Association of tyrosine-phosphorylated p140 with Shc in response to different growth factors. Anti-Shc immunoprecipitates (IP:Shc) of unstimulated (lane 1) or hGM-CSF–stimulated (lane 2) TF-1 cells and from unstimulated (lane 3) or CSF-1–stimulated (lanes 4) BAC1.2F5 cells were analyzed by antiphosphotyrosine immunoblotting (lanes 1 through 4). The positions of p140, p52^Shc, and Ig heavy chain (Ig) are indicated on the left.