Conformational fingerprinting of allosteric modulators in metabotropic glutamate receptor 2
- Northwestern University, United States
- Boehringer Ingelheim Pharmaceuticals, Inc, United States
Abstract
Activation of G protein-coupled receptors (GPCRs) is an allosteric process. It involves conformational coupling between the orthosteric ligand binding site and the G protein binding site. Factors that bind at non-cognate ligand binding sites to alter the allosteric activation process are classified as allosteric modulators and represent a promising class of therapeutics with distinct modes of binding and action. For many receptors, how modulation of signaling is represented at the structural level is unclear. Here, we developed FRET sensors to quantify receptor modulation at each of the three structural domains of metabotropic glutamate receptor 2 (mGluR2). We identified the conformational fingerprint for several allosteric modulators in live cells. This approach enabled us to derive a receptor-centric representation of allosteric modulation and to correlate structural modulation to the standard signaling modulation metrics. Single-molecule FRET analysis revealed that a NAM increases the occupancy of one of the intermediate states while a PAM increases the occupancy of the active state. Moreover, we found that the effect of allosteric modulators on the receptor dynamics is complex and depend on the orthosteric ligand. Collectively, our findings provide a structural mechanism of allosteric modulation in mGluR2 and suggest possible strategies for design of future modulators.
Data availability
All data generated or analyzed during this study are included in the manuscript and supporting files. Accompanying source data is provided for figures 1-4 and tables 1-3. The PDB accession codes for human mGluR2 structures used are 7MTS, 7MTR, 7E9G, 7EPE, and 7EPF.
Article and author information
Author details
Hamid Samareh Afsari
Funding
NIGMS (R01GM140272)
- Reza Vafabakhsh
NIGMS (T32GM-008061)
- Brandon Wey-Hung Liauw
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2022, Liauw et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Conformational fingerprinting of allosteric modulators in metabotropic glutamate receptor 2
eLife 11:e78982.
https://doi.org/10.7554/eLife.78982
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