Insulin but not phorbol ester treatment increases phosphorylation of vinculin by protein kinase C in BC3H‐1 myocytes

[摘要]

Insulin was found to increase protein kinase C activity in BC3H-1 myocytes as determined by in vitro phosphorylation of both a lysine-rich histone fraction (histone III-S) and vinculin. TPA treatment for 20 min or 18 h provoked an apparent loss of histone-directed but not vinculin-directed phosphorylation by cytosolic C-kinase. Thus, chronic TPA-induced ‘desensitization’ or ‘depletion’ of cellular protein kinase C is more apparent than real, and is not a valid means for evaluating the role of C-kinase in hormone action.

[学科分类] 生物化学/生物物理

[关键词] Insulin;Phorbol ester;Protein kinase C;TPA;12-O-tetradecanoyl phorbol-13-acetate;PMSF;phenylmethylsulfonyl fluoride;BSA;bovine serum albumin;PS;phosphatidylserine