Figure 9.

Dose and time-dependent studies on EGF-stimulated Ras activation. Serum-starved RGM1 cells were treated with EGF 1–100 ng/ml for 5–30 minutes. Cell lysates were used to assess Ras activation levels, following the procedure described in Materials and Methods. EGF treatment significantly increased Ras activation, as assessed by the percentage of GTP binding versus controls. A: EGF treatment in doses ranging from 1 to 100 ng/ml caused a maximum response at 10 ng/ml. B: EGF treatment for various time intervals (5–60 minutes) caused a maximum response at 5 minutes. Data are expressed as the mean ± SD from three separate experiments.