Effect of chemical inhibitors on the IL-3–induced activation of different signal transduction pathways in the SCF-dependent EML cells.

EML cells cultured in SCF-containing media were incubated for 60 minutes in (A) the MEK1/2 inhibitors PD98059 and U0126 (lanes 3-6); the PI3 kinase inhibitors wortmannin and Ly294002 (lanes 7-10); and (B) the Jak2 inhibitor (lanes 3 and 4) and Jak3 inhibitor (lanes 5 and 6). The concentration of these different inhibitors is designated in “Materials and methods.” IL-3 (5 ng/mL) was then added where indicated and Western blots using the indicated antibodies were then performed on cell lysates harvested 15 minutes after the addition of IL-3.