Figure 2.

FAK and paxillin are substrates for phosphorylation. The phosphotyrosine content of FAK (top panels) and paxillin (bottom panels) from CE cells coexpressing FAK and c-src (A) or FAK and fyn (B) was examined by immunoprecipitation and Western blotting. (A) FAK (top) and paxillin (bottom) were immunoprecipitated from lysates of CE cells (lane 1) or CE cells expressing RCAS B c-src (lane 2), RCAS A FAK (lane 3), or RCAS A FAK + RCAS B c-src (lane 4). Immune complexes were analyzed by Western blotting using a phosphotyrosine antibody, an anti-FAK rabbit serum, or a paxillin mAb. (B) FAK and paxillin were immunoprecipitated from lysates of CE cells (lane 1) or CE cells expressing RCAS B fyn (lane 2), RCAS A FAK (lane 3), or RCAS B fyn + RCAS A FAK (lane 4) and analyzed as in A.