The phosphatidylcholine pathway of diacylglycerol formation stimulated by phorbol diesters occurs via phospholipase D activation

• Published in: FEBS letters 1988-06, Vol.233 (1), p.153-157
• Main Authors: Cabot, Myles C., Welsh, Clement J., Cao, Hui-ting, Chabbott, Holly
• Format: Article
• Language: English
• Subjects: Analytical, structural and metabolic biochemistry; Animals; Biological and medical sciences; BSA, bovine serum albumin; Cell Line; Choline - metabolism; DG, diacylglycerol; Diacylglycerol; Diglycerides - biosynthesis; Embryo, Mammalian; Enzyme Activation; Fundamental and applied biological sciences. Psychology; Glycerides - biosynthesis; Kinetics; Lipids; Myristic Acid; Myristic Acids - metabolism; Other biological molecules; PA, phosphatidate; PC, phosphatidylcholine; phorbol 12-myristate 13-acetate diester; Phorbol diester; Phorbol Esters - pharmacology; Phosphatidic Acids - biosynthesis; Phosphatidylcholine; Phosphatidylcholines - metabolism; Phospholipase D; Phospholipase D - metabolism; Phospholipases - metabolism; PIP2, phosphatidylinositol 4,5-bisphosphate; PKC, Ca2+-activated, phospholipid-dependent protein kinase C; Propranolol - pharmacology; Protein Kinase C - metabolism; Rats; REF52 cell; Tetradecanoylphorbol Acetate - pharmacology; TLC, thin-layer chromatography. In the naming of PC, PA and DG we do not distinguish between the type of aliphatic linkage to glycerol (ester, ether); TPA,12-O-tetradecanoylphorbol-13-acetate; Vasopressin; Vasopressins - pharmacology; VP, vasopressin
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/0014-5793(88)81374-7

Agonist-induced degradation of phosphatidylcholine (PC) is of interest as this pathway of diacylglycerol (DG) generation may provide added opportunities for the regulation of protein kinase C (PKC). In REF52 cells [ 3H]myristic acid is preferentially incorporated into PC; this, coupled with the use of [ 3H]choline, allows for quantitation of both the water-soluble and the lipid products generated when PC is degraded. In cells prelabeled with [ 3H]choline, TPA stimulated a time-dependent release, into the medium, of choline and not phosphocholine or glycerophosphocholine. Treatment of [ 3H]myristic acid-labeled cells with either phorbol diesters, sn-1,2-dioctanoylglycerol, or vasopressin elicited the formation of labeled phosphatidate (PA) and DG. The temporal pattern of PC hydrolysis in cells treated with TPA is indicative of a precursor (PA)-product (DG) relationship for an enzymatic sequence initiated by phospholipase D. Adding propranolol, a phosphatidate phosphohydrolase inhibitor, eliminated TPA-induced DG formation, whereas PA generation was unaffected. From these data we conclude that TPA elicits DG formation from PC by the sequential actions of phospholipase D and phosphatidate phosphohydrolase.