51
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Englmeier R, Förster F. Cryo-electron tomography for the structural study of mitochondrial translation. Tissue Cell 2018; 57:129-138. [PMID: 30197222 DOI: 10.1016/j.tice.2018.08.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 07/29/2018] [Accepted: 08/22/2018] [Indexed: 12/30/2022]
Abstract
Cryo-electron tomography (cryo-ET) enables the three-dimensional (3D) structural characterization of macromolecular complexes in their physiological environment. Thus, cryo-ET is uniquely suited to study the structural basis of biomolecular processes that are extremely difficult or even impossible to reconstitute using purified components. Translation of mitochondrial genes, which occurs in the secluded interior of mitochondria, falls into this category. Here, we describe the principles of cryo-ET in the context of mitochondrial translation and outline recent developments and challenges of the method. The 3D image of a frozen-hydrated biological sample is computed from its 2D projections, which are acquired using a transmission electron microscope. In conjunction with automated detection of different copies of the molecule of interest and averaging of the corresponding subtomograms, cryo-ET enables macromolecular structure determination in the native environment (i.e. in situ) at sub-nanometer resolution. The preservation of the native environment furthermore allows the extraction of contextual information about the molecules, including the location of specific molecules with respect to membranes, their relative positioning and the spatial organization with respect to other types of macromolecules. Recent preparative developments extend the field of application of cryo-ET from isolated organelles to cultured eukaryotic cells and even tissue, making the traditional borders between molecular and cellular structural biology disappear.
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Affiliation(s)
- Robert Englmeier
- Cryo-Electron Microscopy, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Friedrich Förster
- Cryo-Electron Microscopy, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CH Utrecht, The Netherlands.
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Novel insights into global translational regulation through Pumilio family RNA-binding protein Puf3p revealed by ribosomal profiling. Curr Genet 2018; 65:201-212. [PMID: 29951697 DOI: 10.1007/s00294-018-0862-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 06/16/2018] [Accepted: 06/19/2018] [Indexed: 01/13/2023]
Abstract
RNA binding proteins (RBPs) can regulate the stability, localization, and translation of their target mRNAs. Among them, Puf3p is a well-known Pumilio family RBP whose biology has been intensively studied. Nevertheless, the impact of Puf3p on the translational regulation of its downstream genes still remains to be investigated at the genome-wide level. In this study, we combined ribosome profiling and RNA-Seq in budding yeast (Saccharomyces cerevisiae) to investigate Puf3p's functions in translational regulation. Comparison of translational efficiency (TE) between wild-type and puf3Δ strains demonstrates extensive translational modulation in the absence of Puf3p (over 27% genes are affected at the genome level). Besides confirming its known role in regulating mitochondrial metabolism, our data demonstrate that Puf3p serves as a key post-transcriptional regulator of downstream RBPs by regulating their translational efficiencies, indicating a network of interactions among RBPs at the post-transcriptional level. Furthermore, Puf3p switches the balance of translational flux between mitochondrial and cytosolic ribosome biogenesis to adapt to changes in cellular metabolism. In summary, our results indicate that TE can be utilized as an informative index to interrogate the mechanism underlying RBP functions, and provide novel insights into Puf3p's mode-of-action.
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53
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Samluk L, Chroscicki P, Chacinska A. Mitochondrial protein import stress and signaling. CURRENT OPINION IN PHYSIOLOGY 2018. [DOI: 10.1016/j.cophys.2018.02.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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54
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Jin D, Gu B, Xiong D, Huang G, Huang X, Liu L, Xiao J. A Transcriptomic Analysis of Saccharomyces cerevisiae Under the Stress of 2-Phenylethanol. Curr Microbiol 2018; 75:1068-1076. [PMID: 29666939 DOI: 10.1007/s00284-018-1488-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 03/30/2018] [Indexed: 12/11/2022]
Abstract
2-Phenylethanol (2-PE) is a kind of advanced aromatic alcohol with rose fragrance, which is wildly used for the deployment of flavors and fragrances. Microbial transformation is the most feasible method for the production of natural 2-PE. But a bottleneck problem is the toxicity of 2-PE on the cells. The molecular mechanisms of the toxic effect of 2-PE to Saccharomyces cerevisiae are not well studied. In this study, we analyzed the transcriptomes of S. cerevisiae in the media with and without 2-PE, respectively, using Illumina RNA-Seq technology. We identified 580 differentially expressed genes between S. cerevisiae in two different treatments. GO and KEGG enrichment analyses of these genes suggested that most genes encoding mitochondrial proteins, cytoplasmic, and plasma membrane proteins were significantly up-regulated, whereas the enzymes related to amino acid metabolism were down-regulated. These results indicated that 2-PE suppressed the synthesis of plasma membrane proteins, which suppressed the transport of nutrients required for growth. The findings in this study will provide insight into the inhibitory mechanism of 2-PE to yeast and other microbes.
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Affiliation(s)
- Danfeng Jin
- Institute of Microbiology, Jiangxi Academy of Sciences, Nanchang, 330096, People's Republic of China.
| | - Bintao Gu
- Institute of Microbiology, Jiangxi Academy of Sciences, Nanchang, 330096, People's Republic of China
| | - Dawei Xiong
- Institute of Microbiology, Jiangxi Academy of Sciences, Nanchang, 330096, People's Republic of China
| | - Guochang Huang
- Institute of Microbiology, Jiangxi Academy of Sciences, Nanchang, 330096, People's Republic of China
| | - Xiaoping Huang
- Institute of Microbiology, Jiangxi Academy of Sciences, Nanchang, 330096, People's Republic of China
| | - Lan Liu
- Institute of Microbiology, Jiangxi Academy of Sciences, Nanchang, 330096, People's Republic of China
| | - Jun Xiao
- The First Affiliated Hospital of Nanchang University, Nanchang, 330006, People's Republic of China.
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55
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Stoldt S, Wenzel D, Kehrein K, Riedel D, Ott M, Jakobs S. Spatial orchestration of mitochondrial translation and OXPHOS complex assembly. Nat Cell Biol 2018; 20:528-534. [PMID: 29662179 DOI: 10.1038/s41556-018-0090-7] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 03/20/2018] [Indexed: 12/11/2022]
Abstract
Oxidative phosphorylation (OXPHOS) is vital for the regeneration of the vast majority of ATP in eukaryotic cells 1 . OXPHOS is carried out by large multi-subunit protein complexes in the cristae membranes, which are invaginations of the mitochondrial inner membrane. The OXPHOS complexes are a mix of subunits encoded in the nuclear and mitochondrial genomes. Thus, the assembly of these dual-origin complexes is an enormous logistical challenge for the cell. Using super-resolution microscopy (nanoscopy) and quantitative cryo-immunogold electron microscopy, we determined where specific transcripts are translated and where distinct assembly steps of the dual-origin complexes in the yeast Saccharomyces cerevisiae occur. Our data indicate that the mitochondrially encoded proteins of complex III and complex IV are preferentially inserted in different sites of the inner membrane than those of complex V. We further demonstrate that the early, but not the late, assembly steps of complex III and complex IV occur preferentially in the inner boundary membrane. By contrast, all steps of complex V assembly occur mainly in the cristae membranes. Thus, OXPHOS complex assembly is spatially well orchestrated, probably representing an unappreciated regulatory layer in mitochondrial biogenesis.
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Affiliation(s)
- Stefan Stoldt
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Dirk Wenzel
- Laboratory of Electron Microscopy, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Kirsten Kehrein
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Dietmar Riedel
- Laboratory of Electron Microscopy, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Martin Ott
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Stefan Jakobs
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany. .,Department of Neurology, University Medical Center Göttingen, Göttingen, Germany.
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Böttinger L, Mårtensson CU, Song J, Zufall N, Wiedemann N, Becker T. Respiratory chain supercomplexes associate with the cysteine desulfurase complex of the iron-sulfur cluster assembly machinery. Mol Biol Cell 2018; 29:776-785. [PMID: 29386296 PMCID: PMC5905291 DOI: 10.1091/mbc.e17-09-0555] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Mitochondrial cytochrome bc1 complex and cytochrome c oxidase associate in respiratory chain supercomplexes. We identified a specific association of the iron–sulfur cluster biogenesis desulfurase with the respiratory chain supercomplexes. Our finding reveals a novel link between respiration and iron–sulfur cluster formation. 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.
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Affiliation(s)
- Lena Böttinger
- Institute of Biochemistry and Molecular Biology, Centre for Biochemistry and Molecular Cell Research (ZBMZ), Faculty of Medicine, University of Freiburg, D-79104 Freiburg, Germany
| | - Christoph U Mårtensson
- Institute of Biochemistry and Molecular Biology, Centre for Biochemistry and Molecular Cell Research (ZBMZ), Faculty of Medicine, University of Freiburg, D-79104 Freiburg, Germany.,Faculty of Biology, University of Freiburg, D-79104 Freiburg, Germany
| | - Jiyao Song
- Institute of Biochemistry and Molecular Biology, Centre for Biochemistry and Molecular Cell Research (ZBMZ), Faculty of Medicine, University of Freiburg, D-79104 Freiburg, Germany
| | - Nicole Zufall
- Institute of Biochemistry and Molecular Biology, Centre for Biochemistry and Molecular Cell Research (ZBMZ), Faculty of Medicine, University of Freiburg, D-79104 Freiburg, Germany
| | - Nils Wiedemann
- Institute of Biochemistry and Molecular Biology, Centre for Biochemistry and Molecular Cell Research (ZBMZ), Faculty of Medicine, University of Freiburg, D-79104 Freiburg, Germany.,BIOSS Centre for Biological Signalling Studies, University of Freiburg, D-79104 Freiburg, Germany
| | - Thomas Becker
- Institute of Biochemistry and Molecular Biology, Centre for Biochemistry and Molecular Cell Research (ZBMZ), Faculty of Medicine, University of Freiburg, D-79104 Freiburg, Germany.,BIOSS Centre for Biological Signalling Studies, University of Freiburg, D-79104 Freiburg, Germany
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57
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Bieri P, Greber BJ, Ban N. High-resolution structures of mitochondrial ribosomes and their functional implications. Curr Opin Struct Biol 2018; 49:44-53. [DOI: 10.1016/j.sbi.2017.12.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 12/08/2017] [Accepted: 12/22/2017] [Indexed: 01/06/2023]
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58
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Callegari S, Dennerlein S. Sensing the Stress: A Role for the UPR mt and UPR am in the Quality Control of Mitochondria. Front Cell Dev Biol 2018; 6:31. [PMID: 29644217 PMCID: PMC5882792 DOI: 10.3389/fcell.2018.00031] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 03/12/2018] [Indexed: 01/01/2023] Open
Abstract
Mitochondria exist as compartmentalized units, surrounded by a selectively permeable double membrane. Within is contained the mitochondrial genome and protein synthesis machinery, required for the synthesis of OXPHOS components and ultimately, ATP production. Despite their physical barrier, mitochondria are tightly integrated into the cellular environment. A constant flow of information must be maintained to and from the mitochondria and the nucleus, to ensure mitochondria are amenable to cell metabolic requirements and also to feedback on their functional state. This review highlights the pathways by which mitochondrial stress is signaled to the nucleus, with a particular focus on the mitochondrial unfolded protein response (UPRmt) and the unfolded protein response activated by the mistargeting of proteins (UPRam). Although these pathways were originally discovered to alleviate proteotoxic stress from the accumulation of mitochondrial-targeted proteins that are misfolded or unimported, we review recent findings indicating that the UPRmt can also sense defects in mitochondrial translation. We further discuss the regulation of OXPHOS assembly and speculate on a possible role for mitochondrial stress pathways in sensing OXPHOS biogenesis.
