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Title: HSP101 Interacts with the Proteasome and Promotes the Clearance of Ubiquitylated Protein Aggregates

Abstract

Stressful environments often lead to protein unfolding and the formation of cytotoxic aggregates that can compromise cell survival. The molecular chaperone heat shock protein (HSP) 101 is a protein disaggregase that co-operates with the small HSP (sHSP) and HSP70 chaperones to facilitate removal of such aggregates and is essential for surviving severe heat stress. To better define how HSP101 protects plants, we investigated the localization and targets of this chaperone in Arabidopsis (Arabidopsis thaliana). By following HSP101 tagged with GFP, we discovered that its intracellular distribution is highly dynamic and includes a robust, reversible sequestration into cytoplasmic foci that vary in number and size among cell types and are potentially enriched in aggregated proteins. Affinity isolation of HSP101 recovered multiple proteasome subunits, suggesting a functional interaction. Consistent with this, the GFP-tagged 26S proteasome regulatory particle non-ATPase (RPN) 1a transiently colocalized with HSP101 in cytoplasmic foci during recovery. In addition, analysis of aggregated (insoluble) proteins showed they are extensively ubiquitylated during heat stress, especially in plants deficient in HSP101 or class I sHSPs, implying that protein disaggregation is important for optimal proteasomal degradation. Many potential HSP101 clients, identified by mass spectrometry of insoluble proteins, overlapped with known stress granule constituents andmore » sHSPinteracting proteins, confirming a role for HSP101 in stress granule function. Connections between HSP101, stress granules, proteasomes, and ubiquitylation imply that dynamic coordination between protein disaggregation and proteolysis is required to survive proteotoxic stress caused by protein aggregation at high temperatures.« less

Authors:
ORCiD logo [1];  [2]; ORCiD logo [3]; ORCiD logo [3]; ORCiD logo [2]
  1. Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01009, Department of Biology, Washington University in St. Louis, St. Louis, Missouri 63130
  2. Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01009
  3. Department of Biology, Washington University in St. Louis, St. Louis, Missouri 63130
Publication Date:
Research Org.:
Univ. of Massachusetts, Amherst, MA (United States)
Sponsoring Org.:
USDOE Office of Science (SC); National Institutes of Health (NIH); National Science Foundation (NSF)
OSTI Identifier:
1515079
Alternate Identifier(s):
OSTI ID: 1610879
Grant/Contract Number:  
SC0006646; GM-124452; IOS-1339325
Resource Type:
Published Article
Journal Name:
Plant Physiology (Bethesda)
Additional Journal Information:
Journal Name: Plant Physiology (Bethesda) Journal Volume: 180 Journal Issue: 4; Journal ID: ISSN 0032-0889
Publisher:
American Society of Plant Biologists
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; Plant Sciences

Citation Formats

McLoughlin, Fionn, Kim, Minsoo, Marshall, Richard S., Vierstra, Richard D., and Vierling, Elizabeth. HSP101 Interacts with the Proteasome and Promotes the Clearance of Ubiquitylated Protein Aggregates. United States: N. p., 2019. Web. doi:10.1104/pp.19.00263.
McLoughlin, Fionn, Kim, Minsoo, Marshall, Richard S., Vierstra, Richard D., & Vierling, Elizabeth. HSP101 Interacts with the Proteasome and Promotes the Clearance of Ubiquitylated Protein Aggregates. United States. doi:10.1104/pp.19.00263.
McLoughlin, Fionn, Kim, Minsoo, Marshall, Richard S., Vierstra, Richard D., and Vierling, Elizabeth. Tue . "HSP101 Interacts with the Proteasome and Promotes the Clearance of Ubiquitylated Protein Aggregates". United States. doi:10.1104/pp.19.00263.
@article{osti_1515079,
title = {HSP101 Interacts with the Proteasome and Promotes the Clearance of Ubiquitylated Protein Aggregates},
author = {McLoughlin, Fionn and Kim, Minsoo and Marshall, Richard S. and Vierstra, Richard D. and Vierling, Elizabeth},
abstractNote = {Stressful environments often lead to protein unfolding and the formation of cytotoxic aggregates that can compromise cell survival. The molecular chaperone heat shock protein (HSP) 101 is a protein disaggregase that co-operates with the small HSP (sHSP) and HSP70 chaperones to facilitate removal of such aggregates and is essential for surviving severe heat stress. To better define how HSP101 protects plants, we investigated the localization and targets of this chaperone in Arabidopsis (Arabidopsis thaliana). By following HSP101 tagged with GFP, we discovered that its intracellular distribution is highly dynamic and includes a robust, reversible sequestration into cytoplasmic foci that vary in number and size among cell types and are potentially enriched in aggregated proteins. Affinity isolation of HSP101 recovered multiple proteasome subunits, suggesting a functional interaction. Consistent with this, the GFP-tagged 26S proteasome regulatory particle non-ATPase (RPN) 1a transiently colocalized with HSP101 in cytoplasmic foci during recovery. In addition, analysis of aggregated (insoluble) proteins showed they are extensively ubiquitylated during heat stress, especially in plants deficient in HSP101 or class I sHSPs, implying that protein disaggregation is important for optimal proteasomal degradation. Many potential HSP101 clients, identified by mass spectrometry of insoluble proteins, overlapped with known stress granule constituents and sHSPinteracting proteins, confirming a role for HSP101 in stress granule function. Connections between HSP101, stress granules, proteasomes, and ubiquitylation imply that dynamic coordination between protein disaggregation and proteolysis is required to survive proteotoxic stress caused by protein aggregation at high temperatures.},
doi = {10.1104/pp.19.00263},
journal = {Plant Physiology (Bethesda)},
number = 4,
volume = 180,
place = {United States},
year = {2019},
month = {5}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record
DOI: 10.1104/pp.19.00263

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Cited by: 2 works
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