P4HB and Alzheimer disease: PDI co-localizes with tau protein (Honjo et al., 2010).PDI levels increase 9.49 fold in tangle-bearing neurons in AD patients (Lee et al., 2010a).β-amyloid co-localizes with ERp57 (Erickson et al., 2005).Pharmacological activation of ERp57 reduces amyloid plaques and neurofibrillary tangles in brains, and improved object recognition memory in AD mouse models (Tohda et al., 2012).