Figure 4.

Vav-2 associates with EGFR by means of its SH2 domain. (A) HeLa cells either were left untreated or were treated with EGF, and lysates were immunoprecipitated with anti-Vav-2 antibody as indicated. Washed immunoprecipitates were resolved by SDS/PAGE, transferred onto nitrocellulose, and Western blotted with an anti-phosphotyrosine antibody. Coimmunoprecipitated EGFR is indicated by an arrow. (B) HeLa cells either were left untreated or were treated with EGF, and lysates were incubated with 10 μg of GST alone, GST-SH2, or GST-SH3 (C-terminal) fusion proteins bound to glutathione-agarose beads for 2 hr at 4°C. The beads were then washed and boiled in sample buffer. The samples were resolved by SDS/PAGE, transferred onto nitrocellulose, and Western blotted with an anti-phosphotyrosine antibody to detect the EGFR.