(a) Anti-phosphotyrosine immunoblot. NIH 3T3 cells were treated with FGF (lanes 2, 4, 6, and 8) or left untreated (lanes 1, 3, 5, and 7) and subjected to immunoprecipitation as indicated. Lanes 1 and 2 were loaded with 25 μg total lysate. SHOC-2 immunoprecipitates from FGF-stimulated NIH 3T3 cell lysates are not detected by the anti-phosphotyrosine antibody, PY20 (lane 8). (b) SHOC-2 immunoprecipitates (lanes 7 and 8 from a) stripped and reprobed with anti-SHOC-2 antibodies.