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Elife DOI:10.7554/eLife.49178

Distinct mitochondrial defects trigger the integrated stress response depending on the metabolic state of the cell.

Publication TypeJournal Article
Year of Publication2020
AuthorsMick, E, Titov, DV, Skinner, OS, Sharma, R, Jourdain, AA, Mootha, VK
JournalElife
Volume9
Date Published2020 May 28
ISSN2050-084X
Abstract

Mitochondrial dysfunction is associated with activation of the integrated stress response (ISR) but the underlying triggers remain unclear. We systematically combined acute mitochondrial inhibitors with genetic tools for compartment-specific NADH oxidation to trace mechanisms linking different forms of mitochondrial dysfunction to the ISR in proliferating mouse myoblasts and in differentiated myotubes. In myoblasts, we find that impaired NADH oxidation upon electron transport chain (ETC) inhibition depletes asparagine, activating the ISR via the eIF2α kinase GCN2. In myotubes, however, impaired NADH oxidation following ETC inhibition neither depletes asparagine nor activates the ISR, reflecting an altered metabolic state. ATP synthase inhibition in myotubes triggers the ISR via a distinct mechanism related to mitochondrial inner-membrane hyperpolarization. Our work dispels the notion of a universal path linking mitochondrial dysfunction to the ISR, instead revealing multiple paths that depend both on the nature of the mitochondrial defect and on the metabolic state of the cell.

DOI10.7554/eLife.49178
Pubmed

http://www.ncbi.nlm.nih.gov/pubmed/32463360?dopt=Abstract

Alternate JournalElife
PubMed ID32463360
Grant ListR35GM122455 / NH / NIH HHS / United States
Graduate Student Fellowship / HHMI / Howard Hughes Medical Institute / United States
1F32GM133047-01 / NH / NIH HHS / United States
Postdoctoral Fellowship / SNSF_ / Swiss National Science Foundation / Switzerland