Bestrophin 1 (BEST1) Human Recombinant Protein

This gene encodes a member of the bestrophin gene family. This small gene family is characterized by proteins with a highly conserved N-terminus with four to six transmembrane domains. Bestrophins may form chloride ion channels or may regulate voltage-gated L-type calcium-ion channels. Bestrophins are generally believed to form calcium-activated chloride-ion channels in epithelial cells but they have also been shown to be highly permeable to bicarbonate ion transport in retinal tissue. Mutations in this gene are responsible for juvenile-onset vitelliform macular dystrophy (VMD2), also known as Best macular dystrophy, in addition to adult-onset vitelliform macular dystrophy (AVMD) and other retinopathies. Alternative splicing results in multiple variants encoding distinct isoforms.[provided by RefSeq, Nov 2008]

BEST1: Forms calcium-sensitive chloride channels. Highly permeable to bicarbonate. Defects in BEST1 are the cause of vitelliform macular dystrophy type 2 (VMD2); also known as Best macular dystrophy (BMD). VMD2 is an autosomal dominant form of macular degeneration that usually begins in childhood or adolescence. VMD2 is characterized by typical 'egg-yolk' macular lesions due to abnormal accumulation of lipofuscin within and beneath the retinal pigment epithelium cells. Progression of the disease leads to destruction of the retinal pigment epithelium and vision loss. Defects in BEST1 are the cause of retinitis pigmentosa type 50 (RP50). A retinal dystrophy belonging to the group of pigmentary retinopathies. RP is characterized by retinal pigment deposits visible on fundus examination and primary loss of rod photoreceptor cells followed by secondary loss of cone photoreceptors. Patients typically have night vision blindness and loss of midperipheral visual field. As their condition progresses, they lose their far peripheral visual field and eventually central vision as well. Defects in BEST1 are a cause of adult-onset vitelliform macular dystrophy (AVMD). AVMD is a rare autosomal dominant disorder with incomplete penetrance and highly variable expression. Patients usually become symptomatic in the fourth or fifth decade of life with a protracted disease of decreased visual acuity. Defects in BEST1 are the cause of bestrophinopathy autosomal recessive (ARB). A retinopathy characterized by central visual loss, an absent electro-oculogram light rise, and a reduced electroretinogram. Defects in BEST1 are the cause of vitreoretinochoroidopathy autosomal dominant (ADVIRC). A disorder characterized by vitreoretinochoroidal dystrophy. The clinical presentation is variable and may be associated with cataract, nanophthalmos, microcornea, shallow anterior chamber, and glaucoma. Belongs to the bestrophin family. 3 isoforms of the human protein are produced by alternative splicing.

Protein type: Channel, chloride; Membrane protein, multi-pass; Transporter; Membrane protein, integral; Transporter, ion channel

Chromosomal Location of Human Ortholog: 11q13

Cellular Component: membrane; basolateral plasma membrane; integral to membrane; plasma membrane; cytosol

Molecular Function: chloride channel activity

Biological Process: visual perception; transepithelial chloride transport; detection of light stimulus involved in visual perception; chloride transport; regulation of calcium ion transport; transmembrane transport

Disease: Macular Dystrophy, Vitelliform, 2; Vitreoretinochoroidopathy; Retinitis Pigmentosa 50; Bestrophinopathy, Autosomal Recessive