A tRNA processing enzyme is a key regulator of the mitochondrial unfolded protein response
Abstract
The mitochondrial unfolded protein response (UPRmt) has emerged as a predominant mechanism that preserves mitochondrial function. Consequently, multiple pathways likely exist to modulate UPRmt. We discovered that the tRNA processing enzyme, homolog of ELAC2 (HOE-1), is key to UPRmt regulation in Caenorhabditis elegans. We find that nuclear HOE-1 is necessary and sufficient to robustly activate UPRmt. We show that HOE-1 acts via transcription factors ATFS-1 and DVE-1 that are crucial for UPRmt. Mechanistically, we show that HOE-1 likely mediates its effects via tRNAs, as blocking tRNA export prevents HOE-1-induced UPRmt. Interestingly, we find that HOE-1 does not act via the integrated stress response, which can be activated by uncharged tRNAs, pointing towards its reliance on a new mechanism. Finally, we show that the subcellular localization of HOE-1 is responsive to mitochondrial stress and is subject to negative regulation via ATFS-1. Together, we have discovered a novel RNA-based cellular pathway that modulates UPRmt.
Data availability
All data generated or analyzed during this study are included in the manuscript and supporting files. Source data files have been provided for Figures 5 and 8.
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Author details
Funding
National Institute of General Medical Sciences (R01GM123260)
- James P Held
- Benjamin R Saunders
- Claudia V Pereria
- Maulik R Patel
National Institute on Aging (R00AG052666)
- Gaomin Feng
- Kristopher Burkewitz
National Institute of Environmental Health Sciences (T32ES007028)
- James P Held
National Institute of General Medical Sciences (R35GM145378)
- James P Held
- Benjamin R Saunders
- Maulik R Patel
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2022, Held 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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