The integrated stress response remodels the microtubule organizing center to clear unfolded proteins following proteotoxic stress
- Howard Hughes Medical Institute, The Rockefeller University, United States
- University of Zurich, Switzerland
- Rockefeller University, United States
Abstract
Cells encountering stressful situations activate the integrated stress response (ISR) pathway to limit protein synthesis and redirect translation to better cope. The ISR has also been implicated in cancers, but redundancies in the stress-sensing kinases that trigger the ISR have posed hurdles to dissecting physiological relevance. To overcome this challenge, we targeted the regulatory node of these kinases, namely the S51 phosphorylation site of eukaryotic translation initiation factor eIF2α and genetically replaced eIF2α with eIF2α-S51A in mouse squamous cell carcinoma (SCC) stem cells of skin. While inconsequential under normal growth conditions, the vulnerability of this ISR-null state was unveiled when SCC stem cells experienced proteotoxic stress. Seeking mechanistic insights into the protective roles of the ISR, we combined ribosome profiling and functional approaches to identify and probe the functional importance of translational differences between ISR-competent and ISR-null SCC stem cells when exposed to proteotoxic stress. In doing so, we learned that the ISR redirects translation to centrosomal proteins that orchestrate the microtubule dynamics needed to efficiently concentrate unfolded proteins at the microtubule organizing center so that they can be cleared by the perinuclear degradation machinery. Thus, rather than merely maintaining survival during proteotoxic stress, the ISR also functions in promoting cellular recovery once the stress has subsided. Remarkably, this molecular program is unique to transformed skin stem cells hence exposing a vulnerability in cancer that could be exploited therapeutically.
Data availability
Sequencing data have been deposited in GEO under accession codes GSE193945
Article and author information
Author details
Funding
Howard Hughes Medical Institute
- Elaine Fuchs
Ruth Kirschstein NIH Predoctoral Fellow (F30CA236239)
- Brian Hurwitz
Weill Cornell/Rockefeller/Sloan Kettering Tri-Institutional Medical Scientist Training Program (T32GM007739)
- Brian Hurwitz
HHMI Jane Coffin Childs Associate
- Nicola Guzzi
Damon Runyon Cancer Research Foundation National Mah Jongg League Fellowship (DRG 2409-20)
- Anita Gola
National Institutes of Health (R01-AR27883)
- Elaine Fuchs
Robertson Foundation
- Brian Hurwitz
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: Animal experimentation: All animal procedures used in this study are described in our #20066H protocol named Development and Differentiation in the Skin, which had been previously reviewed and approved by the Rockefeller University Institutional Animal Care and Use Committee (IACUC).
Copyright
© 2022, Hurwitz 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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The integrated stress response remodels the microtubule organizing center to clear unfolded proteins following proteotoxic stress
eLife 11:e77780.
https://doi.org/10.7554/eLife.77780
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