1
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Dinh N, Bonnefoy N. Schizosaccharomyces pombe as a fundamental model for research on mitochondrial gene expression: Progress, achievements and outlooks. IUBMB Life 2024; 76:397-419. [PMID: 38117001 DOI: 10.1002/iub.2801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 11/17/2023] [Indexed: 12/21/2023]
Abstract
Schizosaccharomyces pombe (fission yeast) is an attractive model for mitochondrial research. The organism resembles human cells in terms of mitochondrial inheritance, mitochondrial transport, sugar metabolism, mitogenome structure and dependence of viability on the mitogenome (the petite-negative phenotype). Transcriptions of these genomes produce only a few polycistronic transcripts, which then undergo processing as per the tRNA punctuation model. In general, the machinery for mitochondrial gene expression is structurally and functionally conserved between fission yeast and humans. Furthermore, molecular research on S. pombe is supported by a considerable number of experimental techniques and database resources. Owing to these advantages, fission yeast has significantly contributed to biomedical and fundamental research. Here, we review the current state of knowledge regarding S. pombe mitochondrial gene expression, and emphasise the pertinence of fission yeast as both a model and tool, especially for studies on mitochondrial translation.
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Affiliation(s)
- Nhu Dinh
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, 91198 Gif-sur-Yvette cedex, France
| | - Nathalie Bonnefoy
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, 91198 Gif-sur-Yvette cedex, France
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2
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Luo C, Akhtar M, Min W, Bai X, Ma T, Liu C. Domain of unknown function (DUF) proteins in plants: function and perspective. PROTOPLASMA 2024; 261:397-410. [PMID: 38158398 DOI: 10.1007/s00709-023-01917-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 12/08/2023] [Indexed: 01/03/2024]
Abstract
Domains of unknown function (DUFs), which are deposited in the protein family database (Pfam), are protein domains with conserved amino acid sequences and uncharacterized functions. Proteins with the same DUF were classified as DUF families. Although DUF families are generally not essential for the survival of plants, they play roles in plant development and adaptation. Characterizing the functions of DUFs is important for deciphering biological puzzles. DUFs were generally studied through forward and reverse genetics. Some novelty approaches, especially the determination of crystal structures and interaction partners of the DUFs, should attract more attention. This review described the identification of DUF genes by genome-wide and transcriptome-wide analyses, summarized the function of DUF-containing proteins, and addressed the prospects for future studies in DUFs in plants.
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Affiliation(s)
- Chengke Luo
- School of Agriculture, Ningxia University, Yinchuan, 750021, China
| | - Maryam Akhtar
- College of Life Sciences, Northwest Normal University, Lanzhou, 730070, China
| | - Weifang Min
- School of Agriculture, Ningxia University, Yinchuan, 750021, China
| | - Xiaorong Bai
- School of Agriculture, Ningxia University, Yinchuan, 750021, China
| | - Tianli Ma
- School of Agriculture, Ningxia University, Yinchuan, 750021, China
| | - Caixia Liu
- School of Agriculture, Ningxia University, Yinchuan, 750021, China.
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3
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Golik P. RNA processing and degradation mechanisms shaping the mitochondrial transcriptome of budding yeasts. IUBMB Life 2024; 76:38-52. [PMID: 37596708 DOI: 10.1002/iub.2779] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Accepted: 07/25/2023] [Indexed: 08/20/2023]
Abstract
Yeast mitochondrial genes are expressed as polycistronic transcription units that contain RNAs from different classes and show great evolutionary variability. The promoters are simple, and transcriptional control is rudimentary. Posttranscriptional mechanisms involving RNA maturation, stability, and degradation are thus the main force shaping the transcriptome and determining the expression levels of individual genes. Primary transcripts are fragmented by tRNA excision by RNase P and tRNase Z, additional processing events occur at the dodecamer site at the 3' end of protein-coding sequences. groups I and II introns are excised in a self-splicing reaction that is supported by protein splicing factors encoded by the nuclear genes, or by the introns themselves. The 3'-to-5' exoribonucleolytic complex called mtEXO is the main RNA degradation activity involved in RNA turnover and processing, supported by an auxiliary 5'-to-3' exoribonuclease Pet127p. tRNAs and, to a lesser extent, rRNAs undergo several different base modifications. This complex gene expression system relies on the coordinated action of mitochondrial and nuclear genes and undergoes rapid evolution, contributing to speciation events. Moving beyond the classical model yeast Saccharomyces cerevisiae to other budding yeasts should provide important insights into the coevolution of both genomes that constitute the eukaryotic genetic system.
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Affiliation(s)
- Pawel Golik
- Faculty of Biology, Institute of Genetics and Biotechnology, University of Warsaw, Warsaw, Poland
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
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4
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Wei Q, Chen B, Wang J, Huang M, Gui Y, Sayyed A, Tan BC. PHB3 Is Required for the Assembly and Activity of Mitochondrial ATP Synthase in Arabidopsis. Int J Mol Sci 2023; 24:ijms24108787. [PMID: 37240131 DOI: 10.3390/ijms24108787] [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: 04/12/2023] [Revised: 05/06/2023] [Accepted: 05/10/2023] [Indexed: 05/28/2023] Open
Abstract
Mitochondrial ATP synthase is a multiprotein complex, which consists of a matrix-localized F1 domain (F1-ATPase) and an inner membrane-embedded Fo domain (Fo-ATPase). The assembly process of mitochondrial ATP synthase is complex and requires the function of many assembly factors. Although extensive studies on mitochondrial ATP synthase assembly have been conducted on yeast, much less study has been performed on plants. Here, we revealed the function of Arabidopsis prohibitin 3 (PHB3) in mitochondrial ATP synthase assembly by characterizing the phb3 mutant. The blue native PAGE (BN-PAGE) and in-gel activity staining assays showed that the activities of ATP synthase and F1-ATPase were significantly decreased in the phb3 mutant. The absence of PHB3 resulted in the accumulation of the Fo-ATPase and F1-ATPase intermediates, whereas the abundance of the Fo-ATPase subunit a was decreased in the ATP synthase monomer. Furthermore, we showed that PHB3 could interact with the F1-ATPase subunits β and δ in the yeast two-hybrid system (Y2H) and luciferase complementation imaging (LCI) assay and with Fo-ATPase subunit c in the LCI assay. These results indicate that PHB3 acts as an assembly factor required for the assembly and activity of mitochondrial ATP synthase.
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Affiliation(s)
- Qingqing Wei
- Key Laboratory of Plant Development and Environment Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China
| | - Baoyin Chen
- Key Laboratory of Plant Development and Environment Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China
| | - Junjun Wang
- Key Laboratory of Plant Development and Environment Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China
| | - Manna Huang
- Key Laboratory of Plant Development and Environment Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China
| | - Yuanye Gui
- Key Laboratory of Plant Development and Environment Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China
| | - Aqib Sayyed
- Key Laboratory of Plant Development and Environment Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China
| | - Bao-Cai Tan
- Key Laboratory of Plant Development and Environment Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China
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5
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Staneva D, Vasileva B, Podlesniy P, Miloshev G, Georgieva M. Yeast Chromatin Mutants Reveal Altered mtDNA Copy Number and Impaired Mitochondrial Membrane Potential. J Fungi (Basel) 2023; 9:jof9030329. [PMID: 36983497 PMCID: PMC10058930 DOI: 10.3390/jof9030329] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 03/02/2023] [Accepted: 03/04/2023] [Indexed: 03/30/2023] Open
Abstract
Mitochondria are multifunctional, dynamic organelles important for stress response, cell longevity, ageing and death. Although the mitochondrion has its genome, nuclear-encoded proteins are essential in regulating mitochondria biogenesis, morphology, dynamics and function. Moreover, chromatin structure and epigenetic mechanisms govern the accessibility to DNA and control gene transcription, indirectly influencing nucleo-mitochondrial communications. Thus, they exert crucial functions in maintaining proper chromatin structure, cell morphology, gene expression, stress resistance and ageing. Here, we present our studies on the mtDNA copy number in Saccharomyces cerevisiae chromatin mutants and investigate the mitochondrial membrane potential throughout their lifespan. The mutants are arp4 (with a point mutation in the ARP4 gene, coding for actin-related protein 4-Arp4p), hho1Δ (lacking the HHO1 gene, coding for the linker histone H1), and the double mutant arp4 hho1Δ cells with the two mutations. Our findings showed that the three chromatin mutants acquired strain-specific changes in the mtDNA copy number. Furthermore, we detected the disrupted mitochondrial membrane potential in their chronological lifespan. In addition, the expression of nuclear genes responsible for regulating mitochondria biogenesis and turnover was changed. The most pronounced were the alterations found in the double mutant arp4 hho1Δ strain, which appeared as the only petite colony-forming mutant, unable to grow on respiratory substrates and with partial depletion of the mitochondrial genome. The results suggest that in the studied chromatin mutants, hho1Δ, arp4 and arp4 hho1Δ, the nucleus-mitochondria communication was disrupted, leading to impaired mitochondrial function and premature ageing phenotype in these mutants, especially in the double mutant.
