The role of protein kinase C in the stimulation of phosphatidylcholine synthesis by phospholipase C.
The role of protein kinase C in the stimulation of phosphatidylcholine (PC) synthesis by phospholipase C was investigated. Phospholipase C treatment of Chinese hamster ovary cells (CHO) generates diacylglycerol, which is an activator of protein kinase C. The protein kinase C activator, 12-O-tetradecanoyl-phorbol-13-acetate (TPA) stimulated choline incorporation into two CHO cell lines, a wild-type cell line, WTB, and a mutant cell line, DTG 1-5-4. DTG 1-5-4 is a mutant defective in receptor-mediated endocytosis. A 3-h phospholipase C treatment resulted in the activation and translocation of CTP:phosphocholine cytidylyltransferase in both cell lines. TPA treatment, however, resulted in only a slight (20%) translocation of cytidylyltransferase in WTB; no detectable translocation of cytidylyltransferase was observed in DTG 1-5-4. A decrease in the phosphocholine pools was observed in response to TPA treatment in both cell lines, which indicated that the cytidylyltransferase step was being activated. Phospholipase C stimulated choline incorporation into PC even when protein kinase C had been down-regulated in both cell lines. It was concluded that phospholipase C does not activate PC synthesis by activating protein kinase C.
Jones
G A
GA
Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907.
Kent
C
C
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002460:Cell Line; D002794:Choline / Q000378:metabolism; D006224:Cricetinae; D003412:Cricetulus; D003600:Cytosol / Q000378:metabolism; D004075:Diglycerides / Q000502:physiology; D005260:Female; D007700:Kinetics; D010053:Ovary; D010713:Phosphatidylcholines / Q000096:biosynthesis*; D011493:Protein Kinase C / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D010738:Type C Phospholipases / Q000378:metabolism*
D004075:Diglycerides; D010713:Phosphatidylcholines; D011493:Protein Kinase C; D010738:Type C Phospholipases; D002794:Choline; D013755:Tetradecanoylphorbol Acetate