SAPK/JNK1 MAPK activation.

Cells were cultured in FN/PMA for 3 days and analyzed by Western blot. (A) The upper panel shows that only phosphorylation of SAPK/JNK1 (46 kd) was expressed for up to 2 hours. (B) SB203580 (10 μM and 50 μM*), an inhibitor of SAPK/JNK added 1 hour prior to PMA treatment, blocked phosphorylation of SAPK/JNK1 (46 kd). SFM indicates serum-free medium. The data are representative of 3 separate experiments.