Insulin activates myelin basic protein (p42 MAP) kinase by a protein kinase C-independent pathway in rat adipocytes. Dissociation from glucose transport.
Myelin basic protein kinase (MBPK) activity of rat adipocytes was measured directly or in gels after purification of p42 microtubule-associated protein kinase (MAPK). Insulin and phorbol esters provoked 2- to 3-fold increases in MBPK/MAPK activity within 5-10 min. Whereas phorbol ester effects were blocked by protein kinase C (PKC) depletion or inhibition, insulin effects were fully intact, indicating that insulin activates MBPK/MAPK independently of PKC. In contrast, PKC depletion or inhibition markedly inhibited insulin effects on [3H]2-deoxyglucose uptake, suggesting that this effect requires PKC, rather than a factor within the ras/MAPK cascade.
Yang
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J.A. Haley Veterans' Hospital, Tampa, FL.
Farese
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RV
D017667:Adipocytes / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000302:isolation & purification / Q000378:metabolism*; D002478:Cells, Cultured; D003600:Cytosol / Q000201:enzymology; D003847:Deoxyglucose / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D004822:Epididymis; D005947:Glucose / Q000378:metabolism*; D007328:Insulin / Q000494:pharmacology*; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000378:metabolism; D007700:Kinetics; D008297:Male; D008970:Molecular Weight; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051381:Rats; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D007328:Insulin; D007527:Isoenzymes; D003847:Deoxyglucose; D011493:Protein Kinase C; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D005947:Glucose; D013755:Tetradecanoylphorbol Acetate