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Affiliation(s)
- Sylvie Callegari
- Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Sven Dennerlein
- Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany
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59
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Zhu P, Liu Y, Zhang F, Bai X, Chen Z, Shangguan F, Zhang B, Zhang L, Chen Q, Xie D, Lan L, Xue X, Liang XJ, Lu B, Wei T, Qin Y. Human Elongation Factor 4 Regulates Cancer Bioenergetics by Acting as a Mitochondrial Translation Switch. Cancer Res 2018; 78:2813-2824. [PMID: 29572227 DOI: 10.1158/0008-5472.can-17-2059] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 01/01/2018] [Accepted: 03/20/2018] [Indexed: 11/16/2022]
Abstract
Mitochondria regulate cellular bioenergetics and redox states and influence multiple signaling pathways required for tumorigenesis. In this study, we determined that the mitochondrial translation elongation factor 4 (EF4) is a critical component of tumor progression. EF4 was ubiquitous in human tissues with localization to the mitochondria (mtEF4) and performed quality control on respiratory chain biogenesis. Knockout of mtEF4 induced respiratory chain complex defects and apoptosis, while its overexpression stimulated cancer development. In multiple cancers, expression of mtEF4 was increased in patient tumor tissues. These findings reveal that mtEF4 expression may promote tumorigenesis via an imbalance in the regulation of mitochondrial activities and subsequent variation of cellular redox. Thus, dysregulated mitochondrial translation may play a vital role in the etiology and development of diverse human cancers.Significance: Dysregulated mitochondrial translation drives tumor development and progression. Cancer Res; 78(11); 2813-24. ©2018 AACR.
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Affiliation(s)
- Ping Zhu
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Chaoyang District, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yongzhang Liu
- Attardi Institute of Mitochondrial Biomedicine, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Fenglin Zhang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Chaoyang District, Beijing, China
| | - Xiufeng Bai
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Chaoyang District, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Zilei Chen
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Chaoyang District, Beijing, China.,Attardi Institute of Mitochondrial Biomedicine, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Fugen Shangguan
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Chaoyang District, Beijing, China.,Attardi Institute of Mitochondrial Biomedicine, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Bo Zhang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Chaoyang District, Beijing, China
| | - Lingyun Zhang
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Chaoyang District, Beijing, China
| | - Qianqian Chen
- University of Chinese Academy of Sciences, Beijing, China.,National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Chaoyang District, Beijing, China
| | - Deyao Xie
- Departments of Cardiothoracic Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Linhua Lan
- Attardi Institute of Mitochondrial Biomedicine, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China
| | - Xiangdong Xue
- Laboratory of Controllable Nanopharmaceuticals, CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology of China, Zhongguancun, Beijing, China
| | - Xing-Jie Liang
- Laboratory of Controllable Nanopharmaceuticals, CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology of China, Zhongguancun, Beijing, China
| | - Bin Lu
- Attardi Institute of Mitochondrial Biomedicine, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China.
| | - Taotao Wei
- University of Chinese Academy of Sciences, Beijing, China. .,National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Chaoyang District, Beijing, China
| | - Yan Qin
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Chaoyang District, Beijing, China. .,University of Chinese Academy of Sciences, Beijing, China
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60
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Derbikova KS, Levitsky SA, Chicherin IV, Vinogradova EN, Kamenski PA. Activation of Yeast Mitochondrial Translation: Who Is in Charge? BIOCHEMISTRY (MOSCOW) 2018; 83:87-97. [DOI: 10.1134/s0006297918020013] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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61
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Liu J, Li Y, Chen J, Wang Y, Zou M, Su R, Huang Y. The fission yeast Schizosaccharomyces pombe Mtf2 is required for mitochondrial cox1 gene expression. MICROBIOLOGY-SGM 2018; 164:400-409. [PMID: 29458562 DOI: 10.1099/mic.0.000602] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Mitochondrial gene expression is essential for adenosine triphosphate synthesis via oxidative phosphorylation, which is the universal energy currency of cells. Here, we report the identification and characterization of a homologue of Saccharomyces cerevisiae Mtf2 (also called Nam1) in Schizosaccharomyces pombe. The Δmtf2 mutant with the intron-containing mitochondrial DNA (mtDNA) exhibited impaired growth on a rich medium containing the non-fermentable carbon source glycerol, suggesting that mtf2 is involved in mitochondrial function. mtf2 deletion in a mitochondrial intron-containing background resulted in a barely detectable level of the cox1 mRNA and a reduction in the level of the cob1 mRNA, and severely impaired cox1 translation. In contrast, mtf2 deletion in a mitochondrial intron-less background did not affect the levels of cox1 and cob1 mRNAs. However, Cox1 synthesis could not be restored to the control level in the Δmtf2 mutant with intron-less mtDNA. Our results suggest that unlike its counterpart in S. cerevisiae which plays a general role in synthesis of mtDNA-encoded proteins, S. pombe Mtf2 primarily functions in cox1 translation and the effect of mtf2 deletion on splicing of introns in mtDNA is likely due to a deficiency in the synthesis of intron-encoded maturases.
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Affiliation(s)
- Jinyu Liu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, School of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, PR China
| | - Yan Li
- Jiangsu Key Laboratory for Microbes and Functional Genomics, School of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, PR China
| | - Jie Chen
- Jiangsu Key Laboratory for Microbes and Functional Genomics, School of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, PR China
| | - Yirong Wang
- Jiangsu Key Laboratory for Microbes and Functional Genomics, School of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, PR China
| | - Mengting Zou
- Jiangsu Key Laboratory for Microbes and Functional Genomics, School of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, PR China
| | - Ruyue Su
- Jiangsu Key Laboratory for Microbes and Functional Genomics, School of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, PR China
| | - Ying Huang
- Jiangsu Key Laboratory for Microbes and Functional Genomics, School of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, PR China
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62
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Desai N, Brown A, Amunts A, Ramakrishnan V. The structure of the yeast mitochondrial ribosome. Science 2017; 355:528-531. [PMID: 28154081 DOI: 10.1126/science.aal2415] [Citation(s) in RCA: 132] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 01/05/2017] [Indexed: 01/02/2023]
Abstract
Mitochondria have specialized ribosomes (mitoribosomes) dedicated to the expression of the genetic information encoded by their genomes. Here, using electron cryomicroscopy, we have determined the structure of the 75-component yeast mitoribosome to an overall resolution of 3.3 angstroms. The mitoribosomal small subunit has been built de novo and includes 15S ribosomal RNA (rRNA) and 34 proteins, including 14 without homologs in the evolutionarily related bacterial ribosome. Yeast-specific rRNA and protein elements, including the acquisition of a putatively active enzyme, give the mitoribosome a distinct architecture compared to the mammalian mitoribosome. At an expanded messenger RNA channel exit, there is a binding platform for translational activators that regulate translation in yeast but not mammalian mitochondria. The structure provides insights into the evolution and species-specific specialization of mitochondrial translation.
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Affiliation(s)
- Nirupa Desai
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Alan Brown
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Alexey Amunts
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK.,SciLifeLab, Stockholm University, SE-106 91 Stockholm, Sweden
| | - V Ramakrishnan
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK.
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63
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Plasticity of Mitochondrial Translation. Trends Cell Biol 2017; 27:712-721. [DOI: 10.1016/j.tcb.2017.05.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 05/15/2017] [Accepted: 05/16/2017] [Indexed: 11/21/2022]
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64
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Panozzo C, Laleve A, Tribouillard-Tanvier D, Ostojić J, Sellem CH, Friocourt G, Bourand-Plantefol A, Burg A, Delahodde A, Blondel M, Dujardin G. Chemicals or mutations that target mitochondrial translation can rescue the respiratory deficiency of yeast bcs1 mutants. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:2297-2307. [PMID: 28888990 DOI: 10.1016/j.bbamcr.2017.09.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 08/29/2017] [Accepted: 09/04/2017] [Indexed: 11/28/2022]
Abstract
Bcs1p is a chaperone that is required for the incorporation of the Rieske subunit within complex III of the mitochondrial respiratory chain. Mutations in the human gene BCS1L (BCS1-like) are the most frequent nuclear mutations resulting in complex III-related pathologies. In yeast, the mimicking of some pathogenic mutations causes a respiratory deficiency. We have screened chemical libraries and found that two antibiotics, pentamidine and clarithromycin, can compensate two bcs1 point mutations in yeast, one of which is the equivalent of a mutation found in a human patient. As both antibiotics target the large mtrRNA of the mitoribosome, we focused our analysis on mitochondrial translation. We found that the absence of non-essential translation factors Rrf1 or Mif3, which act at the recycling/initiation steps, also compensates for the respiratory deficiency of yeast bcs1 mutations. At compensating concentrations, both antibiotics, as well as the absence of Rrf1, cause an imbalanced synthesis of respiratory subunits which impairs the assembly of the respiratory complexes and especially that of complex IV. Finally, we show that pentamidine also decreases the assembly of complex I in nematode mitochondria. It is well known that complexes III and IV exist within the mitochondrial inner membrane as supramolecular complexes III2/IV in yeast or I/III2/IV in higher eukaryotes. Therefore, we propose that the changes in mitochondrial translation caused by the drugs or by the absence of translation factors, can compensate for bcs1 mutations by modifying the equilibrium between illegitimate, and thus inactive, and active supercomplexes.
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Affiliation(s)
- C Panozzo
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Evry-Val d'Essonne, Université Paris-Saclay, 91198 Gif sur Yvette Cedex, France
| | - A Laleve
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Evry-Val d'Essonne, Université Paris-Saclay, 91198 Gif sur Yvette Cedex, France
| | - D Tribouillard-Tanvier
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Evry-Val d'Essonne, Université Paris-Saclay, 91198 Gif sur Yvette Cedex, France
| | - J Ostojić
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Evry-Val d'Essonne, Université Paris-Saclay, 91198 Gif sur Yvette Cedex, France
| | - C H Sellem
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Evry-Val d'Essonne, Université Paris-Saclay, 91198 Gif sur Yvette Cedex, France
| | - G Friocourt
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Evry-Val d'Essonne, Université Paris-Saclay, 91198 Gif sur Yvette Cedex, France
| | - A Bourand-Plantefol
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Evry-Val d'Essonne, Université Paris-Saclay, 91198 Gif sur Yvette Cedex, France
| | - A Burg
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Evry-Val d'Essonne, Université Paris-Saclay, 91198 Gif sur Yvette Cedex, France
| | - A Delahodde
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Evry-Val d'Essonne, Université Paris-Saclay, 91198 Gif sur Yvette Cedex, France
| | - M Blondel
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Evry-Val d'Essonne, Université Paris-Saclay, 91198 Gif sur Yvette Cedex, France
| | - G Dujardin
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Evry-Val d'Essonne, Université Paris-Saclay, 91198 Gif sur Yvette Cedex, France.
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Singhal RK, Kruse C, Heidler J, Strecker V, Zwicker K, Düsterwald L, Westermann B, Herrmann JM, Wittig I, Rapaport D. Coi1 is a novel assembly factor of the yeast complex III-complex IV supercomplex. Mol Biol Cell 2017; 28:mbc.E17-02-0093. [PMID: 28794267 PMCID: PMC5620370 DOI: 10.1091/mbc.e17-02-0093] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 07/31/2017] [Accepted: 08/01/2017] [Indexed: 01/30/2023] Open
Abstract
The yeast bc1 complex (complex III) and cytochrome oxidase (complex IV) are mosaics of core subunits encoded by the mitochondrial genome and additional nuclear-encoded proteins imported from the cytosol. Both complexes build in the mitochondrial inner membrane various supramolecular assemblies. The formation of the individual complexes and their supercomplexes depends on the activity of dedicated assembly factors. We identified a so far uncharacterized mitochondrial protein (open reading frame YDR381C-A) as an important assembly factor for complex III, complex IV, and their supercomplexes. Therefore, we named this protein Cox interacting (Coi) 1. Deletion of COI1 results in decreased respiratory growth, reduced membrane potential, and hampered respiration, as well as slow fermentative growth at low temperature. In addition, coi1Δ cells harbour reduced steady-state levels of subunits of complexes III and IV as well as of the assembled complexes and supercomplexes. Interaction of Coi1 with respiratory chain subunits seems transient, as it appears to be a stoichiometric subunit neither of complex III nor of complex IV. Collectively, this work identifies a novel protein that plays a role in the assembly of the mitochondrial respiratory chain.
