Distinct roles of metabotropic glutamate receptor dimerization in agonist activation and G-protein coupling
| Autor: | Patrick Bron, Jean-Philippe Pin, Pauline Scholler, Philippe Rondard, Driss El Moustaine, Jean-Louis Banères, Bernard Mouillac, Rita Rahmeh, Etienne Doumazane, Sébastien Granier |
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| Rok vydání: | 2012 |
| Předmět: |
Multidisciplinary
Metabotropic glutamate receptor 5 Chemistry Inositol Phosphates Metabotropic glutamate receptor 4 Metabotropic glutamate receptor 7 Metabotropic glutamate receptor 6 Glutamic Acid Glutamate binding Biological Sciences Receptors Metabotropic Glutamate Nanostructures Receptors G-Protein-Coupled Cell biology HEK293 Cells Microscopy Electron Transmission GTP-Binding Proteins Metabotropic glutamate receptor Fluorescence Resonance Energy Transfer Humans Metabotropic glutamate receptor 1 Metabotropic glutamate receptor 2 Dimerization |
| Zdroj: | Proceedings of the National Academy of Sciences. 109:16342-16347 |
| ISSN: | 1091-6490 0027-8424 |
| DOI: | 10.1073/pnas.1205838109 |
| Popis: | The eight metabotropic glutamate receptors (mGluRs) are key modulators of synaptic transmission and are considered promising targets for the treatment of various brain disorders. Whereas glutamate acts at a large extracellular domain, allosteric modulators have been identified that bind to the seven transmembrane domain (7TM) of these dimeric G-protein-coupled receptors (GPCRs). We show here that the dimeric organization of mGluRs is required for the modulation of active and inactive states of the 7TM by agonists, but is not necessary for G-protein activation. Monomeric mGlu2, either as an isolated 7TM or in full-length, purified and reconstituted into nanodiscs, couples to G proteins upon direct activation by a positive allosteric modulator. However, only a reconstituted full-length dimeric mGlu2 activates G protein upon glutamate binding, suggesting that dimerization is required for glutamate induced activation. These data show that, even for such well characterized GPCR dimers like mGluR2, a single 7TM is sufficient for G-protein coupling. Despite this observation, the necessity of dimeric architecture for signaling induced by the endogenous ligand glutamate confirms that the central core of signaling complex is dimeric. |
| Databáze: | OpenAIRE |
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