DR is a neural and microvascular complication of diabetes and remains the leading cause of blindness in working-aged people (Fig. 4d).171 Elevated Ksuc level of OPTN at K108 with an unchanged protein stability was found in a treptozotocin (STZ)-induced type 1 diabetes rat model, which results in autophagic flux blockade and accumulation of oxidatively damaged proteins or organelles in the cytoplasm under high-glucose conditions. Here, OPTN is linked to diabetes mellitus.