Structural details of a Class B GPCR-arrestin complex revealed by genetically encoded crosslinkers in living cells

• Published in: Nature communications Vol. 14; no. 1; p. 1151
• Main Authors: Aydin, Yasmin, Böttke, Thore, Lam, Jordy Homing, Ernicke, Stefan, Fortmann, Anna, Tretbar, Maik, Zarzycka, Barbara, Gurevich, Vsevolod V., Katritch, Vsevolod, Coin, Irene
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.03.2023; Nature Publishing Group; Nature Portfolio
• Subjects: 119/118; 631/114/2411; 631/45/612/194; 631/535/1267; 631/57/2266; 82/1; 82/29; 82/80; 96/106; 96/109; 96/95; Amino Acids; Arrestin; beta-Arrestin 1 - chemistry; Cell membranes; Crosslinking; Dynamic stability; G protein-coupled receptors; Genetic code; Humanities and Social Sciences; Life sciences; Models, Molecular; Molecular modelling; multidisciplinary; Parathyroid hormone; Phosphorylation; Proteins; Receptor, Parathyroid Hormone, Type 1 - chemistry; Receptors; Science; Science (multidisciplinary); Secretin; Selectivity; Structure-function relationships
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-023-36797-2

Understanding the molecular basis of arrestin-mediated regulation of GPCRs is critical for deciphering signaling mechanisms and designing functional selectivity. However, structural studies of GPCR-arrestin complexes are hampered by their highly dynamic nature. Here, we dissect the interaction of arrestin-2 (arr2) with the secretin-like parathyroid hormone 1 receptor PTH1R using genetically encoded crosslinking amino acids in live cells. We identify 136 intermolecular proximity points that guide the construction of energy-optimized molecular models for the PTH1R-arr2 complex. Our data reveal flexible receptor elements missing in existing structures, including intracellular loop 3 and the proximal C-tail, and suggest a functional role of a hitherto overlooked positively charged region at the arrestin N-edge. Unbiased MD simulations highlight the stability and dynamic nature of the complex. Our integrative approach yields structural insights into protein-protein complexes in a biologically relevant live-cell environment and provides information inaccessible to classical structural methods, while also revealing the dynamics of the system. The conformation of GPCR-arrestin complexes at the cell membrane, despite available structures, remains uncertain. This work reveals structure and dynamics of the PTH1R-arrestin2 complex, including flexible regions, in live cells.