eIF2B conformation and assembly state regulates the integrated stress response

  1. Michael Schoof
  2. Morgane Boone
  3. Lan Wang
  4. Rosalie Lawrence
  5. Adam Frost  Is a corresponding author
  6. Peter Walter  Is a corresponding author
  1. University of California, San Francisco, United States
  2. Howard Hughes Medical Institute, University of California, San Francisco, United States

Abstract

The integrated stress response (ISR) is activated by phosphorylation of the translation initiation factor eIF2 in response to various stress conditions. Phosphorylated eIF2 (eIF2-P) inhibits eIF2's nucleotide exchange factor eIF2B, a two-fold symmetric heterodecamer assembled from subcomplexes. Here, we monitor and manipulate eIF2B assembly in vitro and in vivo. In the absence of eIF2B's α-subunit, the ISR is induced because unassembled eIF2B tetramer subcomplexes accumulate in cells. Upon addition of the small-molecule ISR inhibitor ISRIB, eIF2B tetramers assemble into active octamers. Surprisingly, ISRIB inhibits the ISR even in the context of fully assembled eIF2B decamers, revealing allosteric communication between the physically distant eIF2, eIF2-P, and ISRIB binding sites. Cryo-EM structures suggest a rocking motion in eIF2B that couples these binding sites. eIF2-P binding converts eIF2B decamers into 'conjoined tetramers' with diminished substrate binding and enzymatic activity. Canonical eIF2-P-driven ISR activation thus arises due to this change in eIF2B's conformational state.

Data availability

All data generated or analysed during this study are included in the manuscript and supporting files.

Article and author information

Author details

  1. Michael Schoof

    Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
    Competing interests
    No competing interests declared.
  2. Morgane Boone

    Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-7807-5542
  3. Lan Wang

    Department of Biochemistry and Biophysics, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, United States
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-8931-7201
  4. Rosalie Lawrence

    Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
    Competing interests
    No competing interests declared.
  5. Adam Frost

    Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
    For correspondence
    adam.frost@ucsf.edu
    Competing interests
    Adam Frost, Reviewing editor, eLife.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-2231-2577
  6. Peter Walter

    Department of Biochemistry and Biophysics, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, United States
    For correspondence
    peter@walterlab.ucsf.edu
    Competing interests
    Peter Walter, PW is an inventor on U.S. Patent 9708247 held by the Regents of the University of California that describes ISRIB and its analogs. Rights to the invention have been licensed by UCSF to Calico..
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-6849-708X

Funding

Howard Hughes Medical Institute (Investigator Grant)

  • Peter Walter

Howard Hughes Medical Institute (HHMI Faculty Scholar Grant)

  • Adam Frost

Calico Life Sciences LLC

  • Peter Walter

The George and Judy Marcus Family Foundation

  • Peter Walter

Damon Runyon Cancer Research Foundation (Postdoctoral Fellowship)

  • Lan Wang

Jane Coffin Childs Memorial Fund for Medical Research (Postdoctoral Fellowship)

  • Rosalie Lawrence

Belgian-American Educational Foundation (Postdoctoral Fellowship)

  • Morgane Boone

Chan Zuckerberg Initiative (Investigator Grant)

  • Adam Frost

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Reviewing Editor

  1. Nahum Sonenberg, McGill University, Canada

Publication history

  1. Received: December 12, 2020
  2. Accepted: March 9, 2021
  3. Accepted Manuscript published: March 10, 2021 (version 1)
  4. Version of Record published: March 24, 2021 (version 2)
  5. Version of Record updated: April 7, 2021 (version 3)

Copyright

© 2021, Schoof 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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  1. Michael Schoof
  2. Morgane Boone
  3. Lan Wang
  4. Rosalie Lawrence
  5. Adam Frost
  6. Peter Walter
(2021)
eIF2B conformation and assembly state regulates the integrated stress response
eLife 10:e65703.
https://doi.org/10.7554/eLife.65703

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