6ocp

Structural highlights

Function

[KCD16_HUMAN] Auxiliary subunit of GABA-B receptors that determine the pharmacology and kinetics of the receptor response. Increases agonist potency and markedly alter the G-protein signaling of the receptors by accelerating onset and promoting desensitization (By similarity). [GABR2_HUMAN] Component of a heterodimeric G-protein coupled receptor for GABA, formed by GABBR1 and GABBR2. Within the heterodimeric GABA receptor, only GABBR1 seems to bind agonists, while GABBR2 mediates coupling to G proteins. 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. Signaling inhibits adenylate cyclase, stimulates phospholipase A2, activates potassium channels, inactivates voltage-dependent calcium-channels and modulates inositol phospholipid hydrolysis. Plays a critical role in the fine-tuning of inhibitory synaptic transmission. 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. Not only implicated in synaptic inhibition but also in hippocampal long-term potentiation, slow wave sleep, muscle relaxation and antinociception.^{[1] [2] [3] [4]}

References

1. ↑ White JH, Wise A, Main MJ, Green A, Fraser NJ, Disney GH, Barnes AA, Emson P, Foord SM, Marshall FH. Heterodimerization is required for the formation of a functional GABA(B) receptor. Nature. 1998 Dec 17;396(6712):679-82. PMID:9872316 doi:http://dx.doi.org/10.1038/25354
2. ↑ Martin SC, Russek SJ, Farb DH. Molecular identification of the human GABABR2: cell surface expression and coupling to adenylyl cyclase in the absence of GABABR1. Mol Cell Neurosci. 1999 Mar;13(3):180-91. PMID:10328880 doi:http://dx.doi.org/S1044-7431(99)90741-8
3. ↑ Nomura R, Suzuki Y, Kakizuka A, Jingami H. Direct detection of the interaction between recombinant soluble extracellular regions in the heterodimeric metabotropic gamma-aminobutyric acid receptor. J Biol Chem. 2008 Feb 22;283(8):4665-73. doi: 10.1074/jbc.M705202200. Epub 2007, Dec 28. PMID:18165688 doi:http://dx.doi.org/10.1074/jbc.M705202200
4. ↑ Geng Y, Xiong D, Mosyak L, Malito DL, Kniazeff J, Chen Y, Burmakina S, Quick M, Bush M, Javitch JA, Pin JP, Fan QR. Structure and functional interaction of the extracellular domain of human GABA(B) receptor GBR2. Nat Neurosci. 2012 Jun 3;15(7):970-8. doi: 10.1038/nn.3133. PMID:22660477 doi:10.1038/nn.3133