Figure 2.

Signal transduction by KPβ, TEL-PDGFRβ and activated JAK2. Ba/F3 cells were transduced with KPβ, TEL-PDGFRβ (TPβ) or JAK2-V617F and cultured in the absence of IL3. (A) Cells were treated with 0.1 μM imatinib or 2 μM JAK inhibitor I for 4 h as indicated. As a control, Ba/F3 cells expressing the empty vector were cultured with or without IL3 for 4 h (left lanes). Cell lysates were immunoblotted with antibodies against phosphorylated or total PLC-γ, ERK1/2 or STAT5. (B) Cells were washed and seeded in microtiter plates in the presence of the indicated inhibitor for 24 h. As a control, Ba/F3 cells were cultured with IL3. Tritiated thymidine was added 4 h before harvest and radioactivity incorporated into DNA was quantified. The effect of both inhibitors was statistically significant in all cell lines (P<0.05).