The ubiquitin pathway targets proteins for degradation through the post-translational covalent attachment of the 76 amino acid protein ubiquitin to ∈-amino lysyl groups on substrate proteins. Two instability determinants recognized by the ubiquitin pathway in Saccharomyces cerevisiae have been identified. One is described by the N-end rule and requires specific destabilizing residues at the substrate protein N-termini along with a proximal lysyl residue for ubiquitin conjugation. The second is a linear uncleavable N-terminal ubiquitin moiety. The ability of these two determinants to function in higher plants was investigated in tobacco protoplast transient transfection assays using DNA encoding variants of well characterized reporter enzymes as substrates: firefly luciferase that is localized to peroxisomes (pxLUC), a cytosolic version of LUC (cLUC), and Escherichia coli β-glucuronidase (GUS). cLUC with phenylalanine encoded at its mature N-terminus was 10-fold less abundant than cLUC with methionine at its mature N-terminus. GUS with phenylalanine encoded at its mature N-terminus was 3-fold less abundant than GUS with methionine at its mature N-terminus. The presence of a uncleavable N-terminal ubiquitin fusion resulted in 50-fold lower protein accumulation of cLUC, but had no effect on GUS. Both instability determinants had a much larger effect on cLUC than on pxLUC, suggesting that these degradation signals are either unrecognized or poorly recognized in the peroxisomes.
Plant Molecular Biology – Springer Journals
Published: Oct 6, 2004
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.
Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.
Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.
All the latest content is available, no embargo periods.
“Hi guys, I cannot tell you how much I love this resource. Incredible. I really believe you've hit the nail on the head with this site in regards to solving the research-purchase issue.”Daniel C.
“Whoa! It’s like Spotify but for academic articles.”@Phil_Robichaud
“I must say, @deepdyve is a fabulous solution to the independent researcher's problem of #access to #information.”@deepthiw
“My last article couldn't be possible without the platform @deepdyve that makes journal papers cheaper.”@JoseServera