Structural basis for the tethered peptide activation of adhesion GPCRs

• Published in: Nature (London) Vol. 604; no. 7907; pp. 763 - 770
• Main Authors: Ping, Yu-Qi, Xiao, Peng, Yang, Fan, Zhao, Ru-Jia, Guo, Sheng-Chao, Yan, Xu, Wu, Xiang, Zhang, Chao, Lu, Yan, Zhao, Fenghui, Zhou, Fulai, Xi, Yue-Tong, Yin, Wanchao, Liu, Feng-Zhen, He, Dong-Fang, Zhang, Dao-Lai, Zhu, Zhong-Liang, Jiang, Yi, Du, Lutao, Feng, Shi-Qing, Schöneberg, Torsten, Liebscher, Ines, Xu, H. Eric, Sun, Jin-Peng
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 28.04.2022; Nature Publishing Group
• Subjects: 101/28; 13/95; 14/1; 38/109; 38/77; 45/70; 631/45/535/1258/1259; 631/45/612/194; 82/16; 82/29; 82/80; 82/83; Adhesion; Binding Sites; Conserved sequence; Coupling; Cross-reactivity; Cryoelectron Microscopy; Electron microscopy; G protein-coupled receptors; Helices; Humanities and Social Sciences; Hydrogen; Hydrogen bonds; Hydrophobicity; Microscopy; multidisciplinary; Mutation; Organogenesis; Peptides; Protein Domains; Protein Structure, Secondary; Proteins; Receptor mechanisms; Receptors; Receptors, G-Protein-Coupled - metabolism; Science; Science (multidisciplinary); Selectivity; Structure-Activity Relationship
• ISSN: 0028-0836; 1476-4687; 1476-4687
• DOI: 10.1038/s41586-022-04619-y

Adhesion G-protein-coupled receptors (aGPCRs) are important for organogenesis, neurodevelopment, reproduction and other processes 1 – 6 . Many aGPCRs are activated by a conserved internal (tethered) agonist sequence known as the Stachel sequence 7 – 12 . Here, we report the cryogenic electron microscopy (cryo-EM) structures of two aGPCRs in complex with G s : GPR133 and GPR114. The structures indicate that the Stachel sequences of both receptors assume an α-helical–bulge–β-sheet structure and insert into a binding site formed by the transmembrane domain (TMD). A hydrophobic interaction motif (HIM) within the Stachel sequence mediates most of the intramolecular interactions with the TMD. Combined with the cryo-EM structures, biochemical characterization of the HIM motif provides insight into the cross-reactivity and selectivity of the Stachel sequences. Two interconnected mechanisms, the sensing of Stachel sequences by the conserved ‘toggle switch’ W 6.53 and the constitution of a hydrogen-bond network formed by Q 7.49 /Y 7.49 and the P 6.47 /V 6.47 φφG 6.50 motif (φ indicates a hydrophobic residue), are important in Stachel sequence-mediated receptor activation and G s coupling. Notably, this network stabilizes kink formation in TM helices 6 and 7 (TM6 and TM7, respectively). A common G s -binding interface is observed between the two aGPCRs, and GPR114 has an extended TM7 that forms unique interactions with G s . Our structures reveal the detailed mechanisms of aGPCR activation by Stachel sequences and their G s coupling. Adhesion GPCRs involved in cell and matrix interactions signal through a distinct self-cleavage, self-activation mechanism.