Epidermal growth factor increases sn-1,2-diacylglycerol levels and activates phospholipase D-catalysed phosphatidylcholine breakdown in Swiss 3T3 cells in the absence of inositol-lipid hydrolysis.
Addition of epidermal growth factor (EGF) to quiescent Swiss 3T3 cells resulted in a sustained increase in cellular diacylglycerol (DG) content in the absence of inositol-lipid hydrolysis. In the presence of non-cytotoxic concentrations of butan-1-ol, EGF stimulated the formation of phosphatidylbutanol, indicating that the EGF receptor was able to couple to the activation of phospholipase D (PLD). EGF-stimulated release of choline from Swiss 3T3 cells suggested that the major substrate for this PLD was phosphatidylcholine. Unlike bombesin-stimulated PLD activity, the response to EGF was not inhibited by a selective protein kinase C (PKC) inhibitor (Ro-31-8220), suggesting that it was not dependent on PKC activation. Pre-treatment of Swiss 3T3 cells with the EGF-receptor tyrosine kinase inhibitor AG18 selectively inhibited EGF-stimulated PLD activity; bombesin-stimulated PLD activity was unaffected. Butan-1-ol inhibited phorbol ester- and bombesin-stimulated DG formation suggesting a role for a coupled PLD/phosphatidate phosphohydrolase pathway; in contrast, EGF-stimulated DG formation was unaffected.
Cook
S J
SJ
Institute of Biochemistry, University of Glasgow, Scotland, U.K.
Wakelam
M J
MJ
D016475:3T3 Cells; D000818:Animals; D001839:Bombesin / Q000494:pharmacology; D002384:Catalysis; D004075:Diglycerides / Q000378:metabolism*; D004789:Enzyme Activation; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D020404:Glycerophospholipids; D007211:Indoles / Q000494:pharmacology; D007295:Inositol Phosphates / Q000378:metabolism; D051379:Mice; D010712:Phosphatidic Acids / Q000096:biosynthesis; D010713:Phosphatidylcholines / Q000378:metabolism*; D010739:Phospholipase D / Q000378:metabolism*; D011493:Protein Kinase C / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
C011439:1,2-diacylglycerol; D004075:Diglycerides; D020404:Glycerophospholipids; D007211:Indoles; D007295:Inositol Phosphates; D010712:Phosphatidic Acids; D010713:Phosphatidylcholines; C068564:phosphatidylbutanol; D004815:Epidermal Growth Factor; D011493:Protein Kinase C; D010739:Phospholipase D; D013755:Tetradecanoylphorbol Acetate; D001839:Bombesin; C064758:Ro 31-8220