Lipid metabolism in fibroblast growth factor-stimulated L6 myoblasts: a receptor mutation (Y766F) abrogates phospholipase D and diacylglycerol kinase activities.
Phosphatidylcholine (PC) hydrolysis induced by basic fibroblast growth factor (bFGF) was studied in rat L6 myoblasts expressing the wild-type FGF receptor-1 (FGFR-1) or a mutant (Y766F) that is incapable of activating phospholipase C-gamma (PLCgamma). Stimulation of FGFR-1 activated phospholipase D (PLD) rapidly and transiently, but did not induce PC-specific PLC activity. Downregulation of protein kinase C blocked bFGF-induced PLD activation but not phosphatidic acid formation by diacylglycerol (DG) kinase. Only phosphoinositide (PI)-derived DG, not PC-derived DG, appeared to be a substrate for DG kinase. Stimulation of FGFR-1(Y766F) did not activate PLD or DG kinase, both of which apparently require initial PLCgamma activation. The Y766F mutation reduced mitogen-activated protein kinase activation but not cell proliferation. We conclude that both PI turnover and PC hydrolysis are dispensable for bFGF-induced mitogenesis.
van Dijk
M C
MC
Division of Cellular Biochemistry, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, Netherlands.
van Blitterswijk
W J
WJ
D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D002455:Cell Division; D002460:Cell Line; D019852:Diacylglycerol Kinase / Q000378:metabolism*; D004075:Diglycerides / Q000378:metabolism; D004789:Enzyme Activation; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology*; D007527:Isoenzymes / Q000378:metabolism; D050356:Lipid Metabolism; D010713:Phosphatidylcholines / Q000378:metabolism; D051966:Phospholipase C gamma; D010739:Phospholipase D / Q000378:metabolism*; D010766:Phosphorylation; D017354:Point Mutation; D011493:Protein Kinase C / Q000378:metabolism; D051381:Rats; D020794:Receptor Protein-Tyrosine Kinases; D051496:Receptor, Fibroblast Growth Factor, Type 1; D017468:Receptors, Fibroblast Growth Factor / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D015398:Signal Transduction; D013379:Substrate Specificity; D010738:Type C Phospholipases / Q000378:metabolism
D004075:Diglycerides; D007527:Isoenzymes; D010713:Phosphatidylcholines; D017468:Receptors, Fibroblast Growth Factor; D016222:Fibroblast Growth Factor 2; D019852:Diacylglycerol Kinase; C496350:Fgfr1 protein, rat; D020794:Receptor Protein-Tyrosine Kinases; D051496:Receptor, Fibroblast Growth Factor, Type 1; D011493:Protein Kinase C; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D010738:Type C Phospholipases; D051966:Phospholipase C gamma; C105598:phosphatidylcholine-specific phospholipase C; D010739:Phospholipase D