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Affiliation(s)
- Dessislava Staneva
- Laboratory of Molecular Genetics, Epigenetics and Longevity, Institute of Molecular Biology "RoumenTsanev", Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
| | - Bela Vasileva
- Laboratory of Molecular Genetics, Epigenetics and Longevity, Institute of Molecular Biology "RoumenTsanev", Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
| | - Petar Podlesniy
- CiberNed (Centro Investigacion Biomedica en Red Enfermedades Neurodegenerativas), 28029 Barcelona, Spain
| | - George Miloshev
- Laboratory of Molecular Genetics, Epigenetics and Longevity, Institute of Molecular Biology "RoumenTsanev", Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
| | - Milena Georgieva
- Laboratory of Molecular Genetics, Epigenetics and Longevity, Institute of Molecular Biology "RoumenTsanev", Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
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Baranowska E, Niedzwiecka K, Panja C, Charles C, Dautant A, di Rago JP, Tribouillard-Tanvier D, Kucharczyk R. Molecular basis of diseases induced by the mitochondrial DNA mutation m.9032 T > C. Hum Mol Genet 2022; 32:1313-1323. [PMID: 36434790 PMCID: PMC10077503 DOI: 10.1093/hmg/ddac292] [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: 09/05/2022] [Revised: 11/08/2022] [Accepted: 11/22/2022] [Indexed: 11/28/2022] Open
Abstract
The mitochondrial DNA mutation m.9032 T > C was previously identified in patients presenting with NARP (Neuropathy Ataxia Retinitis Pigmentosa). Their clinical features had a maternal transmission and patient's cells showed a reduced oxidative phosphorylation capacity, elevated reactive oxygen species (ROS) production and hyperpolarization of the mitochondrial inner membrane, providing evidence that m.9032 T > C is truly pathogenic. This mutation leads to replacement of a highly conserved leucine residue with proline at position 169 of ATP synthase subunit a (L169P). This protein and a ring of identical c-subunits (c-ring) move protons through the mitochondrial inner membrane coupled to ATP synthesis. We herein investigated the consequences of m.9032 T > C on ATP synthase in a strain of Saccharomyces cerevisiae with an equivalent mutation (L186P). The mutant enzyme assembled correctly but was mostly inactive as evidenced by a > 95% drop in the rate of mitochondrial ATP synthesis and absence of significant ATP-driven proton pumping across the mitochondrial membrane. Intragenic suppressors selected from L186P yeast restoring ATP synthase function to varying degrees (30-70%) were identified at the original mutation site (L186S) or in another position of the subunit a (H114Q, I118T). In light of atomic structures of yeast ATP synthase recently described, we conclude from these results that m.9032 T > C disrupts proton conduction between the external side of the membrane and the c-ring, and that H114Q and I118T enable protons to access the c-ring through a modified pathway.
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Affiliation(s)
- Emilia Baranowska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Katarzyna Niedzwiecka
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Chiranjit Panja
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Camille Charles
- Univ. Bordeaux, CNRS, IBGC, UMR 5095, F-33000 Bordeaux, France
| | - Alain Dautant
- Univ. Bordeaux, CNRS, IBGC, UMR 5095, F-33000 Bordeaux, France
| | | | | | - Roza Kucharczyk
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
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7
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Kabala AM, Binko K, Godard F, Charles C, Dautant A, Baranowska E, Skoczen N, Gombeau K, Bouhier M, Becker HD, Ackerman SH, Steinmetz LM, Tribouillard-Tanvier D, Kucharczyk R, di Rago JP. Assembly-dependent translation of subunits 6 (Atp6) and 9 (Atp9) of ATP synthase in yeast mitochondria. Genetics 2022; 220:iyac007. [PMID: 35100419 PMCID: PMC8893259 DOI: 10.1093/genetics/iyac007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 12/30/2021] [Indexed: 12/04/2022] Open
Abstract
The yeast mitochondrial ATP synthase is an assembly of 28 subunits of 17 types of which 3 (subunits 6, 8, and 9) are encoded by mitochondrial genes, while the 14 others have a nuclear genetic origin. Within the membrane domain (FO) of this enzyme, the subunit 6 and a ring of 10 identical subunits 9 transport protons across the mitochondrial inner membrane coupled to ATP synthesis in the extra-membrane structure (F1) of ATP synthase. As a result of their dual genetic origin, the ATP synthase subunits are synthesized in the cytosol and inside the mitochondrion. How they are produced in the proper stoichiometry from two different cellular compartments is still poorly understood. The experiments herein reported show that the rate of translation of the subunits 9 and 6 is enhanced in strains with mutations leading to specific defects in the assembly of these proteins. These translation modifications involve assembly intermediates interacting with subunits 6 and 9 within the final enzyme and cis-regulatory sequences that control gene expression in the organelle. In addition to enabling a balanced output of the ATP synthase subunits, these assembly-dependent feedback loops are presumably important to limit the accumulation of harmful assembly intermediates that have the potential to dissipate the mitochondrial membrane electrical potential and the main source of chemical energy of the cell.
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Affiliation(s)
- Anna M Kabala
- CNRS, IBGC, University of Bordeaux, UMR 5095, F-33000 Bordeaux, France
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 01-224 Warsaw, Poland
| | - Krystyna Binko
- CNRS, IBGC, University of Bordeaux, UMR 5095, F-33000 Bordeaux, France
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 01-224 Warsaw, Poland
| | - François Godard
- CNRS, IBGC, University of Bordeaux, UMR 5095, F-33000 Bordeaux, France
| | - Camille Charles
- CNRS, IBGC, University of Bordeaux, UMR 5095, F-33000 Bordeaux, France
| | - Alain Dautant
- CNRS, IBGC, University of Bordeaux, UMR 5095, F-33000 Bordeaux, France
| | - Emilia Baranowska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 01-224 Warsaw, Poland
| | - Natalia Skoczen
- CNRS, IBGC, University of Bordeaux, UMR 5095, F-33000 Bordeaux, France
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 01-224 Warsaw, Poland
| | - Kewin Gombeau
- CNRS, IBGC, University of Bordeaux, UMR 5095, F-33000 Bordeaux, France
| | - Marine Bouhier
- CNRS, IBGC, University of Bordeaux, UMR 5095, F-33000 Bordeaux, France
| | - Hubert D Becker
- UPR ‘Architecture et Réactivité de l’ARN’, CNRS, Institut de Biologie Moléculaire et Cellulaire, Université de Strasbourg, F-67084 Strasbourg Cedex, France
| | - Sharon H Ackerman
- Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, Detroit, MI 48202, USA
| | - Lars M Steinmetz
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117 Heidelberg, Germany
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
- Stanford Genome Technology Center, Palo Alto, CA 94304, USA
| | | | - Roza Kucharczyk
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 01-224 Warsaw, Poland
| | - Jean-Paul di Rago
- CNRS, IBGC, University of Bordeaux, UMR 5095, F-33000 Bordeaux, France
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8
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Genetic Complementation of ATP Synthase Deficiency Due to Dysfunction of TMEM70 Assembly Factor in Rat. Biomedicines 2022; 10:biomedicines10020276. [PMID: 35203486 PMCID: PMC8869460 DOI: 10.3390/biomedicines10020276] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 01/05/2022] [Accepted: 01/18/2022] [Indexed: 11/17/2022] Open
Abstract
Mutations of the TMEM70 gene disrupt the biogenesis of the ATP synthase and represent the most frequent cause of autosomal recessive encephalo-cardio-myopathy with neonatal onset. Patient tissues show isolated defects in the ATP synthase, leading to the impaired mitochondrial synthesis of ATP and insufficient energy provision. In the current study, we tested the efficiency of gene complementation by using a transgenic rescue approach in spontaneously hypertensive rats with the targeted Tmem70 gene (SHR-Tmem70ko/ko), which leads to embryonic lethality. We generated SHR-Tmem70ko/ko knockout rats expressing the Tmem70 wild-type transgene (SHR-Tmem70ko/ko,tg/tg) under the control of the EF-1α universal promoter. Transgenic rescue resulted in viable animals that showed the variable expression of the Tmem70 transgene across the range of tissues and only minor differences in terms of the growth parameters. The TMEM70 protein was restored to 16–49% of the controls in the liver and heart, which was sufficient for the full biochemical complementation of ATP synthase biogenesis as well as for mitochondrial energetic function in the liver. In the heart, we observed partial biochemical complementation, especially in SHR-Tmem70ko/ko,tg/0 hemizygotes. As a result, this led to a minor impairment in left ventricle function. Overall, the transgenic rescue of Tmem70 in SHR-Tmem70ko/ko knockout rats resulted in the efficient complementation of ATP synthase deficiency and thus in the successful genetic treatment of an otherwise fatal mitochondrial disorder.
