EIF2A and achromatopsia: ATF6f acts alone or forms heterodimers with XBP-1s to induce expression of ER chaperones to promote protein folding and protein degradation through ERAD, which is generally considered cytoprotective.10, 11 Interestingly, mutation of ATF6 causes achromatopsia, a cone degeneration disease; and ATF6 deletion mice develop rod and cone dysfunction with aging.12 PERK phosphorylates and inactivates eukaryotic translation initiation factor 2α (eIF2α) to attenuate global mRNA translation and therefore reduce protein load on the ER.