PARTICIPATION OF DIACYLGLYCEROL KINASE IN MITOGENIC SIGNAL-TRANSDUCTION INDUCED BY PLATELET-DERIVED GROWTH-FACTOR IN VASCULAR SMOOTH-MUSCLECELLS

In rat vascular smooth muscle cells, platelet-derived growth factor (P DGF) stimulated phosphatidic acid synthesis by activating both of the two alternative pathways, diacylglycerol kinase (DGK) and phospholipas e D (PLD). Genistein, a tyrosine kinase inhibitor, inhibited PLD activ ation but not DGK activation, the latter was inhibited selectively by R 59022. PDGF-induced DNA synthesis was partially inhibited by geniste in or R 59022, but these inhibitors had no effect on phorbol ester-ind uced DNA synthesis. Further, the specific effects of these inhibitors on PDGF-induced DNA synthesis were additive. (C) 1994 Academic Press, Inc.