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9
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Franco LVR, Su CH, Tzagoloff A. Modular assembly of yeast mitochondrial ATP synthase and cytochrome oxidase. Biol Chem 2021; 401:835-853. [PMID: 32142477 DOI: 10.1515/hsz-2020-0112] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 02/24/2020] [Indexed: 12/27/2022]
Abstract
The respiratory pathway of mitochondria is composed of four electron transfer complexes and the ATP synthase. In this article, we review evidence from studies of Saccharomyces cerevisiae that both ATP synthase and cytochrome oxidase (COX) are assembled from independent modules that correspond to structurally and functionally identifiable components of each complex. Biogenesis of the respiratory chain requires a coordinate and balanced expression of gene products that become partner subunits of the same complex, but are encoded in the two physically separated genomes. Current evidence indicates that synthesis of two key mitochondrial encoded subunits of ATP synthase is regulated by the F1 module. Expression of COX1 that codes for a subunit of the COX catalytic core is also regulated by a mechanism that restricts synthesis of this subunit to the availability of a nuclear-encoded translational activator. The respiratory chain must maintain a fixed stoichiometry of the component enzyme complexes during cell growth. We propose that high-molecular-weight complexes composed of Cox6, a subunit of COX, and of the Atp9 subunit of ATP synthase play a key role in establishing the ratio of the two complexes during their assembly.
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Affiliation(s)
- Leticia Veloso Ribeiro Franco
- Department of Biological Sciences, Columbia University, New York City, NY 10027, USA.,Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, 05508-000, Brasil
| | - Chen Hsien Su
- Department of Biological Sciences, Columbia University, New York City, NY 10027, USA
| | - Alexander Tzagoloff
- Department of Biological Sciences, Columbia University, New York City, NY 10027, USA
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10
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Mitochondrial Structure and Bioenergetics in Normal and Disease Conditions. Int J Mol Sci 2021; 22:ijms22020586. [PMID: 33435522 PMCID: PMC7827222 DOI: 10.3390/ijms22020586] [Citation(s) in RCA: 75] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 01/03/2021] [Accepted: 01/04/2021] [Indexed: 02/06/2023] Open
Abstract
Mitochondria are ubiquitous intracellular organelles found in almost all eukaryotes and involved in various aspects of cellular life, with a primary role in energy production. The interest in this organelle has grown stronger with the discovery of their link to various pathologies, including cancer, aging and neurodegenerative diseases. Indeed, dysfunctional mitochondria cannot provide the required energy to tissues with a high-energy demand, such as heart, brain and muscles, leading to a large spectrum of clinical phenotypes. Mitochondrial defects are at the origin of a group of clinically heterogeneous pathologies, called mitochondrial diseases, with an incidence of 1 in 5000 live births. Primary mitochondrial diseases are associated with genetic mutations both in nuclear and mitochondrial DNA (mtDNA), affecting genes involved in every aspect of the organelle function. As a consequence, it is difficult to find a common cause for mitochondrial diseases and, subsequently, to offer a precise clinical definition of the pathology. Moreover, the complexity of this condition makes it challenging to identify possible therapies or drug targets.
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Bahri H, Buratto J, Rojo M, Dompierre JP, Salin B, Blancard C, Cuvellier S, Rose M, Ben Ammar Elgaaied A, Tetaud E, di Rago JP, Devin A, Duvezin-Caubet S. TMEM70 forms oligomeric scaffolds within mitochondrial cristae promoting in situ assembly of mammalian ATP synthase proton channel. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1868:118942. [PMID: 33359711 DOI: 10.1016/j.bbamcr.2020.118942] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 11/28/2020] [Accepted: 12/18/2020] [Indexed: 01/14/2023]
Abstract
Mitochondrial ATP-synthesis is catalyzed by a F1Fo-ATP synthase, an enzyme of dual genetic origin enriched at the edge of cristae where it plays a key role in their structure/stability. The enzyme's biogenesis remains poorly understood, both from a mechanistic and a compartmentalization point of view. The present study provides novel molecular insights into this process through investigations on a human protein called TMEM70 with an unclear role in the assembly of ATP synthase. A recent study has revealed the existence of physical interactions between TMEM70 and the subunit c (Su.c), a protein present in 8 identical copies forming a transmembrane oligomeric ring (c-ring) within the ATP synthase proton translocating domain (Fo). Herein we analyzed the ATP-synthase assembly in cells lacking TMEM70, mitochondrial DNA or F1 subunits and observe a direct correlation between TMEM70 and Su.c levels, regardless of the status of other ATP synthase subunits or of mitochondrial bioenergetics. Immunoprecipitation, two-dimensional blue-native/SDS-PAGE, and pulse-chase experiments reveal that TMEM70 forms large oligomers that interact with Su.c not yet incorporated into ATP synthase complexes. Moreover, discrete TMEM70-Su.c complexes with increasing Su.c contents can be detected, suggesting a role for TMEM70 oligomers in the gradual assembly of the c-ring. Furthermore, we demonstrate using expansion super-resolution microscopy the specific localization of TMEM70 at the inner cristae membrane, distinct from the MICOS component MIC60. Taken together, our results show that TMEM70 oligomers provide a scaffold for c-ring assembly and that mammalian ATP synthase is assembled within inner cristae membranes.
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Affiliation(s)
- Hela Bahri
- Université Bordeaux, IBGC, UMR 5095, F-33000 Bordeaux, France; CNRS, IBGC, UMR 5095, F-33000 Bordeaux, France; Laboratoire de génétique, Immunologie et Pathologie Humaine, Faculté des sciences de Tunis, Université Tunis-El Manar FST, Tunis, Tunisie
| | - Jeremie Buratto
- Université Bordeaux, IBGC, UMR 5095, F-33000 Bordeaux, France; CNRS, IBGC, UMR 5095, F-33000 Bordeaux, France; Université Bordeaux, CNRS, IPB, CBMN (UMR 5248), Institut Européen de Chimie et Biologie, 2 rue Robert Escarpit, F-33600 Pessac, France
| | - Manuel Rojo
- Université Bordeaux, IBGC, UMR 5095, F-33000 Bordeaux, France; CNRS, IBGC, UMR 5095, F-33000 Bordeaux, France
| | - Jim Paul Dompierre
- Université Bordeaux, IBGC, UMR 5095, F-33000 Bordeaux, France; CNRS, IBGC, UMR 5095, F-33000 Bordeaux, France
| | - Bénédicte Salin
- Université Bordeaux, IBGC, UMR 5095, F-33000 Bordeaux, France; CNRS, IBGC, UMR 5095, F-33000 Bordeaux, France
| | - Corinne Blancard
- Université Bordeaux, IBGC, UMR 5095, F-33000 Bordeaux, France; CNRS, IBGC, UMR 5095, F-33000 Bordeaux, France
| | - Sylvain Cuvellier
- Université Bordeaux, IBGC, UMR 5095, F-33000 Bordeaux, France; CNRS, IBGC, UMR 5095, F-33000 Bordeaux, France
| | - Marie Rose
- Université Bordeaux, IBGC, UMR 5095, F-33000 Bordeaux, France; CNRS, IBGC, UMR 5095, F-33000 Bordeaux, France
| | - Amel Ben Ammar Elgaaied
- Laboratoire de génétique, Immunologie et Pathologie Humaine, Faculté des sciences de Tunis, Université Tunis-El Manar FST, Tunis, Tunisie
| | - Emmanuel Tetaud
- Université Bordeaux, IBGC, UMR 5095, F-33000 Bordeaux, France; CNRS, IBGC, UMR 5095, F-33000 Bordeaux, France; Laboratoire de Microbiologie Fondamentale et Pathogénicité UMR-CNRS 5234, 146 rue Léo Saignat, CEDEX F-33076 Bordeaux, France
| | - Jean-Paul di Rago
- Université Bordeaux, IBGC, UMR 5095, F-33000 Bordeaux, France; CNRS, IBGC, UMR 5095, F-33000 Bordeaux, France
| | - Anne Devin
- Université Bordeaux, IBGC, UMR 5095, F-33000 Bordeaux, France; CNRS, IBGC, UMR 5095, F-33000 Bordeaux, France
| | - Stéphane Duvezin-Caubet
- Université Bordeaux, IBGC, UMR 5095, F-33000 Bordeaux, France; CNRS, IBGC, UMR 5095, F-33000 Bordeaux, France.
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12
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Itoh Y, Naschberger A, Mortezaei N, Herrmann JM, Amunts A. Analysis of translating mitoribosome reveals functional characteristics of translation in mitochondria of fungi. Nat Commun 2020; 11:5187. [PMID: 33056988 PMCID: PMC7560712 DOI: 10.1038/s41467-020-18830-w] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 09/11/2020] [Indexed: 11/16/2022] Open
Abstract
Mitoribosomes are specialized protein synthesis machineries in mitochondria. However, how mRNA binds to its dedicated channel, and tRNA moves as the mitoribosomal subunit rotate with respect to each other is not understood. We report models of the translating fungal mitoribosome with mRNA, tRNA and nascent polypeptide, as well as an assembly intermediate. Nicotinamide adenine dinucleotide (NAD) is found in the central protuberance of the large subunit, and the ATPase inhibitory factor 1 (IF1) in the small subunit. The models of the active mitoribosome explain how mRNA binds through a dedicated protein platform on the small subunit, tRNA is translocated with the help of the protein mL108, bridging it with L1 stalk on the large subunit, and nascent polypeptide paths through a newly shaped exit tunnel involving a series of structural rearrangements. An assembly intermediate is modeled with the maturation factor Atp25, providing insight into the biogenesis of the mitoribosomal large subunit and translation regulation.
