Figure 4.

Hydrogen peroxide (H₂O₂)-induced ER stress and activation of GSK3β-TIP60-ULK1 pathway. (a) H₂O₂-induced ER stress. HeLa cells were treated with H₂O₂ (1 or 3 mM). Cell lysates were gathered at the indicated time points and blotted for the ER stress markers as indicated. (b) H₂O₂-induced activation of GSK3β, TIP60 and ULK1. HeLa cells were treated with H₂O₂ (1 mM) with or without 4-PBA (2 mM) for the indicated time. Cell lysates were blotted as indicated. Densitometric analyses of the western blots are shown as curves. Data represent mean±S.E.M. of three independent experiments (*P<0.05; **P<0.01 (two-tailed Student's t-test)). (c–e) The effect of modulating GSK3β-TIP60-ULK1 pathway on H₂O₂-induced change in LC3BII. HeLa cells were treated as described in Figures 3b, e and f, except that H₂O₂ (1 mM)and bafilomycin A1 (400 μM) for another 18 h. The lysates were immunoblotted as indicated. LC3BII level was determined. Data represent the mean±S.E.M. of three independent experiments (*P<0.05; **P<0.01; NS, not significant (two-way analysis of variance (ANOVA) followed by Tukey's test))