Figure 3.

Activation of the protein kinase RNA-like endoplasmic reticulum kinase (PERK)-dependent UPR signaling pathway within retinal ganglion cells (RGCs). POAG pathogenesis, on the molecular level, is correlated with the accumulation of aberrant proteins, such as mutant myocilin, within the ER lumen, which evokes ER stress conditions within the RGCs, subsequent significant elevation of the intraocular pressure (IOP) and activation of the PERK-dependent unfolded protein response (UPR) signaling pathway. Under mild to moderate ER stress conditions, UPR has a pro-adaptive role, whereas severe or long-termed ER stress conditions trigger activation of the pro-apoptotic branch of the UPR, directly leading to RGCs’ apoptosis.