Lecat-Guillet Nathalie, Monnier Carine, Rovira Xavier, Kniazeff Julie, Lamarque Laurent, Zwier Jurriaan M, Trinquet Eric, Pin Jean-Philippe, Rondard Philippe
Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, University of Montpellier, 141 rue de la Cardonille, 34094 Montpellier, France.
Cisbio Bioassays, F-30200 Codolet, France.
Cell Chem Biol. 2017 Mar 16;24(3):360-370. doi: 10.1016/j.chembiol.2017.02.011. Epub 2017 Mar 9.
The main inhibitory neurotransmitter, γ-aminobutyric acid (GABA), modulates many synapses by activating the G protein-coupled receptor GABA, 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 GABA receptor remains poorly understood. Here, we have developed FRET-based conformational GABA sensors 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 GABA receptor and should facilitate the screening and identification of new chemicals targeting this receptor.
主要抑制性神经递质γ-氨基丁酸（GABA）通过激活G蛋白偶联受体GABA来调节许多突触，该受体是各种治疗应用的靶点。它是由GB1和GB2组成的必需异二聚体，可由正变构调节剂（PAM）调节。GABA受体激活的分子机制仍知之甚少。在这里，我们开发了与高通量筛选兼容的基于荧光共振能量转移（FRET）的构象GABA传感器。我们确定了受体激活后细胞外和跨膜结构域内发生的构象变化，这些变化比在相关的代谢型谷氨酸受体中观察到的变化小。这些传感器还能够区分不同效力的激动剂以及具有不同作用模式的PAM，而使用传统功能测定法并非总是能够做到这一点。我们的研究为GABA受体的激活机制带来了重要的新信息，并应有助于筛选和鉴定靶向该受体的新化学物质。
