Repetitive Peroxide Exposure Reveals Pleiotropic Mitogen-Activated Protein Kinase Signaling Mechanisms
Figure 4
Repeated peroxide exposure differentially affects tyrosine kinase responses in PC12 cells. (a) Comparison of levels of peroxide-induced ERK1/2 activation, Pyk2 generic tyrosine and tyrosine-402 phosphorylation, c-Src tyrosine-418 phosphorylation and EGFR tyrosine phosphorylation between R1 and R4 responses. (b) The histogram depicts the quantitation of mean ± standard error for three individual experiments for the data represented in panel (a). The represented fold changes in ERK1/2, Pyk2 Tyr-402, Pyk2 generic tyrosine phosphorylation, c-Src Tyr-418 and EGFR tyrosine phosphorylation were calculated relative to the non-stimulated phosphorylation value prior to either R1 (black bars) or R4 (grey bars). (c) Chemical sensitivity of R1 versus R4 ERK1/2 phosphorylation responses to acute-recovery peroxide exposure paradigms. Preincubation times and chemical concentrations for AG1478, BAPTA-AM and PP2 were as used before in Figure 3. (d) The histogram depicts the quantitation of the mean ± standard error for three individual experiments for the data represented in panel (c) (R1-black bars; R4-grey bars). For statistical analysis probability values indicated are *, **.
