| Structural highlights
Function
[GRM2_HUMAN] G-protein coupled receptor for glutamate. 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 activity. May mediate suppression of neurotransmission or may be involved in synaptogenesis or synaptic stabilization.[1] [2] [3] [4]
Publication Abstract from PubMed
Family C G-protein-coupled receptors (GPCRs) operate as obligate dimers with extracellular domains that recognize small ligands, leading to G-protein activation on the transmembrane (TM) domains of these receptors by an unknown mechanism(1). Here we show structures of homodimers of the family C metabotropic glutamate receptor 2 (mGlu2) in distinct functional states and in complex with heterotrimeric Gi. Upon activation of the extracellular domain, the two transmembrane domains undergo extensive rearrangement in relative orientation to establish an asymmetric TM6-TM6 interface that promotes conformational changes in the cytoplasmic domain of one protomer. Nucleotide-bound Gi can be observed pre-coupled to inactive mGlu2, but its transition to the nucleotide-free form seems to depend on establishing the active-state TM6-TM6 interface. In contrast to family A and B GPCRs, G-protein coupling does not involve the cytoplasmic opening of TM6 but is facilitated through the coordination of intracellular loops 2 and 3, as well as a critical contribution from the C terminus of the receptor. The findings highlight the synergy of global and local conformational transitions to facilitate a new mode of G-protein activation.
G-protein activation by a metabotropic glutamate receptor.,Seven AB, Barros-Alvarez X, de Lapeyriere M, Papasergi-Scott MM, Robertson MJ, Zhang C, Nwokonko RM, Gao Y, Meyerowitz JG, Rocher JP, Schelshorn D, Kobilka BK, Mathiesen JM, Skiniotis G Nature. 2021 Jun 30. pii: 10.1038/s41586-021-03680-3. doi:, 10.1038/s41586-021-03680-3. PMID:34194039[5]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Gonzalez-Maeso J, Ang RL, Yuen T, Chan P, Weisstaub NV, Lopez-Gimenez JF, Zhou M, Okawa Y, Callado LF, Milligan G, Gingrich JA, Filizola M, Meana JJ, Sealfon SC. Identification of a serotonin/glutamate receptor complex implicated in psychosis. Nature. 2008 Mar 6;452(7183):93-7. doi: 10.1038/nature06612. Epub 2008 Feb 24. PMID:18297054 doi:http://dx.doi.org/10.1038/nature06612
- ↑ Delille HK, Becker JM, Burkhardt S, Bleher B, Terstappen GC, Schmidt M, Meyer AH, Unger L, Marek GJ, Mezler M. Heterocomplex formation of 5-HT2A-mGlu2 and its relevance for cellular signaling cascades. Neuropharmacology. 2012 Jun;62(7):2184-91. doi: 10.1016/j.neuropharm.2012.01.010., Epub 2012 Jan 25. PMID:22300836 doi:http://dx.doi.org/10.1016/j.neuropharm.2012.01.010
- ↑ Moreno JL, Muguruza C, Umali A, Mortillo S, Holloway T, Pilar-Cuellar F, Mocci G, Seto J, Callado LF, Neve RL, Milligan G, Sealfon SC, Lopez-Gimenez JF, Meana JJ, Benson DL, Gonzalez-Maeso J. Identification of three residues essential for 5-hydroxytryptamine 2A-metabotropic glutamate 2 (5-HT2A.mGlu2) receptor heteromerization and its psychoactive behavioral function. J Biol Chem. 2012 Dec 28;287(53):44301-19. doi: 10.1074/jbc.M112.413161. Epub, 2012 Nov 5. PMID:23129762 doi:http://dx.doi.org/10.1074/jbc.M112.413161
- ↑ Flor PJ, Lindauer K, Puttner I, Ruegg D, Lukic S, Knopfel T, Kuhn R. Molecular cloning, functional expression and pharmacological characterization of the human metabotropic glutamate receptor type 2. Eur J Neurosci. 1995 Apr 1;7(4):622-9. PMID:7620613
- ↑ Seven AB, Barros-Alvarez X, de Lapeyriere M, Papasergi-Scott MM, Robertson MJ, Zhang C, Nwokonko RM, Gao Y, Meyerowitz JG, Rocher JP, Schelshorn D, Kobilka BK, Mathiesen JM, Skiniotis G. G-protein activation by a metabotropic glutamate receptor. Nature. 2021 Jun 30. pii: 10.1038/s41586-021-03680-3. doi:, 10.1038/s41586-021-03680-3. PMID:34194039 doi:http://dx.doi.org/10.1038/s41586-021-03680-3
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