Redox-abhängige Steuerung mitochondrialer Intermembranraumproteine
Zusammenfassung der Projektergebnisse
The intermembrane space (IMS) of mitochondria contains about 50 to 100 proteins, many of which contain conserved disulfide bonds. All IMS proteins are synthesized on cytosolic ribosomes and are imported through the pore of the TOM complex. The IMS protein Mia40 plays two essential and experimental separable functions in the biogenesis of IMS proteins. First, its hydrophobic substrate binding cleft serves as docking site for cytosolic IMS precursors. Binding to Mia40 is essential for the translocation of IMS proteins across the outer membrane. Secondly, Mia40 serves as oxidoreductase which introduces disulfide bonds into substrates that are bound to its hydrophobic substrate binding cleft. The Mia40-mediated protein import can occur independent of disulfide bond formation, however, in vivo, both reactions are kinetically and functionally coordinated. Mia40 interacts with many different IMS proteins to promote their import and oxidative folding. In this project we studied the biogenesis and function of a number of model proteins in detail: Atp23 is a soluble IMS protease that contains five disulfide bonds. Each single disulfide bond is dispensable for Atp23 stability and function, however, a version lacking all cysteines is unable to fold and is rapidly degraded. Nevertheless, a cysteine-less variant of Atp23 is still efficiently bound by Mia40 and imported into the IMS. In vitro, Mia40 prevents this model protein from aggregation, thus exhibits a chaperone-like activity. Mrp10 is the only so far identified Mia40 substrates that is fully translocated into the matrix. This protein is initially imported into the IMS in a Mia40-mediated manner. It forms a helixloop-helix structure in the IMS that is stabilized by two disulfide bonds before it translocates across the inner membrane. In the matrix it assembles into the small subunit of the mitochondrial ribosome. Mia40-dependent oxidation is important for proteolytic stability of Mrp10. Tim17 differs from other Mia40 substrate as it is embedded into the inner membrane. Although Mia40 is critical for the import of Tim17 across the IMS, the disulfide bond in Tim17 is formed by Erv1, the sulfhydryl oxidase that maintains Mia40 oxidized. Oxidation of Tim17 is critical for efficient gating of the mitochondrial inner membrane translocase. In this project we characterized the mechanisms by which the protein oxidation machinery of the IMS promotes the import and folding of its substrates. Moreover, we characterized the biogenesis and function of a number of Mia40 substrates, most of which are conserved factors present in mitochondria of yeast, animals and humans.
Projektbezogene Publikationen (Auswahl)
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2008. In Vitro Import of Proteins into Isolated Mitochondria. Methods in Molecular Biology 457, 85-94
Bihlmaier K, Bien M, and Herrmann JM
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2008. The zinc-binding protein Hot13 promotes oxidation of the mitochondrial import receptor Mia40. EMBO Rep. 9, 1107-1113
Mesecke N, Bihlmaier K, Grumbt B, Longen S, Terziyska N, Hell K and Herrmann JM
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2009 Systematic Analysis of the Twin Cx(9)C Protein Family. J Mol Biol. 393, 356-368
Longen S, Bien M, Bihlmaier K, Kloeppel C, Kauff F, Hammermeister M, Westermann B, Herrmann JM, Riemer J
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2010. In yeast redistribution of Sod1 to the mitochondrial intermembrane space provides protection against respiration derived oxidative stress. Biochem Biophys Res Commun. 403, 114-119
Klöppel C, Michels C, Zimmer J, Herrmann JM, Riemer J
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2010. Mitochondrial disulfide bond formation is driven by intersubunit electron transfer in Erv1 and proofread by glutathione. Mol Cell 37, 516-528
Bien M, Longen S, Wagener N, Chwalla I, Herrmann JM, Riemer J
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2012. Atp23 biogenesis reveals a chaperone-like folding activity of Mia40 in the IMS of mitochondria. EMBO J. 31, 4348-4358
Weckbecker D, Longen S, Riemer J, Herrmann JM
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2013. Inaccurately assembled cytochrome c oxidase can lead to oxidative stress-induced growth arrest. Antioxid Redox Signal. 18, 1597-1612
Bode M, Longen S, Morgan B, Peleh V, Dick TP, Bihlmaier K, Herrmann JM
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2013. Protein import and oxidative folding in the mitochondrial intermembrane space of intact mammalian cells. Mol Biol Cell. 24, 2160-2170
Fischer M, Horn S, Belkacemi A, Kojer K, Petrungaro C, Habich M, Ali M, Kuttner V, Bien M, Kauff F, Dengjel J, Herrmann JM, Riemer J
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2014. Protein oxidation in the intermembrane space of mitochondria is substrate-specific rather than general. Microbial Cell 1, 81-93
Peleh V, Riemer J, Dancis A, Herrmann JM
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2014. The Disulfide Relay of the Intermembrane Space Oxidizes the Ribosomal Subunit Mrp10 on Its Transit into the Mitochondrial Matrix. Developmental Cell 28, 30-42
Longen S, Woellhaf MW, Petrungaro C, Riemer J, Herrmann JM
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2015. Import of proteins into isolated yeast mitochondria. Methods Mol Biol. 1270, 37-50
Peleh V, Ramesh A, Herrmann JM
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2015. Kinetic control by limiting glutaredoxin amounts enables thiol oxidation in the reducing mitochondrial IMS. Mol Biol Cell. 26, 195-204
Kojer K, Peleh V, Calabrese G, Herrmann JM, Riemer J
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2015. Redox-regulated dynamic interplay between Cox19 and the copper-binding protein Cox11 in the intermembrane space of mitochondria facilitates biogenesis of cytochrome c oxidase. Mol Biol Cell 26, 2385-401
Bode M, Woellhaf MW, Bohnert M, van der Laan M, Sommer F, Jung M, Zimmermann R, Schroda M, Herrmann JM
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2016. A disulfide bond in the TIM23 complex is crucial for voltage gating and mitochondrial protein import. J Cell Biol. 214, 417-31
Ramesh A, Peleh V, Martinez-Caballero S, Wollweber F, Sommer F, van der Laan M, Schroda M, Alexander RT, Campo ML, Herrmann JM
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2016. Mia40 is a trans-site receptor that drives protein import into the mitochondrial intermembrane space by hydrophobic substrate binding. eLIFE 25;5. pii: e16177
Peleh V, Cordat, E, Herrmann JM
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2017. Erv1 of Arabidopsis thaliana can directly oxidize mitochondrial intermembrane space proteins in the absence of redox-active Mia40. BMC Biology, 15:106
Peleh, V, Zannini F, Backes S, Rouhier N, Herrmann JM