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Affiliation(s)
- Ravi K Singhal
- Interfaculty Institute of Biochemistry, University of Tübingen, Hoppe-Seyler-Str. 4, 72076 Tübingen, Germany
| | - Christine Kruse
- Interfaculty Institute of Biochemistry, University of Tübingen, Hoppe-Seyler-Str. 4, 72076 Tübingen, Germany
| | - Juliana Heidler
- Functional Proteomics, SFB 815 Core Unit, Faculty of Medicine, Goethe-University, Frankfurt am Main, Germany
| | - Valentina Strecker
- Functional Proteomics, SFB 815 Core Unit, Faculty of Medicine, Goethe-University, Frankfurt am Main, Germany
| | - Klaus Zwicker
- Institute of Biochemistry I, Faculty of Medicine, Goethe-University Frankfurt, 60590 Frankfurt am Main, Germany
| | - Lea Düsterwald
- Cell Biology, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | | | | | - Ilka Wittig
- Functional Proteomics, SFB 815 Core Unit, Faculty of Medicine, Goethe-University, Frankfurt am Main, Germany
- Cluster of Excellence "Macromolecular Complexes", Goethe University, Frankfurt am Main, Germany
- German Center of Cardiovascular Research (DZHK), Partner site RheinMain, Frankfurt, Germany
| | - Doron Rapaport
- Interfaculty Institute of Biochemistry, University of Tübingen, Hoppe-Seyler-Str. 4, 72076 Tübingen, Germany
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66
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Schwarzhans JP, Luttermann T, Wibberg D, Winkler A, Hübner W, Huser T, Kalinowski J, Friehs K. A Mitochondrial Autonomously Replicating Sequence from Pichia pastoris for Uniform High Level Recombinant Protein Production. Front Microbiol 2017; 8:780. [PMID: 28512458 PMCID: PMC5411459 DOI: 10.3389/fmicb.2017.00780] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 04/18/2017] [Indexed: 12/14/2022] Open
Abstract
Pichia pastoris is a non-conventional methylotrophic yeast that is widely used for recombinant protein production, typically by stably integrating the target gene into the genome as part of an expression cassette. However, the comparatively high clonal variability associated with this approach usually necessitates a time intense screening step in order to find strains with the desired productivity. Some of the factors causing this clonal variability can be overcome using episomal vectors containing an autonomously replicating sequence (ARS). Here, we report on the discovery, characterization, and application of a fragment of mitochondrial DNA from P. pastoris for use as an ARS. First encountered as an off-target event in an experiment aiming for genomic integration, the newly created circular plasmid named “pMito” consists of the expression cassette and a fragment of mitochondrial DNA. Multiple matches to known ARS consensus sequence motifs, but no exact match to known chromosomal ARS from P. pastoris were detected on the fragment, indicating the presence of a novel ARS element. Different variants of pMito were successfully used for transformation and their productivity characteristics were assayed. All analyzed clones displayed a highly uniform expression level, exceeding by up to fourfold that of a reference with a single copy integrated in its genome. Expressed GFP could be localized exclusively to the cytoplasm via super-resolution fluorescence microscopy, indicating that pMito is present in the nucleus. While expression levels were homogenous among pMito clones, an apparent upper limit of expression was visible that could not be explained based on the gene dosage. Further investigation is necessary to fully understand the bottle-neck hindering this and other ARS vectors in P. pastoris from reaching their full capability. Lastly, we could demonstrate that the mitochondrial ARS from P. pastoris is also suitable for episomal vector transformation in Saccharomyces cerevisiae, widening the potential for biotechnological application. pMito displayed strong potential to reduce clonal variability in experiments targeting recombinant protein production. These findings also showcase the as of yet largely untapped potential of mitochondrial ARS from different yeasts for biotechnological applications.
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Affiliation(s)
- Jan-Philipp Schwarzhans
- Fermentation Engineering, Faculty of Technology, Bielefeld UniversityBielefeld, Germany.,Microbial Genomics and Biotechnology, Center for Biotechnology (CeBiTec), Bielefeld UniversityBielefeld, Germany
| | - Tobias Luttermann
- Fermentation Engineering, Faculty of Technology, Bielefeld UniversityBielefeld, Germany.,Microbial Genomics and Biotechnology, Center for Biotechnology (CeBiTec), Bielefeld UniversityBielefeld, Germany
| | - Daniel Wibberg
- Genome Research of Industrial Microorganisms, CeBiTec, Bielefeld UniversityBielefeld, Germany
| | - Anika Winkler
- Microbial Genomics and Biotechnology, Center for Biotechnology (CeBiTec), Bielefeld UniversityBielefeld, Germany
| | - Wolfgang Hübner
- Biomolecular Photonics, Faculty of Physics, Bielefeld UniversityBielefeld, Germany
| | - Thomas Huser
- Biomolecular Photonics, Faculty of Physics, Bielefeld UniversityBielefeld, Germany
| | - Jörn Kalinowski
- Microbial Genomics and Biotechnology, Center for Biotechnology (CeBiTec), Bielefeld UniversityBielefeld, Germany
| | - Karl Friehs
- Fermentation Engineering, Faculty of Technology, Bielefeld UniversityBielefeld, Germany
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67
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Barros MH, Tzagoloff A. Aep3p-dependent translation of yeast mitochondrial ATP8. Mol Biol Cell 2017; 28:1426-1434. [PMID: 28404747 PMCID: PMC5449143 DOI: 10.1091/mbc.e16-11-0775] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 03/29/2017] [Accepted: 04/04/2017] [Indexed: 12/14/2022] Open
Abstract
Yeast Aep3p, previously reported to stabilize mitochondrial ATP8 mRNA, also activates its translation. Temperature-sensitive aep3 mutants are specifically defective in translating ATP8 at the restrictive temperature. The respiratory deficiency of aep3 mutants is rescued by expression in the cytoplasm of allotopic ATP8. Translation of mitochondrial gene products in Saccharomyces cerevisiae depends on mRNA-specific activators that bind to the 5’ untranslated regions and promote translation on mitochondrial ribosomes. Here we find that Aep3p, previously shown to stabilize the bicistronic ATP8-ATP6 mRNA and facilitate initiation of translation from unformylated methionine, also activates specifically translation of ATP8. This is supported by several lines of evidence. Temperature-sensitive aep3 mutants are selectively blocked in incorporating [35S]methionine into Atp8p at nonpermissive but not at the permissive temperature. This phenotype is not a consequence of defective transcription or processing of the pre-mRNA. Neither is it explained by turnover of Aep3p, as evidenced by the failure of aep3 mutants to express a recoded ARG8m when this normally nuclear gene is substituted for ATP8 in mitochondrial DNA. Finally, translational of ATP8 mRNA in aep3 mutants is partially rescued by recoded allotopic ATP8 (nATP8) in a high-expression plasmid or in a CEN plasmid in the presence of recessive mutations in genes involved in stability and polyadenylation of RNA.
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Affiliation(s)
- Mario H Barros
- Departamento de Microbiologia, Universidade de Sao Paulo, Sao Paulo 05508-900, Brazil
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68
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Abstract
SIGNIFICANCE In the last years, metabolic reprogramming, fluctuations in bioenergetic fuels, and modulation of oxidative stress became new key hallmarks of tumor development. In cancer, elevated glucose uptake and high glycolytic rate, as a source of adenosine triphosphate, constitute a growth advantage for tumors. This represents the universally known Warburg effect, which gave rise to one major clinical application for detecting cancer cells using glucose analogs: the positron emission tomography scan imaging. Recent Advances: Glucose utilization and carbon sources in tumors are much more heterogeneous than initially thought. Indeed, new studies emerged and revealed a dual capacity of tumor cells for glycolytic and oxidative phosphorylation (OXPHOS) metabolism. OXPHOS metabolism, which relies predominantly on mitochondrial respiration, exhibits fine-tuned regulation of respiratory chain complexes and enhanced antioxidant response or detoxification capacity. CRITICAL ISSUES OXPHOS-dependent cancer cells use alternative oxidizable substrates, such as glutamine and fatty acids. The diversity of carbon substrates fueling neoplastic cells is indicative of metabolic heterogeneity, even within tumors sharing the same clinical diagnosis. Metabolic switch supports cancer cell stemness and their bioenergy-consuming functions, such as proliferation, survival, migration, and invasion. Moreover, reactive oxygen species-induced mitochondrial metabolism and nutrient availability are important for interaction with tumor microenvironment components. Carcinoma-associated fibroblasts and immune cells participate in the metabolic interplay with neoplastic cells. They collectively adapt in a dynamic manner to the metabolic needs of cancer cells, thus participating in tumorigenesis and resistance to treatments. FUTURE DIRECTIONS Characterizing the reciprocal metabolic interplay between stromal, immune, and neoplastic cells will provide a better understanding of treatment resistance. Antioxid. Redox Signal. 26, 462-485.
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Affiliation(s)
- Géraldine Gentric
- 1 Stress and Cancer Laboratory, Équipe Labelisée LNCC, Institut Curie , Paris, France .,2 Inserm , U830, Paris, France
| | - Virginie Mieulet
- 1 Stress and Cancer Laboratory, Équipe Labelisée LNCC, Institut Curie , Paris, France .,2 Inserm , U830, Paris, France
| | - Fatima Mechta-Grigoriou
- 1 Stress and Cancer Laboratory, Équipe Labelisée LNCC, Institut Curie , Paris, France .,2 Inserm , U830, Paris, France
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69
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Vendramin R, Marine JC, Leucci E. Non-coding RNAs: the dark side of nuclear-mitochondrial communication. EMBO J 2017; 36:1123-1133. [PMID: 28314780 DOI: 10.15252/embj.201695546] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 11/26/2016] [Accepted: 12/15/2016] [Indexed: 12/15/2022] Open
Abstract
Mitochondria are critical hubs for the integration of several key metabolic processes implicated in cell growth and survival. They originated from bacterial ancestors through endosymbiosis, following the transfer of more than 90% of their endosymbiont genome to the host cell nucleus. Over time, a mutually beneficial symbiotic relationship has been established, which relies on continuous and elaborate signaling mechanisms between this life-essential organelle and its host. The ability of mitochondria to signal their functional state and trigger compensatory and adaptive cellular responses has long been recognized, but the underlying molecular mechanisms involved have remained poorly understood. Recent evidence indicates that non-coding RNAs (ncRNAs) may contribute to the synchronization of a series of essential cellular and mitochondrial biological processes, acting as "messengers" between the nucleus and the mitochondria. Here, we discuss the emerging putative roles of ncRNAs in various bidirectional signaling pathways established between the host cell and its mitochondria, and how the dysregulation of these pathways may lead to aging-related diseases, including cancer, and offer new promising therapeutic avenues.
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Affiliation(s)
- Roberto Vendramin
- Laboratory for Molecular Cancer Biology, Department of Oncology, KU Leuven, Leuven, Belgium.,VIB Center for Cancer Biology, VIB, Leuven, Belgium
| | - Jean-Christophe Marine
- Laboratory for Molecular Cancer Biology, Department of Oncology, KU Leuven, Leuven, Belgium.,VIB Center for Cancer Biology, VIB, Leuven, Belgium
| | - Eleonora Leucci
- Laboratory for Molecular Cancer Biology, Department of Oncology, KU Leuven, Leuven, Belgium .,RNA Molecular Biology, Center for Microscopy and Molecular Imaging, Université Libre de Bruxelles (ULB), Charleroi, Belgium
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70
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Regulation of Mammalian Mitochondrial Gene Expression: Recent Advances. Trends Biochem Sci 2017; 42:625-639. [PMID: 28285835 PMCID: PMC5538620 DOI: 10.1016/j.tibs.2017.02.003] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 02/02/2017] [Accepted: 02/10/2017] [Indexed: 01/03/2023]
Abstract
Perturbation of mitochondrial DNA (mtDNA) gene expression can lead to human pathologies. Therefore, a greater appreciation of the basic mechanisms of mitochondrial gene expression is desirable to understand the pathophysiology of associated disorders. Although the purpose of the mitochondrial gene expression machinery is to provide only 13 proteins of the oxidative phosphorylation (OxPhos) system, recent studies have revealed its remarkable and unexpected complexity. We review here the latest breakthroughs in our understanding of the post-transcriptional processes of mitochondrial gene expression, focusing on advances in analyzing the mitochondrial epitranscriptome, the role of mitochondrial RNA granules (MRGs), the benefits of recently obtained structures of the mitochondrial ribosome, and the coordination of mitochondrial and cytosolic translation to orchestrate the biogenesis of OxPhos complexes. The genetic system required for mitochondrial gene expression is housed within the mitochondrial matrix, with all the necessary RNAs being provided by transcription of the mtDNA itself. Our understanding of the extent and nature of post-transcriptional modifications of mtRNA, the epitranscriptome, is rapidly expanding. Several required nucleus-encoded enzymes have recently been identified. mtRNA maturation factors localize in distinct foci, termed mtRNA granules, with newly transcribed RNA. These foci may allow spatiotemporal control of mtRNA processing. Recent high-resolution structures obtained via cryo-electron microscopy have rapidly advanced our understanding of the specialized adaptations of the mitochondrial ribosome. Production of respiratory complexes requires tight coordination between the cytoplasmic and mitochondrial translation systems.
