S1P induces c-Src-dependent p42/p44 MAPK and p38 MAPK activation.

HPAEpiCs were pretreated without or with PP1, AG1478, or AG1296 for 1 h, and then incubated with S1P for the indicated time intervals. The levels of (A) phospho-p42/p44 MAPK, (B) phospho-p38 MAPK, or (C) phospho-JNK1/2 were determined by Western blot. Data are expressed as representatives of three independent experiments. (D) Cells were transfected with siRNA of scrambled, c-Src, EGFR, or PDGFR, and then incubated with S1P (10 μM) for the indicated time intervals. The levels of phospho-p38 MAPK, phospho-p42/p44 MAPK, phospho-JNK1/2, and GAPDH proteins were determined by Western blot.