1. Biochemistry and Chemical Biology
  2. Cell Biology
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Proteasome storage granules protect proteasomes from autophagic degradation upon carbon starvation

  1. Richard Scott Marshall
  2. Richard David Vierstra  Is a corresponding author
  1. Washington University in St. Louis, United States
Research Article
  • Cited 45
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Cite this article as: eLife 2018;7:e34532 doi: 10.7554/eLife.34532

Abstract

26S proteasome abundance is tightly regulated at multiple levels, including the elimination of excess or inactive particles by autophagy. In yeast, this proteaphagy occurs upon nitrogen starvation but not carbon starvation, which instead stimulates the rapid sequestration of proteasomes into cytoplasmic puncta termed proteasome storage granules (PSGs). Here, we show that PSGs help protect proteasomes from autophagic degradation. Both the core protease and regulatory particle sub-complexes are sequestered separately into PSGs via pathways dependent on the accessory proteins Blm10 and Spg5, respectively. Modulating PSG formation, either by perturbing cellular energy status or pH, or by genetically eliminating factors required for granule assembly, not only influences the rate of proteasome degradation, but also impacts cell viability upon recovery from carbon starvation. PSG formation and concomitant protection against proteaphagy also occurs in Arabidopsis, suggesting that PSGs represent an evolutionarily conserved cache of proteasomes that can be rapidly re-mobilized based on energy availability.

Article and author information

Author details

  1. Richard Scott Marshall

    Department of Biology, Washington University in St. Louis, St. Louis, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-6844-1078
  2. Richard David Vierstra

    Department of Biology, Washington University in St. Louis, St. Louis, United States
    For correspondence
    rdvierstra@wustl.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-0210-3516

Funding

U.S. Department of Energy (DE-FG02-88ER13968)

  • Richard David Vierstra

National Science Foundation (IOS-1329956)

  • Richard David Vierstra

National Institutes of Health (R01-GM124452-01A1)

  • Richard David Vierstra

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

Reviewing Editor

  1. Raymond J Deshaies, California Institute of Technology, United States

Publication history

  1. Received: December 21, 2017
  2. Accepted: April 5, 2018
  3. Accepted Manuscript published: April 6, 2018 (version 1)
  4. Version of Record published: May 11, 2018 (version 2)

Copyright

© 2018, Marshall & Vierstra

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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