FIG. 5.

UV-induced tyrosine phosphorylation of Gab1 by SFK. (A) Wild-type fibroblasts were irradiated with UV-B light (0, 100, 200, or 400 J/m²) and incubated at 37°C for 20 min. Cell lysates (300 μg of total proteins) were immunoprecipitated with an anti-Gab1 antibody, resolved by SDS-PAGE, and immunoblotted (IB) with an anti-PY or an anti-Gab1 antibody. (B) Cells were pretreated with PP2 at the indicated doses for 30 min and then irradiated with UV-B light (400 J/m²). Cell lysates were immunoprecipitated and immunoblotted as above. (C) Wild-type (+/+) and Gab1^−/− (−/−) cells were pretreated with PP2, exposed to UV-B light (400 J/m²), and incubated at 37°C for 1 h. Equal amounts of cell lysates (30 μg of total proteins) were immunoblotted with anti-p-JNK1/2 or anti-JNK2 antibodies. (D) SYF or SYF + c-Src cells were treated with UV-B (0, 100, 200, or 400 J/m²), and incubated at 37°C for 1 h. JNK activation was detected by immunoblotting using an anti-p-JNK antibody. The membrane was stripped and immunoblotted with anti-JNK antibody as loading control.