Activation of downstream effector proteins in TEL-FGFR3 transfectants. (A) Multiplex Western blot analysis of lysates of polyclonal TF-V5–transfected Ba/F3 cells that had been incubated in the presence or absence of SU5402. Western blotting of lysates of cells that were transfected with mock and incubated with IL-3 (lane 1), mock driven with IL-3 for 30 minutes (lane 2), ΔHLH-TF-V5 (lane 3), TF-V5 (lane 4), or TF-V5 and incubated in the presence of 0.1% DMSO (lane 5), 5 μM SU5402 (lane 6), 10 μM SU5402 (lane 7), or 25 μM SU5402 (lane 8) for 1 hour was performed. K562 cells were used as a positive control for phosphorylated MAPK, Akt, and STAT-5, and a negative control for phosphorylated p38 MAPK and STAT-3 (lane 9). (B) Hypothetical schema of TEL-FGFR3–induced signal transduction pathway and the effects of the pharmacologic inhibitors used in this study.