Fig. 4.

EGFR activation and participation in sPLA₂-IIA–induced Ras and ERK activation: role of PKC. Serum-starved 1321N1 cells were preincubated with the inhibitors, when indicated, and stimulated with sPLA₂-IIA or vehicle for the indicated times. RasGTP was analyzed after a 30-minute preincubation with AG1478 (A), ERK phosphorylation was analyzed by Western blot with phospho-ERK antibody in a time course after preincubation with 1-μM AG1478 for 30 minutes (B), EGFR phosphorylation was also checked by Western blot with antiphospho-EGFR, (C) a time course of sPLA₂-IIA, and (D) a 5-minute stimulation with sPLA₂-IIA in the absence or presence of 1-μM PMA overnight. The experiments shown are representative of the results obtained in at least 3 trials for each condition.