It is worth noting here that although both Drosophila and mouse models of adRP describe a protective role for Perk in retinal degeneration (Athanasiou et al., 2017; Chiang et al., 2012; Vasudevan et al., 2020), there has been conflicting evidence on the role of ATF4 in the mouse adRP model (Bhootada et al., 2016). Here, ATF4 is linked to retinal degeneration.