Gamma-aminobutyric acid type B receptor subunit 1

UniProtKB accession:  Q9Z0U4

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UniProtKB description:  Component of a heterodimeric G-protein coupled receptor for GABA, formed by GABBR1 and GABBR2 (PubMed:9872315, PubMed:9872317, PubMed:9872744). Within the heterodimeric GABA receptor, only GABBR1 seems to bind agonists, while GABBR2 mediates coupling to G proteins (PubMed:9872317, PubMed:10658574). Ligand binding causes a conformation change that triggers signaling via guanine nucleotide-binding proteins (G proteins) and modulates the activity of down-stream effectors, such as adenylate cyclase (PubMed:10075644, PubMed:9872315, PubMed:9872744, PubMed:10924501). Signaling inhibits adenylate cyclase, stimulates phospholipase A2, activates potassium channels, inactivates voltage-dependent calcium-channels and modulates inositol phospholipid hydrolysis (PubMed:9069281, PubMed:10457184, PubMed:9872315, PubMed:9872744, PubMed:10924501, PubMed:10692480). Calcium is required for high affinity binding to GABA (PubMed:10692480). Plays a critical role in the fine-tuning of inhibitory synaptic transmission (PubMed:9872744). Pre-synaptic GABA receptor inhibits neurotransmitter release by down-regulating high-voltage activated calcium channels, whereas postsynaptic GABA receptor decreases neuronal excitability by activating a prominent inwardly rectifying potassium (Kir) conductance that underlies the late inhibitory postsynaptic potentials (PubMed:9872744, PubMed:10924501, PubMed:10692480). Not only implicated in synaptic inhibition but also in hippocampal long-term potentiation, slow wave sleep, muscle relaxation and antinociception (By similarity).