hGM-CSF induces the association of tyrosine-phosphorylated Shc with Grb2. Cell lysates from unstimulated (lanes 1, 3, and 5) or hGM-CSF–stimulated TF-1 cells (lanes 2, 4, and 6) and from control NIH 3T3 (lanes 7 and 9) or v-fes–transformed NIH 3T3 cells (lanes 8 and 10) were analyzed either directly (lanes 1 and 2) or after immunoprecipitation with anti-Shc (lanes 3, 4, 7, and 8) or anti-Grb2 (lanes 5, 6, 9, and 10) antibodies. Total cell lysates and immunoprecipitates were analyzed by SDS-PAGE and immunoblotting using anti-Grb2 antibodies (lanes 1 through 10). The positions of Grb2 and the Ig heavy chain (Ig) are indicated on the left. Molecular weight markers are indicated on the right.