Constitutive tyrosine phosphorylation of STAT3 in 239 cells cotransfected with D816H mutant c-kit and STAT3.

Each plasmid alone (1.5 μg) or in combinations as indicated was transfected into 293 cells mediated by DOSPER reagents. Forty-eight hours later, cellular lysates were obtained from the cells and analyzed by Western blotting. The blot in the upper panel was probed with the antibody against tyrosine-phosphorylated STAT3. The blot from upper panel was stripped and reprobed with the antibody against the internal domain of STAT3, as shown in the lower panel.