title: G-protein-coupled receptor inactivation by an allosteric inverse-agonist antibody.
abstract: G-protein-coupled receptors are the largest class of cell-surface receptors, and these membrane proteins exist in equilibrium between inactive and active states. Conformational changes induced by extracellular ligands binding to G-protein-coupled receptors result in a cellular response through the activation of G proteins. The A(2A) adenosine receptor (A(2A)AR) is responsible for regulating blood flow to the cardiac muscle and is important in the regulation of glutamate and dopamine release in the brain. Here we report the raising of a mouse monoclonal antibody against human A(2A)AR that prevents agonist but not antagonist binding to the extracellular ligand-binding pocket, and describe the structure of A(2A)AR in complex with the antibody Fab fragment (Fab2838). This structure reveals that Fab2838 recognizes the intracellular surface of A(2A)AR and that its complementarity-determining region, CDR-H3, penetrates into the receptor. CDR-H3 is located in a similar position to the G-protein carboxy-terminal fragment in the active opsin structure and to CDR-3 of the nanobody in the active β(2)-adrenergic receptor structure, but locks A(2A)AR in an inactive conformation. These results suggest a new strategy to modulate the activity of G-protein-coupled receptors.
authors.affiliation: Iwata Human Receptor Crystallography Project, ERATO, Japan Science and Technology Agency, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501, Japan.
authors.forename: Tomoya
authors.initials: T
authors.lastname: Hino
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Arakawa
authors.forename: Hiroko
authors.initials: H
authors.lastname: Iwanari
authors.forename: Takami
authors.initials: T
authors.lastname: Yurugi-Kobayashi
authors.forename: Chiyo
authors.initials: C
authors.lastname: Ikeda-Suno
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Nakada-Nakura
authors.forename: Osamu
authors.initials: O
authors.lastname: Kusano-Arai
authors.forename: Simone
authors.initials: S
authors.lastname: Weyand
authors.forename: Tatsuro
authors.initials: T
authors.lastname: Shimamura
authors.forename: Norimichi
authors.initials: N
authors.lastname: Nomura
authors.forename: Alexander D
authors.initials: AD
authors.lastname: Cameron
authors.forename: Takuya
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Takao
authors.initials: T
authors.lastname: Hamakubo
authors.forename: So
authors.initials: S
authors.lastname: Iwata
authors.forename: Takeshi
authors.initials: T
authors.lastname: Murata
mesh_terms: D000494:Allosteric Regulation / Q000187:drug effects*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000494:pharmacology*; D022801:Complementarity Determining Regions / Q000276:immunology; D054314:Drug Inverse Agonism; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000276:immunology / Q000494:pharmacology; D008024:Ligands; D051379:Mice; D008958:Models, Molecular; D055355:Opsins / Q000276:immunology; D010843:Pichia; D011487:Protein Conformation / Q000187:drug effects; D043705:Receptor, Adenosine A2A / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D043562:Receptors, G-Protein-Coupled / Q000819:agonists / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D022801:Complementarity Determining Regions; D007140:Immunoglobulin Fab Fragments; D008024:Ligands; D055355:Opsins; D043705:Receptor, Adenosine A2A; D043562:Receptors, G-Protein-Coupled