title: FRET-Based Sensors Unravel Activation and Allosteric Modulation of the GABABReceptor.
abstract: The main inhibitory neurotransmitter, γ-aminobutyric acid (GABA), modulates many synapses by activating the G protein-coupled receptor GABAB, which is a target for various therapeutic applications. It is an obligatory heterodimer made of GB1 and GB2 that can be regulated by positive allosteric modulators (PAMs). The molecular mechanism of activation of the GABABreceptor remains poorly understood. Here, we have developed FRET-based conformational GABABsensors compatible with high-throughput screening. We identified conformational changes occurring within the extracellular and transmembrane domains upon receptor activation, which are smaller than those observed in the related metabotropic glutamate receptors. These sensors also allow discrimination between agonists of different efficacies and between PAMs that have different modes of action, which has not always been possible using conventional functional assays. Our study brings important new information on the activation mechanism of the GABABreceptor and should facilitate the screening and identification of new chemicals targeting this receptor.
authors.affiliation: Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, University of Montpellier, 141 rue de la Cardonille, 34094 Montpellier, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Lecat-Guillet
authors.affiliation: Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, University of Montpellier, 141 rue de la Cardonille, 34094 Montpellier, France.
authors.forename: Carine
authors.initials: C
authors.lastname: Monnier
authors.affiliation: Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, University of Montpellier, 141 rue de la Cardonille, 34094 Montpellier, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: Rovira
authors.affiliation: Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, University of Montpellier, 141 rue de la Cardonille, 34094 Montpellier, France.
authors.forename: Julie
authors.initials: J
authors.lastname: Kniazeff
authors.affiliation: Cisbio Bioassays, F-30200 Codolet, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Lamarque
authors.affiliation: Cisbio Bioassays, F-30200 Codolet, France.
authors.forename: Jurriaan M
authors.initials: JM
authors.lastname: Zwier
authors.affiliation: Cisbio Bioassays, F-30200 Codolet, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Trinquet
authors.affiliation: Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, University of Montpellier, 141 rue de la Cardonille, 34094 Montpellier, France.
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Pin
authors.affiliation: Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, University of Montpellier, 141 rue de la Cardonille, 34094 Montpellier, France. Electronic address: philippe.rondard@igf.cnrs.fr.
authors.forename: Philippe
authors.initials: P
authors.lastname: Rondard
mesh_terms: D000494:Allosteric Regulation; D002118:Calcium / Q000032:analysis / Q000378:metabolism; D031541:Fluorescence Resonance Energy Transfer; D058786:GABA-B Receptor Agonists / Q000737:chemistry / Q000378:metabolism; D058788:GABA-B Receptor Antagonists / Q000737:chemistry / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism; D018080:Receptors, GABA-B / Q000737:chemistry / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000737:chemistry / Q000378:metabolism
chemical_list: D058786:GABA-B Receptor Agonists; D058788:GABA-B Receptor Antagonists; D021122:Protein Subunits; D018080:Receptors, GABA-B; D005680:gamma-Aminobutyric Acid; D002118:Calcium
keywords: ACP tag; SNAP tag; allostery; biased ligand; biosensors; lanthanide-based resonance energy transfer LRET; molecular pharmacology; signal transduction; time-resolved FRET