Figure 4. HGF induced activation and phosphorylation of p42/p44 MAP kinases in ARPE-19 cells

Sub-confluent cells were treated with HGF for indicated times. Some cells were treated with MAP kinase inhibitor PD98059 (30 mM) for 1 h prior to HGF treatment. A: Kinetics of MAP kinase activity. Phosphorylated MAP kinase (Tyr204; active MAPK) was immunoprecipitated from cell lysates. The immunoprecipitate was incubated with Elk 1 fusion protein and phosphorylation of Elk 1 at Ser383 was measured by western blot analysis using a phospho-specific Elk 1 (Ser383) antibody followed by ECL detection. B: Kinetics of phosphorylation of p42/p44 MAP kinases. Protein equivalent aliquots of cells from each time point were analyzed by western blot using a phospho-specific p42/p44 MAP kinases antibody or total p42/p44 MAP kinases antibody. Bars indicate the mean and standard deviation of three independent experiments. Asterisk indicates level of statistical significance for p<0.05.