1. Biochemistry and Chemical Biology
  2. Structural Biology and Molecular Biophysics

Conformational fingerprinting of allosteric modulators in metabotropic glutamate receptor 2

  1. Brandon Wey-Hung Liauw
  2. Arash Foroutan
  3. Michael R Schamber
  4. Weifeng Lu
  5. Hamid Samareh Afsari  Is a corresponding author
  6. Reza Vafabakhsh  Is a corresponding author
  1. Northwestern University, United States
  2. Boehringer Ingelheim Pharmaceuticals, Inc, United States
https://doi.org/10.7554/eLife.78982
Share this article
Cite this article
  1. Brandon Wey-Hung Liauw
  2. Arash Foroutan
  3. Michael R Schamber
  4. Weifeng Lu
  5. Hamid Samareh Afsari
  6. Reza Vafabakhsh
(2022)
Conformational fingerprinting of allosteric modulators in metabotropic glutamate receptor 2
eLife 11:e78982.
https://doi.org/10.7554/eLife.78982
  2. Download BibTeX
  3. Download .RIS

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.

The following previously published data sets were used

Article and author information

Author details

  1. Brandon Wey-Hung Liauw

    Department of Molecular Biosciences, Northwestern University, Evanston, United States
    Competing interests
    No competing interests declared.

  2. Arash Foroutan

    Department of Molecular Biosciences, Northwestern University, Evanston, United States
    Competing interests
    No competing interests declared.

  3. Michael R Schamber

    Department of Molecular Biosciences, Northwestern University, Evanston, United States
    Competing interests
    No competing interests declared.

  4. Weifeng Lu

    Department of Molecular Biosciences, Northwestern University, Evanston, United States
    Competing interests
    No competing interests declared.

  5. Hamid Samareh Afsari

    Boehringer Ingelheim Pharmaceuticals, Inc, Ridgefield, United States
    For correspondence
    hamid.samareh_afsari@boehringer-ingelheim.com
    Competing interests
    Hamid Samareh Afsari, is affiliated with Boehringer Ingelheim Pharma GmbH & Co. The author has no financial interests to declare..
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-5839-4765

  6. Reza Vafabakhsh

    Department of Molecular Biosciences, Northwestern University, Evanston, United States
    For correspondence
    reza.vafabakhsh@northwestern.edu
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-8384-3203

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.

Metrics

  • 2,004
    views
  • 436
    downloads
  • 11
    citations

Views, downloads and citations are aggregated across all versions of this paper published by eLife.

Download links

A two-part list of links to download the article, or parts of the article, in various formats.

Downloads (link to download the article as PDF)

Open citations (links to open the citations from this article in various online reference manager services)

Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)

  1. Brandon Wey-Hung Liauw
  2. Arash Foroutan
  3. Michael R Schamber
  4. Weifeng Lu
  5. Hamid Samareh Afsari
  6. Reza Vafabakhsh
(2022)
Conformational fingerprinting of allosteric modulators in metabotropic glutamate receptor 2
eLife 11:e78982.
https://doi.org/10.7554/eLife.78982

Share this article

https://doi.org/10.7554/eLife.78982

Categories and tags

Further reading

    1. Biochemistry and Chemical Biology
    2. Microbiology and Infectious Disease

    On the role of VP3-PI3P interaction in birnavirus endosomal membrane targeting

    Flavia A Zanetti, Ignacio Fernandez ... Laura Ruth Delgui
    Research Article

    Birnaviruses are a group of double-stranded RNA (dsRNA) viruses infecting birds, fish, and insects. Early endosomes (EE) constitute the platform for viral replication. Here, we study the mechanism of birnaviral targeting of EE membranes. Using the Infectious Bursal Disease Virus (IBDV) as a model, we validate that the viral protein 3 (VP3) binds to phosphatidylinositol-3-phosphate (PI3P) present in EE membranes. We identify the domain of VP3 involved in PI3P-binding, named P2 and localized in the core of VP3, and establish the critical role of the arginine at position 200 (R200), conserved among all known birnaviruses. Mutating R200 abolishes viral replication. Moreover, we propose a two-stage modular mechanism for VP3 association with EE. Firstly, the carboxy-terminal region of VP3 adsorbs on the membrane, and then the VP3 core reinforces the membrane engagement by specifically binding PI3P through its P2 domain, additionally promoting PI3P accumulation.

    1. Biochemistry and Chemical Biology
    2. Microbiology and Infectious Disease

    Cellular Energy Production: Mycofactocin and the mycobacterial electron transport chain

    Stephanie M Stuteley, Ghader Bashiri
    Insight

    In the bacterium M. smegmatis, an enzyme called MftG allows the cofactor mycofactocin to transfer electrons released during ethanol metabolism to the electron transport chain.

    1. Biochemistry and Chemical Biology
    2. Structural Biology and Molecular Biophysics

    A conformational fingerprint for amyloidogenic light chains

    Cristina Paissoni, Sarita Puri ... Carlo Camilloni
    Research Article

    Both immunoglobulin light-chain (LC) amyloidosis (AL) and multiple myeloma (MM) share the overproduction of a clonal LC. However, while LCs in MM remain soluble in circulation, AL LCs misfold into toxic-soluble species and amyloid fibrils that accumulate in organs, leading to distinct clinical manifestations. The significant sequence variability of LCs has hindered the understanding of the mechanisms driving LC aggregation. Nevertheless, emerging biochemical properties, including dimer stability, conformational dynamics, and proteolysis susceptibility, distinguish AL LCs from those in MM under native conditions. This study aimed to identify a2 conformational fingerprint distinguishing AL from MM LCs. Using small-angle X-ray scattering (SAXS) under native conditions, we analyzed four AL and two MM LCs. We observed that AL LCs exhibited a slightly larger radius of gyration and greater deviations from X-ray crystallography-determined or predicted structures, reflecting enhanced conformational dynamics. SAXS data, integrated with molecular dynamics simulations, revealed a conformational ensemble where LCs adopt multiple states, with variable and constant domains either bent or straight. AL LCs displayed a distinct, low-populated, straight conformation (termed H state), which maximized solvent accessibility at the interface between constant and variable domains. Hydrogen-deuterium exchange mass spectrometry experimentally validated this H state. These findings reconcile diverse experimental observations and provide a precise structural target for future drug design efforts.