VEGF promotes Hsp90 binding to APAF-1.

Cell extracts were immunoprecipitated using an APAF-1–specific antibody and probed with a Hsp90-specific antibody. APAF-1 binding to Hsp90 was seen after VEGF stimulation for 12 hours. As a protein loading control, total APAF-1 levels are also shown. Coincubation with GA blocked the effects of VEGF, as seen for Bcl-2. Western blotting results were quantified by densitometry and are shown as the ratio between densitometry values in treated versus untreated (control) cells. Each experiment was repeated 3 times, and the SD between the different ratios was calculated and is shown. Double asterisks indicate GA significantly blocks APAF-1 binding to Hsp90.