Figure 4. Inhibition of PDGFR impairs EGF-mediated Akt activation.

WT MEFs were serum starved for 24 hours; with or without pretreatment with 2.5 μM AG1295 (PDGFR inhibitor [PDGFRi]) or 0.1 μM AG1478 (EGFR inhibitor [EGFRi]) for 30 minutes; and then stimulated with 50 ng/ml PDGFbb or EGF for 10 minutes. Cell lysates were then subjected to immunoblot analysis (A) or immunoprecipitation for EGFR, followed by immunoblotting (B). Note equivalent suppression of p-Akt levels by both AG1478 and AG1295 pretreatment in EGF-stimulated cells (A). AG1295 does not prevent tyrosine phosphorylation of EGFR by EGF (B).