Activation of protein kinase C in neutrophil cytoplasts. Localization of protein substrates and possible relationship with stimulus-response coupling.
Treatment of enucleated, granule-free neutrophil cytoplasts with the protein kinase C activator phorbol 12-O-myristate-13-acetate (PMA) causes an increased 32P-incorporation into a variety of polypeptides. Permeabilization of PMA-stimulated, 32P-labeled cytoplasts by 0.01% digitonin fully releases the majority of these phosphorylated proteins. A statistically significant correlation is found between the extent of PMA-induced activation of generation of superoxide anion (O2-) and the phosphorylation of a cytosolic polypeptide with an apparent Mr of 46,000, whose 32P-labeling is also enhanced by the treatment of cytoplasts with 1-oleyl-2-acetylglycerol, the Ca2+ ionophore ionomycin or latex beads. Furthermore, treatment of cytoplasts with the protein kinase C inhibitor trifluoperazine markedly inhibits the 32P-labeling of proteins in the 40 000 Mr range, including the 46 kDa polypeptide, and almost totally abolishes the activation of O2- production by PMA.
Gennaro
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R
Florio
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C
Romeo
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D
D000818:Animals; D002417:Cattle; D004789:Enzyme Activation; D008970:Molecular Weight; D009504:Neutrophils / Q000187:drug effects / Q000201:enzymology*; D009940:Organoids / Q000201:enzymology; D010539:Permeability; D010766:Phosphorylation; D011493:Protein Kinase C; D011494:Protein Kinases / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014268:Trifluoperazine / Q000494:pharmacology
D011506:Proteins; D013481:Superoxides; D014268:Trifluoperazine; D011494:Protein Kinases; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate