Insulin increases membrane protein kinase C activity in rat diaphragm.
Calcium/phospholipid-dependent protein kinase activity (protein kinase C) was identified in rat diaphragm membrane and cytosol fractions by means of in vitro phosphorylation either of histones or of a specific 87 kDa protein substrate, combined with phosphopeptide-mapping techniques. Both insulin and tumor-promoting phorbol ester treatment of the diaphragm preparations led to increased protein kinase C activity in the membrane fractions. In contrast to the phorbol ester, however, insulin did not induce a concomitant decrease in cytosolic activity, indicating that translocation of the enzyme had not taken place. Thus, insulin appears to increase specifically membrane protein kinase C activity in rat skeletal muscle, possibly through a mechanism not identical to that induced by phorbol esters.
D000818:Animals; D003600:Cytosol / Q000378:metabolism; D003964:Diaphragm / Q000201:enzymology*; D004789:Enzyme Activation / Q000187:drug effects; D066298:In Vitro Techniques; D007328:Insulin / Q000494:pharmacology*; D006656:Protamine Kinase / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D012508:Sarcolemma / Q000201:enzymology*; D012519:Sarcoplasmic Reticulum / Q000201:enzymology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D007328:Insulin; D006656:Protamine Kinase; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate