Vesicle-Associated Membrane Protein-Associated Protein B/C (VAPB) Antibody – Rabbit Polyclonal

The protein encoded by this gene is a type IV membrane protein found in plasma and intracellular vesicle membranes. The encoded protein is found as a homodimer and as a heterodimer with VAPA. This protein also can interact with VAMP1 and VAMP2 and may be involved in vesicle trafficking. [provided by RefSeq, Jul 2008]

VAPB: Participates in the endoplasmic reticulum unfolded protein response (UPR) by inducing ERN1/IRE1 activity. Involved in cellular calcium homeostasis regulation. Defects in VAPB are the cause of amyotrophic lateral sclerosis type 8 (ALS8). ALS8 is a familial form of amyotrophic lateral sclerosis, a neurodegenerative disorder affecting upper and lower motor neurons and resulting in fatal paralysis. Sensory abnormalities are absent. Death usually occurs within 2 to 5 years. The etiology of amyotrophic lateral sclerosis is likely to be multifactorial, involving both genetic and environmental factors. The disease is inherited in 5-10% of cases leading to familial forms. Defects in VAPB are a cause of spinal muscular atrophy proximal adult autosomal dominant (SMAPAD); also called late-onset spinal muscular atrophy Finkel type. A form of spinal muscular atrophy, a neuromuscular disorder characterized by degeneration of the anterior horn cells of the spinal cord, leading to symmetrical muscle weakness and atrophy. SMAPAD is characterized by proximal muscle weakness that begins in the lower limbs and then progresses to upper limbs, onset in late adulthood (after third decade) and a benign course. Most of the patients remain ambulatory 10 to 40 years after clinical onset. Belongs to the VAMP-associated protein (VAP) (TC 9.B.17) family. 2 isoforms of the human protein are produced by alternative splicing.

Protein type: Membrane protein, integral

Chromosomal Location of Human Ortholog: 20q13.33

Cellular Component: endoplasmic reticulum; endoplasmic reticulum membrane; Golgi apparatus; Golgi membrane; integral to membrane

Molecular Function: beta-tubulin binding; enzyme binding; FFAT motif binding; microtubule binding; protein binding; protein heterodimerization activity; protein homodimerization activity

Biological Process: cellular calcium ion homeostasis; endoplasmic reticulum organization and biogenesis; ER to Golgi vesicle-mediated transport; negative regulation of viral protein levels in host cell; positive regulation of viral genome replication; sphingolipid biosynthetic process; sphingolipid metabolic process; unfolded protein response; unfolded protein response, activation of signaling protein activity; virus-host interaction

Disease: Amyotrophic Lateral Sclerosis 8; Spinal Muscular Atrophy, Late-onset, Finkel Type