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

Version 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.

Metrics

  • 3,394
    views
  • 572
    downloads
  • 38
    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. 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

Share this article

https://doi.org/10.7554/eLife.50793

Further reading

    1. Biochemistry and Chemical Biology
    2. Cell Biology
    Jiabin Pan, Rui Zhou ... Xiang-dong Li
    Research Article

    Transport and localization of melanosome at the periphery region of melanocyte are depended on myosin-5a (Myo5a), which associates with melanosome by interacting with its adaptor protein melanophilin (Mlph). Mlph contains four functional regions, including Rab27a-binding domain, Myo5a GTD-binding motif (GTBM), Myo5a exon F-binding domain (EFBD), and actin-binding domain (ABD). The association of Myo5a with Mlph is known to be mediated by two specific interactions: the interaction between the exon-F-encoded region of Myo5a and Mlph-EFBD and that between Myo5a-GTD and Mlph-GTBM. Here, we identify a third interaction between Myo5a and Mlph, that is, the interaction between the exon-G-encoded region of Myo5a and Mlph-ABD. The exon-G/ABD interaction is independent from the exon-F/EFBD interaction and is required for the association of Myo5a with melanosome. Moreover, we demonstrate that Mlph-ABD interacts with either the exon-G or actin filament, but cannot interact with both of them simultaneously. Based on above findings, we propose a new model for the Mlph-mediated Myo5a transportation of melanosomes.

    1. Cell Biology
    Yuhao Wang, Linhao Ruan ... Rong Li
    Research Article

    Mitochondria are the cellular energy hub and central target of metabolic regulation. Mitochondria also facilitate proteostasis through pathways such as the ‘mitochondria as guardian in cytosol’ (MAGIC) whereby cytosolic misfolded proteins (MPs) are imported into and degraded inside mitochondria. In this study, a genome-wide screen in Saccharomyces cerevisiae uncovered that Snf1, the yeast AMP-activated protein kinase (AMPK), inhibits the import of MPs into mitochondria while promoting mitochondrial biogenesis under glucose starvation. We show that this inhibition requires a downstream transcription factor regulating mitochondrial gene expression and is likely to be conferred through substrate competition and mitochondrial import channel selectivity. We further show that Snf1/AMPK activation protects mitochondrial fitness in yeast and human cells under stress induced by MPs such as those associated with neurodegenerative diseases.