title: A Hydrogen-Bonded Polar Network in the Core of the Glucagon-Like Peptide-1 Receptor Is a Fulcrum for Biased Agonism: Lessons from Class B Crystal Structures.
abstract: The glucagon-like peptide 1 (GLP-1) receptor is a class B G protein-coupled receptor (GPCR) that is a key target for treatments for type II diabetes and obesity. This receptor, like other class B GPCRs, displays biased agonism, though the physiologic significance of this is yet to be elucidated. Previous work has implicated R2.60(190), N3.43(240), Q7.49(394), and H6.52(363) as key residues involved in peptide-mediated biased agonism, with R2.60(190), N3.43(240), and Q7.49(394) predicted to form a polar interaction network. In this study, we used novel insight gained from recent crystal structures of the transmembrane domains of the glucagon and corticotropin releasing factor 1 (CRF1) receptors to develop improved models of the GLP-1 receptor that predict additional key molecular interactions with these amino acids. We have introduced E6.53(364)A, N3.43(240)Q, Q7.49(394)N, and N3.43(240)Q/Q7.49(394)N mutations to probe the role of predicted H-bonding and charge-charge interactions in driving cAMP, calcium, or extracellular signal-regulated kinase (ERK) signaling. A polar interaction between E6.53(364) and R2.60(190) was predicted to be important for GLP-1- and exendin-4-, but not oxyntomodulin-mediated cAMP formation and also ERK1/2 phosphorylation. In contrast, Q7.49(394), but not R2.60(190)/E6.53(364) was critical for calcium mobilization for all three peptides. Mutation of N3.43(240) and Q7.49(394) had differential effects on individual peptides, providing evidence for molecular differences in activation transition. Collectively, this work expands our understanding of peptide-mediated signaling from the GLP-1 receptor and the key role that the central polar network plays in these events.
authors.affiliation: Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia (D.W., C.K., T.Q., T.C., S.G.B.F., A.C., P.M.S.); School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, UK (C.A.R., K.J.S., J.C.M.); School of Life and Health Sciences, Aston University, Birmingham, UK (J.S.); and Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ (L.J.M.) denise.wootten@monash.edu patrick.sexton@monash.edu.
authors.forename: Denise
authors.initials: D
authors.lastname: Wootten
authors.affiliation: Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia (D.W., C.K., T.Q., T.C., S.G.B.F., A.C., P.M.S.); School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, UK (C.A.R., K.J.S., J.C.M.); School of Life and Health Sciences, Aston University, Birmingham, UK (J.S.); and Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ (L.J.M.).
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Reynolds
authors.affiliation: Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia (D.W., C.K., T.Q., T.C., S.G.B.F., A.C., P.M.S.); School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, UK (C.A.R., K.J.S., J.C.M.); School of Life and Health Sciences, Aston University, Birmingham, UK (J.S.); and Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ (L.J.M.).
authors.forename: Cassandra
authors.initials: C
authors.lastname: Koole
authors.affiliation: Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia (D.W., C.K., T.Q., T.C., S.G.B.F., A.C., P.M.S.); School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, UK (C.A.R., K.J.S., J.C.M.); School of Life and Health Sciences, Aston University, Birmingham, UK (J.S.); and Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ (L.J.M.).
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Smith
authors.affiliation: Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia (D.W., C.K., T.Q., T.C., S.G.B.F., A.C., P.M.S.); School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, UK (C.A.R., K.J.S., J.C.M.); School of Life and Health Sciences, Aston University, Birmingham, UK (J.S.); and Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ (L.J.M.).
authors.forename: Juan C
authors.initials: JC
authors.lastname: Mobarec
authors.affiliation: Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia (D.W., C.K., T.Q., T.C., S.G.B.F., A.C., P.M.S.); School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, UK (C.A.R., K.J.S., J.C.M.); School of Life and Health Sciences, Aston University, Birmingham, UK (J.S.); and Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ (L.J.M.).
authors.forename: John
authors.initials: J
authors.lastname: Simms
authors.affiliation: Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia (D.W., C.K., T.Q., T.C., S.G.B.F., A.C., P.M.S.); School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, UK (C.A.R., K.J.S., J.C.M.); School of Life and Health Sciences, Aston University, Birmingham, UK (J.S.); and Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ (L.J.M.).
authors.forename: Tezz
authors.initials: T
authors.lastname: Quon
authors.affiliation: Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia (D.W., C.K., T.Q., T.C., S.G.B.F., A.C., P.M.S.); School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, UK (C.A.R., K.J.S., J.C.M.); School of Life and Health Sciences, Aston University, Birmingham, UK (J.S.); and Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ (L.J.M.).
authors.forename: Thomas
authors.initials: T
authors.lastname: Coudrat
authors.affiliation: Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia (D.W., C.K., T.Q., T.C., S.G.B.F., A.C., P.M.S.); School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, UK (C.A.R., K.J.S., J.C.M.); School of Life and Health Sciences, Aston University, Birmingham, UK (J.S.); and Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ (L.J.M.).
authors.forename: Sebastian G B
authors.initials: SG
authors.lastname: Furness
authors.affiliation: Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia (D.W., C.K., T.Q., T.C., S.G.B.F., A.C., P.M.S.); School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, UK (C.A.R., K.J.S., J.C.M.); School of Life and Health Sciences, Aston University, Birmingham, UK (J.S.); and Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ (L.J.M.).
authors.forename: Laurence J
authors.initials: LJ
authors.lastname: Miller
authors.affiliation: Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia (D.W., C.K., T.Q., T.C., S.G.B.F., A.C., P.M.S.); School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, UK (C.A.R., K.J.S., J.C.M.); School of Life and Health Sciences, Aston University, Birmingham, UK (J.S.); and Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ (L.J.M.).
authors.forename: Arthur
authors.initials: A
authors.lastname: Christopoulos
authors.affiliation: Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia (D.W., C.K., T.Q., T.C., S.G.B.F., A.C., P.M.S.); School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, UK (C.A.R., K.J.S., J.C.M.); School of Life and Health Sciences, Aston University, Birmingham, UK (J.S.); and Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ (L.J.M.).
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Sexton
mesh_terms: D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D003460:Crystallization; D052216:Glucagon-Like Peptide 1 / Q000819:agonists* / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D006860:Hydrogen Bonding; D008958:Models, Molecular; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding / Q000502:physiology; D017433:Protein Structure, Secondary
chemical_list: D010446:Peptide Fragments; D052216:Glucagon-Like Peptide 1