FIG. 3.

Effect of PI 3-kinase, mitogen-activated protein kinase, and Src kinase pathway on SCF-induced cell cycle progression in G1E-ER4 cells. (A) G1E-ER4 cells were cultured in the presence of SCF (50 ng/ml) and wortmannin or PD98059 or PP1. Cell cycle analysis was performed by propidium iodide staining followed by FACS analysis. Bars denote the percentage of cells in G₀/G₁ phase of cell cycle ± standard deviation (SD) of one of the two representative experiments performed in triplicates. Asterisks indicate P < 0.05 for 1 μM and 5 μM PP1 versus dimethyl sulfoxide (DMSO). (B and C) G1E-ER4 cells were cultured in the presence of SCF (50 ng/ml) and increasing doses of PP1, wortmannin, or PD98059. An equal amount of protein was resolved on a 10% SDS-polyacrylamide gel and subjected to Western blot analysis with an anti-c-Myc antibody. Position of c-Myc is indicated. As a loading control, the same blot was probed with an anti-CDK2 antibody (total protein [B]).