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Affiliation(s)
- Yuzuru Itoh
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, 17165, Solna, Sweden
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 17165, Solna, Sweden
| | - Andreas Naschberger
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, 17165, Solna, Sweden
| | - Narges Mortezaei
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, 17165, Solna, Sweden
| | - Johannes M Herrmann
- Cell Biology, University of Kaiserslautern, Erwin-Schrödinger-Straße 13, 67663, Kaiserslautern, Germany
| | - Alexey Amunts
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, 17165, Solna, Sweden.
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 17165, Solna, Sweden.
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13
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Kovalčíková J, Vrbacký M, Pecina P, Tauchmannová K, Nůsková H, Kaplanová V, Brázdová A, Alán L, Eliáš J, Čunátová K, Kořínek V, Sedlacek R, Mráček T, Houštěk J. TMEM70 facilitates biogenesis of mammalian ATP synthase by promoting subunit c incorporation into the rotor structure of the enzyme. FASEB J 2019; 33:14103-14117. [DOI: 10.1096/fj.201900685rr] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Jana Kovalčíková
- Department of Bioenergetics, Institute of Physiology, The Czech Academy of Sciences, Prague, Czech Republic
| | - Marek Vrbacký
- Department of Bioenergetics, Institute of Physiology, The Czech Academy of Sciences, Prague, Czech Republic
| | - Petr Pecina
- Department of Bioenergetics, Institute of Physiology, The Czech Academy of Sciences, Prague, Czech Republic
| | - Kateřina Tauchmannová
- Department of Bioenergetics, Institute of Physiology, The Czech Academy of Sciences, Prague, Czech Republic
| | - Hana Nůsková
- Department of Bioenergetics, Institute of Physiology, The Czech Academy of Sciences, Prague, Czech Republic
| | - Vilma Kaplanová
- Department of Bioenergetics, Institute of Physiology, The Czech Academy of Sciences, Prague, Czech Republic
| | - Andrea Brázdová
- Department of Bioenergetics, Institute of Physiology, The Czech Academy of Sciences, Prague, Czech Republic
| | - Lukáš Alán
- Department of Bioenergetics, Institute of Physiology, The Czech Academy of Sciences, Prague, Czech Republic
| | - Jan Eliáš
- Department of Bioenergetics, Institute of Physiology, The Czech Academy of Sciences, Prague, Czech Republic
| | - Kristýna Čunátová
- Department of Bioenergetics, Institute of Physiology, The Czech Academy of Sciences, Prague, Czech Republic
| | - Vladimír Kořínek
- Laboratory of Cell and Developmental Biology, Institute of Molecular Genetics, The Czech Academy of Sciences, Prague, Czech Republic
| | - Radislav Sedlacek
- Institute of Molecular Genetics, The Czech Academy of Sciences, Prague, Czech Republic
- Laboratory of Transgenic Models of Diseases and Czech Centre for Phenogenomics, The Czech Academy of Sciences, Prague, Czech Republic
| | - Tomáš Mráček
- Department of Bioenergetics, Institute of Physiology, The Czech Academy of Sciences, Prague, Czech Republic
| | - Josef Houštěk
- Department of Bioenergetics, Institute of Physiology, The Czech Academy of Sciences, Prague, Czech Republic
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14
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Barros MH, McStay GP. Modular biogenesis of mitochondrial respiratory complexes. Mitochondrion 2019; 50:94-114. [PMID: 31669617 DOI: 10.1016/j.mito.2019.10.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 09/04/2019] [Accepted: 10/10/2019] [Indexed: 11/29/2022]
Abstract
Mitochondrial function relies on the activity of oxidative phosphorylation to synthesise ATP and generate an electrochemical gradient across the inner mitochondrial membrane. These coupled processes are mediated by five multi-subunit complexes that reside in this inner membrane. These complexes are the product of both nuclear and mitochondrial gene products. Defects in the function or assembly of these complexes can lead to mitochondrial diseases due to deficits in energy production and mitochondrial functions. Appropriate biogenesis and function are mediated by a complex number of assembly factors that promote maturation of specific complex subunits to form the active oxidative phosphorylation complex. The understanding of the biogenesis of each complex has been informed by studies in both simple eukaryotes such as Saccharomyces cerevisiae and human patients with mitochondrial diseases. These studies reveal each complex assembles through a pathway using specific subunits and assembly factors to form kinetically distinct but related assembly modules. The current understanding of these complexes has embraced the revolutions in genomics and proteomics to further our knowledge on the impact of mitochondrial biology in genetics, medicine, and evolution.
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Affiliation(s)
- Mario H Barros
- Departamento de Microbiologia - Instituto de Ciências Biomédicas, Universidade de São Paulo, Brazil.
| | - Gavin P McStay
- Department of Biological Sciences, Staffordshire University, Stoke-on-Trent, United Kingdom.
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15
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Guedes-Monteiro RF, Franco LV, Moda BS, Tzagoloff A, Barros MH. 5′ processing of Saccharomyces cerevisiae mitochondrial tRNAs requires expression of multiple genes. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1866:806-818. [DOI: 10.1016/j.bbamcr.2019.02.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 01/31/2019] [Accepted: 02/03/2019] [Indexed: 01/02/2023]
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16
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Kucharczyk R, Dautant A, Godard F, Tribouillard-Tanvier D, di Rago JP. Functional investigation of an universally conserved leucine residue in subunit a of ATP synthase targeted by the pathogenic m.9176 T>G mutation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1860:52-59. [PMID: 30414414 DOI: 10.1016/j.bbabio.2018.11.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 10/06/2018] [Accepted: 11/07/2018] [Indexed: 01/10/2023]
Abstract
Protons are transported from the mitochondrial matrix to the intermembrane space of mitochondria during the transfer of electrons to oxygen and shuttled back to the matrix by the a subunit and a ring of identical c subunits across the membrane domain (FO) of ATP synthase, which is coupled to ATP synthesis. A mutation (m.9176 T > G) of the mitochondrial ATP6 gene that replaces an universally conserved leucine residue into arginine at amino acid position 217 of human subunit a (aL217R) has been associated to NARP (Neuropathy, Ataxia and Retinitis Pigmentosa) and MILS (Maternally Inherited Leigh's Syndrome) diseases. We previously showed that an equivalent thereof in Saccharomyces cerevisiae (aL237R) severely impairs subunit a assembly/stability and decreases by >90% the rate of mitochondrial ATP synthesis. Herein we identified three spontaneous first-site intragenic suppressors (aR237M, aR237T and aR237S) that fully restore ATP synthase assembly. However, mitochondrial ATP synthesis rate was only partially recovered (40-50% vs wild type yeast). In light of recently described high-resolution yeast ATP synthase structures, the detrimental consequences of the aL237R change can be explained by steric and electrostatic hindrance with the universally conserved subunit a arginine residue (aR176) that is essential to FO activity. aL237 together with three other nearby hydrophobic residues have been proposed to prevent ion shortage between two physically separated hydrophilic pockets within the FO. Our results suggest that aL237 favors subunit c-ring rotation by optimizing electrostatic interaction between aR176 and an acidic residue in subunit c (cE59) known to be essential also to the activity of FO.
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Affiliation(s)
- Roza Kucharczyk
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland.
| | - Alain Dautant
- Institut de Biochimie et Génétique Cellulaires, CNRS-Bordeaux University (UMR5095), 1 Rue Camille Saint-Saëns, Bordeaux 33077 cedex, France
| | - François Godard
- Institut de Biochimie et Génétique Cellulaires, CNRS-Bordeaux University (UMR5095), 1 Rue Camille Saint-Saëns, Bordeaux 33077 cedex, France
| | - Déborah Tribouillard-Tanvier
- Institut de Biochimie et Génétique Cellulaires, CNRS-Bordeaux University (UMR5095), 1 Rue Camille Saint-Saëns, Bordeaux 33077 cedex, France
| | - Jean-Paul di Rago
- Institut de Biochimie et Génétique Cellulaires, CNRS-Bordeaux University (UMR5095), 1 Rue Camille Saint-Saëns, Bordeaux 33077 cedex, France..
