IMPG2 and retinitis pigmentosa 1: In IMPG2 KO mice, impaired autophagy, gliosis, and apoptotic cell death are induced by ER stress in both rod and cone retinal cells.307 Since activated autophagy is impaired and the autophagy flux is decreased, autophagy functioning in RHO accumulation is harmful to cell survival.319 However, in P10 models, ER stress arouses defective autophagy in the early stage of RP.314 In these cases, autophagy possesses a time-dependent dual function for retinal degeneration.