title: Allosteric modulation in monomers and oligomers of a G protein-coupled receptor.
abstract: The M2 muscarinic receptor is the prototypic model of allostery in GPCRs, yet the molecular and the supramolecular determinants of such effects are unknown. Monomers and oligomers of the M2 muscarinic receptor therefore have been compared to identify those allosteric properties that are gained in oligomers. Allosteric interactions were monitored by means of a FRET-based sensor of conformation at the allosteric site and in pharmacological assays involving mutants engineered to preclude intramolecular effects. Electrostatic, steric, and conformational determinants of allostery at the atomic level were examined in molecular dynamics simulations. Allosteric effects in monomers were exclusively negative and derived primarily from intramolecular electrostatic repulsion between the allosteric and orthosteric ligands. Allosteric effects in oligomers could be positive or negative, depending upon the allosteric-orthosteric pair, and they arose from interactions within and between the constituent protomers. The complex behavior of oligomers is characteristic of muscarinic receptors in myocardial preparations.
authors.affiliation: Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Canada.
authors.forename: Rabindra V
authors.identifier: 0000-0002-1478-5422
authors.initials: RV
authors.lastname: Shivnaraine
authors.affiliation: Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Canada.
authors.forename: Brendan
authors.initials: B
authors.lastname: Kelly
authors.affiliation: Department of Physiology, University of Toronto, Toronto, Canada.
authors.forename: Krishana S
authors.initials: KS
authors.lastname: Sankar
authors.affiliation: Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Canada.
authors.forename: Dar'ya S
authors.initials: DS
authors.lastname: Redka
authors.affiliation: Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Canada.
authors.forename: Yi Rang
authors.initials: YR
authors.lastname: Han
authors.affiliation: Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Canada.
authors.forename: Fei
authors.initials: F
authors.lastname: Huang
authors.affiliation: Departments of Psychiatry and Pharmacology, Hershey Medical Center, Hershey, United States.
authors.forename: Gwendolynne
authors.initials: G
authors.lastname: Elmslie
authors.affiliation: Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Canada.
authors.forename: Daniel
authors.initials: D
authors.lastname: Pinto
authors.affiliation: Department of Physics, University of Toronto, Toronto, Canada.
authors.forename: Yuchong
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Physiology, University of Toronto, Toronto, Canada.
authors.forename: Jonathan V
authors.initials: JV
authors.lastname: Rocheleau
authors.affiliation: Department of Physics, University of Toronto, Toronto, Canada.
authors.forename: Claudiu C
authors.initials: CC
authors.lastname: Gradinaru
authors.affiliation: Departments of Psychiatry and Pharmacology, Hershey Medical Center, Hershey, United States.
authors.forename: John
authors.initials: J
authors.lastname: Ellis
authors.affiliation: Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Canada.
authors.forename: James W
authors.initials: JW
authors.lastname: Wells
mesh_terms: D000494:Allosteric Regulation / Q000235:genetics*; D000495:Allosteric Site / Q000235:genetics; D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D008024:Ligands; D008968:Molecular Conformation; D056004:Molecular Dynamics Simulation; D011485:Protein Binding; D055503:Protein Multimerization / Q000235:genetics; D043585:Receptor, Muscarinic M2 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D043562:Receptors, G-Protein-Coupled / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D008024:Ligands; D043585:Receptor, Muscarinic M2; D043562:Receptors, G-Protein-Coupled
keywords: FRET; GPCR; allosteric modulation; biochemistry; biophysics; cooperativity; molecular dynamics; muscarinic; oligomer; structural biology