ATF4 and retinal degeneration: We have demonstrated that mice expressing mutant and truncated rhodopsins show dramatically elevated ATF4 levels (Kunte et al., 2012; Rana et al., 2014; Bhootada et al., 2016), while other investigators have detected ATF4 upregulation in different models of inherited retinal degeneration (Comitato et al., 2016; Lobo et al., 2016; Ooe et al., 2017).