Fig. 6. Interaction with PtdIns(3,4,5)P₃ is crucial for PDGF-induced activation of PLD1. HepG2 cells stably expressing mutant Y40/51 PDGFßR were transiently transfected as indicated. PLD activity was measured for 2 minutes in the presence of PDGF (25 ng/ml). To inhibit PI3K, cells were treated with 50 µM LY 294002 for 20 minutes before treatment with PDGF. Data are representative of three separate experiments. Error bars indicate standard deviations. Immunoblots in the inset show that the expression levels of PLD were similar.