Regulation of membrane-bound PKC in adult cardiac ventricular myocytes.
Activation of protein kinase C (PKC) is thought to involve translocation to the particulate fraction. The present study demonstrates a membrane-associated, inactive pool of PKC in adult rat ventricular myocytes. Membranes were isolated from stimulated (phorbol 12-myristate 13-acetate (PMA), endothelin-1 (ET-1)) or control myocytes and PKC activity determined in the absence (active PKC) or presence (total PKC) of PMA. An inactive, PMA-responsive, pool of PKC was detected. In intact myocytes, PMA or ET-1 induced a translocation of PKC epsilon from the cytosol into the particulate fraction. In contrast, ET-1 decreased both total and active PKC in the membranes: this decrease was associated with a loss of PKC epsilon immunoreactivity. PMA increased the amount of membrane-associated, inactive PKC. Our results demonstrate the presence of a membrane-associated pool of PKC in cardiac myocytes that is differentially modulated by ET-1 or PMA.
Boivin
Benoit
B
Institut de Cardiologie de Montréal, Centre de Recherche, 5000 rue Bélanger est, H1T 1C8, Montreal, Quebec, Canada.
Allen
Bruce G
BG
D000367:Age Factors; D000818:Animals; D002273:Carcinogens / Q000494:pharmacology; D002462:Cell Membrane / Q000201:enzymology; D019332:Endothelin-1 / Q000494:pharmacology; D006352:Heart Ventricles / Q000166:cytology; D008297:Male; D032383:Myocytes, Cardiac / Q000201:enzymology*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D013379:Substrate Specificity; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D002273:Carcinogens; D019332:Endothelin-1; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate