7sf8
GPR56 (ADGRG1) 7TM domain bound to tethered agonist in complex with G protein heterotrimer
Structural highlights
FunctionGNA13_HUMAN Guanine nucleotide-binding proteins (G proteins) are involved as modulators or transducers in various transmembrane signaling systems (PubMed:15240885, PubMed:16705036, PubMed:16787920, PubMed:27084452). Activates effector molecule RhoA by binding and activating RhoGEFs (ARHGEF1/p115RhoGEF, ARHGEF11/PDZ-RhoGEF and ARHGEF12/LARG) (PubMed:12515866, PubMed:15240885). GNA13-dependent Rho signaling subsequently regulates transcription factor AP-1 (activating protein-1) (By similarity). Promotes tumor cell invasion and metastasis by activating RhoA/ROCK signaling pathway (PubMed:16705036, PubMed:16787920, PubMed:27084452). Inhibits CDH1-mediated cell adhesion in process independent from Rho activation (PubMed:11976333).[UniProtKB:P27601][1] [2] [3] [4] [5] [6] Publication Abstract from PubMedAdhesion G-protein-coupled receptors (aGPCRs) are characterized by the presence of auto-proteolysing extracellular regions that are involved in cell-cell and cell-extracellular matrix interactions(1). Self cleavage within the aGPCR auto-proteolysis-inducing (GAIN) domain produces two protomers-N-terminal and C-terminal fragments-that remain non-covalently attached after receptors reach the cell surface(1). Upon dissociation of the N-terminal fragment, the C-terminus of the GAIN domain acts as a tethered agonist (TA) peptide to activate the seven-transmembrane domain with a mechanism that has been poorly understood(2-5). Here we provide cryo-electron microscopy snapshots of two distinct members of the aGPCR family, GPR56 (also known as ADGRG1) and latrophilin 3 (LPHN3 (also known as ADGRL3)). Low-resolution maps of the receptors in their N-terminal fragment-bound state indicate that the GAIN domain projects flexibly towards the extracellular space, keeping the encrypted TA peptide away from the seven-transmembrane domain. High-resolution structures of GPR56 and LPHN3 in their active, G-protein-coupled states, reveal that after dissociation of the extracellular region, the decrypted TA peptides engage the seven-transmembrane domain core with a notable conservation of interactions that also involve extracellular loop 2. TA binding stabilizes breaks in the middle of transmembrane helices 6 and 7 that facilitate aGPCR coupling and activation of heterotrimeric G proteins. Collectively, these results enable us to propose a general model for aGPCR activation. The tethered peptide activation mechanism of adhesion GPCRs.,Barros-Alvarez X, Nwokonko RM, Vizurraga A, Matzov D, He F, Papasergi-Scott MM, Robertson MJ, Panova O, Yardeni EH, Seven AB, Kwarcinski FE, Su H, Peroto MC, Meyerowitz JG, Shalev-Benami M, Tall GG, Skiniotis G Nature. 2022 Apr;604(7907):757-762. doi: 10.1038/s41586-022-04575-7. Epub 2022 , Apr 13. PMID:35418682[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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