Gabrd
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.
Function
Delta subunit of the heteropentameric ligand-gated chloride channel gated by gamma-aminobutyric acid (GABA), a major inhibitory neurotransmitter in the brain (By similarity). 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) (By similarity). When activated by GABA, GABAARs selectively allow the flow of chloride anions across the cell membrane down their electrochemical gradient (By similarity). GABAARs containing delta/GABRD subunits are predominantly expressed and located in extrasynaptic or perisynaptic positions on hippocampus and cerebellar granule cells, and contribute to the tonic GABAergic inhibition (PubMed:9464994). GABAAR containing alpha-4-beta-3-delta subunits 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 (By similarity).
Sequence Similarities
Belongs to the ligand-gated ion channel (TC 1.A.9) family. Gamma-aminobutyric acid receptor (TC 1.A.9.5) subfamily. GABRD sub-subfamily.
Tissue Specificity
Found in the brain, in cerebellar granule cells (PubMed:9464994). Expressed in lungs, in alveolar epithelium (PubMed:17003036).
Cellular localization
- Cell membrane
- Multi-pass membrane protein
- Delta subunits are found only on the extrasynaptic somatic and dendritic membranes.
Alternative names
Gamma-aminobutyric acid receptor subunit delta, GABA(A) receptor subunit delta, GABAAR subunit delta, Gabrd