A) Characterization of an antibody to the Bim phosphorylation site Thr112 on BimEL (Thr56 on BimL). 293T cells were transfected with an empty expression vector or a vector that expresses BimL. The expression of BimL and phosphoThr56-BimL was detected by immunoblot analysis of cells extracts. The effect of co-expression of constitutively activated JNK1 (JNK1*) and the replacement of Thr56 with an Ala residue is shown.
B) Homozygous BimLoxP, BimT112A, and Bim3SA primary MEF were serum-starved or treated with serum (S) (10% fetal bovine serum; 30 mins) or UV light (60 J/m2; 60 mins). Cell extracts were examined using antibodies to Bim, phospho-Thr112-Bim, phosphoSer65-Bim, and Tubulin.
C) Wild-type and Jnk1−/− Jnk2−/− (Jnk−/−) fibroblasts were serum-starved or treated with serum (S) or UV light. Cell extracts were examined using antibodies to Bim, phospho- Thr112-Bim, phosphoSer65-Bim, and Tubulin. The basal phosphorylation of BimEL on Ser65 was slightly increased in JNK-deficient fibroblasts compared with wild-type fibroblasts.
D) Jnk1−/− Jnk2−/− (Jnk−/−) fibroblasts were serum-starved or treated with serum and/or the MEK inhibitor U0126 (30 mins). Cell extracts were examined using antibodies to phospho-ERK, ERK, phospho-Thr112-Bim, and Bim.