Open AccessRedox Regulation of the Mitochondrial Quality Control Protease Oma1
Author(s) -
Iryna Bohovych,
Jonathan V. Dietz,
Samantha Swenson,
Nataliya Zahayko,
Oleh Khalimonchuk
Publication year - 2019
Publication title -
antioxidants and redox signaling
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.277
H-Index - 190
eISSN - 1557-7716
pISSN - 1523-0864
DOI - 10.1089/ars.2018.7642
Subject(s) - microbiology and biotechnology , protease , mitochondrion , intermembrane space , redox , proteases , biochemistry , biology , function (biology) , cysteine , proteostasis , proteolysis , chemistry , enzyme , bacterial outer membrane , gene , organic chemistry , escherichia coli
Aims: Normal mitochondrial function and integrity are crucial for cellular physiology. Given the paramount role of mitochondrial quality control proteases in these processes, our study focused on investigating mechanisms by which the activity of a key quality control protease Oma1 is regulated under normal conditions and in response to homeostatic insults. Results: Oma1 was found to be a redox-dependent protein that exists in a semi-oxidized state in yeast and mammalian mitochondria. Biochemical and genetic analyses provide evidence that activity and stability of the Oma1 oligomeric complex can be dynamically tuned in a reduction/oxidation-sensitive manner. Mechanistically, these features appear to be mediated by two intermembrane space (IMS)-exposed highly conserved cysteine residues, Cys 272 and Cys 332 . These residues form a disulfide bond, which likely plays a structural role and influences conformational stability and activity of the Oma1 high-mass complex. Finally, in line with these findings, engineered Oma1 substrate is shown to engage with the protease in a redox-sensitive manner. Innovation: This study provides new insights into the function of the Oma1 protease, a central controller of mitochondrial membrane homeostasis and dynamics, and reveals the novel conserved mechanism of the redox-dependent regulation of Oma1. Conclusion: Disulfide bonds formed by IMS-exposed residues Cys 272 and Cys 332 play an important evolutionarily conserved role in the regulation of Oma1 function. We propose that the redox status of these cysteines may act as a redox-tunable switch to optimize Oma1 proteolytic function for specific cellular conditions or homeostatic challenges.