Bim is regulated by the PI3-K and MEK/MAPK signaling pathways. BMCMCs were left untreated or were treated with SCF alone or with SCF in combination with inhibitors. (A) Cells were treated with the PI3-K inhibitor LY294002, and the levels of phosphorylation of Akt(Ser473), FOXO3a(Ser253), and Bim were analyzed by Western blotting. (B) Cells were treated with the MEK/MAPK inhibitor PD98059, and the levels of phosphorylation of Akt(Ser473), ERK1/2, and Bim were analyzed by Western blotting. Comparable results were obtained in at least 3 separate experiments.