Endothelin-1, phorbol esters and phenylephrine stimulate MAP kinase activities in ventricular cardiomyocytes.
ET-1 stimulated MBP kinase activity in cultured cardiomyocytes. Maximal activation (3.5-fold) was at 5 min. EC50 was 0.2 nM. PMA or PE also increased MBP kinase (4- or 2.5-fold, respectively). Pre-treatment with PMA down-regulated the subsequent response to ET-1 or PMA. ET-1- or PMA-stimulated MBP kinase was resolved into 2 major (peaks II and IV) and 2 minor peaks by FPLC on Mono Q. Peaks II and IV were inactivated by either LAR or PP2A. Renatured MBP kinase activities following SDS-PAGE in MBP-containing gels and immunoblot analysis showed that peak II was a p42 MAP kinase and peak IV was a p44 MAP kinase.
Department of Cardiac Medicine, National Heart and Lung Institute, University of London, UK.
M A
MA
Bogoyevitch
P E
PE
Glennon
P H
PH
Sugden
D000595:Amino Acid Sequence; D000818:Animals; D000831:Animals, Newborn; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D006332:Cardiomegaly / Q000201:enzymology; D002478:Cells, Cultured; D002853:Chromatography, Liquid / Q000379:methods; D004195:Disease Models, Animal; D016232:Endothelins / Q000494:pharmacology*; D004789:Enzyme Activation; D038362:Glycogen Synthase Kinase 3; D008969:Molecular Sequence Data; D009206:Myocardium / Q000201:enzymology*; D010656:Phenylephrine / Q000494:pharmacology*; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D011494:Protein Kinases / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
D016232:Endothelins; D010656:Phenylephrine; D011494:Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D038362:Glycogen Synthase Kinase 3; D010749:Phosphoprotein Phosphatases; D013755:Tetradecanoylphorbol Acetate