FIG. 8.

Effect of EGF on the phosphorylation of Erk1/2, p38, and JNK/SAPK MAP kinases in CD14-CHO cells and inhibition by PD98059. (A) Phosphorylation of Erk1/2 MAP kinase by EGF. CD14-CHO cells were cultured with EGF (50 ng/ml) for 30 min. The cells were lysed, and the lysates were analyzed by immunoblotting using an antibody to Erk1/2, phospho-Erk1/2, p38, phospho-p38, JNK/SAPK, or phospho-JNK/SAPK. (B) Inhibition of EGF-induced Erk1/2 phosphorylation by PD98059. CD14-CHO cells were pretreated with 20 μM PD98059 for 1 h and then treated with EGF for 30 min. The cells were lysed, and the lysates were analyzed by immunoblotting.