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71
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Kruszewski J, Golik P. Pentatricopeptide Motifs in the N-Terminal Extension Domain of Yeast Mitochondrial RNA Polymerase Rpo41p Are Not Essential for Its Function. BIOCHEMISTRY. BIOKHIMIIA 2016; 81:1101-1110. [PMID: 27908235 DOI: 10.1134/s0006297916100084] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The core mitochondrial RNA polymerase is a single-subunit enzyme that in yeast Saccharomyces cerevisiae is encoded by the nuclear RPO41 gene. It is an evolutionary descendant of the bacteriophage RNA polymerases, but it includes an additional unconserved N-terminal extension (NTE) domain that is unique to the organellar enzymes. This domain mediates interactions between the polymerase and accessory regulatory factors, such as yeast Sls1p and Nam1p. Previous studies demonstrated that deletion of the entire NTE domain results only in a temperature-dependent respiratory deficiency. Several sequences related to the pentatricopeptide (PPR) motifs were identified in silico in Rpo41p, three of which are located in the NTE domain. PPR repeat proteins are a large family of organellar RNA-binding factors, mostly involved in posttranscriptional gene expression mechanisms. To study their function, we analyzed the phenotype of strains bearing Rpo41p variants where each of these motifs was deleted. We found that deletion of any of the three PPR motifs in the NTE domain does not affect respiratory growth at normal temperature, and it results in a moderate decrease in mtDNA stability. Steady-state levels of COX1 and COX2 mRNAs are also moderately affected. Only the deletion of the second motif results in a partial respiratory deficiency, manifested only at elevated temperature. Our results thus indicate that the PPR motifs do not play an essential role in the function of the NTE domain of the mitochondrial RNA polymerase.
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Affiliation(s)
- J Kruszewski
- University of Warsaw, Institute of Genetics and Biotechnology, Faculty of Biology, Warsaw, 02-106, Poland.
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72
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Translational regulation of mitochondrial biogenesis. Biochem Soc Trans 2016; 44:1717-1724. [DOI: 10.1042/bst20160071c] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 08/30/2016] [Accepted: 09/02/2016] [Indexed: 01/08/2023]
Abstract
Mitochondria are generated by the expression of genes on both nuclear and mitochondrial genome. Mitochondrial biogenesis is highly plastic in response to cellular energy demand, developmental signals and environmental stimuli. Mechanistic target of rapamycin (mTOR) pathway regulates mitochondrial biogenesis to co-ordinate energy homeostasis with cell growth. The local translation of mitochondrial proteins on the outer membrane facilitates their efficient import and thereby allows prodigious mitochondrial biogenesis during rapid cell growth and proliferation. We postulate that the local translation may also allow cells to promote mitochondrial biogenesis selectively based on the fitness of individual organelle. MDI–Larp complex promotes the biogenesis of healthy mitochondria and thereby is essential for the selective transmission of healthy mitochondria. On the other hand, PTEN-induced putative kinase 1 (PINK1)–Pakin activates protein synthesis on damaged mitochondria to maintain the organelle homeostasis and activity. We also summarize some recent progress on miRNAs' regulation on mitochondrial biogenesis.
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73
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Abstract
The dual genetic origin of mitochondrial respiratory chain complexes leads to the synthesis of subunits by mitochondrial and cytosolic ribosomes. Now, Richter-Dennerlein et al. report that membrane-integrated assembly factors associate with ribosome nascent chain complexes in human mitochondria to coordinate translational plasticity with the import of subunits from the cytosol.
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Affiliation(s)
- Heike Rampelt
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany.
| | - Nikolaus Pfanner
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany.
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74
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Cao X, Qin Y. Mitochondrial translation factors reflect coordination between organelles and cytoplasmic translation via mTOR signaling: Implication in disease. Free Radic Biol Med 2016; 100:231-237. [PMID: 27101739 DOI: 10.1016/j.freeradbiomed.2016.04.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 04/11/2016] [Accepted: 04/13/2016] [Indexed: 12/24/2022]
Abstract
Mitochondria are semi-autonomous organelle possessing their own translation machinery to biosynthesize mitochondrial DNA (mtDNA)-encoded polypeptides, which are the core subunits of oxidative phosphorylation (OXPHOS) complexes. Mitochondrial translation elongation factor 4 (mtEF4) is a key quality control factor in mitochondrial translation (mt-translation) that regulates mitochondrial tRNA translocation and modulates cellular responses by influencing cytoplasmic translation (ct-translation). In addition to mtEF4, mt-translational activators, mitochondrial microRNAs (mitomiRs), and MITRAC have been reported recently as crucial mt-translation regulators. Here, we focus on the novel ways how these factors regulate mt-translation, discuss the main cellular response of mammalian target of rapamycin (mTOR) signalling upon mt-translation defects, and summarize the related human diseases.
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Affiliation(s)
- Xintao Cao
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yan Qin
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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75
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Ribosome-Associated Mba1 Escorts Cox2 from Insertion Machinery to Maturing Assembly Intermediates. Mol Cell Biol 2016; 36:2782-2793. [PMID: 27550809 PMCID: PMC5086520 DOI: 10.1128/mcb.00361-16] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 07/08/2016] [Accepted: 08/17/2016] [Indexed: 01/25/2023] Open
Abstract
The three conserved core subunits of the cytochrome c oxidase are encoded by mitochondria in close to all eukaryotes. The Cox2 subunit spans the inner membrane twice, exposing the N and C termini to the intermembrane space. For this, the N terminus is exported cotranslationally by Oxa1 and subsequently undergoes proteolytic maturation in Saccharomyces cerevisiae. Little is known about the translocation of the C terminus, but Cox18 has been identified to be a critical protein in this process. Here we find that the scaffold protein Cox20, which promotes processing of Cox2, is in complex with the ribosome receptor Mba1 and translating mitochondrial ribosomes in a Cox2-dependent manner. The Mba1-Cox20 complex accumulates when export of the C terminus of Cox2 is blocked by the loss of the Cox18 protein. While Cox20 engages with Cox18, Mba1 is no longer present at this stage. Our analyses indicate that Cox20 associates with nascent Cox2 and Mba1 to promote Cox2 maturation cotranslationally. We suggest that Mba1 stabilizes the Cox20-ribosome complex and supports the handover of Cox2 to the Cox18 tail export machinery.
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76
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Richter-Dennerlein R, Oeljeklaus S, Lorenzi I, Ronsör C, Bareth B, Schendzielorz AB, Wang C, Warscheid B, Rehling P, Dennerlein S. Mitochondrial Protein Synthesis Adapts to Influx of Nuclear-Encoded Protein. Cell 2016; 167:471-483.e10. [PMID: 27693358 PMCID: PMC5055049 DOI: 10.1016/j.cell.2016.09.003] [Citation(s) in RCA: 136] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 08/01/2016] [Accepted: 08/30/2016] [Indexed: 12/11/2022]
Abstract
Mitochondrial ribosomes translate membrane integral core subunits of the oxidative phosphorylation system encoded by mtDNA. These translation products associate with nuclear-encoded, imported proteins to form enzyme complexes that produce ATP. Here, we show that human mitochondrial ribosomes display translational plasticity to cope with the supply of imported nuclear-encoded subunits. Ribosomes expressing mitochondrial-encoded COX1 mRNA selectively engage with cytochrome c oxidase assembly factors in the inner membrane. Assembly defects of the cytochrome c oxidase arrest mitochondrial translation in a ribosome nascent chain complex with a partially membrane-inserted COX1 translation product. This complex represents a primed state of the translation product that can be retrieved for assembly. These findings establish a mammalian translational plasticity pathway in mitochondria that enables adaptation of mitochondrial protein synthesis to the influx of nuclear-encoded subunits. Mitochondrial ribosomes display translational plasticity COX1 translation in mitochondria is stalled in the absence of nuclear-encoded COX4 A ribosome nascent chain complex of COX1 is a primed state for complex IV assembly MITRAC regulates translation via COX1 ribosome nascent chain complexes interaction
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Affiliation(s)
- Ricarda Richter-Dennerlein
- Department of Cellular Biochemistry, University Medical Centre Göttingen, GZMB, 37073 Göttingen, Germany
| | - Silke Oeljeklaus
- Department of Biochemistry and Functional Proteomics, Faculty of Biology, University Freiburg, 79104 Freiburg, Germany
| | - Isotta Lorenzi
- Department of Cellular Biochemistry, University Medical Centre Göttingen, GZMB, 37073 Göttingen, Germany
| | - Christin Ronsör
- Department of Cellular Biochemistry, University Medical Centre Göttingen, GZMB, 37073 Göttingen, Germany
| | - Bettina Bareth
- Department of Cellular Biochemistry, University Medical Centre Göttingen, GZMB, 37073 Göttingen, Germany
| | | | - Cong Wang
- Department of Cellular Biochemistry, University Medical Centre Göttingen, GZMB, 37073 Göttingen, Germany
| | - Bettina Warscheid
- Department of Biochemistry and Functional Proteomics, Faculty of Biology, University Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Peter Rehling
- Department of Cellular Biochemistry, University Medical Centre Göttingen, GZMB, 37073 Göttingen, Germany; Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany.
| | - Sven Dennerlein
- Department of Cellular Biochemistry, University Medical Centre Göttingen, GZMB, 37073 Göttingen, Germany
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77
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Abstract
Oxidative phosphorylation (OXPHOS) is the mechanism whereby ATP, the major energy source for the cell, is produced by harnessing cellular respiration in the mitochondrion. This is facilitated by five multi-subunit complexes housed within the inner mitochondrial membrane. These complexes, with the exception of complex II, are of a dual genetic origin, requiring expression from nuclear and mitochondrial genes. Mitochondrially encoded mRNA is translated on the mitochondrial ribosome (mitoribosome) and the recent release of the near atomic resolution structure of the mammalian mitoribosome has highlighted its peculiar features. However, whereas some aspects of mitochondrial translation are understood, much is to be learnt about the presentation of mitochondrial mRNA to the mitoribosome, the biogenesis of the machinery, the exact role of the membrane, the constitution of the translocon/insertion machinery and the regulation of translation in the mitochondrion. This review addresses our current knowledge of mammalian mitochondrial gene expression, highlights key questions and indicates how defects in this process can result in profound mitochondrial disease.