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17
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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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18
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19
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Abstract
Mitochondria are the power stations of the eukaryotic cell, using the energy released by the oxidation of glucose and other sugars to produce ATP. Electrons are transferred from NADH, produced in the citric acid cycle in the mitochondrial matrix, to oxygen by a series of large protein complexes in the inner mitochondrial membrane, which create a transmembrane electrochemical gradient by pumping protons across the membrane. The flow of protons back into the matrix via a proton channel in the ATP synthase leads to conformational changes in the nucleotide binding pockets and the formation of ATP. The three proton pumping complexes of the electron transfer chain are NADH-ubiquinone oxidoreductase or complex I, ubiquinone-cytochrome c oxidoreductase or complex III, and cytochrome c oxidase or complex IV. Succinate dehydrogenase or complex II does not pump protons, but contributes reduced ubiquinone. The structures of complex II, III and IV were determined by x-ray crystallography several decades ago, but complex I and ATP synthase have only recently started to reveal their secrets by advances in x-ray crystallography and cryo-electron microscopy. The complexes I, III and IV occur to a certain extent as supercomplexes in the membrane, the so-called respirasomes. Several hypotheses exist about their function. Recent cryo-electron microscopy structures show the architecture of the respirasome with near-atomic detail. ATP synthase occurs as dimers in the inner mitochondrial membrane, which by their curvature are responsible for the folding of the membrane into cristae and thus for the huge increase in available surface that makes mitochondria the efficient energy plants of the eukaryotic cell.
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Affiliation(s)
- Joana S Sousa
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Edoardo D'Imprima
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Janet Vonck
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany.
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20
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Naumenko N, Morgenstern M, Rucktäschel R, Warscheid B, Rehling P. INA complex liaises the F 1F o-ATP synthase membrane motor modules. Nat Commun 2017; 8:1237. [PMID: 29093463 PMCID: PMC5665977 DOI: 10.1038/s41467-017-01437-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2017] [Accepted: 09/18/2017] [Indexed: 01/11/2023] Open
Abstract
The F1F0-ATP synthase translates a proton flux across the inner mitochondrial membrane into a mechanical rotation, driving anhydride bond formation in the catalytic portion. The complex’s membrane-embedded motor forms a proteinaceous channel at the interface between Atp9 ring and Atp6. To prevent unrestricted proton flow dissipating the H+-gradient, channel formation is a critical and tightly controlled step during ATP synthase assembly. Here we show that the INA complex (INAC) acts at this decisive step promoting Atp9-ring association with Atp6. INAC binds to newly synthesized mitochondrial-encoded Atp6 and Atp8 in complex with maturation factors. INAC association is retained until the F1-portion is built on Atp6/8 and loss of INAC causes accumulation of the free F1. An independent complex is formed between INAC and the Atp9 ring. We conclude that INAC maintains assembly intermediates of the F1 F0-ATP synthase in a primed state for the terminal assembly step–motor module formation. The inner membrane assembly complex (INAC) interacts with components of the F1F0-ATP synthase but its function remains unclear. Here the authors show that INAC associates with two distinct complexes during F1F0-ATP synthase formation, which points towards a safeguarding role during proton-conducting channel assembly.
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Affiliation(s)
- Nataliia Naumenko
- Department of Cellular Biochemistry, University Medical Center Göttingen, GZMB, D-37073, Göttingen, Germany
| | - Marcel Morgenstern
- Department of Biochemistry and Functional Proteomics, Faculty of Biology, University Freiburg, D-79104, Freiburg, Germany
| | - Robert Rucktäschel
- Department of Cellular Biochemistry, University Medical Center Göttingen, GZMB, D-37073, Göttingen, Germany
| | - Bettina Warscheid
- Department of Biochemistry and Functional Proteomics, Faculty of Biology, University Freiburg, D-79104, Freiburg, Germany.,BIOSS Centre for Biological Signalling Studies, University of Freiburg, D-79104, Freiburg, Germany
| | - Peter Rehling
- Department of Cellular Biochemistry, University Medical Center Göttingen, GZMB, D-37073, Göttingen, Germany. .,Max Planck Institute for Biophysical Chemistry, D-37077, Göttingen, Germany.
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21
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Woellhaf MW, Sommer F, Schroda M, Herrmann JM. Proteomic profiling of the mitochondrial ribosome identifies Atp25 as a composite mitochondrial precursor protein. Mol Biol Cell 2016; 27:3031-3039. [PMID: 27582385 PMCID: PMC5063612 DOI: 10.1091/mbc.e16-07-0513] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 08/18/2016] [Accepted: 08/23/2016] [Indexed: 11/15/2022] Open
Abstract
Whereas the structure and function of cytosolic ribosomes are well characterized, we only have a limited understanding of the mitochondrial translation apparatus. Using SILAC-based proteomic profiling, we identified 13 proteins that cofractionated with the mitochondrial ribosome, most of which play a role in translation or ribosomal biogenesis. One of these proteins is a homologue of the bacterial ribosome-silencing factor (Rsf). This protein is generated from the composite precursor protein Atp25 upon internal cleavage by the matrix processing peptidase MPP, and in this respect, it differs from all other characterized mitochondrial proteins of baker's yeast. We observed that cytosolic expression of Rsf, but not of noncleaved Atp25 protein, is toxic. Our results suggest that eukaryotic cells face the challenge of avoiding negative interference from the biogenesis of their two distinct translation machineries.
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Affiliation(s)
- Michael W Woellhaf
- Cell Biology, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Frederik Sommer
- Molecular Biotechnology and Systems Biology, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Michael Schroda
- Molecular Biotechnology and Systems Biology, University of Kaiserslautern, 67663 Kaiserslautern, Germany
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22
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Fristedt R, Martins NF, Strenkert D, Clarke CA, Suchoszek M, Thiele W, Schöttler MA, Merchant SS. The thylakoid membrane protein CGL160 supports CF1CF0 ATP synthase accumulation in Arabidopsis thaliana. PLoS One 2015; 10:e0121658. [PMID: 25835989 PMCID: PMC4383579 DOI: 10.1371/journal.pone.0121658] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 02/11/2015] [Indexed: 11/18/2022] Open
Abstract
The biogenesis of the major thylakoid protein complexes of the photosynthetic apparatus requires auxiliary proteins supporting individual assembly steps. Here, we identify a plant lineage specific gene, CGL160, whose homolog, atp1, co-occurs with ATP synthase subunits in an operon-like arrangement in many cyanobacteria. Arabidopsis thaliana T-DNA insertion mutants, which no longer accumulate the nucleus-encoded CGL160 protein, accumulate less than 25% of wild-type levels of the chloroplast ATP synthase. Severe cosmetic or growth phenotypes result under either short day or fluctuating light growth conditions, respectively, but this is ameliorated under long day constant light growth conditions where the growth, ATP synthase activity and photosynthetic electron transport of the mutants are less affected. Accumulation of other photosynthetic complexes is largely unaffected in cgl160 mutants, suggesting that CGL160 is a specific assembly or stability factor for the CF1CF0 complex. CGL160 is not found in the mature assembled complex but it does interact specifically with subunits of ATP synthase, predominantly those in the extrinsic CF1 sub-complex. We suggest therefore that it may facilitate the assembly of CF1 into the holocomplex.
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Affiliation(s)
- Rikard Fristedt
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, California, United States of America
- Institute for Genomics and Proteomics UCLA, Los Angeles, California, United States of America
| | | | - Daniela Strenkert
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, California, United States of America
| | - Cornelia A. Clarke
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, California, United States of America
| | - Monika Suchoszek
- Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany
| | - Wolfram Thiele
- Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany
| | | | - Sabeeha S. Merchant
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, California, United States of America
- Institute for Genomics and Proteomics UCLA, Los Angeles, California, United States of America
- * E-mail:
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23
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Kehrein K, Schilling R, Möller-Hergt BV, Wurm CA, Jakobs S, Lamkemeyer T, Langer T, Ott M. Organization of Mitochondrial Gene Expression in Two Distinct Ribosome-Containing Assemblies. Cell Rep 2015; 10:843-853. [PMID: 25683707 DOI: 10.1016/j.celrep.2015.01.012] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 11/17/2014] [Accepted: 12/31/2014] [Indexed: 12/27/2022] Open
Abstract
Mitochondria contain their own genetic system that provides subunits of the complexes driving oxidative phosphorylation. A quarter of the mitochondrial proteome participates in gene expression, but how all these factors are orchestrated and spatially organized is currently unknown. Here, we established a method to purify and analyze native and intact complexes of mitochondrial ribosomes. Quantitative mass spectrometry revealed extensive interactions of ribosomes with factors involved in all the steps of posttranscriptional gene expression. These interactions result in large expressosome-like assemblies that we termed mitochondrial organization of gene expression (MIOREX) complexes. Superresolution microscopy revealed that most MIOREX complexes are evenly distributed throughout the mitochondrial network, whereas a subset is present as nucleoid-MIOREX complexes that unite the whole spectrum of organellar gene expression. Our work therefore provides a conceptual framework for the spatial organization of mitochondrial protein synthesis that likely developed to facilitate gene expression in the organelle.
