P4HB and amyotrophic lateral sclerosis: PDI is an ER protein, but in disease conditions, triggered by redox PTMs in particular, it can translocate to the cytoplasm where it localizes to inclusions containing ALS-associated proteins (Turano et al., 2002; Honjo et al., 2011; Walker and Atkin, 2011; Farg et al., 2012; Jeon et al., 2014; Valle and Carrì, 2017; Matsusaki et al., 2020; Parakh et al., 2020).