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78
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Richman TR, Spåhr H, Ermer JA, Davies SMK, Viola HM, Bates KA, Papadimitriou J, Hool LC, Rodger J, Larsson NG, Rackham O, Filipovska A. Loss of the RNA-binding protein TACO1 causes late-onset mitochondrial dysfunction in mice. Nat Commun 2016; 7:11884. [PMID: 27319982 PMCID: PMC4915168 DOI: 10.1038/ncomms11884] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 05/09/2016] [Indexed: 11/30/2022] Open
Abstract
The recognition and translation of mammalian mitochondrial mRNAs are poorly understood. To gain further insights into these processes in vivo, we characterized mice with a missense mutation that causes loss of the translational activator of cytochrome oxidase subunit I (TACO1). We report that TACO1 is not required for embryonic survival, although the mutant mice have substantially reduced COXI protein, causing an isolated complex IV deficiency. We show that TACO1 specifically binds the mt-Co1 mRNA and is required for translation of COXI through its association with the mitochondrial ribosome. We determined the atomic structure of TACO1, revealing three domains in the shape of a hook with a tunnel between domains 1 and 3. Mutations in the positively charged domain 1 reduce RNA binding by TACO1. The Taco1 mutant mice develop a late-onset visual impairment, motor dysfunction and cardiac hypertrophy and thus provide a useful model for future treatment trials for mitochondrial disease. Mutations in the translational activator of cytochrome c oxidase subunit I (TACO1) causes cytochrome c oxidase deficiency and Leigh Syndrome in patients. Here, the authors characterize mice with a mutation that causes lack of TACO1 expression, identifying a mouse model that could be useful for preclinical trials.
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Affiliation(s)
- Tara R Richman
- Harry Perkins Institute of Medical Research and Centre for Medical Research, University of Western Australia, Nedlands, Western Australia 6009, Australia
| | - Henrik Spåhr
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, D-50931 Cologne, Germany
| | - Judith A Ermer
- Harry Perkins Institute of Medical Research and Centre for Medical Research, University of Western Australia, Nedlands, Western Australia 6009, Australia
| | - Stefan M K Davies
- Harry Perkins Institute of Medical Research and Centre for Medical Research, University of Western Australia, Nedlands, Western Australia 6009, Australia
| | - Helena M Viola
- School of Anatomy, Physiology and Human Biology, University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Kristyn A Bates
- Experimental and Regenerative Neuroscience, School of Animal Biology, University of Western Australia Crawley, Western Australia 6009, Australia
| | - John Papadimitriou
- School of Pathology and Laboratory Medicine, University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Livia C Hool
- School of Anatomy, Physiology and Human Biology, University of Western Australia, Crawley, Western Australia 6009, Australia.,Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales 2010, Australia
| | - Jennifer Rodger
- Experimental and Regenerative Neuroscience, School of Animal Biology, University of Western Australia Crawley, Western Australia 6009, Australia
| | - Nils-Göran Larsson
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, D-50931 Cologne, Germany.,Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm 17177, Sweden
| | - Oliver Rackham
- Harry Perkins Institute of Medical Research and Centre for Medical Research, University of Western Australia, Nedlands, Western Australia 6009, Australia.,School of Chemistry and Biochemistry, University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Aleksandra Filipovska
- Harry Perkins Institute of Medical Research and Centre for Medical Research, University of Western Australia, Nedlands, Western Australia 6009, Australia.,School of Chemistry and Biochemistry, University of Western Australia, Crawley, Western Australia 6009, Australia
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79
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Ostojić J, Panozzo C, Bourand-Plantefol A, Herbert CJ, Dujardin G, Bonnefoy N. Ribosome recycling defects modify the balance between the synthesis and assembly of specific subunits of the oxidative phosphorylation complexes in yeast mitochondria. Nucleic Acids Res 2016; 44:5785-97. [PMID: 27257059 PMCID: PMC4937339 DOI: 10.1093/nar/gkw490] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 05/20/2016] [Indexed: 01/07/2023] Open
Abstract
Mitochondria have their own translation machinery that produces key subunits of the OXPHOS complexes. This machinery relies on the coordinated action of nuclear-encoded factors of bacterial origin that are well conserved between humans and yeast. In humans, mutations in these factors can cause diseases; in yeast, mutations abolishing mitochondrial translation destabilize the mitochondrial DNA. We show that when the mitochondrial genome contains no introns, the loss of the yeast factors Mif3 and Rrf1 involved in ribosome recycling neither blocks translation nor destabilizes mitochondrial DNA. Rather, the absence of these factors increases the synthesis of the mitochondrially-encoded subunits Cox1, Cytb and Atp9, while strongly impairing the assembly of OXPHOS complexes IV and V. We further show that in the absence of Rrf1, the COX1 specific translation activator Mss51 accumulates in low molecular weight forms, thought to be the source of the translationally-active form, explaining the increased synthesis of Cox1. We propose that Rrf1 takes part in the coordination between translation and OXPHOS assembly in yeast mitochondria. These interactions between general and specific translation factors might reveal an evolutionary adaptation of the bacterial translation machinery to the set of integral membrane proteins that are translated within mitochondria.
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Affiliation(s)
- Jelena Ostojić
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, UEVE, 91198, Gif-sur-Yvette cedex, France
| | - Cristina Panozzo
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, UEVE, 91198, Gif-sur-Yvette cedex, France
| | - Alexa Bourand-Plantefol
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, UEVE, 91198, Gif-sur-Yvette cedex, France
| | - Christopher J Herbert
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, UEVE, 91198, Gif-sur-Yvette cedex, France
| | - Geneviève Dujardin
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, UEVE, 91198, Gif-sur-Yvette cedex, France
| | - Nathalie Bonnefoy
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, UEVE, 91198, Gif-sur-Yvette cedex, France
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80
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Bareth B, Nikolov M, Lorenzi I, Hildenbeutel M, Mick DU, Helbig C, Urlaub H, Ott M, Rehling P, Dennerlein S. Oms1 associates with cytochrome c oxidase assembly intermediates to stabilize newly synthesized Cox1. Mol Biol Cell 2016; 27:1570-80. [PMID: 27030670 PMCID: PMC4865315 DOI: 10.1091/mbc.e15-12-0811] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 03/23/2016] [Accepted: 03/24/2016] [Indexed: 12/18/2022] Open
Abstract
The mitochondrial cytochrome c oxidase assembles in the inner membrane from subunits of dual genetic origin. The assembly process of the enzyme is initiated by membrane insertion of the mitochondria-encoded Cox1 subunit. During complex maturation, transient assembly intermediates, consisting of structural subunits and specialized chaperone-like assembly factors, are formed. In addition, cofactors such as heme and copper have to be inserted into the nascent complex. To regulate the assembly process, the availability of Cox1 is under control of a regulatory feedback cycle in which translation of COX1 mRNA is stalled when assembly intermediates of Cox1 accumulate through inactivation of the translational activator Mss51. Here we isolate a cytochrome c oxidase assembly intermediate in preparatory scale from coa1Δ mutant cells, using Mss51 as bait. We demonstrate that at this stage of assembly, the complex has not yet incorporated the heme a cofactors. Using quantitative mass spectrometry, we define the protein composition of the assembly intermediate and unexpectedly identify the putative methyltransferase Oms1 as a constituent. Our analyses show that Oms1 participates in cytochrome c oxidase assembly by stabilizing newly synthesized Cox1.
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Affiliation(s)
- Bettina Bareth
- Department of Cellular Biochemistry, University Medical Center Göttingen, D-37073 Göttingen, Germany
| | - Miroslav Nikolov
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, D-37077 Göttingen, Germany
| | - Isotta Lorenzi
- Department of Cellular Biochemistry, University Medical Center Göttingen, D-37073 Göttingen, Germany
| | - Markus Hildenbeutel
- Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden
| | - David U Mick
- Department of Cellular Biochemistry, University Medical Center Göttingen, D-37073 Göttingen, Germany
| | - Christin Helbig
- Department of Cellular Biochemistry, University Medical Center Göttingen, D-37073 Göttingen, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, D-37077 Göttingen, Germany Bioanalytik Group, Department of Clinical Chemistry, University Medical Center Göttingen, D-37075 Göttingen, Germany
| | - Martin Ott
- Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden
| | - Peter Rehling
- Department of Cellular Biochemistry, University Medical Center Göttingen, D-37073 Göttingen, Germany Max Planck Institute for Biophysical Chemistry, D-37077 Göttingen, Germany
| | - Sven Dennerlein
- Department of Cellular Biochemistry, University Medical Center Göttingen, D-37073 Göttingen, Germany
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81
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Couvillion MT, Soto IC, Shipkovenska G, Churchman LS. Synchronized mitochondrial and cytosolic translation programs. Nature 2016; 533:499-503. [PMID: 27225121 PMCID: PMC4964289 DOI: 10.1038/nature18015] [Citation(s) in RCA: 225] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 04/18/2016] [Indexed: 01/21/2023]
Abstract
Oxidative phosphorylation (OXPHOS) is fundamental for life. OXPHOS complexes pose a unique challenge for the cell, because their subunits are encoded on two different genomes, the nuclear genome and the mitochondrial genome. Genomic approaches designed to study nuclear/cytosolic and bacterial gene expression have not been broadly applied to the mitochondrial system; thus the co-regulation of OXPHOS genes remains largely unexplored. Here we globally monitored mitochondrial and nuclear gene expression processes in Saccharomyces cerevisiae during mitochondrial biogenesis, when OXPHOS complexes are synthesized. Nuclear- and mitochondrial-encoded OXPHOS transcript levels do not increase concordantly. Instead, we observe that mitochondrial and cytosolic translation are rapidly and dynamically regulated in a strikingly synchronous fashion. Furthermore, the coordinated translation programs are controlled unidirectionally through the intricate and dynamic control of cytosolic translation. Thus the nuclear genome carefully directs the coordination of mitochondrial and cytosolic translation to orchestrate the timely synthesis of each OXPHOS complex, representing an unappreciated regulatory layer shaping the mitochondrial proteome. Our whole-cell genomic profiling approach establishes a foundation for global gene regulatory studies of mitochondrial biology.
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Affiliation(s)
- Mary T Couvillion
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Iliana C Soto
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Gergana Shipkovenska
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - L Stirling Churchman
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
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82
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Levchenko M, Wuttke JM, Römpler K, Schmidt B, Neifer K, Juris L, Wissel M, Rehling P, Deckers M. Cox26 is a novel stoichiometric subunit of the yeast cytochrome c oxidase. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:1624-32. [PMID: 27083394 DOI: 10.1016/j.bbamcr.2016.04.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 03/31/2016] [Accepted: 04/06/2016] [Indexed: 11/25/2022]
Abstract
The cytochrome c oxidase (COX) is the terminal enzyme of the respiratory chain. The complex accepts electrons from cytochrome c and passes them onto molecular oxygen. This process contributes to energy capture in the form of a membrane potential across the inner membrane. The enzyme complex assembles in a stepwise process from the three mitochondria-encoded core subunits Cox1, Cox2 and Cox3, which associate with nuclear-encoded subunits and cofactors. In the yeast Saccharomyces cerevisiae, the cytochrome c oxidase associates with the bc1-complex into supercomplexes, allowing efficient energy transduction. Here we report on Cox26 as a protein found in respiratory chain supercomplexes containing cytochrome c oxidase. Our analyses reveal Cox26 as a novel stoichiometric structural subunit of the cytochrome c oxidase. A loss of Cox26 affects cytochrome c oxidase activity and respirasome organization.
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Affiliation(s)
- Maria Levchenko
- Department of Cellular Biochemistry, University Medical Center Göttingen, D-37073 Göttingen, Germany
| | - Jan-Moritz Wuttke
- Department of Cellular Biochemistry, University Medical Center Göttingen, D-37073 Göttingen, Germany
| | - Katharina Römpler
- Department of Cellular Biochemistry, University Medical Center Göttingen, D-37073 Göttingen, Germany
| | - Bernhard Schmidt
- Department of Cellular Biochemistry, University Medical Center Göttingen, D-37073 Göttingen, Germany
| | - Klaus Neifer
- Department of Cellular Biochemistry, University Medical Center Göttingen, D-37073 Göttingen, Germany
| | - Lisa Juris
- Department of Cellular Biochemistry, University Medical Center Göttingen, D-37073 Göttingen, Germany
| | - Mirjam Wissel
- Department of Cellular Biochemistry, University Medical Center Göttingen, D-37073 Göttingen, Germany
| | - Peter Rehling
- Department of Cellular Biochemistry, University Medical Center Göttingen, D-37073 Göttingen, Germany; Max Planck Institute for Biophysical Chemistry, D-37077 Göttingen, Germany.
| | - Markus Deckers
- Department of Cellular Biochemistry, University Medical Center Göttingen, D-37073 Göttingen, Germany
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83
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Abstract
Mitochondrial ribosomes (mitoribosomes) perform protein synthesis inside mitochondria, the organelles responsible for energy conversion and adenosine triphosphate production in eukaryotic cells. Throughout evolution, mitoribosomes have become functionally specialized for synthesizing mitochondrial membrane proteins, and this has been accompanied by large changes to their structure and composition. We review recent high-resolution structural data that have provided unprecedented insight into the structure and function of mitoribosomes in mammals and fungi.