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Affiliation(s)
- Kirsten Kehrein
- Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden
| | - Ramon Schilling
- Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden
| | - Braulio Vargas Möller-Hergt
- Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden
| | - Christian A Wurm
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, 37070 Göttingen, Germany
| | - Stefan Jakobs
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, 37070 Göttingen, Germany; Department of Neurology, University of Göttingen Medical School, 37073 Göttingen, Germany; Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), 37073 Göttingen, Germany
| | - Tobias Lamkemeyer
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
| | - Thomas Langer
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany; Institute for Genetics, University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine (CMMC), University of Cologne, 50931 Cologne, Germany; Max-Planck-Institute for Biology of Aging, 50931 Cologne, Germany
| | - Martin Ott
- Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden.
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24
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Rühle T, Leister D. Assembly of F1F0-ATP synthases. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:849-60. [PMID: 25667968 DOI: 10.1016/j.bbabio.2015.02.005] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Revised: 01/28/2015] [Accepted: 02/02/2015] [Indexed: 12/31/2022]
Abstract
F1F0-ATP synthases are multimeric protein complexes and common prerequisites for their correct assembly are (i) provision of subunits in appropriate relative amounts, (ii) coordination of membrane insertion and (iii) avoidance of assembly intermediates that uncouple the proton gradient or wastefully hydrolyse ATP. Accessory factors facilitate these goals and assembly occurs in a modular fashion. Subcomplexes common to bacteria and mitochondria, but in part still elusive in chloroplasts, include a soluble F1 intermediate, a membrane-intrinsic, oligomeric c-ring, and a membrane-embedded subcomplex composed of stator subunits and subunit a. The final assembly step is thought to involve association of the preformed F1-c10-14 with the ab2 module (or the ab8-stator module in mitochondria)--mediated by binding of subunit δ in bacteria or OSCP in mitochondria, respectively. Despite the common evolutionary origin of F1F0-ATP synthases, the set of auxiliary factors required for their assembly in bacteria, mitochondria and chloroplasts shows clear signs of evolutionary divergence. This article is part of a Special Issue entitled: Chloroplast Biogenesis.
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Affiliation(s)
- Thilo Rühle
- Plant Molecular Biology (Botany), Department Biology I, Ludwig-Maximilians-Universität München (LMU), Großhaderner Straße 2, 82152 Planegg-Martinsried, Germany.
| | - Dario Leister
- Plant Molecular Biology (Botany), Department Biology I, Ludwig-Maximilians-Universität München (LMU), Großhaderner Straße 2, 82152 Planegg-Martinsried, Germany.
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25
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Su CH, McStay GP, Tzagoloff A. Assembly of the rotor component of yeast mitochondrial ATP synthase is enhanced when Atp9p is supplied by Atp9p-Cox6p complexes. J Biol Chem 2014; 289:31605-16. [PMID: 25253699 DOI: 10.1074/jbc.m114.602706] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Atp9p ring is one of several assembly modules of yeast mitochondrial ATP synthase. The ring, composed of 10 copies of Atp9p, is part of the rotor that couples proton translocation to synthesis or hydrolysis of ATP. We present evidence that before its assembly with other ATP synthase modules, most of Atp9p is present in at least three complexes with masses of 200-400 kDa that co-immunopurify with Cox6p. Pulse-labeling analysis disclosed a time-dependent reduction of radiolabeled Atp9p in the complexes and an increase of Atp9p in the ring form of wild type yeast and of mss51, pet111, and pet494 mutants lacking Cox1p, Cox2p, and Cox3p, respectively. Ring formation was not significantly different from wild type in an mss51 or atp10 mutant. The atp10 mutation blocks the interaction of the Atp9p ring with other modules of the ATP synthase. In contrast, ring formation was reduced in a cox6 mutant, consistent with a role of Cox6p in oligomerization of Atp9p. Cox6p involvement in ATP synthase assembly is also supported by studies showing that ring formation in cells adapting from fermentative to aerobic growth was less efficient in mitochondria of the cox6 mutant than the parental respiratory-competent strain or a cox4 mutant. We speculate that the constitutive and Cox6p-independent rate of Atp9p oligomerization may be sufficient to produce the level of ATP synthase needed for maintaining a membrane potential but limiting for optimal oxidative phosphorylation.
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Affiliation(s)
- Chen-Hsien Su
- From the Department of Biological Sciences, Columbia University, New York, New York 10128 and
| | - Gavin P McStay
- Department of Life Sciences, New York Institute of Technology, Old Westbury, New York 11568
| | - Alexander Tzagoloff
- From the Department of Biological Sciences, Columbia University, New York, New York 10128 and
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Rühle T, Razeghi JA, Vamvaka E, Viola S, Gandini C, Kleine T, Schünemann D, Barbato R, Jahns P, Leister D. The Arabidopsis protein CONSERVED ONLY IN THE GREEN LINEAGE160 promotes the assembly of the membranous part of the chloroplast ATP synthase. PLANT PHYSIOLOGY 2014; 165:207-26. [PMID: 24664203 PMCID: PMC4012581 DOI: 10.1104/pp.114.237883] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Accepted: 03/23/2014] [Indexed: 05/18/2023]
Abstract
The chloroplast F1Fo-ATP synthase/ATPase (cpATPase) couples ATP synthesis to the light-driven electrochemical proton gradient. The cpATPase is a multiprotein complex and consists of a membrane-spanning protein channel (comprising subunit types a, b, b', and c) and a peripheral domain (subunits α, β, γ, δ, and ε). We report the characterization of the Arabidopsis (Arabidopsis thaliana) CONSERVED ONLY IN THE GREEN LINEAGE160 (AtCGL160) protein (AtCGL160), conserved in green algae and plants. AtCGL160 is an integral thylakoid protein, and its carboxyl-terminal portion is distantly related to prokaryotic ATP SYNTHASE PROTEIN1 (Atp1/UncI) proteins that are thought to function in ATP synthase assembly. Plants without AtCGL160 display an increase in xanthophyll cycle activity and energy-dependent nonphotochemical quenching. These photosynthetic perturbations can be attributed to a severe reduction in cpATPase levels that result in increased acidification of the thylakoid lumen. AtCGL160 is not an integral cpATPase component but is specifically required for the efficient incorporation of the c-subunit into the cpATPase. AtCGL160, as well as a chimeric protein containing the amino-terminal part of AtCGL160 and Synechocystis sp. PCC6803 Atp1, physically interact with the c-subunit. We conclude that AtCGL160 and Atp1 facilitate the assembly of the membranous part of the cpATPase in their hosts, but loss of their functions provokes a unique compensatory response in each organism.
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Kratochvílová H, Hejzlarová K, Vrbacký M, Mráček T, Karbanová V, Tesařová M, Gombitová A, Cmarko D, Wittig I, Zeman J, Houštěk J. Mitochondrial membrane assembly of TMEM70 protein. Mitochondrion 2014; 15:1-9. [DOI: 10.1016/j.mito.2014.02.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 02/04/2014] [Accepted: 02/18/2014] [Indexed: 01/09/2023]
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HEJZLAROVÁ K, MRÁČEK T, VRBACKÝ M, KAPLANOVÁ V, KARBANOVÁ V, NŮSKOVÁ H, PECINA P, HOUŠTĚK J. Nuclear Genetic Defects of Mitochondrial ATP Synthase. Physiol Res 2014; 63:S57-71. [DOI: 10.33549/physiolres.932643] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Disorders of ATP synthase, the key enzyme of mitochondrial energy provision belong to the most severe metabolic diseases presenting as early-onset mitochondrial encephalo-cardiomyopathies. Up to now, mutations in four nuclear genes were associated with isolated deficiency of ATP synthase. Two of them, ATP5A1 and ATP5E encode enzyme’s structural subunits α and ε, respectively, while the other two ATPAF2 and TMEM70 encode specific ancillary factors that facilitate the biogenesis of ATP synthase. All these defects share a similar biochemical phenotype with pronounced decrease in the content of fully assembled and functional ATP synthase complex. However, substantial differences can be found in their frequency, molecular mechanism of pathogenesis, clinical manifestation as well as the course of the disease progression. While for TMEM70 the number of reported patients as well as spectrum of the mutations is steadily increasing, mutations in ATP5A1, ATP5E and ATPAF2 genes are very rare. Apparently, TMEM70 gene is highly prone to mutagenesis and this type of a rare mitochondrial disease has a rather frequent incidence. Here we present overview of individual reported cases of nuclear mutations in ATP synthase and discuss, how their analysis can improve our understanding of the enzyme biogenesis.
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Affiliation(s)
| | | | | | | | | | | | | | - J. HOUŠTĚK
- Department of Bioenergetics, Institute of Physiology Academy of Sciences of the Czech Republic, Prague, Czech Republic
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Abstract
The mitochondrion is arguably the most complex organelle in the budding yeast cell cytoplasm. It is essential for viability as well as respiratory growth. Its innermost aqueous compartment, the matrix, is bounded by the highly structured inner membrane, which in turn is bounded by the intermembrane space and the outer membrane. Approximately 1000 proteins are present in these organelles, of which eight major constituents are coded and synthesized in the matrix. The import of mitochondrial proteins synthesized in the cytoplasm, and their direction to the correct soluble compartments, correct membranes, and correct membrane surfaces/topologies, involves multiple pathways and macromolecular machines. The targeting of some, but not all, cytoplasmically synthesized mitochondrial proteins begins with translation of messenger RNAs localized to the organelle. Most proteins then pass through the translocase of the outer membrane to the intermembrane space, where divergent pathways sort them to the outer membrane, inner membrane, and matrix or trap them in the intermembrane space. Roughly 25% of mitochondrial proteins participate in maintenance or expression of the organellar genome at the inner surface of the inner membrane, providing 7 membrane proteins whose synthesis nucleates the assembly of three respiratory complexes.
