APP and Alzheimer disease: ER stress may lead to an accumulation of β-amyloid (Aβ) and amyloid precursor protein (APP), and indeed stimulation of expression of other DnaJ family BiP co-chaperones has been shown to ameliorate the accumulation of Aβ in cellular Alzheimer’s disease models (Evans et al., 2006; Mansson et al., 2014).