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Affiliation(s)
- Basil J Greber
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, CH-8093 Zurich, Switzerland; .,*Present address: California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, California 94720-3220
| | - Nenad Ban
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, CH-8093 Zurich, Switzerland;
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84
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Mayorga JP, Camacho-Villasana Y, Shingú-Vázquez M, García-Villegas R, Zamudio-Ochoa A, García-Guerrero AE, Hernández G, Pérez-Martínez X. A Novel Function of Pet54 in Regulation of Cox1 Synthesis in Saccharomyces cerevisiae Mitochondria. J Biol Chem 2016; 291:9343-55. [PMID: 26929411 DOI: 10.1074/jbc.m116.721985] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Indexed: 12/21/2022] Open
Abstract
Cytochrome c oxidase assembly requires the synthesis of the mitochondria-encoded core subunits, Cox1, Cox2, and Cox3. In yeast, Pet54 protein is required to activate translation of the COX3 mRNA and to process the aI5β intron on the COX1 transcript. Here we report a third, novel function of Pet54 on Cox1 synthesis. We observed that Pet54 is necessary to achieve an efficient Cox1 synthesis. Translation of the COX1 mRNA is coupled to the assembly of cytochrome c oxidase by a mechanism that involves Mss51. This protein activates translation of the COX1 mRNA by acting on the COX1 5'-UTR, and, in addition, it interacts with the newly synthesized Cox1 protein in high molecular weight complexes that include the factors Coa3 and Cox14. Deletion of Pet54 decreased Cox1 synthesis, and, in contrast to what is commonly observed for other assembly mutants, double deletion of cox14 or coa3 did not recover Cox1 synthesis. Our results show that Pet54 is a positive regulator of Cox1 synthesis that renders Mss51 competent as a translational activator of the COX1 mRNA and that this role is independent of the assembly feedback regulatory loop of Cox1 synthesis. Pet54 may play a role in Mss51 hemylation/conformational change necessary for translational activity. Moreover, Pet54 physically interacts with the COX1 mRNA, and this binding was independent of the presence of Mss51.
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Affiliation(s)
- Juan Pablo Mayorga
- From the Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico
| | - Yolanda Camacho-Villasana
- From the Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico
| | - Miguel Shingú-Vázquez
- the Department of Biochemistry and Molecular Biology, School of Biomedical Sciences Monash University, Clayton, Victoria 3800, Australia, and
| | - Rodolfo García-Villegas
- From the Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico
| | - Angélica Zamudio-Ochoa
- From the Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico
| | - Aldo E García-Guerrero
- From the Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico
| | - Greco Hernández
- the Division of Basic Research, National Institute of Cancer (INCan), Mexico City 14080, Mexico
| | - Xochitl Pérez-Martínez
- From the Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico,
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85
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Lasserre JP, Dautant A, Aiyar RS, Kucharczyk R, Glatigny A, Tribouillard-Tanvier D, Rytka J, Blondel M, Skoczen N, Reynier P, Pitayu L, Rötig A, Delahodde A, Steinmetz LM, Dujardin G, Procaccio V, di Rago JP. Yeast as a system for modeling mitochondrial disease mechanisms and discovering therapies. Dis Model Mech 2016; 8:509-26. [PMID: 26035862 PMCID: PMC4457039 DOI: 10.1242/dmm.020438] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Mitochondrial diseases are severe and largely untreatable. Owing to the many essential processes carried out by mitochondria and the complex cellular systems that support these processes, these diseases are diverse, pleiotropic, and challenging to study. Much of our current understanding of mitochondrial function and dysfunction comes from studies in the baker's yeast Saccharomyces cerevisiae. Because of its good fermenting capacity, S. cerevisiae can survive mutations that inactivate oxidative phosphorylation, has the ability to tolerate the complete loss of mitochondrial DNA (a property referred to as ‘petite-positivity’), and is amenable to mitochondrial and nuclear genome manipulation. These attributes make it an excellent model system for studying and resolving the molecular basis of numerous mitochondrial diseases. Here, we review the invaluable insights this model organism has yielded about diseases caused by mitochondrial dysfunction, which ranges from primary defects in oxidative phosphorylation to metabolic disorders, as well as dysfunctions in maintaining the genome or in the dynamics of mitochondria. Owing to the high level of functional conservation between yeast and human mitochondrial genes, several yeast species have been instrumental in revealing the molecular mechanisms of pathogenic human mitochondrial gene mutations. Importantly, such insights have pointed to potential therapeutic targets, as have genetic and chemical screens using yeast. Summary: In this Review, we discuss the use of budding yeast to understand mitochondrial diseases and help in the search for their treatments.
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Affiliation(s)
- Jean-Paul Lasserre
- University Bordeaux-CNRS, IBGC, UMR 5095, 1 rue Camille Saint-Saëns, Bordeaux F-33000, France
| | - Alain Dautant
- University Bordeaux-CNRS, IBGC, UMR 5095, 1 rue Camille Saint-Saëns, Bordeaux F-33000, France
| | - Raeka S Aiyar
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Meyerhofstrasse 1, Heidelberg 69117, Germany
| | - Roza Kucharczyk
- Department of Genetics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw 02-106, Poland
| | - Annie Glatigny
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Université Paris-Sud, 1 avenue de la terrasse, Gif-sur-Yvette 91198, France
| | - Déborah Tribouillard-Tanvier
- Institut National de la Santé et de la Recherche Médicale UMR1078, Université de Bretagne Occidentale, Faculté de Médecine et des Sciences de la Santé, Etablissement Français du Sang (EFS) Bretagne, CHRU Brest, Hôpital Morvan, Laboratoire de Génétique Moléculaire, Brest F-29200, France
| | - Joanna Rytka
- Department of Genetics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw 02-106, Poland
| | - Marc Blondel
- Institut National de la Santé et de la Recherche Médicale UMR1078, Université de Bretagne Occidentale, Faculté de Médecine et des Sciences de la Santé, Etablissement Français du Sang (EFS) Bretagne, CHRU Brest, Hôpital Morvan, Laboratoire de Génétique Moléculaire, Brest F-29200, France
| | - Natalia Skoczen
- University Bordeaux-CNRS, IBGC, UMR 5095, 1 rue Camille Saint-Saëns, Bordeaux F-33000, France Department of Genetics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw 02-106, Poland
| | - Pascal Reynier
- UMR CNRS 6214-INSERM U1083, Angers 49933, Cedex 9, France Département de Biochimie et Génétique, Centre Hospitalier Universitaire d'Angers, Angers 49933, Cedex 9, France
| | - Laras Pitayu
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Université Paris-Sud, rue Gregor Mendel, Orsay 91405, France
| | - Agnès Rötig
- Inserm U1163, Hôpital Necker-Enfants-Malades, Institut Imagine, Université Paris Descartes-Sorbonne Paris Cité, 149 rue de Sèvres, Paris 75015, France
| | - Agnès Delahodde
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Université Paris-Sud, rue Gregor Mendel, Orsay 91405, France
| | - Lars M Steinmetz
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Meyerhofstrasse 1, Heidelberg 69117, Germany Stanford Genome Technology Center, Department of Biochemistry, Stanford University, Palo Alto, CA 94304, USA Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305-5301, USA
| | - Geneviève Dujardin
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Université Paris-Sud, 1 avenue de la terrasse, Gif-sur-Yvette 91198, France
| | - Vincent Procaccio
- UMR CNRS 6214-INSERM U1083, Angers 49933, Cedex 9, France Département de Biochimie et Génétique, Centre Hospitalier Universitaire d'Angers, Angers 49933, Cedex 9, France
| | - Jean-Paul di Rago
- University Bordeaux-CNRS, IBGC, UMR 5095, 1 rue Camille Saint-Saëns, Bordeaux F-33000, France
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86
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Aphasizheva I, Maslov DA, Qian Y, Huang L, Wang Q, Costello CE, Aphasizhev R. Ribosome-associated pentatricopeptide repeat proteins function as translational activators in mitochondria of trypanosomes. Mol Microbiol 2016; 99:1043-58. [PMID: 26713541 DOI: 10.1111/mmi.13287] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/22/2015] [Indexed: 12/20/2022]
Abstract
Mitochondrial ribosomes of Trypanosoma brucei are composed of 9S and 12S rRNAs, eubacterial-type ribosomal proteins, polypeptides lacking discernible motifs and approximately 20 pentatricopeptide repeat (PPR) RNA binding proteins. Several PPRs also populate the polyadenylation complex; among these, KPAF1 and KPAF2 function as general mRNA 3' adenylation/uridylation factors. The A/U-tail enables mRNA binding to the small ribosomal subunit and is essential for translation. The presence of A/U-tail also correlates with requirement for translation of certain mRNAs in mammalian and insect parasite stages. Here, we inquired whether additional PPRs activate translation of individual mRNAs. Proteomic analysis identified KRIPP1 and KRIPP8 as components of the small ribosomal subunit in mammalian and insect forms, but also revealed their association with the polyadenylation complex in the latter. RNAi knockdowns demonstrated essential functions of KRIPP1 and KRIPP8 in the actively respiring insect stage, but not in the mammalian stage. In the KRIPP1 knockdown, A/U-tailed mRNA encoding cytochrome c oxidase subunit 1 declined concomitantly with the de novo synthesis of this subunit whereas polyadenylation and translation of cyb mRNA were unaffected. In contrast, the KRIPP8 knockdown inhibited A/U-tailing and translation of both CO1 and cyb mRNAs. Our findings indicate that ribosome-associated PPRs may selectively activate mRNAs for translation.
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Affiliation(s)
- Inna Aphasizheva
- Department of Molecular and Cell Biology, Boston University Goldman School of Dental Medicine, Boston, MA, 02118, USA
| | - Dmitri A Maslov
- Department of Biology, University of California, Riverside, CA, 92521, USA
| | - Yu Qian
- Department of Molecular and Cell Biology, Boston University Goldman School of Dental Medicine, Boston, MA, 02118, USA
| | - Lan Huang
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, 92697, USA
| | - Qi Wang
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, 02118, USA
| | - Catherine E Costello
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, 02118, USA
| | - Ruslan Aphasizhev
- Department of Molecular and Cell Biology, Boston University Goldman School of Dental Medicine, Boston, MA, 02118, USA.,Department of Biochemistry, Boston University School of Medicine, Boston, MA, 02118, USA
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87
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Kuzmenko A, Derbikova K, Salvatori R, Tankov S, Atkinson GC, Tenson T, Ott M, Kamenski P, Hauryliuk V. Aim-less translation: loss of Saccharomyces cerevisiae mitochondrial translation initiation factor mIF3/Aim23 leads to unbalanced protein synthesis. Sci Rep 2016; 6:18749. [PMID: 26728900 PMCID: PMC4700529 DOI: 10.1038/srep18749] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 11/09/2015] [Indexed: 12/22/2022] Open
Abstract
The mitochondrial genome almost exclusively encodes a handful of transmembrane constituents of the oxidative phosphorylation (OXPHOS) system. Coordinated expression of these genes ensures the correct stoichiometry of the system’s components. Translation initiation in mitochondria is assisted by two general initiation factors mIF2 and mIF3, orthologues of which in bacteria are indispensible for protein synthesis and viability. mIF3 was thought to be absent in Saccharomyces cerevisiae until we recently identified mitochondrial protein Aim23 as the missing orthologue. Here we show that, surprisingly, loss of mIF3/Aim23 in S. cerevisiae does not indiscriminately abrogate mitochondrial translation but rather causes an imbalance in protein production: the rate of synthesis of the Atp9 subunit of F1F0 ATP synthase (complex V) is increased, while expression of Cox1, Cox2 and Cox3 subunits of cytochrome c oxidase (complex IV) is repressed. Our results provide one more example of deviation of mitochondrial translation from its bacterial origins.
