Figure 1. The down-regulation of Bim protein occurs downstream of the activation of Erk1/2 and Kit mutant in Kit-driven leukemic cells.

(A) Whole cell extracts from 606HS2 and 931HS2 cells treated or not (–) for 4 h with the Mek inhibitor UO126 (10 µM) were fractionated by SDS-PAGE and immunoblotted using antibodies raised against the phosphorylated forms of Erk1/Erk2(Thr202-Tyr204) and Bim (Ser65) and the constitutive form of Bim, Erk1/Erk2, Mcl1 and Bcl_XL,. *indicate the band corresponding to the phosphorylated form of Bim_EL. Molecular weight standards are indicated on the right. (B) Whole cell extracts from 606HS2 and 931HS2 cells treated or not (–) for 4 h with Kit inhibitors PP1 (4 µM), PP2 (4 µM) and Imatinib Mesilate (IM: 0.75 µM) were immunoblotted using indicated antibodies. Data are a representative experiment out of three. (C) Whole cell extracts from human HMC-1.2 cells treated or not (–) for 4 h with Mek inhibitor UO126 (15 µM) or Kit inhibitors IM (10 µM), PP1 (10 µM) and PP2 (10 µM) or PI3K inhibitor NVP-BEZ235 (25 nM) were analyzed by immunoblotting using indicated antibodies. Data are a representative experiment out of three.