Redistribution of protein kinase C during mitogenesis of human B lymphocytes.
G0 human tonsillar B-lymphocytes were stimulated to divide by the polyclonal mitogen Staphylococcus Aureus Cowan strain 1 (SAC) and by the combined use of 12-O-tetradecanoyl phorbol-13-acetate (TPA) and the calcium ionophore ionomycin. The activities of protein kinase C, which requires Ca++ and phospholipid as co-factors, and a proteolytically cleaved form of this enzyme (protein kinase M), which is independent of calcium and phospholipid control, were determined in soluble and particulate fractions obtained from activated B cells. Treatment of G0 B cells with SAC or TPA together with ionomycin caused redistribution of protein kinase C from the soluble to the particulate fraction where the 80,000-Dalton protein kinase C was cleaved to give rise to a 50,000-Dalton form of the kinase which was also found in the cytoplasm. These data suggest that redistribution and proteolytic cleavage of protein kinase C are key signal transduction events in B cell mitogenesis.
D001402:B-Lymphocytes / Q000201:enzymology* / Q000648:ultrastructure; D002154:Calpain / Q000378:metabolism; D002453:Cell Cycle; D003593:Cytoplasm / Q000201:enzymology; D004987:Ethers / Q000494:pharmacology; D006801:Humans; D015759:Ionomycin; D008213:Lymphocyte Activation; D008566:Membranes / Q000201:enzymology; D014066:Palatine Tonsil / Q000166:cytology; D011493:Protein Kinase C / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D004987:Ethers; D015759:Ionomycin; D011493:Protein Kinase C; D002154:Calpain; D013755:Tetradecanoylphorbol Acetate