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Affiliation(s)
- Anton Kuzmenko
- University of Tartu, Institute of Technology, Nooruse 1, 50411 Tartu, Estonia.,Molecular Biology Department, Faculty of Biology, M.V. Lomonosov Moscow State University, 1/12 Leninskie Gory, 119991 Moscow, Russia
| | - Ksenia Derbikova
- Molecular Biology Department, Faculty of Biology, M.V. Lomonosov Moscow State University, 1/12 Leninskie Gory, 119991 Moscow, Russia
| | - Roger Salvatori
- Department of Biochemistry and Biophysics, Center for Biomembrane Research, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Stoyan Tankov
- University of Tartu, Institute of Technology, Nooruse 1, 50411 Tartu, Estonia
| | - Gemma C Atkinson
- University of Tartu, Institute of Technology, Nooruse 1, 50411 Tartu, Estonia.,Department of Molecular Biology, Umeå University, Building 6K, 6L University Hospital Area, SE-901 87 Umeå, Sweden.,Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Building 6K and 6L, University Hospital Area, SE-901 87 Umeå, Sweden
| | - Tanel Tenson
- University of Tartu, Institute of Technology, Nooruse 1, 50411 Tartu, Estonia
| | - Martin Ott
- Department of Biochemistry and Biophysics, Center for Biomembrane Research, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Piotr Kamenski
- Molecular Biology Department, Faculty of Biology, M.V. Lomonosov Moscow State University, 1/12 Leninskie Gory, 119991 Moscow, Russia
| | - Vasili Hauryliuk
- University of Tartu, Institute of Technology, Nooruse 1, 50411 Tartu, Estonia.,Department of Molecular Biology, Umeå University, Building 6K, 6L University Hospital Area, SE-901 87 Umeå, Sweden.,Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Building 6K and 6L, University Hospital Area, SE-901 87 Umeå, Sweden
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88
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Richter-Dennerlein R, Dennerlein S, Rehling P. Integrating mitochondrial translation into the cellular context. Nat Rev Mol Cell Biol 2015; 16:586-92. [PMID: 26535422 DOI: 10.1038/nrm4051] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mitochondrial-encoded subunits of the oxidative phosphorylation system assemble with nuclear-encoded subunits into enzymatic complexes. Recent findings showed that mitochondrial translation is linked to other mitochondrial functions, as well as to cellular processes. The supply of mitochondrial-encoded proteins is coordinated by the coupling of mitochondrial protein synthesis with assembly of respiratory chain complexes. MicroRNAs imported from the cytoplasm into mitochondria were, surprisingly, found to act as regulators of mitochondrial translation. In turn, translation in mitochondria controls cellular proliferation, and mitochondrial ribosomal subunits contribute to the cytoplasmic stress response. Thus, translation in mitochondria is apparently integrated into cellular processes.
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89
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Kolondra A, Labedzka-Dmoch K, Wenda JM, Drzewicka K, Golik P. The transcriptome of Candida albicans mitochondria and the evolution of organellar transcription units in yeasts. BMC Genomics 2015; 16:827. [PMID: 26487099 PMCID: PMC4618339 DOI: 10.1186/s12864-015-2078-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 10/13/2015] [Indexed: 02/06/2023] Open
Abstract
Background Yeasts show remarkable variation in the organization of their mitochondrial genomes, yet there is little experimental data on organellar gene expression outside few model species. Candida albicans is interesting as a human pathogen, and as a representative of a clade that is distant from the model yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe. Unlike them, it encodes seven Complex I subunits in its mtDNA. No experimental data regarding organellar expression were available prior to this study. Methods We used high-throughput RNA sequencing and traditional RNA biology techniques to study the mitochondrial transcriptome of C. albicans strains BWP17 and SN148. Results The 14 protein-coding genes, two ribosomal RNA genes, and 24 tRNA genes are expressed as eight primary polycistronic transcription units. We also found transcriptional activity in the noncoding regions, and antisense transcripts that could be a part of a regulatory mechanism. The promoter sequence is a variant of the nonanucleotide identified in other yeast mtDNAs, but some of the active promoters show significant departures from the consensus. The primary transcripts are processed by a tRNA punctuation mechanism into the monocistronic and bicistronic mature RNAs. The steady state levels of various mature transcripts exhibit large differences that are a result of posttranscriptional regulation. Transcriptome analysis allowed to precisely annotate the positions of introns in the RNL (2), COB (2) and COX1 (4) genes, as well as to refine the annotation of tRNAs and rRNAs. Comparative study of the mitochondrial genome organization in various Candida species indicates that they undergo shuffling in blocks usually containing 2–3 genes, and that their arrangement in primary transcripts is not conserved. tRNA genes with their associated promoters, as well as GC-rich sequence elements play an important role in these evolutionary events. Conclusions The main evolutionary force shaping the mitochondrial genomes of yeasts is the frequent recombination, constantly breaking apart and joining genes into novel primary transcription units. The mitochondrial transcription units are constantly rearranged in evolution shaping the features of gene expression, such as the presence of secondary promoter sites that are inactive, or act as “booster” promoters, simplified transcriptional regulation and reliance on posttranscriptional mechanisms. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-2078-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Adam Kolondra
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106, Warsaw, Poland.
| | - Karolina Labedzka-Dmoch
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106, Warsaw, Poland.
| | - Joanna M Wenda
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106, Warsaw, Poland.
| | - Katarzyna Drzewicka
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106, Warsaw, Poland.
| | - Pawel Golik
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106, Warsaw, Poland. .,Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106, Warsaw, Poland.
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90
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Armengod ME, Meseguer S, Villarroya M, Prado S, Moukadiri I, Ruiz-Partida R, Garzón MJ, Navarro-González C, Martínez-Zamora A. Modification of the wobble uridine in bacterial and mitochondrial tRNAs reading NNA/NNG triplets of 2-codon boxes. RNA Biol 2015; 11:1495-507. [PMID: 25607529 DOI: 10.4161/15476286.2014.992269] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Posttranscriptional modification of the uridine located at the wobble position (U34) of tRNAs is crucial for optimization of translation. Defects in the U34 modification of mitochondrial-tRNAs are associated with a group of rare diseases collectively characterized by the impairment of the oxidative phosphorylation system. Retrograde signaling pathways from mitochondria to nucleus are involved in the pathophysiology of these diseases. These pathways may be triggered by not only the disturbance of the mitochondrial (mt) translation caused by hypomodification of tRNAs, but also as a result of nonconventional roles of mt-tRNAs and mt-tRNA-modifying enzymes. The evolutionary conservation of these enzymes supports their importance for cell and organismal functions. Interestingly, bacterial and eukaryotic cells respond to stress by altering the expression or activity of these tRNA-modifying enzymes, which leads to changes in the modification status of tRNAs. This review summarizes recent findings about these enzymes and sets them within the previous data context.
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Affiliation(s)
- M Eugenia Armengod
- a Laboratory of RNA Modification and Mitochondrial Diseases ; Centro de Investigación Príncipe Felipe ; Valencia , Spain
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91
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Roloff GA, Henry MF. Mam33 promotes cytochrome c oxidase subunit I translation in Saccharomyces cerevisiae mitochondria. Mol Biol Cell 2015; 26:2885-94. [PMID: 26108620 PMCID: PMC4571327 DOI: 10.1091/mbc.e15-04-0222] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 06/16/2015] [Indexed: 12/22/2022] Open
Abstract
Expression of genes encoded by the mitochondrial genome is dependent on gene-specific translational activators. Mam33, the yeast homologue of p32/gC1qR/C1QBP/HABP1, promotes the translation of Cox1, a core catalytic subunit of respiratory chain complex IV. Three mitochondrial DNA–encoded proteins, Cox1, Cox2, and Cox3, comprise the core of the cytochrome c oxidase complex. Gene-specific translational activators ensure that these respiratory chain subunits are synthesized at the correct location and in stoichiometric ratios to prevent unassembled protein products from generating free oxygen radicals. In the yeast Saccharomyces cerevisiae, the nuclear-encoded proteins Mss51 and Pet309 specifically activate mitochondrial translation of the largest subunit, Cox1. Here we report that Mam33 is a third COX1 translational activator in yeast mitochondria. Mam33 is required for cells to adapt efficiently from fermentation to respiration. In the absence of Mam33, Cox1 translation is impaired, and cells poorly adapt to respiratory conditions because they lack basal fermentative levels of Cox1.
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Affiliation(s)
- Gabrielle A Roloff
- Department of Molecular Biology, Rowan University School of Osteopathic Medicine, and Graduate School of Biomedical Sciences, Rowan University, Stratford, NJ 08084
| | - Michael F Henry
- Department of Molecular Biology, Rowan University School of Osteopathic Medicine, and Graduate School of Biomedical Sciences, Rowan University, Stratford, NJ 08084
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92
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Opa1 overexpression ameliorates the phenotype of two mitochondrial disease mouse models. Cell Metab 2015; 21:845-54. [PMID: 26039449 PMCID: PMC4457891 DOI: 10.1016/j.cmet.2015.04.016] [Citation(s) in RCA: 165] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 02/13/2015] [Accepted: 04/12/2015] [Indexed: 02/07/2023]
Abstract
Increased levels of the mitochondria-shaping protein Opa1 improve respiratory chain efficiency and protect from tissue damage, suggesting that it could be an attractive target to counteract mitochondrial dysfunction. Here we show that Opa1 overexpression ameliorates two mouse models of defective mitochondrial bioenergetics. The offspring from crosses of a constitutive knockout for the structural complex I component Ndufs4 (Ndufs4(-/-)), and of a muscle-specific conditional knockout for the complex IV assembly factor Cox15 (Cox15(sm/sm)), with Opa1 transgenic (Opa1(tg)) mice showed improved motor skills and respiratory chain activities compared to the naive, non-Opa1-overexpressing, models. While the amelioration was modest in Ndufs4(-/-)::Opa1(tg) mice, correction of cristae ultrastructure and mitochondrial respiration, improvement of motor performance and prolongation of lifespan were remarkable in Cox15(sm/sm)::Opa1(tg) mice. Mechanistically, respiratory chain supercomplexes were increased in Cox15(sm/sm)::Opa1(tg) mice, and residual monomeric complex IV was stabilized. In conclusion, cristae shape amelioration by controlled Opa1 overexpression improves two mouse models of mitochondrial disease.
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93
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De Silva D, Tu YT, Amunts A, Fontanesi F, Barrientos A. Mitochondrial ribosome assembly in health and disease. Cell Cycle 2015; 14:2226-50. [PMID: 26030272 DOI: 10.1080/15384101.2015.1053672] [Citation(s) in RCA: 130] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The ribosome is a structurally and functionally conserved macromolecular machine universally responsible for catalyzing protein synthesis. Within eukaryotic cells, mitochondria contain their own ribosomes (mitoribosomes), which synthesize a handful of proteins, all essential for the biogenesis of the oxidative phosphorylation system. High-resolution cryo-EM structures of the yeast, porcine and human mitoribosomal subunits and of the entire human mitoribosome have uncovered a wealth of new information to illustrate their evolutionary divergence from their bacterial ancestors and their adaptation to synthesis of highly hydrophobic membrane proteins. With such structural data becoming available, one of the most important remaining questions is that of the mitoribosome assembly pathway and factors involved. The regulation of mitoribosome biogenesis is paramount to mitochondrial respiration, and thus to cell viability, growth and differentiation. Moreover, mutations affecting the rRNA and protein components produce severe human mitochondrial disorders. Despite its biological and biomedical significance, knowledge on mitoribosome biogenesis and its deviations from the much-studied bacterial ribosome assembly processes is scarce, especially the order of rRNA processing and assembly events and the regulatory factors required to achieve fully functional particles. This article focuses on summarizing the current available information on mitoribosome assembly pathway, factors that form the mitoribosome assembly machinery, and the effect of defective mitoribosome assembly on human health.
