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Mitochondrial Localization and Function of SESN2
Author(s) -
Budanov Andrei V.,
Kovaleva Irina,
Tokarchuk Artem,
Zheltukhin Andrey O.,
Dalina Alexandra A.,
Lyamzaev Konstantin G.,
Haidurov Alexander,
Chumakov Peter M.
Publication year - 2020
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2020.34.s1.06567
Subject(s) - mtorc1 , microbiology and biotechnology , mitochondrion , autophagy , biology , chemistry , signal transduction , biochemistry , apoptosis , pi3k/akt/mtor pathway
The goal of this study was to understand the potential mechanisms responsible for the regulation of metabolism and mitochondrial functions by SESTRIN2 (SESN2) and other members of the SESTRIN protein family. Our studies are based on cell fractionation and microscopy analyses to determine the localization of SESN2 and on the C. elegans model to define the role of SESTRINs in mitochondrial respiration. SESN2 is a member of evolutionarily conserved SESTRIN protein family found in the majority of the Metazoa species. SESN2 is transcriptionally activated by many stress factors including metabolic derangements, oxidants, and DNA‐damage. As a result, SESN2 suppresses oxidative stress, tunes up metabolic pathways, and regulates cell viability. Many of the activities of SESN2 are linked to regulation of mechanistic target of rapamycin complex 1 kinase (mTORC1) that plays the central role in the regulation of cell growth, metabolism, and autophagy. SESN2 inhibits mTORC1 activity through the interaction with the GATOR2 protein complex that prevents the inhibitory effect of GATOR2 on the GATOR1 protein complex and relieves an inhibitory effect of GATOR1 towards RagA/B GTPases, the major activators of mTORC1. Despite the well‐established role of SESN2 in the mTORC1 inhibition, some other SESN2 activities are not well characterized. As established by us and other groups, SESN2 can control mitochondrial respiration and cell death via mTORC1‐independent mechanisms. We hypothesized that these processes can be explained by the direct effects of SESN2 on mitochondria. To study the potential localization of SESN2 on mitochondria we performed mitochondrial fractionation from different human cancer cell lines and observed that considerable amounts of SESN2 protein were co‐purified with mitochondria. According to the results of treatment with proteases, SESN2 was located on the outer mitochondrial membrane. While we observed no association of SESN2 with the AKAP1 protein, as was previously reported, we found that the mitochondrial localization of SESN2 depends on GATOR2. We determine that mitochondrial SESN2 might be responsible for the regulation of the accumulation of reactive oxygen species and respiration in mammalian cells and C. elegans . We have shown that SESN2 is associated with mitochondria and can be directly involved in direct regulation of mitochondria functions. Support or Funding Information This work was supported by Russian Science Foundation grant 17‐14‐01420.