7mts
CryoEM Structure of mGlu2 - Gi ComplexCryoEM Structure of mGlu2 - Gi Complex
Structural highlights
FunctionGRM2_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 PubMedFamily 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. See AlsoReferences
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