Inhibition of neutrophil NADPH oxidase assembly by a myristoylated pseudosubstrate of protein kinase C

Verhoeven, A.J., Leusen, J.H., Kessels, G.C., Hilarius, P.M., de Bont, D.B. and Liskamp, R.M.J. (1993) Inhibition of neutrophil NADPH oxidase assembly by a myristoylated pseudosubstrate of protein kinase C. Journal of Biological Chemistry, 268(25), pp. 18593-8.

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Publisher's URL: http://www.jbc.org/content/268/25/18593.abstract

Abstract

To further define the role played by protein kinase C (PKC) in the activation of the neutrophil NADPH oxidase, we have utilized a pseudosubstrate of PKC which was myristoylated at the N terminus. In electropermeabilized neutrophils, the myristoylated pseudosubstrate Phe-Ala-Arg-Lys-Gly-Ala-Leu-Arg-Gln (myr-psi PKC) inhibited PMA-induced protein phosphorylations and activation of the NADPH oxidase, induced either by PMA or by the receptor agonist formyl-methionyl-leucyl-phenylalanine. Both the pseudosubstrate lacking the N-terminal myristate (psi PKC) and a myristoylated control peptide (Phe-Ala-Glu-Asp-Gly-Ala-Leu-Glu-Gln, myr-CP) were without effect on these responses. The myristoylated pseudosubstrate was also tested in a cell-free system, in which NADPH oxidase activation can be achieved by addition of SDS and guanosine 5'-3-O-(thio)triphosphate in a staurosporine-insensitive manner. Myr-psi PKC, but not psi PKC or myr-CP, proved to be a potent inhibitor of NADPH oxidase activity in the cell-free system, indicating that the inhibition observed in permeabilized neutrophils may have been caused by an effect other than PKC inhibition. In the presence of myr-psi PKC, translocation in the cell-free system of the cytosolic oxidase components p47-phox and p67-phox to the plasma membrane was inhibited. From these results we conclude that myristoylation profoundly increases the ability of pseudosubstrates of PKC to inhibit not only PKC-mediated phosphorylations, but also NADPH oxidase activation. The latter effect, however, is most probably not related to PKC inhibition but may indicate a critical role of the membrane surface charge in the translocation of the cytosolic oxidase components p47-phox and p67-phox.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Liskamp, Professor Robert
Authors: Verhoeven, A.J., Leusen, J.H., Kessels, G.C., Hilarius, P.M., de Bont, D.B., and Liskamp, R.M.J.
College/School:College of Science and Engineering > School of Chemistry
Journal Name:Journal of Biological Chemistry
Publisher:American Society for Biochemistry and Molecular Biology, Inc.
ISSN:0021-9258
ISSN (Online):1083-351X

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