Anti-Aquaporin 4 Antibody

Aquaporin-4 (UniProt: P55087; also known as AQP-4, Mercurial-insensitive water channel, MIWC, WCH4) is encoded by the AGP4 gene (Gene ID: 361) in human. Aquaporin-4 is a multi-pass membrane protein that forms a water-specific channel and serves as an osmoreceptor that regulates body water balance and mediates water flow within the central nervous system. Its extracellular domains are localized to amino acids 58-64, 137-155, and 206-231); its transmembrane domains are in amino acids 37-57, 65-85, 116-136, 156-176, 185-205, and 232-252); and the cytoplasmic domain is in amino acids 1-36, 86-115, 177-184, and 253-323). Aquaporin-4 is largely expressed in the brain and the skeletal muscle and at lower levels in heart, kidney, and lung tissue. Phosphorylation of Aquaporin-4 at Serine 180 by protein kinase C is shown to reduce conductance by about 50%, whereas phosphorylation at Serine 111 by protein kinase G in response to glutamate can increase conductance by about 40%. Two isoforms of Aquaporin-4 have been described that are produced by alternative splicing. Antibodies to Aquaporin-4 can serve as useful serum markers to distinguishing neuromyelitis Optica (NM) from multiple sclerosis. Clone mCCD does not cause redistribution of Aquaporin-4 and also it does not affect coaggregation astrocytic CD32-B and Aquaporin-4. (Ref.: Hinson, SR et al. (2017). Proc. Natl. Acad. Sci. USA 114(21); 5491-5496).