FIG. 6.

Effect of inhibition of p44/42 MAPK signaling on the EGF-induced expression of LIP. Inhibition of p44/42 MAPK activation with U0126 reduces expression of LIP. MCF10A cells were serum starved for 24 h and then treated with increasing concentrations of U0126, a potent MEK1/2 inhibitor, for 30 min prior to addition of EGF (10 ng/ml). Cells were then harvested at either 5 min (for p44/42 MAPK-P and total p44/42 MAPK detection; lower panels) or 16 h (for LIP detection; upper panel) after addition of EGF. Whole-cell extracts (100 μg) were analyzed via SDS-PAGE and Western blotting. The C/EBPβ blot was stripped and incubated with a polyclonal antibody to β-actin to estimate loading and transfer of proteins.