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Lertwattanasakul N, Murata M, Rodrussamee N, Limtong S, Kosaka T, Yamada M. Essentiality of respiratory activity for pentose utilization in thermotolerant yeast Kluyveromyces marxianus DMKU 3-1042. Antonie van Leeuwenhoek 2013; 103:933-45. [PMID: 23338601 DOI: 10.1007/s10482-012-9874-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Accepted: 12/31/2012] [Indexed: 11/26/2022]
Abstract
By random integrative mutagenesis with a kanMX4 cassette in Kluyveromyces marxianus DMKU 3-1042, we obtained three mutants of COX15, ATP25 and CYC3 encoding a cytochrome oxidase assembly factor (singleton), a transcription factor required for assembly of the Atp9p subunit of mitochondrial ATP synthase and cytochrome c heme lyase, respectively, as mutants lacking growth capability on xylose and/or arabinose. They exhibited incapability of growth on non-fermentable carbon sources, such as acetate or glycerol, and thermosensitiveness. Their biomass formation in glucose medium was reduced, but ethanol yields were increased with a high ethanol level in the medium, compared to those of the parental strain. Experiments with respiratory inhibitors showed that cox15 and cyc3, but not atp25, were able to grow in glucose medium containing antimycin A and that the atp25 mutant was KCN-resistant. Activities of NADH and ubiquinol oxidases in membrane fractions of each mutant became a half of that of the parent and negligible, respectively, and their remaining NADH oxidase activities were found to be resistant to KCN. Absolute absorption spectral analysis revealed that the peak corresponding to a + a 3 was very small in atp25 and negligible in cox15 and cyc3. These findings suggest that the K. marxianus strain possesses an alternative KCN-resistant oxidase that is located between primary dehydrogenases and the ubiquinone pool and that the respiratory activity is essential for utilization of pentoses.
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Affiliation(s)
- Noppon Lertwattanasakul
- Applied Molecular Bioscience, Graduate School of Medicine, Yamaguchi University, Ube, 755-8505, Japan.
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31
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Abstract
Pulse-chase labeling of isolated yeast mitochondria identifies new assembly intermediates of Cox1p, characterizes their compositions, and orders them sequentially. The results indicate that cytochrome oxidase is assembled from separate modules, each consisting of different mitochondrial and nuclear gene products. Previous studies of yeast cytochrome oxidase (COX) biogenesis identified Cox1p, one of the three mitochondrially encoded core subunits, in two high–molecular weight complexes combined with regulatory/assembly factors essential for expression of this subunit. In the present study we use pulse-chase labeling experiments in conjunction with isolated mitochondria to identify new Cox1p intermediates and place them in an ordered pathway. Our results indicate that before its assimilation into COX, Cox1p transitions through five intermediates that are differentiated by their compositions of accessory factors and of two of the eight imported subunits. We propose a model of COX biogenesis in which Cox1p and the two other mitochondrial gene products, Cox2p and Cox3p, constitute independent assembly modules, each with its own complement of subunits. Unlike their bacterial counterparts, which are composed only of the individual core subunits, the final sequence in which the mitochondrial modules associate to form the holoenzyme may have been conserved during evolution.
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Affiliation(s)
- Gavin P McStay
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
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Häuser R, Pech M, Kijek J, Yamamoto H, Titz B, Naeve F, Tovchigrechko A, Yamamoto K, Szaflarski W, Takeuchi N, Stellberger T, Diefenbacher ME, Nierhaus KH, Uetz P. RsfA (YbeB) proteins are conserved ribosomal silencing factors. PLoS Genet 2012; 8:e1002815. [PMID: 22829778 PMCID: PMC3400551 DOI: 10.1371/journal.pgen.1002815] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2012] [Accepted: 05/21/2012] [Indexed: 11/18/2022] Open
Abstract
The YbeB (DUF143) family of uncharacterized proteins is encoded by almost all bacterial and eukaryotic genomes but not archaea. While they have been shown to be associated with ribosomes, their molecular function remains unclear. Here we show that YbeB is a ribosomal silencing factor (RsfA) in the stationary growth phase and during the transition from rich to poor media. A knock-out of the rsfA gene shows two strong phenotypes: (i) the viability of the mutant cells are sharply impaired during stationary phase (as shown by viability competition assays), and (ii) during transition from rich to poor media the mutant cells adapt slowly and show a growth block of more than 10 hours (as shown by growth competition assays). RsfA silences translation by binding to the L14 protein of the large ribosomal subunit and, as a consequence, impairs subunit joining (as shown by molecular modeling, reporter gene analysis, in vitro translation assays, and sucrose gradient analysis). This particular interaction is conserved in all species tested, including Escherichia coli, Treponema pallidum, Streptococcus pneumoniae, Synechocystis PCC 6803, as well as human mitochondria and maize chloroplasts (as demonstrated by yeast two-hybrid tests, pull-downs, and mutagenesis). RsfA is unrelated to the eukaryotic ribosomal anti-association/60S-assembly factor eIF6, which also binds to L14, and is the first such factor in bacteria and organelles. RsfA helps cells to adapt to slow-growth/stationary phase conditions by down-regulating protein synthesis, one of the most energy-consuming processes in both bacterial and eukaryotic cells. The YbeB/DUF143 family of proteins is one of the most widely conserved proteins with homologues present in almost all bacteria and eukaryotic organelles such as mitochondria and chloroplasts (but not archaea). While it has been shown that these proteins associate with ribosomes, their molecular function remained mysterious. Here we show that a knock-out of the ybeB gene causes a dramatic adaptation block during a shift from rich to poor media and seriously deteriorates the viability during stationary phase. YbeB of six different species binds to ribosomal protein L14. This interaction blocks the association of the two ribosomal subunits and, as a consequence, translation. YbeB is thus renamed “RsfA” (ribosomal silencing factor A). RsfA inhibits translation when nutrients are depleted (or when cells are in stationary phase), which helps the cell to save energy and nutrients, a critical function for all cells that are regularly struggling with limited resources.
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Affiliation(s)
- Roman Häuser
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
- German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Markus Pech
- Abteilung Vingron, AG Ribosomen Max-Planck-Institut für Molekulare Genetik, Berlin, Germany
- Institut für Medizinische Physik und Biophysik, Charité–Universitätsmedizin Berlin, Berlin, Germany
| | - Jaroslaw Kijek
- Abteilung Vingron, AG Ribosomen Max-Planck-Institut für Molekulare Genetik, Berlin, Germany
- Institut für Medizinische Physik und Biophysik, Charité–Universitätsmedizin Berlin, Berlin, Germany
| | - Hiroshi Yamamoto
- Abteilung Vingron, AG Ribosomen Max-Planck-Institut für Molekulare Genetik, Berlin, Germany
- Institut für Medizinische Physik und Biophysik, Charité–Universitätsmedizin Berlin, Berlin, Germany
| | - Björn Titz
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Florian Naeve
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | | | - Kaori Yamamoto
- Abteilung Vingron, AG Ribosomen Max-Planck-Institut für Molekulare Genetik, Berlin, Germany
- Institut für Medizinische Physik und Biophysik, Charité–Universitätsmedizin Berlin, Berlin, Germany
| | - Witold Szaflarski
- Abteilung Vingron, AG Ribosomen Max-Planck-Institut für Molekulare Genetik, Berlin, Germany
- Department of Histology and Embryology, Poznan University of Medical Sciences, Poznan, Poland
| | - Nono Takeuchi
- Department of Medical Genome Sciences, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa-shi, Chiba, Japan
| | - Thorsten Stellberger
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Markus E. Diefenbacher
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Knud H. Nierhaus
- Abteilung Vingron, AG Ribosomen Max-Planck-Institut für Molekulare Genetik, Berlin, Germany
- Institut für Medizinische Physik und Biophysik, Charité–Universitätsmedizin Berlin, Berlin, Germany
- * E-mail: (KHN); (PU)
| | - Peter Uetz
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
- Proteros Biostructures, Martinsried, Germany
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia, United States of America
- * E-mail: (KHN); (PU)
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Wanschers BFJ, Szklarczyk R, Pajak A, van den Brand MAM, Gloerich J, Rodenburg RJT, Lightowlers RN, Nijtmans LG, Huynen MA. C7orf30 specifically associates with the large subunit of the mitochondrial ribosome and is involved in translation. Nucleic Acids Res 2012; 40:4040-51. [PMID: 22238375 PMCID: PMC3351149 DOI: 10.1093/nar/gkr1271] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In a comparative genomics study for mitochondrial ribosome-associated proteins, we identified C7orf30, the human homolog of the plant protein iojap. Gene order conservation among bacteria and the observation that iojap orthologs cannot be transferred between bacterial species predict this protein to be associated with the mitochondrial ribosome. Here, we show colocalization of C7orf30 with the large subunit of the mitochondrial ribosome using isokinetic sucrose gradient and 2D Blue Native polyacrylamide gel electrophoresis (BN-PAGE) analysis. We co-purified C7orf30 with proteins of the large subunit, and not with proteins of the small subunit, supporting interaction that is specific to the large mitoribosomal complex. Consistent with this physical association, a mitochondrial translation assay reveals negative effects of C7orf30 siRNA knock-down on mitochondrial gene expression. Based on our data we propose that C7orf30 is involved in ribosomal large subunit function. Sequencing the gene in 35 patients with impaired mitochondrial translation did not reveal disease-causing mutations in C7orf30.
