Fig. 3

APE1 mediates ABS-induced YAP1 activation. A Representative immunofluorescence images of APE1 (red) and YAP1 (green) in FLO-1 cells exposed to ABS (200 µM, pH 4, 20 min) followed by 3 h recovery with or without APE1 knockdown. DAPI (blue) was used for nuclear staining. B Quantification of immunofluorescence stain intensity using ImageJ. C Cytosolic and nuclear fractions from FLO-1 (left) and OE33 (right) cells transfected with si-Ctrl or si-APE1 and treated with ABS (200 µM, pH 4, 20 min) followed by recovery in complete media for indicated timepoints were evaluated by western blot for the levels of APE1 and YAP1. β-tubulin and p84 were used as a loading control for cytosolic and nuclear fractions, respectively. D 8xCTIIC luciferase reporter assay was used to measure YAP1 transcriptional activity in FLO-1 and OE33 cells transfected with si-Ctrl or si-APE1 and exposed or not to ABS treatment (200 µM, pH 4, 20 min) followed by 3 h recovery. The luciferase reporter activity values were normalized to Renilla expression levels. Values are represented as mean ± SEM of three independent experiments. * P < 0.05; ** P < 0.01; *** P < 0.001