Demonstration of Functionally Different Interactions between Phospholipase C-γ and the Two Types of Platelet-derived Growth Factor Receptors

摘要: Phosphorylated tyrosine residues in receptor kinases serve as binding sites for signal transduction molecules. We have identified two autophosphorylation sites, Tyr-988 and Tyr-1018, the platelet-derived growth factor (PDGF) alpha-receptor carboxyl-terminal tail, which are involved of phospholipase C-gamma (PLC-gamma). The capacities Y988F Y1018F mutant PDGF alpha-receptors, expressed porcine aortic endothelial cells, to bind PLC-gamma 60 5% that wild-type receptor, respectively. but not unphosphorylated peptides containing Tyr-1018 able compete with intact immobilized SH2 domains; a phosphorylated peptide competes 10 times less efficiently. complex between is more stable than beta-receptor. However, stimulation results smaller fraction tyrosine-phosphorylated accumulation inositol trisphosphate cells expressing compared conclude tail PLC-gamma, this association leads only relatively low level phosphorylation activation PLC-gamma.