Fig. 1.

Effect of mutation of Y783 or Y1253 on PDGF-induced PLC-γ1 activation. (A) Schematic representation of the domain organization of rat PLC-γ1. (B) Null TV-1 cells expressing wild-type (WT) PLC-γ1 or its Y783F or Y1253F mutants were left unstimulated or stimulated for 10 min with PDGF (50 ng/ml), and cell lysates were then subjected to immunoblot analysis with antibodies to PLC-γ1 (α-PLC-γ1) or with antibodies specific for PLC-γ1 phosphorylated either on Y783 (α-pY783) or on Y1253 (α-pY1253). (C) Null TV-1 cells expressing wild-type PLC-γ1 or the Y783F or Y1253F mutant were metabolically labeled with myo-[³H]inositol and then stimulated with PDGF (50 ng/ml) for the indicated times. The amount of [³H]inositol phosphates in cell lysates was measured. Data are the means of two independent experiments.