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Selective impairment of protein kinase C isotypes in murine macrophage by Leismania donovani

Selective impairment of protein kinase C isotypes in murine macrophage by Leismania donovani Leishmania donovani, an obligate intracellular parasite resides and multiplies within macrophage of the reticuloendothelial system. The intracellular signalling mechanism involved in the impaired oxidative response in leishmaniasis has not yet been clearly established. Generation of superoxide anion (O2 –) is supposed to be the first line of host defence during microbial invasion. We found a substantial inhibition of superoxide anion generation in parasitized macrophages, which was just the reverse in case of macrophages challenged with Lipophosphoglycan (LPG) deficient attenuated leishmanial parasite UR-6. The generation of O2 – essentially needs the prior activation of protein kinase C (PKC) mediated phosphorylation events. Our study proposed that phosphorylation of 67, 54, 47 and 36 kDa proteins was attenuated during infection. This was supported by PKC activity study, where Ca-dependent PKC activity was inhibited but, Ca-independent PKC activity was enhanced. This result was further confirmed by using isotype specific pseudosubstrate inhibitors of Ca-dependent PKC β and Ca-independent PKC ζ. Application of β-pseudosubstrate could not alter the Ca-dependent PKC activity but ζ-pseudosubstrate inhibited the Ca-independent PKC activity in infected macrophages. Our immunoblot analysis with specific antibody against PKC β and PKC ζ isotypes showed down regulation of PKC β-II expression with concomitant induction of PKC ζ. Such inhibition of Ca-dependent PKC β was reversed in macrophages treated with UR-6. Taken together, our observations revealed that infection with L. donovani selectively attenuates both the expression and activity of Ca-dependent PKC β. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Molecular and Cellular Biochemistry Springer Journals

Selective impairment of protein kinase C isotypes in murine macrophage by Leismania donovani

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References (79)

Publisher
Springer Journals
Copyright
Copyright © 2001 by Kluwer Academic Publishers
Subject
Life Sciences; Cardiology; Medical Biochemistry; Oncology; Biochemistry, general
ISSN
0300-8177
eISSN
1573-4919
DOI
10.1023/A:1011048210691
Publisher site
See Article on Publisher Site

Abstract

Leishmania donovani, an obligate intracellular parasite resides and multiplies within macrophage of the reticuloendothelial system. The intracellular signalling mechanism involved in the impaired oxidative response in leishmaniasis has not yet been clearly established. Generation of superoxide anion (O2 –) is supposed to be the first line of host defence during microbial invasion. We found a substantial inhibition of superoxide anion generation in parasitized macrophages, which was just the reverse in case of macrophages challenged with Lipophosphoglycan (LPG) deficient attenuated leishmanial parasite UR-6. The generation of O2 – essentially needs the prior activation of protein kinase C (PKC) mediated phosphorylation events. Our study proposed that phosphorylation of 67, 54, 47 and 36 kDa proteins was attenuated during infection. This was supported by PKC activity study, where Ca-dependent PKC activity was inhibited but, Ca-independent PKC activity was enhanced. This result was further confirmed by using isotype specific pseudosubstrate inhibitors of Ca-dependent PKC β and Ca-independent PKC ζ. Application of β-pseudosubstrate could not alter the Ca-dependent PKC activity but ζ-pseudosubstrate inhibited the Ca-independent PKC activity in infected macrophages. Our immunoblot analysis with specific antibody against PKC β and PKC ζ isotypes showed down regulation of PKC β-II expression with concomitant induction of PKC ζ. Such inhibition of Ca-dependent PKC β was reversed in macrophages treated with UR-6. Taken together, our observations revealed that infection with L. donovani selectively attenuates both the expression and activity of Ca-dependent PKC β.

Journal

Molecular and Cellular BiochemistrySpringer Journals

Published: Oct 7, 2004

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