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Affiliation(s)
- Dasmanthie De Silva
- a Department of Biochemistry and Molecular Biology ; University of Miami Miller School of Medicine ; Miami , FL USA
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94
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Zamudio-Ochoa A, Camacho-Villasana Y, García-Guerrero AE, Pérez-Martínez X. The Pet309 pentatricopeptide repeat motifs mediate efficient binding to the mitochondrial COX1 transcript in yeast. RNA Biol 2014; 11:953-67. [PMID: 25181249 PMCID: PMC4179968 DOI: 10.4161/rna.29780] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Mitochondrial synthesis of Cox1, the largest subunit of the cytochrome c oxidase complex, is controlled by Mss51 and Pet309, two mRNA-specific translational activators that act via the COX1 mRNA 5′-UTR through an unknown mechanism. Pet309 belongs to the pentatricopeptide repeat (PPR) protein family, which is involved in RNA metabolism in mitochondria and chloroplasts, and its sequence predicts at least 12 PPR motifs in the central portion of the protein. Deletion of these motifs selectively disrupted translation but not accumulation of the COX1 mRNA. We used RNA coimmunoprecipitation assays to show that Pet309 interacts with the COX1 mRNA in vivo and that this association is present before processing of the COX1 mRNA from the ATP8/6 polycistronic mRNA. This association was not affected by deletion of 8 of the PPR motifs but was undetectable after deletion of the entire 12-PPR region. However, interaction of the Pet309 protein lacking 12 PPR motifs with the COX1 mRNA was detected after overexpression of the mutated form of the protein, suggesting that deletion of this region decreased the binding affinity for the COX1 mRNA without abolishing it entirely. Moreover, binding of Pet309 to the COX1 mRNA was affected by deletion of Mss51. This work demonstrates an in vivo physical interaction between a yeast mitochondrial translational activator and its target mRNA and shows the cooperativity of the PPR domains of Pet309 in interaction with the COX1 mRNA.
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Affiliation(s)
- Angélica Zamudio-Ochoa
- Departamento de Genética Molecular; Instituto de Fisiología Celular; Universidad Nacional Autónoma de México; México
| | - Yolanda Camacho-Villasana
- Departamento de Genética Molecular; Instituto de Fisiología Celular; Universidad Nacional Autónoma de México; México
| | - Aldo E García-Guerrero
- Departamento de Genética Molecular; Instituto de Fisiología Celular; Universidad Nacional Autónoma de México; México
| | - Xochitl Pérez-Martínez
- Departamento de Genética Molecular; Instituto de Fisiología Celular; Universidad Nacional Autónoma de México; México
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95
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The strictly aerobic yeast Yarrowia lipolytica tolerates loss of a mitochondrial DNA-packaging protein. EUKARYOTIC CELL 2014; 13:1143-57. [PMID: 24972935 DOI: 10.1128/ec.00092-14] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Mitochondrial DNA (mtDNA) is highly compacted into DNA-protein structures termed mitochondrial nucleoids (mt-nucleoids). The key mt-nucleoid components responsible for mtDNA condensation are HMG box-containing proteins such as mammalian mitochondrial transcription factor A (TFAM) and Abf2p of the yeast Saccharomyces cerevisiae. To gain insight into the function and organization of mt-nucleoids in strictly aerobic organisms, we initiated studies of these DNA-protein structures in Yarrowia lipolytica. We identified a principal component of mt-nucleoids in this yeast and termed it YlMhb1p (Y. lipolytica mitochondrial HMG box-containing protein 1). YlMhb1p contains two putative HMG boxes contributing both to DNA binding and to its ability to compact mtDNA in vitro. Phenotypic analysis of a Δmhb1 strain lacking YlMhb1p resulted in three interesting findings. First, although the mutant exhibits clear differences in mt-nucleoids accompanied by a large decrease in the mtDNA copy number and the number of mtDNA-derived transcripts, its respiratory characteristics and growth under most of the conditions tested are indistinguishable from those of the wild-type strain. Second, our results indicate that a potential imbalance between subunits of the respiratory chain encoded separately by nuclear DNA and mtDNA is prevented at a (post)translational level. Third, we found that mtDNA in the Δmhb1 strain is more prone to mutations, indicating that mtHMG box-containing proteins protect the mitochondrial genome against mutagenic events.
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96
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Kuzmenko AV, Levitskii SA, Vinogradova EN, Atkinson GC, Hauryliuk V, Zenkin N, Kamenski PA. Protein biosynthesis in mitochondria. BIOCHEMISTRY (MOSCOW) 2014; 78:855-66. [PMID: 24228873 DOI: 10.1134/s0006297913080014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Translation, that is biosynthesis of polypeptides in accordance with information encoded in the genome, is one of the most important processes in the living cell, and it has been in the spotlight of international research for many years. The mechanisms of protein biosynthesis in bacteria and in the eukaryotic cytoplasm are now understood in great detail. However, significantly less is known about translation in eukaryotic mitochondria, which is characterized by a number of unusual features. In this review, we summarize current knowledge about mitochondrial translation in different organisms while paying special attention to the aspects of this process that differ from cytoplasmic protein biosynthesis.
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Affiliation(s)
- A V Kuzmenko
- Department of Molecular Biology, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119991, Russia.
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97
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Amunts A, Brown A, Bai XC, Llácer JL, Hussain T, Emsley P, Long F, Murshudov G, Scheres SH, Ramakrishnan V. Structure of the yeast mitochondrial large ribosomal subunit. Science 2014; 343:1485-1489. [PMID: 24675956 PMCID: PMC4046073 DOI: 10.1126/science.1249410] [Citation(s) in RCA: 442] [Impact Index Per Article: 44.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Mitochondria have specialized ribosomes that have diverged from their bacterial and cytoplasmic counterparts. We have solved the structure of the yeast mitoribosomal large subunit using single-particle cryo-electron microscopy. The resolution of 3.2 angstroms enabled a nearly complete atomic model to be built de novo and refined, including 39 proteins, 13 of which are unique to mitochondria, as well as expansion segments of mitoribosomal RNA. The structure reveals a new exit tunnel path and architecture, unique elements of the E site, and a putative membrane docking site.
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Affiliation(s)
- Alexey Amunts
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
| | - Alan Brown
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
| | - Xiao-chen Bai
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
| | - Jose L. Llácer
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
| | - Tanweer Hussain
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
| | - Paul Emsley
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
| | - Fei Long
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
| | - Garib Murshudov
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
| | - Sjors H.W. Scheres
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
| | - V. Ramakrishnan
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
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98
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Boczonadi V, Horvath R. Mitochondria: impaired mitochondrial translation in human disease. Int J Biochem Cell Biol 2014; 48:77-84. [PMID: 24412566 PMCID: PMC3988845 DOI: 10.1016/j.biocel.2013.12.011] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Revised: 11/13/2013] [Accepted: 12/26/2013] [Indexed: 10/28/2022]
Abstract
Defects of the mitochondrial protein synthesis cause a subgroup of mitochondrial diseases, which are usually associated with decreased activities of multiple respiratory chain (RC) enzymes. The clinical presentations of these disorders are often disabling, progressive or fatal, affecting the brain, liver, skeletal muscle, heart and other organs. Currently there are no effective cures for these disorders and treatment is at best symptomatic. The diagnosis in patients with multiple respiratory chain complex defects is particularly difficult because of the massive number of nuclear genes potentially involved in intra-mitochondrial protein synthesis. Many of these genes are not yet linked to human disease. Whole exome sequencing rapidly changed the diagnosis of these patients by identifying the primary defect in DNA, and preventing the need for invasive and complex biochemical testing. Better understanding of the mitochondrial protein synthesis apparatus will help us to explore disease mechanisms and will provide clues for developing novel therapies.
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Affiliation(s)
- Veronika Boczonadi
- Institute of Genetic Medicine, Wellcome Trust Centre for Mitochondrial Research, Newcastle University, Newcastle upon Tyne, UK
| | - Rita Horvath
- Institute of Genetic Medicine, Wellcome Trust Centre for Mitochondrial Research, Newcastle University, Newcastle upon Tyne, UK.
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99
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Janska H, Kwasniak M. Mitoribosomal regulation of OXPHOS biogenesis in plants. FRONTIERS IN PLANT SCIENCE 2014; 5:79. [PMID: 24634672 PMCID: PMC3942809 DOI: 10.3389/fpls.2014.00079] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 02/19/2014] [Indexed: 05/20/2023]
Abstract
The ribosome filter hypothesis posits that ribosomes are not simple non-selective translation machines but may also function as regulatory elements in protein synthesis. Recent data supporting ribosomal filtering come from plant mitochondria where it has been shown that translation of mitochondrial transcripts encoding components of oxidative phosphorylation complexes (OXPHOS) and of mitoribosomes can be differentially affected by alterations in mitoribosomes. The biogenesis of mitoribosome was perturbed by silencing of a gene encoding a small-subunit protein of the mitoribosome in Arabidopsis thaliana. As a consequence, the mitochondrial OXPHOS and ribosomal transcripts were both upregulated, but only the ribosomal proteins were oversynthesized, while the OXPHOS subunits were actually depleted. This finding implies that the heterogeneity of plant mitoribosomes found in vivo could contribute to the functional selectivity of translation under distinct conditions. Furthermore, global analysis indicates that biogenesis of OXPHOS complexes in plants can be regulated at different levels of mitochondrial and nuclear gene expression, however, the ultimate coordination of genome expression occurs at the complex assembly level.
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Affiliation(s)
- Hanna Janska
- *Correspondence: Hanna Janska, Molecular Biology of the Cell Department, Faculty of Biotechnology, University of Wroclaw, F. Joliot-Curie 14A, 50-383 Wroclaw, Poland e-mail:
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100
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Ostojić J, Glatigny A, Herbert CJ, Dujardin G, Bonnefoy N. Does the study of genetic interactions help predict the function of mitochondrial proteins in Saccharomyces cerevisiae? Biochimie 2013; 100:27-37. [PMID: 24262604 DOI: 10.1016/j.biochi.2013.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 11/06/2013] [Indexed: 10/26/2022]
Abstract
Mitochondria are complex organelles of eukaryotic cells that contain their own genome, encoding key subunits of the respiratory complexes. The successive steps of mitochondrial gene expression are intimately linked, and are under the control of a large number of nuclear genes encoding factors that are imported into mitochondria. Investigating the relationships between these genes and their interaction networks, and whether they reveal direct or indirect partners, can shed light on their role in mitochondrial biogenesis, as well as identify new actors in this process. These studies, mainly developed in yeasts, are significant because mammalian equivalents of such yeast genes are candidate genes in mitochondrial pathologies. In practice, studies of physical, chemical and genetic interactions can be undertaken. The search for genetic interactions, either aggravating or alleviating the phenotype of the starting mutants, has proved to be particularly powerful in yeast since even subtle changes in respiratory phenotypes can be screened in a very efficient way. In addition, several high throughput genetic approaches have recently been developed. In this review we analyze the genetic network of three genes involved in different steps of mitochondrial gene expression, from the transcription and translation of mitochondrial RNAs to the insertion of newly synthesized proteins into the inner mitochondrial membrane, and we examine their relevance to our understanding of mitochondrial biogenesis. We find that these genetic interactions are seldom redundant with physical interactions, and thus bring a considerable amount of original and significant information as well as open new areas of research.
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Affiliation(s)
- Jelena Ostojić
- Centre de Génétique Moléculaire, CNRS UPR3404 Associated to the University Paris XI-Sud, Avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex, France
| | - Annie Glatigny
- Centre de Génétique Moléculaire, CNRS UPR3404 Associated to the University Paris XI-Sud, Avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex, France
| | - Christopher J Herbert
- Centre de Génétique Moléculaire, CNRS UPR3404 Associated to the University Paris XI-Sud, Avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex, France
| | - Geneviève Dujardin
- Centre de Génétique Moléculaire, CNRS UPR3404 Associated to the University Paris XI-Sud, Avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex, France
| | - Nathalie Bonnefoy
- Centre de Génétique Moléculaire, CNRS UPR3404 Associated to the University Paris XI-Sud, Avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex, France.
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