Protein kinase C promotes arachidonate mobilization through enhancement of CoA-independent transacylase activity in platelets.
A role for protein kinase C in arachidonate mobilization was demonstrated. Treatment of rat platelets with phorbol myristate acetate (PMA) or the diacylglycerol 1-oleoyl-2-acetylglycerol increased the transfer rate of arachidonate (AA) from phosphatidylcholine to phosphatidylethanolamine and stimulated AA release. The transfer dose-dependently induced by PMA was inhibited by staurosporine. Ether phospholipids were the acceptors of AA in these stimulated transfer reactions. Membrane-bound protein kinase C activity was enhanced by PMA, and this increase was inhibited by staurosporine. AA transfer between phospholipids is due to the action of polyunsaturated-fatty-acid-specific transacylases. For this purpose, transacylase activities were assayed in cell-free systems from PMA-treated platelets. We observed that the CoA-independent transacylase activity was modulated in parallel to AA transfer as a function of PMA concentration. Taken together, the data show that protein kinase C activation might promote the mobilization of AA in platelets through the enhancement of CoA-independent transacylase activity.
Breton
M
M
URA 1283 CNRS, CHU Saint-Antoine, Paris, France.
Colard
O
O
D000214:Acyl Coenzyme A / Q000097:blood*; D000217:Acyltransferases / Q000097:blood*; D000470:Alkaloids / Q000494:pharmacology; D000818:Animals; D016718:Arachidonic Acid / Q000097:blood*; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism*; D003065:Coenzyme A / Q000494:pharmacology; D004075:Diglycerides / Q000494:pharmacology; D007700:Kinetics; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000097:blood*; D051381:Rats; D011919:Rats, Inbred Strains; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D000214:Acyl Coenzyme A; D000470:Alkaloids; D004075:Diglycerides; D016718:Arachidonic Acid; C038237:1-oleoyl-2-acetylglycerol; D000217:Acyltransferases; D011493:Protein Kinase C; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate; D003065:Coenzyme A