol Evol 4:1017–1029. https ://doi. 188:7551–7561. https ://doi.org/10.1128/JB.00596 -06 org/10.1093/gbe/evs07 8 241. Boyd ES, Thomas KM, Dai Y et al (2014) Interplay between oxy- 225. Beltrán NC, Horváthová L, Jedelský PL et al (2013) Iron-induced gen and Fe–S cluster biogenesis: insights from the Suf pathway. changes in the proteome of Trichomonas vaginalis hydrogeno- Biochemistry 53:5834–5847. https://doi.or g/10.1021/bi500488r somes. PLoS One 8:e65148. https ://doi.or g/10.1371/jour n 242. Riboldi GP, Larson TJ, Frazzon J (2011) Enterococcus faeca- al.pone.00651 48 lis sufCDSUB complements Escherichia coli sufABCDSE. 226. Gorrell TE (1985) Effect of culture medium iron content on the FEMS Microbiol Lett 320:15–24. https ://doi.or g/10.111 biochemical composition and metabolism of Trichomonas vagi-1/j.1574-6968.2011.02284 .x nalis. J Bacteriol 161:1228–1230 243. Riboldi GP, Verli H, Frazzon J (2009) Structural studies of the 227. Figueroa-Angulo E, Calla-Choque J, Mancilla-Olea M, Arroyo R Enterococcus faecalis SufU [Fe–S] cluster protein. BMC Bio- (2015) RNA-binding proteins in Trichomonas vaginalis: atypical chem 10:3–10. https ://doi.org/10.1186/1471-2091-10-3 multifunctional proteins. Biomolecules 5:3354–3395. https://doi. 244. Xu XM, Møller SG (2004) AtNAP7 is a plastidic SufC-like org/10.3390/biom5 04335 4 ATP-binding cassette/ATPase essential for Arabidopsis embryo- 228. Clemens DL, Johnson PJ (2000) Failure to detect DNA in genesis. Proc Natl Acad Sci USA 101:9143–9148. https ://doi. hydrogenosomes of Trichomonas vaginalis by nick translation org/10.1073/pnas.04007 99101 and immunomicroscopy. Mol Biochem Parasitol 106:307–313. 245. Xu XM, Adams S, Chua N-H, Møller SG (2005) AtNAP1 rep- https ://doi.org/10.1016/S0166 -6851(99)00220 -0 resents an atypical SufB protein in Arabidopsis plastids. J Biol 229. Dolezal P, Dancis A, Lesuisse E et al (2007) Frataxin, a con- Chem 280:6648–6654. https://doi.or g/10.1074/jbc.M413082200 served mitochondrial protein, in the hydrogenosome of Trich- 246. Møller SG, Kunkel T, Chua NH (2001) A plastidic ABC protein omonas vaginalis. Eukaryot Cell 6:1431–1438. https ://doi. involved in intercompartmental communication of light signal- org/10.1128/EC.00027 -07 ing. Genes Dev 15:90–103. https ://doi.org/10.1101/gad.85010 1 230. Sutak R, Dolezal P, Fiumera HL et al (2004) Mitochondrial-type 247. Romsang A, Duang-Nkern J, Leesukon P et al (2014) The iron– assembly of FeS centers in the hydrogenosomes of the amito- sulphur cluster biosynthesis regulator IscR contributes to iron chondriate eukaryote Trichomonas vaginalis. Proc Natl Acad homeostasis and resistance to oxidants in Pseudomonas aer- Sci USA 101:10368–10373. https://doi.or g/10.1073/pnas.04013 uginosa. PLoS One 9:e86763. https ://doi.or g/10.1371/jour n 19101 al.pone.00867 63 231. Schneider RE, Brown MT, Shiflett AM et al (2011) The Tricho- 248. van der Gulik PTS, Hoff WD, Speijer D (2017) In defence of the monas vaginalis hydrogenosome proteome is highly reduced three-domains of life paradigm. BMC Evol Biol 17:218. https :// relative to mitochondria, yet complex compared with mito-doi.org/10.1186/s1286 2-017-1059-z somes. Int J Parasitol 41:1421–1434. https ://doi.org/10.1016/j. 249. Embley TM (2006) Multiple secondary origins of the anaero- ijpar a.2011.10.001 bic lifestyle in eukaryotes. Philos Trans R Soc Lond B Biol Sci 232. Smutná T, Pilarová K, Tarábek J et al (2014) Novel functions 361:1055–1067. https ://doi.org/10.1098/rstb.2006.1844 of an iron–sulfur flavoprotein from Trichomonas vaginalis 1 3
JBIC Journal of Biological Inorganic Chemistry – Springer Journals
Published: Apr 5, 2018
It’s your single place to instantly
discover and read the research
that matters to you.
Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.
All for just $49/month
Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly
Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.
All the latest content is available, no embargo periods.
“Whoa! It’s like Spotify but for academic articles.”@Phil_Robichaud