Figure 4.

p80 is a putative substrate for Src-family kinases. (A) Caveolae-like fractions isolated from EphA5–Fc-stimulated fibroblasts were solubilized in TX-100 at 37°C for 30 min and incubated with 50 μg of either purified GST or GST–Src–SH2 fusion proteins. Protein complexes were pelleted by low-speed centrifugation and analyzed by Western blotting using the phosphotyrosine-specific antibody 4G10. (B) Caveolar fractions were isolated from ephrin-A5-expressing cells that had been treated with either Fc or EphA5–Fc in the presence or absence of PP1 (as indicated). Samples were analyzed as above with GST–Src–SH2 fusion protein and Western blotting with 4G10. Molecular mass markers are indicated (kD).