Ras N-17 blocks Crk-induced GCKR activation. HEK 293T cells were cotransfected constructs directing the expression of HA-GCKR in conjunction with Crk-I (lanes 2, 3), Crk-II (lanes 4, 5), CrkL (lanes 6, 7), or a control plasmid (lane 1) in the presence (lanes 3, 5, 7) or absence of Ras N-17 (lanes 1, 2, 4, 6).

HA-GCKR immunoprecipitates were assayed for activity using an in vitro kinase with MBP as a substrate. The fold induction compared to HA-GCKR immunoprecipitate from the control transfection is indicated. Levels of Crk-I, Crk-II, CrkL, Ras N-17, and HA-GCKR expression as detected by immunoblotting are shown. These experiments were performed twice.