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Nils Wiedemann  - - - 
Top co-authors See all
Matthias Groszer

866 shared publications

Sara Zocher

845 shared publications

Patrick Matthias

466 shared publications

Helmut E. Meyer

227 shared publications

Karina Wagner

209 shared publications

Institut für Biochemie und Molekularbiologie, Zentrum für Biochemie und Molekulare Zellforschung Fakultät für Biologie, Universität Freiburg, Hermann‐Herder‐Strasse 7, 79104, Freiburg, Germany

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Distribution of Articles published per year 
(1970 - 2018)
Total number of journals
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37
 
Publications See all
Article 0 Reads 0 Citations Respiratory chain supercomplexes associate with the cysteine desulfurase complex of the iron–sulfur cluster assembly mac... Lena Böttinger, Christoph U. Mårtensson, Jiyao Song, Nicole ... Published: 01 April 2018
Molecular Biology of the Cell, doi: 10.1091/mbc.e17-09-0555
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Mitochondria are the powerhouses of eukaryotic cells. The activity of the respiratory chain complexes generates a proton gradient across the inner membrane, which is used by the F1FO-ATP synthase to produce ATP for cellular metabolism. In baker's yeast Saccharomyces cerevisiae the cytochrome bc1 complex (complex III) and cytochrome c oxidase (complex IV) associate in respiratory chain supercomplexes. Iron-sulfur clusters (ISC) form reactive centers of respiratory chain complexes. The assembly of ISC occurs in the mitochondrial matrix and is essential for cell viability. The cysteine desulfurase Nfs1 provides sulfur for ISC assembly and forms with partner proteins the ISC-biogenesis desulfurase complex (ISD complex). Here, we report an unexpected interaction of the active ISD complex with the cytochrome bc1 complex and cytochrome c oxidase. The individual deletion of complex III or complex IV blocks the association of the ISD complex with respiratory chain components. We conclude that the ISD complex binds selectively to respiratory chain supercomplexes. We propose that this molecular link contributes to coordination of iron-sulfur cluster formation with respiratory activity.
Article 0 Reads 0 Citations Metabolic profiling of isolated mitochondria and cytoplasm reveals compartment-specific metabolic responses Daqiang Pan, Caroline Lindau, Simon Lagies, Nils Wiedemann, ... Published: 31 March 2018
Metabolomics, doi: 10.1007/s11306-018-1352-x
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Subcellular compartmentalization enables eukaryotic cells to carry out different reactions at the same time, resulting in different metabolite pools in the subcellular compartments. Thus, mutations affecting the mitochondrial energy metabolism could cause different metabolic alterations in mitochondria compared to the cytoplasm. Given that the metabolite pool in the cytosol is larger than that of other subcellular compartments, metabolic profiling of total cells could miss these compartment-specific metabolic alterations. To reveal compartment-specific metabolic differences, mitochondria and the cytoplasmic fraction of baker’s yeast Saccharomyces cerevisiae were isolated and subjected to metabolic profiling. Mitochondria were isolated through differential centrifugation and were analyzed together with the remaining cytoplasm by gas chromatography–mass spectrometry (GC–MS) based metabolic profiling. Seventy-two metabolites were identified, of which eight were found exclusively in mitochondria and sixteen exclusively in the cytoplasm. Based on the metabolic signature of mitochondria and of the cytoplasm, mutants of the succinate dehydrogenase (respiratory chain complex II) and of the FOF1-ATP-synthase (complex V) can be discriminated in both compartments by principal component analysis from wild-type and each other. These mitochondrial oxidative phosphorylation machinery mutants altered not only citric acid cycle related metabolites but also amino acids, fatty acids, purine and pyrimidine intermediates and others. By applying metabolomics to isolated mitochondria and the corresponding cytoplasm, compartment-specific metabolic signatures can be identified. This subcellular metabolomics analysis is a powerful tool to study the molecular mechanism of compartment-specific metabolic homeostasis in response to mutations affecting the mitochondrial metabolism.
Article 1 Read 1 Citation Membrane protein insertion through a mitochondrial β-barrel gate Alexandra I. C. Höhr, Caroline Lindau, Christophe Wirth, Jia... Published: 18 January 2018
Science, doi: 10.1126/science.aah6834
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The biogenesis of mitochondria, chloroplasts, and Gram-negative bacteria requires the insertion of β-barrel proteins into the outer membranes. Homologous Omp85 proteins are essential for membrane insertion of β-barrel precursors. It is unknown if precursors are threaded through the Omp85-channel interior and exit laterally or if they are translocated into the membrane at the Omp85-lipid interface. We have mapped the interaction of a precursor in transit with the mitochondrial Omp85-channel Sam50 in the native membrane environment. The precursor is translocated into the channel interior, interacts with an internal loop, and inserts into the lateral gate by β-signal exchange. Transport through the Omp85-channel interior followed by release through the lateral gate into the lipid phase may represent a basic mechanism for membrane insertion of β-barrel proteins.
Conference 10 Reads 0 Citations Mitochondrial metabolomics reveals compartment-specific metabolic responses in yeast cells Daqiang Pan, Caroline Lindau, Simon Lagies, Stefan Günther, ... Published: 20 November 2017
The 2nd International Electronic Conference on Metabolomics, doi: 10.3390/iecm-2-04981
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Article 2 Reads 2 Citations Identification of new channels by systematic analysis of the mitochondrial outer membrane Vivien Krüger, Malayko Montilla-Martinez, Lars Ellenrieder, ... Published: 15 September 2017
The Journal of Cell Biology, doi: 10.1083/jcb.201706043
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The mitochondrial outer membrane is essential for communication between mitochondria and the rest of the cell and facilitates the transport of metabolites, ions, and proteins. All mitochondrial outer membrane channels known to date are β-barrel membrane proteins, including the abundant voltage-dependent anion channel and the cation-preferring protein-conducting channels Tom40, Sam50, and Mdm10. We analyzed outer membrane fractions of yeast mitochondria and identified four new channel activities: two anion-preferring channels and two cation-preferring channels. We characterized the cation-preferring channels at the molecular level. The mitochondrial import component Mim1 forms a channel that is predicted to have an α-helical structure for protein import. The short-chain dehydrogenase-related protein Ayr1 forms an NADPH-regulated channel. We conclude that the mitochondrial outer membrane contains a considerably larger variety of channel-forming proteins than assumed thus far. These findings challenge the traditional view of the outer membrane as an unspecific molecular sieve and indicate a higher degree of selectivity and regulation of metabolite fluxes at the mitochondrial boundary.
Article 1 Read 21 Citations Mitochondrial Machineries for Protein Import and Assembly Nils Wiedemann, Nikolaus Pfanner Published: 20 June 2017
Annual Review of Biochemistry, doi: 10.1146/annurev-biochem-060815-014352
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Mitochondria are essential organelles with numerous functions in cellular metabolism and homeostasis. Most of the >1,000 different mitochondrial proteins are synthesized as precursors in the cytosol and are imported into mitochondria by five transport pathways. The protein import machineries of the mitochondrial membranes and aqueous compartments reveal a remarkable variability of mechanisms for protein recognition, translocation, and sorting. The protein translocases do not operate as separate entities but are connected to each other and to machineries with functions in energetics, membrane organization, and quality control. Here, we discuss the versatility and dynamic organization of the mitochondrial protein import machineries. Elucidating the molecular mechanisms of mitochondrial protein translocation is crucial for understanding the integration of protein translocases into a large network that controls organelle biogenesis, function, and dynamics. Expected final online publication date for the Annual Review of Biochemistry Volume 86 is June 20, 2017. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.