title: Role of protein kinase C in transmembrane signaling.
abstract: Many extracellular signals elicit Ca2+ mobilization and diacylglycerol formation in their target cells. Diacylglycerol is derived from the receptor-linked phosphoinositide turnover and serves as a second messenger for the activation of protein kinase C in the presence of Ca2+ and phosphatidylserine. Unique diacylglycerols such as 1-oleoyl-2-acetyl-glycerol, which activate intracellular protein kinase C when added to intact cells, have been synthesized. Tumor-promoting phorbol esters substitute for such diacylglycerols and directly activate protein kinase C in both intact cell and cell-free systems. Under appropriate conditions, the synthetic diacylglycerols and phorbol esters induce protein kinase C activation without Ca2+ mobilization, whereas Ca2+ ionophore A23187 induces Ca2+ mobilization without protein kinase C activation. Using these substances, we have obtained evidence that both protein C and Ca2+ are involved in and play a synergistic role in exocytosis, cell division, and other cellular functions. In this article, the role of protein kinase C in transmembrane signaling is discussed.
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000201:enzymology; D001921:Brain / Q000201:enzymology; D002118:Calcium / Q000494:pharmacology; D002450:Cell Communication; D002462:Cell Membrane / Q000201:enzymology; D004075:Diglycerides / Q000494:pharmacology; D004789:Enzyme Activation; D006728:Hormones / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D008214:Lymphocytes / Q000201:enzymology; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D013379:Substrate Specificity; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D004075:Diglycerides; D006728:Hormones; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium