Figure 2

EGFR signaling determines Rac1 levels and p38 phosphorylation. Normal cells and papilloma cells cultured in serum-free medium were starved of growth factors for 24 h, stimulated with 20 ng/mL EGF for 48 h in the presence or absence of the EGFR inhibitor PD153035, and cell extracts analyzed by Western blot for Rac1 and phosphorylated and total p38. Control cells did not receive EGF. A typical Western blot is shown. Bar graphs show mean ± SD of three separate experiments with each type of cells, with values normalized to β-actin and expressed relative to the unstimulated level in normal cells, *P < 0.05 compared with unstimulated cells of each type.