Role of protein kinase C in calcium-mediated signal transduction.
Information from certain extracellular signals, including a group of peptide hormones and some neurotransmitters, appears to flow from the cell surface into the cell interior through two pathways, protein kinase C activation and Ca2+ mobilization, both of which become available by a single ligand-receptor interaction. Under normal conditions protein kinase C is activated by association with membrane phospholipids in the presence of 1,2-diacylglycerol. This diacylglycerol may arise in the membrane only transiently from the receptor-mediated hydrolysis of inositol phospholipids. By using a synthetic permeable diacylglycerol or tumour-promoting phorbol ester (as a substitute for active diacylglycerol) it has been shown that signal passage through this protein kinase pathway is an essential prerequisite, often synergistic to that via the Ca2+ pathway, for full physiological responses, such as transmitter release and exocytosis, to be obtained. Presumably, such a role of protein kinase C may be extrapolated to the activation of many other cellular processes, including membrane conductance, gene expression and some metabolic reactions, as well as to the modulation of other receptor-mediated signal pathways. Some morphological findings with monoclonal antibodies raised against protein kinase C are presented.
D000818:Animals; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D004075:Diglycerides / Q000494:pharmacology; D004789:Enzyme Activation; D008563:Membrane Lipids / Q000502:physiology; D010743:Phospholipids / Q000502:physiology; D011493:Protein Kinase C / Q000378:metabolism*; D013917:Thrombin / Q000502:physiology
D004075:Diglycerides; D008563:Membrane Lipids; D010743:Phospholipids; D011493:Protein Kinase C; D013917:Thrombin; D002118:Calcium