BEST1
Domain
The C-terminal auto-inhibitory segment (AS) modulates the open/closed conformation of the channel (PubMed:35789156). In a closed conformation, the C-terminal auto-inhibitory segment constricts the channel concentrically by wrapping around the channel periphery in an inter-protomer manner (PubMed:35789156). To allow chloride movement, the C-terminal auto-inhibitory segment opens partially, leading to significantly smaller chloride movement (PubMed:35789156).
Function
Ligand-gated anion channel that allows the movement of anions across cell membranes when activated by calcium (Ca2+) (PubMed:11904445, PubMed:12907679, PubMed:18179881, PubMed:18400985, PubMed:19853238, PubMed:21330666, PubMed:26200502, PubMed:26720466, PubMed:35789156). Allows the movement of chloride and hydrogencarbonate (PubMed:11904445, PubMed:12907679, PubMed:18179881, PubMed:18400985, PubMed:19853238, PubMed:21330666, PubMed:26200502, PubMed:26720466, PubMed:35789156). Found in a partially open conformation leading to significantly smaller chloride movement (PubMed:35789156). Upon F2R/PAR-1 activation, the sequestered calcium is released into the cytosol of astrocytes, leading to the (Ca2+)-dependent release of L-glutamate into the synaptic cleft that targets the neuronal postsynaptic GRIN2A/NMDAR receptor resulting in the synaptic plasticity regulation (By similarity). Upon activation of the norepinephrine-alpha-1 adrenergic receptor signaling pathway, transports as well D-serine than L-glutamate in a (Ca2+)-dependent manner, leading to activation of adjacent NMDAR receptors and therefore regulates the heterosynaptic long-term depression and metaplasticity during initial memory acquisition (By similarity). Releases the 4-aminobutanoate neurotransmitter in a (Ca2+)-dependent manner, and participates in its tonic release from cerebellar glial cells (By similarity).
Involvement in disease
Macular dystrophy, vitelliform, 2
VMD2
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.
None
The disease is caused by variants affecting the gene represented in this entry.
Retinitis pigmentosa 50
RP50
A retinal dystrophy belonging to the group of pigmentary retinopathies. Retinitis pigmentosa 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.
None
The disease is caused by variants affecting the gene represented in this entry.
Bestrophinopathy, autosomal recessive
ARB
A retinopathy characterized by loss of central vision, an absent electro-oculogram light rise, and electroretinogram anomalies.
None
The disease is caused by variants affecting the gene represented in this entry.
Vitreoretinochoroidopathy
VRCP
An autosomal dominant ocular disorder characterized by vitreoretinochoroidal dystrophy. The clinical presentation is variable. VRCP may be associated with cataract, nanophthalmos, microcornea, shallow anterior chamber, and glaucoma.
None
The disease is caused by variants affecting the gene represented in this entry.
Sequence Similarities
Belongs to the anion channel-forming bestrophin (TC 1.A.46) family. Calcium-sensitive chloride channel subfamily.
Tissue Specificity
Predominantly expressed in the basolateral membrane of the retinal pigment epithelium.
Cellular localization
- Cell membrane
- Multi-pass membrane protein
- Basolateral cell membrane
- Multi-pass membrane protein
- Localized at the surface membrane of microdomains adjacent to glutamatergic synapses.
Alternative names
VMD2, BEST1, Bestrophin-1, TU15B, Vitelliform macular dystrophy protein 2