Activation of mitogen-activated protein kinase by protein kinase C isotypes alpha, beta I and gamma, but not epsilon.
Treatment of CHO.T cells with either PMA or insulin led to the activation of MAP kinase by approximately 3-fold, and p90rsk by approximately 4-fold. Over-expression of the alpha, beta I or gamma isoforms of protein kinase C caused a substantial enhancement of the effect of PMA on the activation of MAP kinase and p90rsk, however, the effect of insulin was unchanged. Over-expression of the epsilon isoform of protein kinase C did not alter the effect of either PMA or insulin on the activation of MAP kinase and p90rsk. The results suggest that protein kinase C isotypes, alpha, beta I and gamma, but not epsilon, can mediate MAP kinase activation by PMA, and strongly support the hypothesis that protein kinase C isoforms can initiate distinct signalling pathways.
Young
S W
SW
Department of Biochemistry, School of Medical Sciences, University of Bristol, UK.
Dickens
M
M
Tavaré
J M
JM
D000818:Animals; D016466:CHO Cells; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D006224:Cricetinae; D004789:Enzyme Activation / Q000187:drug effects; D004790:Enzyme Induction; D006801:Humans; D007328:Insulin / Q000494:pharmacology; D007527:Isoenzymes / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D019893:Ribosomal Protein S6 Kinases; D015398:Signal Transduction / Q000187:drug effects; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D007328:Insulin; D007527:Isoenzymes; D011994:Recombinant Proteins; D017346:Protein Serine-Threonine Kinases; D019893:Ribosomal Protein S6 Kinases; D011493:Protein Kinase C; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D013755:Tetradecanoylphorbol Acetate