Association of RAFTK with Grb2 upon stimulation by VRP. HEL-JW cells were serum-starved, then stimulated with VRP for the indicated times. TCLs were prepared, immunoprecipitated with anti-RAFTK antiserum, and then subjected to serial immunoblot analysis with anti-Grb2 antibody (upper panel) and anti-RAFTK antiserum (bottom panel). Normal rabbit serum was used as a negative control for the immunoprecipitations. The changes in the association of RAFTK with Grb2 are indicated (by fold increase).