Pharmacological hallmarks of allostery at the M4 muscarinic receptor elucidated through structure and dynamics

Vuckovic, Z. et al. (2023) Pharmacological hallmarks of allostery at the M4 muscarinic receptor elucidated through structure and dynamics. eLife, 12, e83477. (doi: 10.7554/elife.83477) (PMID:37248726) (PMCID:PMC10229135)

Abstract

Allosteric modulation of G protein-coupled receptors (GPCRs) is a major paradigm in drug discovery. Despite decades of research, a molecular-level understanding of the general principles that govern the myriad pharmacological effects exerted by GPCR allosteric modulators remains limited. The M4 muscarinic acetylcholine receptor (M4 mAChR) is a validated and clinically relevant allosteric drug target for several major psychiatric and cognitive disorders. In this study, we rigorously quantified the affinity, efficacy, and magnitude of modulation of two different positive allosteric modulators, LY2033298 (LY298) and VU0467154 (VU154), combined with the endogenous agonist acetylcholine (ACh) or the high-affinity agonist iperoxo (Ipx), at the human M4 mAChR. By determining the cryo-electron microscopy structures of the M4 mAChR, bound to a cognate Gi1 protein and in complex with ACh, Ipx, LY298-Ipx, and VU154-Ipx, and applying molecular dynamics simulations, we determine key molecular mechanisms underlying allosteric pharmacology. In addition to delineating the contribution of spatially distinct binding sites on observed pharmacology, our findings also revealed a vital role for orthosteric and allosteric ligand–receptor–transducer complex stability, mediated by conformational dynamics between these sites, in the ultimate determination of affinity, efficacy, cooperativity, probe dependence, and species variability. There results provide a holistic framework for further GPCR mechanistic studies and can aid in the discovery and design of future allosteric drugs.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Tobin, Andrew

Creator Roles

Tobin, A.: Conceptualization, Resources, Funding acquisition, Project administration, Writing – review and editing

• Authors: Vuckovic, Z., Wang, J., Pham, V., Mobbs, J. I., Belousoff, M. J., Bhattarai, A., Burger, W. A.C., Thompson, G., Yeasmin, M., Nawaratne, V., Leach, K., van der Westhuizen, E. T., Khajehali, E., Liang, Y.-L., Glukhova, A., Wootten, D., Lindsley, C. W., Tobin, A., Sexton, P., Danev, R., Valant, C., Miao, Y., Christopoulos, A., and Thal, D. M.
• College/School: College of Medical Veterinary and Life Sciences > School of Molecular Biosciences
• Research Centre: Mazumdar-Shaw Advanced Research Centre (ARC) > Technologies Touching Life
• Journal Name: eLife
• Publisher: eLife Sciences Publications
• ISSN: 2050-084X
• ISSN (Online): 291297
• Copyright Holders: Copyright © 2023 Vuckovic, Wang, Pham et al.
• First Published: First published in eLife 12: e83477
• Publisher Policy: Reproduced under a Creative Commons License

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
173304		Collaborative Network to Define the Molecular Determinants of G Protein Coupled Receptor Clinical Efficacy	Andrew Tobin	Wellcome Trust (WELLCOTR)	201529/Z/16/Z	MCSB - Molecular Pharmacology