Figure 4.

Schematic diagram of the impact of ERS on OS. During ERS, misfolded proteins are accumulated in the ER. GSH helps to reduce the quantities of misfolded proteins by converting non-native disulfide bonds into native disulfide bonds. This event decreases the amount of GSH in the cells. On the other hand, the PDI-FAD-EROI reaction also affects the redox balance in the cells. During the oxidative folding process, PDI receives electrons from the polypeptide substrate chain. FAD, which is recruited by ERO1, conducts a redox reaction on the PDI and produces hydrogen peroxide, which is a type of ROS. As a result, the levels of ROS are increased, while the amount of GSH decreases. Therefore, it disturbs the redox balance and causes OS in the cells. * ERO1, ER Oxidoreductin 1; FAD, Flavin Adenine Dinucleotide; GSSG/GSH, glutathione/glutathione disulfide; PDI, Protein Disulfide Isomerase.