TY - JOUR
T1 - Structure and Dynamics of Adrenomedullin Receptors AM1 and AM2 Reveal Key Mechanisms in the Control of Receptor Phenotype by Receptor Activity-Modifying Proteins
AU - Liang, Yi Lynn
AU - Belousoff, Matthew J.
AU - Fletcher, Madeleine M.
AU - Zhang, Xin
AU - Khoshouei, Maryam
AU - Deganutti, Giuseppe
AU - Koole, Cassandra
AU - Furness, Sebastian G.B.
AU - Miller, Laurence J.
AU - Hay, Debbie L.
AU - Christopoulos, Arthur
AU - Reynolds, Christopher A.
AU - Danev, Radostin
AU - Wootten, Denise
AU - Sexton, Patrick M.
N1 - Publisher Copyright:
Copyright © 2020 American Chemical Society.
PY - 2020/4/10
Y1 - 2020/4/10
N2 - Adrenomedullin (AM) and calcitonin gene-related peptide (CGRP) receptors are critically important for metabolism, vascular tone, and inflammatory response. AM receptors are also required for normal lymphatic and blood vascular development and angiogenesis. They play a pivotal role in embryo implantation and fertility and can provide protection against hypoxic and oxidative stress. CGRP and AM receptors are heterodimers of the calcitonin receptor-like receptor (CLR) and receptor activity-modifying protein 1 (RAMP1) (CGRPR), as well as RAMP2 or RAMP3 (AM1R and AM2R, respectively). However, the mechanistic basis for RAMP modulation of CLR phenotype is unclear. In this study, we report the cryo-EM structure of the AM1R in complex with AM and Gs at a global resolution of 3.0 Å, and structures of the AM2R in complex with either AM or intermedin/adrenomedullin 2 (AM2) and Gs at 2.4 and 2.3 Å, respectively. The structures reveal distinctions in the primary orientation of the extracellular domains (ECDs) relative to the receptor core and distinct positioning of extracellular loop 3 (ECL3) that are receptor-dependent. Analysis of dynamic data present in the cryo-EM micrographs revealed additional distinctions in the extent of mobility of the ECDs. Chimeric exchange of the linker region of the RAMPs connecting the TM helix and the ECD supports a role for this segment in controlling receptor phenotype. Moreover, a subset of the motions of the ECD appeared coordinated with motions of the G protein relative to the receptor core, suggesting that receptor ECD dynamics could influence G protein interactions. This work provides fundamental advances in our understanding of GPCR function and how this can be allosterically modulated by accessory proteins.
AB - Adrenomedullin (AM) and calcitonin gene-related peptide (CGRP) receptors are critically important for metabolism, vascular tone, and inflammatory response. AM receptors are also required for normal lymphatic and blood vascular development and angiogenesis. They play a pivotal role in embryo implantation and fertility and can provide protection against hypoxic and oxidative stress. CGRP and AM receptors are heterodimers of the calcitonin receptor-like receptor (CLR) and receptor activity-modifying protein 1 (RAMP1) (CGRPR), as well as RAMP2 or RAMP3 (AM1R and AM2R, respectively). However, the mechanistic basis for RAMP modulation of CLR phenotype is unclear. In this study, we report the cryo-EM structure of the AM1R in complex with AM and Gs at a global resolution of 3.0 Å, and structures of the AM2R in complex with either AM or intermedin/adrenomedullin 2 (AM2) and Gs at 2.4 and 2.3 Å, respectively. The structures reveal distinctions in the primary orientation of the extracellular domains (ECDs) relative to the receptor core and distinct positioning of extracellular loop 3 (ECL3) that are receptor-dependent. Analysis of dynamic data present in the cryo-EM micrographs revealed additional distinctions in the extent of mobility of the ECDs. Chimeric exchange of the linker region of the RAMPs connecting the TM helix and the ECD supports a role for this segment in controlling receptor phenotype. Moreover, a subset of the motions of the ECD appeared coordinated with motions of the G protein relative to the receptor core, suggesting that receptor ECD dynamics could influence G protein interactions. This work provides fundamental advances in our understanding of GPCR function and how this can be allosterically modulated by accessory proteins.
KW - G protein-coupled receptor
KW - adrenomedullin
KW - allosteric modulation
KW - calcitonin gene-related peptide
KW - cryo-electron microscopy
KW - receptor activity-modifying protein
KW - receptor structure-function
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U2 - 10.1021/acsptsci.9b00080
DO - 10.1021/acsptsci.9b00080
M3 - Article
AN - SCOPUS:85084485340
SN - 2575-9108
VL - 3
SP - 263
EP - 284
JO - ACS Pharmacology and Translational Science
JF - ACS Pharmacology and Translational Science
IS - 2
ER -