Epidermal growth factor stimulates the production of phosphatidylinositol monophosphate and the breakdown of polyphosphoinositides in A431 cells.

摘要: The effects of epidermal growth factor (EGF) on the metabolism phosphatidylinositol were examined using A431 cells labeled with either 32PO3(4)- or myo-[3H] inositol. EGF was found to increase incorporation phosphate into phosphatidic acid, 4-monophosphate, and 4,5-diphosphate as early 15 s after addition hormone. These changes be due two cycle. First, stimulated breakdown diacylglycerol an inositol triphosphate. In addition, induced a rise in levels 4-monophosphate. EGF-dependent increases both triphosphate production 4-monophosphate inhibited by pretreatment 12-O-tetradecanoylphorbol-13-acetate. Treatment pertussis toxin did not inhibit these responses. However, treatment cholera selectively abolished ability stimulate monophosphate but alter hormone induce diphosphate. mimicked forskolin, cAMP analogs, isobutyl-methylxanthine. data demonstrate that stimulates findings are consistent hypothesis independently kinase. Based inability cyclic nucleotides mimic this response, effect kinase may mediated via guanine nucleotide-binding protein is involved production.