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gamma-aminobutyric acid (GABA) B receptor, 1 (GABBR1, GPRC3A)
Function:
1) receptor for GABA Ca+2 required for high affinity binding to GABA
2) activity of this receptor mediated by Gi-proteins
a) inhibit adenylyl cyclase activity
b) stimulates phospholipase A2
c) activates K+ channels
d) inactivates voltage-dependent Ca+2-channels
e) modulates inositol phospholipids hydrolysis
3) fine-tuning of inhibitory synaptic transmission
4) pre-synaptic GABA-B-R inhibit neurotransmitter release via down-regulating high-voltage activated Ca+2 channels
5) postsynaptic GABA-B-R decrease neuronal excitability via activating a inwardly rectifying K+ (Kir) conductance associated with late inhibitory postsynaptic potentials
6) hippocampal long-term potentiation
7) slow wave sleep
8) muscle relaxation
9) antinociception
10) activated by (-)-baclofen, blocked by phaclofen.
Structure:
- serpentine receptor
- heterodimer of GABA-B-R1 & GABA-B-R2, neither of which is effective on its own;
- homodimeric assembly does not seem to occur
Expression:
- expressed in brain > heart, small intestine, uterus, kidney, lung, trachea, colon, small intestine, stomach, bone marrow, thymus, mammary gland.
- isoform 1A: granular cells, molecular layer
- isoform 1B: Purkinje cells
- soform 1E: peripheral tissues
General
gamma-aminobutyric acid (GABA) B receptor
Properties
SIZE: MW = 108 kD
entity length = 961 aa
COMPARTMENT: cellular membrane
MOTIF: signal sequence {1-14}
exoplasmic domain {15-591}
MOTIF: N-glycosylation site {N24}
Sushi domain {30-96}
N-glycosylation site {N84}
Sushi domain {98-159}
cysteine residue {C100}
MODIFICATION: cysteine residue {C145}
cysteine residue {C131}
MODIFICATION: cysteine residue {C157}
cysteine residue {C145}
MODIFICATION: cysteine residue {C100}
cysteine residue {C157}
MODIFICATION: cysteine residue {C131}
N-glycosylation site {N409}
N-glycosylation site {N440}
N-glycosylation site {N482}
N-glycosylation site {N502}
N-glycosylation site {N514}
transmembrane domain {592-612}
cytoplasmic loop {613-631}
transmembrane domain {632-652}
exoplasmic loop {653-667}
transmembrane domain {668-688}
cytoplasmic loop {689-710}
transmembrane domain {711-731}
exoplasmic loop {732-768}
transmembrane domain {769-789}
cytoplasmic loop {790-804}
transmembrane domain {805-825}
exoplasmic loop {826-833}
transmembrane domain {834-854}
cytoplasmic domain {855-961}
MOTIF: coiled coil {869-925}
Thr phosphorylation site {T930}
MISC-INFO: LIGAND = GABA
INHIBITOR = PHACLOFEN
Database Correlations
OMIM 603540
UniProt Q9UBS5
PFAM correlations
Entrez Gene 2550
References
- VanDongen AM, Codina J, Olate J, Mattera R, Joho R,
Birnbaumer L, Brown AM.
Newly identified brain potassium channels gated by the guanine
nucleotide binding protein Go.
Science. 1988 Dec 9;242(4884):1433-7.
PMID: 3144040
- Baumann PA, Wicki P, Stierlin C, Waldmeier PC.
Investigations on GABAB receptor-mediated autoinhibition of
GABA release.
Naunyn Schmiedebergs Arch Pharmacol. 1990 Jan-Feb;341(1-2):88-93.
PMID: 2156176
- UniProt :accession Q9UBS5