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. 2013 Sep;18(3):447-58.
doi: 10.2478/s11658-013-0099-7. Epub 2013 Jul 27.

The NTPase/helicase domain of hepatitis C virus nonstructural protein 3 inhibits protein kinase C independently of its NTPase activity

Philip Hartjen  1 , Bastian Höchst, Denise Heim, Henning von der Kammer, Judith Lucke, Michael Reinholz, Andrea Baier, Ralf Smeets, Henning Wege, Peter Borowski, Julian Schulze Zur Wiesch
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The NTPase/helicase domain of hepatitis C virus nonstructural protein 3 inhibits protein kinase C independently of its NTPase activity

Philip Hartjen et al. Cell Mol Biol Lett. 2013 Sep.

Abstract

Helicase motif VI is a short arginine-rich motif within the NTPase/helicase domain of the non-structural protein 3 (NS3) of the hepatitis C virus (HCV). We previously demonstrated that it reduces the catalytic activity and intracellular shuttling of protein kinase C (PKC). Thus, NS3-mediated PKC inhibition may be involved in HCV-associated hepatocellular carcinoma (HCC). In this study, we expand on our earlier results, which were obtained in experiments with short fragments of NS3, to show for the first time that the catalytically active, longer C-terminal NTPase/helicase of NS3 acts as a potent PKC inhibitor in vitro. PKC inhibition assays with the NTPase-inactive mutant NS3h-D1316A revealed a mixed type kinetic inhibition pattern. A broad range of 11 PKC isotypes was tested and all of the PKC isotypes were inhibited with IC₅₀-values in the low micromolar range. These findings were confirmed for the wild-type NTPase/helicase domain in a non-radiometric PKC inhibition assay with ATP regeneration to rule out any effect of ATP hydrolysis caused by its NTPase activity. PKCα was inhibited with a micromolar IC₅₀ in this assay, which compares well with our result for NS3h-D1316A (IC₅₀ = 0.7 μM). In summary, these results confirm that catalytically active NS3 NTPase/helicase can act in an analogous manner to shorter NS3 fragments as a pseudosubstrate inhibitor of PKC.

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References

    1. El-Serag HB, Rudolph KL. Hepatocellular carcinoma: epidemiology and molecular carcinogenesis. Gastroenterology. 2007;132:2557–2576. doi: 10.1053/j.gastro.2007.04.061. - DOI - PubMed
    1. Borowski P, Heiland M, Oehlmann K, Becker B, Kornetzky L, Feucht H, Laufs R. Non-structural protein 3 of hepatitis C virus inhibits phosphorylation mediated by cAMP-dependent protein kinase. Eur. J. Biochem. 1996;237:611–618. doi: 10.1111/j.1432-1033.1996.0611p.x. - DOI - PubMed
    1. Borowski P, Resch K, Schmitz H, Heiland M. A synthetic peptide derived from the non-structural protein 3 of hepatitis C virus serves as a specific substrate for PKC. Biol. Chem. 2000;381:19–27. doi: 10.1515/BC.2000.003. - DOI - PubMed
    1. Borowski P, Kuhl R, Laufs R, Schulze zur Wiesch J, Heiland M. Identification and characterization of a histone binding site of the nonstructural protein 3 of hepatitis C virus. J. Clin. Virol. 1999;13:61–69. doi: 10.1016/S1386-6532(99)00007-4. - DOI - PubMed
    1. Borowski P, Schulze zur Wiesch J, Resch K, Feucht H, Laufs R, Schmitz H. Protein kinase C recognizes the protein kinase A-binding motif of nonstructural protein 3 of hepatitis C virus. J. Biol. Chem. 1999;274:30722–30728. doi: 10.1074/jbc.274.43.30722. - DOI - PubMed

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