Unstructured regions in IRE1α specify BiP-mediated destabilisation of the luminal domain dimer and repression of the UPR

  1. Niko Amin-Wetzel
  2. Lisa Neidhardt
  3. Yahui Yan
  4. Matthias P Mayer
  5. David Ron  Is a corresponding author
  1. University of Cambridge, United Kingdom
  2. University of Heidelberg, Germany

Abstract

Coupling of endoplasmic reticulum stress to dimerisation‑dependent activation of the UPR transducer IRE1 is incompletely understood. Whilst the luminal co-chaperone ERdj4 promotes a complex between the Hsp70 BiP and IRE1's stress-sensing luminal domain (IRE1LD) that favours the latter's monomeric inactive state and loss of ERdj4 de-represses IRE1, evidence linking these cellular and in vitro observations is presently lacking. We report that enforced loading of endogenous BiP onto endogenous IRE1α repressed UPR signalling in CHO cells and deletions in the IRE1α locus that de-repressed the UPR in cells, encode flexible regions of IRE1LD that mediated BiP‑induced monomerisation in vitro. Changes in the hydrogen exchange mass spectrometry profile of IRE1LD induced by ERdj4 and BiP confirmed monomerisation and were consistent with active destabilisation of the IRE1LD dimer. Together, these observations support a competition model whereby waning ER stress passively partitions ERdj4 and BiP to IRE1LD to initiate active repression of UPR signalling.

Data availability

Diffraction data have been deposited in PDB under the accession code 6SHCAll data generated or analysed during this study are included in the manuscript and supporting files. Source data files have been provided for Figures 1 - 7.

The following data sets were generated

Article and author information

Author details

  1. Niko Amin-Wetzel

    Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, United Kingdom
    Competing interests
    No competing interests declared.
  2. Lisa Neidhardt

    Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, United Kingdom
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-0256-5040
  3. Yahui Yan

    Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-6934-9874
  4. Matthias P Mayer

    Zentrum für Molekulare Biologie der Universität Heidelberg, University of Heidelberg, Heidelberg, Germany
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-7859-3112
  5. David Ron

    Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
    For correspondence
    dr360@medschl.cam.ac.uk
    Competing interests
    David Ron, Senior editor, eLife.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-3014-5636

Funding

Medical Research Council

  • Niko Amin-Wetzel

European Molecular Biology Organization

  • Lisa Neidhardt

Deutsche Forschungsgemeinschaft (SFB1036 TP9)

  • Matthias P Mayer

Wellcome (Wellcome 996 100140)

  • David Ron

Wellcome (Wellcome 200848/Z/16/Z)

  • David Ron

Deutsche Forschungsgemeinschaft (MA 1278/4-3)

  • Matthias P Mayer

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

Reviewing Editor

  1. Linda M Hendershot, St. Jude Children's Research Hospital, United States

Publication history

  1. Received: August 2, 2019
  2. Accepted: December 23, 2019
  3. Accepted Manuscript published: December 24, 2019 (version 1)
  4. Version of Record published: February 3, 2020 (version 2)

Copyright

© 2019, Amin-Wetzel 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. Niko Amin-Wetzel
  2. Lisa Neidhardt
  3. Yahui Yan
  4. Matthias P Mayer
  5. David Ron
(2019)
Unstructured regions in IRE1α specify BiP-mediated destabilisation of the luminal domain dimer and repression of the UPR
eLife 8:e50793.
https://doi.org/10.7554/eLife.50793

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