Figure 6. SUMOylation of DBC1 at K591 enhances oxidative stress-apoptosis. (A) DBC1 KO cells were transiently transfected with HA-vector, HA-DBC1-WT, or HA-DBC1-K591R as indicated. Cell viability assay was conducted to analyze cell apoptosis rate changes in the three types of cells under 40 mU GO treatment for 5 hours. (B) Calcein/PI Cell Viability/Cytotoxicity assay analyzed cell apoptosis of the three types of cells under the same treatment as in A. Scale bar, 100 μm. (C) Quantification of the PI-DNA puncta in panel B. *p < 0.05, ***p < 0.001. (D) TUNEL labeling assay under the same treatment as indicated. Scale bar, 100 μm. (E) Quantification of the TUNEL Labeling puncta in panel (D). ****p < 0.0001.