Repetitive Peroxide Exposure Reveals Pleiotropic Mitogen-Activated Protein Kinase Signaling Mechanisms
Figure 5
Grb2 association with EGFR or Pyk2 is differentially affected by repeated peroxide exposure. (a) Representative western blots of phosphotyrosine and Grb2 content of EGFR immunoprecipitates from cells stimulated to R1 or the R4 level with 100 μM hydrogen peroxide. (b) EGFR immunoprecipitate tyrosine phosphorylation status in response to R1 hydrogen peroxide exposure (NS—non-stimulated). (c) Peroxide-induced fold changes in the Grb2 content of EGFR immunoprecipitates at the R1 response point. (d) EGFR immunoprecipitate tyrosine phosphorylation status in response to R4 hydrogen peroxide exposure (PS—pre-stimulated basal level prior to R4). (e) Peroxide-induced fold changes in the Grb2 content of EGFR immunoprecipitates at the R4 response point. (f) Representative western blots of Pyk2 Tyrosine 881 phosphorylation and Grb2 content of Pyk2 immunoprecipitates from cells stimulated to R1 or the R4 level with 100 μM hydrogen peroxide. (g) Pyk2 immunoprecipitate tyrosine-881 phosphorylation status in response to R1 hydrogen peroxide exposure. (h) Peroxide-induced fold changes in the Grb2 content of Pyk2 immunoprecipitates at the R1 response point. (i) Pyk2 immunoprecipitate tyrosine-881 phosphorylation status in response to R4 hydrogen peroxide exposure. (j) Peroxide-induced fold changes in the Grb2 content of Pyk2 immunoprecipitates at the R4 response point. The histograms in each panel depict the quantitation of the mean ± standard error for three individual experiments. For statistical analysis *, **.
