title: Ligand-Dependent Modulation of G Protein Conformation Alters Drug Efficacy.
abstract: G protein-coupled receptor (GPCR) signaling, mediated by hetero-trimeric G proteins, can be differentially controlled by agonists. At a molecular level, this is thought to occur principally via stabilization of distinct receptor conformations by individual ligands. These distinct conformations control subsequent recruitment of transducer and effector proteins. Here, we report that ligand efficacy at the calcitonin GPCR (CTR) is also correlated with ligand-dependent alterations to G protein conformation. We observe ligand-dependent differences in the sensitivity of the G protein ternary complex to disruption by GTP, due to conformational differences in the receptor-bound G protein hetero-trimer. This results in divergent agonist-dependent receptor-residency times for the hetero-trimeric G protein and different accumulation rates for downstream second messengers. This study demonstrates that factors influencing efficacy extend beyond receptor conformation(s) and expands understanding of the molecular basis for how G proteins control/influence efficacy. This has important implications for the mechanisms that underlie ligand-mediated biased agonism. VIDEO ABSTRACT.
authors.affiliation: Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, 3052 VIC, Australia. Electronic address: sebastian.furness@monash.edu.
authors.forename: Sebastian George Barton
authors.initials: SGB
authors.lastname: Furness
authors.affiliation: Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, 3052 VIC, Australia.
authors.forename: Yi-Lynn
authors.initials: YL
authors.lastname: Liang
authors.affiliation: Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, 3052 VIC, Australia.
authors.forename: Cameron James
authors.initials: CJ
authors.lastname: Nowell
authors.affiliation: Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, 3052 VIC, Australia.
authors.forename: Michelle Louise
authors.initials: ML
authors.lastname: Halls
authors.affiliation: Department of Medicine, Austin Health, University of Melbourne, Austin Campus, Heidelberg, VIC 3084, Australia.
authors.forename: Peter John
authors.initials: PJ
authors.lastname: Wookey
authors.affiliation: Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, 3052 VIC, Australia.
authors.forename: Emma
authors.initials: E
authors.lastname: Dal Maso
authors.affiliation: Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3, Aoba, Aramaki, Aoba-ku, Sendai 980-0065, Japan; Japan Science and Technology Agency (JST), Precursory Research for Embryonic Sciences and Technology (PRESTO), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan.
authors.forename: Asuka
authors.initials: A
authors.lastname: Inoue
authors.affiliation: Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, 3052 VIC, Australia.
authors.forename: Arthur
authors.initials: A
authors.lastname: Christopoulos
authors.affiliation: Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, 3052 VIC, Australia.
authors.forename: Denise
authors.initials: D
authors.lastname: Wootten
authors.affiliation: Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, 3052 VIC, Australia. Electronic address: patrick.sexton@monash.edu.
authors.forename: Patrick Michael
authors.initials: PM
authors.lastname: Sexton
mesh_terms: D000244:Adenosine Diphosphate / Q000096:biosynthesis; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D019204:GTP-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism / Q000494:pharmacology*; D006801:Humans; D008024:Ligands; D011487:Protein Conformation; D055503:Protein Multimerization; D018003:Receptors, Calcitonin / Q000819:agonists* / Q000737:chemistry* / Q000378:metabolism
chemical_list: D008024:Ligands; D018003:Receptors, Calcitonin; D000244:Adenosine Diphosphate; D006160:Guanosine Triphosphate; D019204:GTP-Binding Proteins
keywords: BRET; CTR; FRET; G protein-coupled receptor; GPCR; TIRF; calcitonin; calcitonin receptor; efficacy; native PAGE