Figure 4.

c-Src phosphorylation is involved in the signaling pathway of OA-Alb–induced superoxide production. HK-2 cells were incubated at pH 6.4 (A) or at pH 7.0 (B), with or without OA-Alb stimulation (15 g/L) for the indicated times. Total cell lysates (diluted to 1 mg/ml) were immunoprecipitated with an anti-Pyk2 antibody and were then immunoblotted with anti-Pyk2, anti–c-Src, or p-Tyr antibodies. (A) Phosphorylated c-Src was coimmunoprecipitated with Pyk2 upon OA-Alb stimulation at pH 6.4. The lower panel indicates quantification of phosphorylated c-Src, which was normalized to the level of total Pyk2 protein. The data are expressed as the mean ± SEM of four independent experiments. The statistical significance of the differences are indicated (*P < 0.05). (B) At pH 7.0, c-Src was not coimmunoprecipitated with Pyk2. All gel data are representative of four independent experiments. p-Tyr, anti-phosphotyrosine.