Localization
Cell membrane,Cell junction,Synapse,Postsynaptic cell membrane,Perikaryon,Cell projection,Dendrite;
Function
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:9872315, PubMed:9872317, Ref.4, PubMed:10075644, 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:9872315, PubMed:9872317, PubMed:10457184, PubMed:9872744, PubMed:10924501). Plays a critical role in the fine-tuning of inhibitory synaptic transmission (PubMed:9872317, PubMed:10457184, 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). Not only implicated in synaptic inhibition but also in hippocampal long-term potentiation, slow wave sleep, muscle relaxation and antinociception (By similarity).