The PI-3K and Ras/MAPK pathways converge on ERK.

KS1767 cells in 1% serum were incubated with the indicated individual signaling inhibitors in the presence (+) or absence (−) of bFGF stimulation and lysates were assayed for levels of total ERK (ERK1/2) or activated ERK (pERK) by Western blot analysis. (B) Inhibition of both pathways abrogates ERK phosphorylation in response to bFGF. Lysates from cells incubated in the presence of both inhibitors were assayed for levels of total ERK (ERK1/2) or control protein.