title: Epidermal-growth-factor-induced production of phosphatidylalcohols by HeLa cells and A431 cells through activation of phospholipase D.
abstract: In response to epidermal growth factor (EGF), HeLa cells and A431 cells rapidly accumulate substantial amounts of phosphatidic acid (up to 0.16 and 0.2 micrograms/10(6) cells respectively), which represents approx. 0.17% of total phospholipid. Phosphatidic acid may be a potential product of diacylglycerol kinase and/or of phospholipase D. To evaluate the contribution of phospholipase D, the phosphatidyl-transfer reaction to a primary alcohol (mostly butan-1-ol; 0.2%) was measured; this reaction is known to be mediated exclusively by phospholipase D in intact cells. In HeLa and in A431 cells prelabelled with [1-14C]oleic acid, EGF (10 and 100 nM respectively) caused a 3-fold increase in radioactive phosphatidylbutanol within 5 min at the expense of labelled phosphatidic acid. Dose-response relationships showed 10 nM- and 100 nM-EGF to be maximally effective in HeLa cells and A431 cells respectively. Mass determinations showed that the phosphatidylbutanol formed within 5 min represented only part of the phosphatidic acid. Depletion of protein kinase C by pretreatment of A431 cells for 17 h with the phorbol ester phorbol 12-myristate 13-acetate (0.1 microM) did not impair EGF-induced formation of phosphatidylbutanol, thus indicating that the reaction was independent of this enzyme. Since phosphatidic acid is suggested to exert second-messenger functions as well as to induce biophysical changes in cellular membranes, its formation, including that via the phospholipase D pathway, may represent an important link between extracellular signals and intracellular targets.
authors.affiliation: Department of Pathochemistry, German Cancer Research Center, Heidelberg.
authors.forename: M
authors.initials: M
authors.lastname: Kaszkin
authors.forename: L
authors.initials: L
authors.lastname: Seidler
authors.forename: R
authors.initials: R
authors.lastname: Kast
authors.forename: V
authors.initials: V
authors.lastname: Kinzel
mesh_terms: D004075:Diglycerides / Q000378:metabolism; D004789:Enzyme Activation; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D020404:Glycerophospholipids; D006367:HeLa Cells; D006801:Humans; D010712:Phosphatidic Acids / Q000378:metabolism*; D010716:Phosphatidylinositols / Q000378:metabolism; D010739:Phospholipase D / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured
chemical_list: D004075:Diglycerides; D020404:Glycerophospholipids; D010712:Phosphatidic Acids; D010716:Phosphatidylinositols; C068564:phosphatidylbutanol; C051521:phosphatidylethanol; D004815:Epidermal Growth Factor; D011493:Protein Kinase C; D010739:Phospholipase D; D013755:Tetradecanoylphorbol Acetate