Fig 2: PRDX2 is associated with the cell-cycle and autophagy phenotypes of CRC. Scatter plot showing the correlation between the mRNA level of PRDX2 and those of CCNA2, CCNB1, CDK1, CDK4, BECN1 and ULK1.

Fig 3: PRDX2 increases MDM2-induced p53 ubiquitination.A The degradation of p53 depends on the activation of the proteasome. Cells in the NC and shPRDX2 groups were treated with MG132 (20 µM) for 6 h; p53 and PRDX2 expression was measured by western blotting. C, E Total ubiquitinated protein levels in the NC and shPRDX2 groups were measured by western blotting. D, F PRDX2 increased the ubiquitin level of p53. Whole-cell lysates were immunoprecipitated with an anti-p53 antibody; the immunocomplexes were examined by WB with an anti-Ub antibody, and whole-cell lysates were subjected to western blot analysis with the indicated antibodies. B p53 ubiquitination was MDM2-dependent. The cells in the NC and shPRDX2 groups were transfected with siMDM2, and the expression of the indicated protein was measured by western blotting.

Fig 4: Silencing PRDX2-induced p53 protein upregulation.A, B RT-PCR was used to measure the mRNA level of p53 in the NC and shPRDX2 groups. C, E HCT116 and LoVo cells were treated with actinomycin (ActD 5 nM), total protein was harvested at the indicated time point, and p53 protein expression was measured by western blotting. D, F HCT116 and LoVo cells were treated with cycloheximide (CHX 20 nM). Total protein was harvested at different time points, and p53 protein expression was measured by western blot analysis, quantified by densitometry, and plotted against time to determine the half-life of p53. G p53 expression and localization were tested by immunofluorescence. DAPI was used to visualize the nucleus.

Fig 5: Prdx2 and Oxr1 possess holdase activity. (A-C) DTT-induced insulin aggregation assay using recombinant Prdx2 and Oxr1-C with lysozyme as a negative control. Absorbance readings at 650 nm were taken every 3 min (A). Quantification of the aggregation rate (B) and absorbance at endpoint (C) are shown. (D-F) Thermally-induced citrate synthase (CS) aggregation assay using recombinant Prdx2 and Oxr1-C. Absorbance readings at 360 nm were taken every 3 min (D). Aggregation rate (E) and absorbance at end point (F) are shown. (G-I) DTT-induced insulin aggregation assay using two concentrations (6 µM and 9 µM) of recombinant Oxr1-C or human OXR1-FL (6 µM), in parallel with human TBC1D24 and the TLDc domain of TBC1D24 (TBC1D24 TLDc). Absorbance readings at 650 nm were taken every 3 min (G). Quantification of the aggregation rate (H) and absorbance at endpoint (I) are presented. (A-I) All values are shown as normalized to the background signal. Data are represented as mean ± SEM. B, C, H, I, E, F: t-test, *p < 0.05, **p < 0.01, ***p < 0.001 as compared to insulin (B, C, H, I) or CS (E, F), ##p < 0.01, ###p < 0.001 as compared to insulin + Prdx2 (B, C, H, I) or CS + Prdx2 (E, F), §§§p < 0.001 as compared to insulin + Oxr1-C 6 µM (H, I).