Activation of TrkA-RON induces phosphorylation of multiple downstream targets. (A) Representation of the TrkA-RON fusion protein transduced into erythroblasts. The extracellular portion of TrkA (italicized amino acids) was fused to the total transmembrane domain and intracellular tail of RON (boldface amino acids). (B-C) TrkA-RON-expressing and empty vector control cells were factor deprived and restimulated with EPO (5 U/mL; 10 minutes) or NGF (100 ng/mL; 10 minutes), as indicated. (B) Western blots containing Gab1 and Gab2 immunoprecipitates were stained with antiphosphotyrosine antibodies and antibodies against Gab1 and Gab2. Positions of Gab1 and Gab2 are indicated by arrows; positions of size markers are indicated in kDa. (C) Western blots containing whole-cell lysates were stained for Tyr694/699-phosphorylated Stat5, Ser473-phosphorylated PKB, and Thr202/Tyr204-phosphorylated ERK1/2. To control for equal loading, the blot was restained with anti-Stat5 and anti-ERK1/2.