Journal
JOURNAL OF BIOLOGICAL CHEMISTRY
Volume 290, Issue 34, Pages 20804-20814Publisher
AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
DOI: 10.1074/jbc.M115.669440
Keywords
-
Categories
Funding
- National Institutes of Health Ruth L. Kirschstein National Research Service Awards [GM871082, GM007185]
- National Institutes of Health [R01 GM061721, R01 GM071775]
- UCLA Cota-Robles Fellowship
- American Heart Association [0640076N]
- Muscular Dystrophy Association [022398]
Ask authors/readers for more resources
A redox-regulated import pathway consisting of Mia40 and Erv1 mediates the import of cysteine-rich proteins into the mitochondrial intermembrane space. Mia40 is the oxidoreductase that inserts two disulfide bonds into the substrate simultaneously. However, Mia40 has one redox-active cysteine pair, resulting in ambiguity about how Mia40 accepts numerous electrons during substrate oxidation. In this study, we have addressed the oxidation of Tim13 in vitro and in organello. Reductants such as glutathione and ascorbate inhibited both the oxidation of the substrate Tim13 in vitro and the import of Tim13 and Cmc1 into isolated mitochondria. In addition, a ternary complex consisting of Erv1, Mia40, and substrate, linked by disulfide bonds, was not detected in vitro. Instead, Mia40 accepted six electrons from substrates, and this fully reduced Mia40 was sensitive to protease, indicative of conformational changes in the structure. Mia40 in mitochondria from the erv1-101 mutant was also trapped in a completely reduced state, demonstrating that Mia40 can accept up to six electrons as substrates are imported. Therefore, these studies support that Mia40 functions as an electron sink to facilitate the insertion of two disulfide bonds into substrates.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available