title: Endogenous substrates of rat heart protein kinase C type I, II, and III isozymic forms in cardiac sarcolemma.
abstract: The endogenous substrate proteins of rat cardiac protein kinase C type I, II, and III isozymic forms were studied in rat cardiac sarcolemma. The 19-, 21-, 29-, 35-, and 95-kDa proteins were phosphorylated by both types II and III, but not type I. The extent of phosphorylation by individual protein kinase C isozymic forms was additive and equal to the extent of phosphorylation observed when a mixture of isozymic forms was employed. The extent of phosphorylation of the 21-kDa protein by type III was much higher than that by type II. These results suggest that the protein kinase C isozymes have preferences for specific endogenous substrate proteins. The phosphorylation of these endogenous substrate proteins by protein kinase C isozymes probably plays a role in cardiac cell functions.
authors.affiliation: Department of Pharmacology, Faculty of Medicine, University of Toronto, Ont., Canada.
authors.forename: Y
authors.initials: Y
authors.lastname: Qu
authors.forename: J
authors.initials: J
authors.lastname: Torchia
authors.forename: T D
authors.initials: TD
authors.lastname: Phan
authors.forename: P H
authors.initials: PH
authors.lastname: Wu
authors.forename: A K
authors.initials: AK
authors.lastname: Sen
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology; D004075:Diglycerides / Q000494:pharmacology; D006352:Heart Ventricles / Q000201:enzymology; D007527:Isoenzymes; D008565:Membrane Proteins / Q000378:metabolism; D009206:Myocardium / Q000201:enzymology*; D010718:Phosphatidylserines / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D012508:Sarcolemma / Q000201:enzymology*; D013379:Substrate Specificity
chemical_list: D004075:Diglycerides; D007527:Isoenzymes; D008565:Membrane Proteins; D010718:Phosphatidylserines; D011493:Protein Kinase C; D002118:Calcium