P4HB and amyotrophic lateral sclerosis: PDI associates with misfolded protein inclusions in patients with ALS (Honjo et al., 2011, Parakh et al., 2018), cellular models (Jeon et al., 2014, Farg et al., 2012), and canine degenerative myelopathy (DM) (Chang et al., 2019), and both PDI and ERp57 inhibit the formation of mutant SOD1 inclusions in neuronal cells (Walker et al., 2010, Parakh et al., 2018).