Abnormal behavior of protein kinase C in the human myeloma cell line, RPMI 8226.
Protein kinase C activity of the human myeloma cell line, RPMI 8226, was studied after prepurification on DEAE-cellulose. The total protein kinase activity, eluted at 0.12 M NaCl, was 493 nmol/min/10(10) cells, but 38% was associated with membranes. The lipid dependence of cytosolic and membrane activities was only 52% and 21%, respectively. This activity increased with time, to as much as 200% for the membrane fraction after 7 days, whereas lipid dependence and the PDBu binding properties were lost. This modified activity was not due to the extinction of a copurifying endogenous inhibitor nor to classical PKC proteolysis. TPA-treatment of these cels is accompanied by a rapid, selective and complete loss of lipid-dependent activity of the cytosol, thus benefiting co-migrating lipid independent activity, with no membrane fraction recovery or PKM formation.
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CNRS URA 530, Interactions membranaires, Université Montpellier II, France.
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D000818:Animals; D001921:Brain / Q000201:enzymology; D002458:Cell Fractionation; D002460:Cell Line; D002462:Cell Membrane / Q000201:enzymology; D002848:Chromatography, DEAE-Cellulose; D003600:Cytosol / Q000201:enzymology; D006801:Humans; D007700:Kinetics; D009101:Multiple Myeloma / Q000201:enzymology; D015240:Phorbol 12,13-Dibutyrate / Q000378:metabolism; D011485:Protein Binding; D011493:Protein Kinase C / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013997:Time Factors
D015240:Phorbol 12,13-Dibutyrate; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate