FIG. 2.

Potentiation of EGFR-mediated activation of MAPK and JNK by overexpression of Gab1. 293T cells were transiently transfected with increasing amounts (0.5, 2, and 4 μg) of Gab1 expression vector and a constant amount (100 ng) of EGFR (four rightmost lanes) and HA-tagged Erk2 (left) or HA-tagged JNK1 (right) (1.5 μg each). At 48 h posttransfection, cells were lysed and kinase assays were performed as described in Materials and Methods (top blots). Expression of the transfected proteins was determined by immunoblotting total cell lysates with the antibodies indicated beside the lower rows of blots.