cS5^F interacts with Gab2 and PI3-K and induces Akt activation in transformed bone marrow cells. (A) Stat5 was immunoprecipitated from 2 cS5^F-expressing BM-cell lysates (BM1 and BM2). Subsequently, the content in p85 and Gab2 proteins was evaluated in the Stat5 immunoprecipitates by Western blotting using the indicated antisera. Cell lysates were also immunoprecipitated with an isotypic control IgG antibody. (B) BM-cell lysates from 2 mice that received a transplant of cS5^F or from 2 control GFPv mice (top) and lysates from GFPv BM and cS5^F BM cells stimulated or not with IL-3 (10 ng/mL) for 30 minutes (bottom) were analyzed by Western blotting with the indicated antibodies. (C) cS5^F-expressing BM and control GFPv BM cells cultured in the presence of SCF and SCF + IL-3, respectively, were incubated or not with different concentrations of LY294002 for 48 hours. The number of living cells was determined daily using the trypan blue dye exclusion method. Results are the mean of 3 independent experiments.