Figure 4.

VEGF-stimulated phosphorylation of VEGFR-2 in HN33 cells. Cultures were exposed to control conditions (Con), HGD for 24 h (HGD), or HGD for 24 h in the presence of 100 ng/ml of VEGF (HGD + VEGF). Protein was immunoprecipitated with a mouse monoclonal antibody against amino acids 1158–1345 of mouse Flk-1/VEGFR-2, and Western blotting was performed using a mouse monoclonal antibody against p-Tyr, which specifically detects phosphotyrosine-containing proteins. Horseradish peroxidase-conjugated anti-mouse secondary antibody was visualized as described in Materials and Methods.