Tyrosine phosphorylation of paxillin and its association with RAFTK following VRP stimulation. Serum-starved HEL-JW cells were stimulated with VRP for the indicated times. TCLs were immunoprecipitated with antipaxillin antibody or normal mouse IgG as a negative control. (A) The immunoprecipitates were subjected to serial immunoblot analysis with antiphosphotyrosine (upper panel), and antipaxillin (bottom panel) antibody. (B) the immunoprecipitates were immunoblotted with either anti-RAFTK antiserum (upper panel) or antipaxillin antibody (bottom panel). (C) TCLs were also incubated with GST-RAFTK fusion protein or GST protein alone followed by incubation with Glutathione-Sepharose 4B beads. The precipitated complexes were then subjected to immunoblot analysis with antipaxillin antibody. The fold increases in the phosphorylation of paxillin and its association with RAFTK are indicated based on densitometry values.