Vesicle-associated membrane protein-associated protein B (VAPB) is an integral membrane protein localized to the endoplasmic reticulum (ER) membrane. VAPB has been implicated in various cellular processes,including ER stress,the unfolded protein response (UPR) and calcium homeostasis regulation. The mutations in the gene of VAPB cause amyotrophic lateral sclerosis 8 (ALS8) and some other related forms of motor neuron disease including late onset spinal muscular atrophy.