| comment |
-
FUNCTION Beta subunit of the heteropentameric ligand-gated chloride channel gated by gamma-aminobutyric acid (GABA), a major inhibitory neurotransmitter in the brain (PubMed:14993607, PubMed:18514161, PubMed:22243422, PubMed:22303015, PubMed:24909990, PubMed:26950270, PubMed:30602789). GABA-gated chloride channels, also named GABA(A) receptors (GABAAR), consist of five subunits arranged around a central pore and contain GABA active binding site(s) located at the alpha and beta subunit interface(s) (PubMed:24909990, PubMed:30140029, PubMed:30602789). GABAARs containing beta-3/GABRB3 subunit are found at both synaptic and extrasynaptic sites (By similarity). When activated by GABA, GABAARs selectively allow the flow of chloride anions across the cell membrane down their electrochemical gradient (PubMed:14993607, PubMed:22303015, PubMed:26950270, PubMed:30602789). Chloride influx into the postsynaptic neuron following GABAAR opening decreases the neuron ability to generate a new action potential, thereby reducing nerve transmission (PubMed:22303015, PubMed:26950270). GABAARs containing alpha-1 and beta-3 subunits exhibit synaptogenic activity; the gamma-2 subunit being necessary but not sufficient to induce rapid synaptic contacts formation (PubMed:25489750). Extrasynaptic beta-3 receptors contribute to the tonic GABAergic inhibition (By similarity). GABAARs containing alpha-1, beta-3 and epsilon subunits may also permit spontaneous chloride channel activity while preserving the structural information required for GABA-gated openings (By similarity). Beta-containing GABAARs can simultaneously bind GABA and histamine where histamine binds at the interface of two neighboring beta subunits, which may be involved in the regulation of sleep and wakefulness (PubMed:18281286, PubMed:24909990, PubMed:35355020). Plays an important role in somatosensation and in the production of antinociception (By similarity).CATALYTIC ACTIVITY chloride(in) = chloride(out)ACTIVITY REGULATION Potentiated by histamine.SUBUNIT Heteropentamer, formed by a combination of alpha (GABRA1-6), beta (GABRB1-3), gamma (GABRG1-3), delta (GABRD), epsilon (GABRE), rho (GABRR1-3), pi (GABRP) and theta (GABRQ) chains, each subunit exhibiting distinct physiological and pharmacological properties (PubMed:14993607, PubMed:18281286, PubMed:18514161, PubMed:22243422, PubMed:22303015, PubMed:24909990, PubMed:30140029, PubMed:30602789, PubMed:35355020). Can form functional homopentamers (in vitro) (PubMed:22303015). Interacts with UBQLN1 (By similarity). May interact with KIF21B (By similarity). Identified in a complex of 720 kDa composed of LHFPL4, NLGN2, GABRA1, GABRB2, GABRG2 and GABRB3 (By similarity). Interacts with LHFPL4 (By similarity). Interacts with GIT1; this interaction is required for synaptic GABRB3 surface stability and inhibitory synapse strength (By similarity).INTERACTION Isoforms differ in their signal region.DOMAIN GABAARs subunits share a common topological structure: a peptide sequence made up of a long extracellular N-terminal, four transmembrane domains, intracellular or cytoplasmic domain located between the third and the fourth transmembrane domains.POLYMORPHISM GABRB3 variants may be associated with insomnia, a condition of inability to initiate or maintain sleep [MIM:137192].DISEASE Disease susceptibility is associated with variants affecting the gene represented in this entry.DISEASE The disease is caused by variants affecting the gene represented in this entry.SIMILARITY Belongs to the ligand-gated ion channel (TC 1.A.9) family. Gamma-aminobutyric acid receptor (TC 1.A.9.5) subfamily. GABRB3 sub-subfamily.ONLINE INFORMATION Forbidden fruit - Issue 56 of March 2005
|
