Illuminating the activation mechanisms and allosteric properties of metabotropic glutamate receptors

New sensor technology to study mGluR activation and conformational change in living cells using Tag-lite substrates and IP-One (by IGF and Cisbio bioassays).

Doumazane E, Scholler P, Fabre L, Zwier JM, Trinquet E, Pin JP, Rondard P.


Institut de Génomique Fonctionnelle, Montpellier, France. Cisbio Bioassays, Codolet, France.

Proc Natl Acad Sci U S A. 2013;110(15):E1416-25.

In multimeric cell-surface receptors, the conformational changes of the extracellular ligand-binding domains (ECDs) associated with receptor activation remain largely unknown. This is the case for the dimeric metabotropic glutamate receptors even though a number of ECD structures have been solved. Here, using an innovative approach based on cell-surface labeling and FRET, we demonstrate that a reorientation of the ECDs is associated with receptor and G-protein activation. Our approach helps identify partial agonists and highlights allosteric interactions between the effector and binding domains. Any approach expected to stabilize the active conformation of the effector domain increased the agonist potency in stabilizing the active ECDs conformation. These data provide key information on the structural dynamics and drug action at metabotropic glutamate receptors and validate an approach for tackling such analysis on other receptors.

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