Figure 4. Src and PI3K are involved in flow- but not HGF-induced Gab1 activation.

Critical role of Src and PI3K in flow-induced Gab1 tyrosine phosphorylation (A and C), but not HGF-induced Gab1 tyrosine phosphorylation (B and D). HUVECs were treated with vehicle (0.1% DMSO) or specific inhibitor of Src activity (PP2, 1 µM), or PI3K (LY294002, 10 µM), then exposed to laminar flow (12 dynes/cm²), or HGF (10 ng/mL) for 15 min. Cell lysates were prepared and probed with the indicated antibodies by Western blot analysis. Quantification of each panel was provided under each panel, *P<0.05, **P<0.01 versus vehicle control (DMSO); #P<0.05, ##P<0.01, ###P<0.001 versus DMSO + flow or HGF. E, Src and PI3K are involved in flow- but not HGF-induced Gab1 membrane localization. HUVECs were infected with recombinant adenovirus constructs encoding the GFP-tagged human Gab1 at the multiplicity of infection (M.O.I., 30) for 24 h, then treated with vehicle (0.1% DMSO) or specific inhibitor of Src activity (PP2, 1 µM), or PI3K (LY294002, 10 µM), before exposure to laminar flow (12 dynes/cm²), or HGF (10 ng/mL) for 15 min. HUVECs were fixed with 3.7% formaldehyde in PBS and the images were captured using an oil immersion 60× objective lens.