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Affiliation(s)
- Bas F J Wanschers
- Centre for Molecular and Biomolecular Informatics, Radboud University Nijmegen Medical Centre, The Netherlands
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34
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Rorbach J, Gammage PA, Minczuk M. C7orf30 is necessary for biogenesis of the large subunit of the mitochondrial ribosome. Nucleic Acids Res 2012; 40:4097-109. [PMID: 22238376 PMCID: PMC3351152 DOI: 10.1093/nar/gkr1282] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Defects of the translation apparatus in human mitochondria are known to cause disease, yet details of how protein synthesis is regulated in this organelle remain to be unveiled. Here, we characterize a novel human protein, C7orf30 that contributes critically to mitochondrial translation and specifically associates with the large subunit of the mitochondrial ribosome (mt-LSU). Inactivation of C7orf30 in human cells by RNA interference results in respiratory incompetence owing to reduced mitochondrial translation rates without any appreciable effects on the steady-state levels of mitochondrial mRNAs and rRNAs. Ineffective translation in C7orf30-depleted cells or cells overexpressing a dominant-negative mutant of the protein results from aberrant assembly of mt-LSU and consequently reduced formation of the monosome. These findings lead us to propose that C7orf30 is a human assembly and/or stability factor involved in the biogenesis of the large subunit of the mitochondrial ribosome.
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Affiliation(s)
- Joanna Rorbach
- MRC Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
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35
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Francis BR, Thorsness PE. Hsp90 and mitochondrial proteases Yme1 and Yta10/12 participate in ATP synthase assembly in Saccharomyces cerevisiae. Mitochondrion 2011; 11:587-600. [PMID: 21439406 DOI: 10.1016/j.mito.2011.03.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Revised: 02/22/2011] [Accepted: 03/15/2011] [Indexed: 10/18/2022]
Abstract
Hsc82 and Hsp82, the Hsp90 family proteins of yeast, are both required for fermentative growth at 37°C. Inactivation of either of the mitochondrial AAA proteases, Yme1 or Yta10/12, allows fermentative growth of hsc82∆ or hsp82∆ strains at 37°C. Genetic evidence indicates interaction of Hsc82/Hsp82 with the Yme1 and Yta10/Yta12 complexes in promoting F(1)F(o)-ATPase activity, with Hsc82 specifically required for F(1)-ATPase assembly. A previously reported mutation in Rpt3, one of the six ATPases of the proteasome, suppresses yme1∆ phenotypes and increases transcription of HSC82 but not HSP82. These genetic interactions describe a functional role for Hsp90 proteins in mitochondrial biogenesis.
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Affiliation(s)
- Brian R Francis
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA
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36
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Modular assembly of yeast mitochondrial ATP synthase. EMBO J 2011; 30:920-30. [PMID: 21266956 DOI: 10.1038/emboj.2010.364] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2010] [Accepted: 12/16/2010] [Indexed: 11/08/2022] Open
Abstract
The mitochondrial ATP synthase (F(1)-F(0) complex) of Saccharomces cerevisiae is a composite of different structural and functional units that jointly couple ATP synthesis and hydrolysis to proton transfer across the inner membrane. In organello, pulse labelling and pulse-chase experiments have enabled us to track the mitochondrially encoded Atp6p, Atp8p and Atp9p subunits of F(0) and to identify different assembly intermediates into which they are assimilated. Surprisingly, these core subunits of F(0) segregated into two different assembly intermediates one of which is composed of Atp6p, Atp8p, at least two stator subunits, and the Atp10p chaperone while the second consists of the F(1) ATPase and Atp9p ring. These studies show that assembly of the ATP synthase is not a single linear process, as previously thought, but rather involves two separate but coordinately regulated pathways that converge at the end stage.
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Expression and processing of the TMEM70 protein. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1807:144-9. [DOI: 10.1016/j.bbabio.2010.10.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Revised: 09/30/2010] [Accepted: 10/05/2010] [Indexed: 11/18/2022]
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Bhadauria V, Wang LX, Peng YL. Proteomic changes associated with deletion of the Magnaporthe oryzae conidial morphology-regulating gene COM1. Biol Direct 2010; 5:61. [PMID: 21040590 PMCID: PMC2989938 DOI: 10.1186/1745-6150-5-61] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Accepted: 11/02/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The rice blast disease caused by Magnaporthe oryzae is a major constraint on world rice production. The conidia produced by this fungal pathogen are the main source of disease dissemination. The morphology of conidia may be a critical factor in the spore dispersal and virulence of M. oryzae in the field. Deletion of a conidial morphology regulating gene encoding putative transcriptional regulator COM1 in M. oryzae resulted in aberrant conidial shape, reduced conidiation and attenuated virulence. RESULTS In this study, a two-dimensional gel electrophoresis/matrix assisted laser desorption ionization- time of flight mass spectrometry (2-DE/MALDI-TOF MS) based proteomics approach was employed to identify the cellular and molecular components regulated by the COM1 protein (COM1p) that might contribute to the aberrant phenotypes in M. oryzae. By comparing the conidial proteomes of COM1 deletion mutant and its isogenic wild-type strain P131, we identified a potpourri of 31 proteins that exhibited statistically significant alterations in their abundance levels. Of these differentially regulated proteins, the abundance levels of nine proteins were elevated and twelve were reduced in the Δcom1 mutant. Three proteins were detected only in the Δcom1 conidial proteome, whereas seven proteins were apparently undetectable. The data obtained in the study suggest that the COM1p plays a key role in transcriptional reprogramming of genes implicated in melanin biosynthesis, carbon and energy metabolism, structural organization of cell, lipid metabolism, amino acid metabolism, etc. Semi-quantitative RT-PCR analysis revealed the down-regulation of genes encoding enzymes involved in melanin biosynthesis in the COM1 mutant. CONCLUSIONS Our results suggest that the COM1p may regulate the transcription of genes involved in various cellular processes indispensable for conidial development and appressorial penetration. These functions are likely to contribute to the effects of COM1p upon the aberrant phenotypes of M. oryzae.
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Affiliation(s)
- Vijai Bhadauria
- State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Molecular Plant Pathology, China Agricultural University, Beijing 100193, China
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Havlícková V, Kaplanová V, Nůsková H, Drahota Z, Houstek J. Knockdown of F1 epsilon subunit decreases mitochondrial content of ATP synthase and leads to accumulation of subunit c. BIOCHIMICA ET BIOPHYSICA ACTA 2010; 1797:1124-9. [PMID: 20026007 DOI: 10.1016/j.bbabio.2009.12.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 12/11/2009] [Accepted: 12/13/2009] [Indexed: 10/20/2022]
Abstract
The subunit epsilon of mitochondrial ATP synthase is the only F1 subunit without a homolog in bacteria and chloroplasts and represents the least characterized F1 subunit of the mammalian enzyme. Silencing of the ATP5E gene in HEK293 cells resulted in downregulation of the activity and content of the mitochondrial ATP synthase complex and of ADP-stimulated respiration to approximately 40% of the control. The decreased content of the epsilon subunit was paralleled by a decrease in the F1 subunits alpha and beta and in the Fo subunits a and d while the content of the subunit c was not affected. The subunit c was present in the full-size ATP synthase complex and in subcomplexes of 200-400 kDa that neither contained the F1 subunits, nor the Fo subunits. The results indicate that the epsilon subunit is essential for the assembly of F1 and plays an important role in the incorporation of the hydrophobic subunit c into the F1-c oligomer rotor of the mitochondrial ATP synthase complex.
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Affiliation(s)
- Vendula Havlícková
- Department of Bioenergetics, Institute of Physiology and Centre for Applied Genomics, Academy of Sciences of the Czech Republic, 142 20 Prague
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Lipinski KA, Kaniak-Golik A, Golik P. Maintenance and expression of the S. cerevisiae mitochondrial genome--from genetics to evolution and systems biology. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:1086-98. [PMID: 20056105 DOI: 10.1016/j.bbabio.2009.12.019] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2009] [Revised: 12/18/2009] [Accepted: 12/24/2009] [Indexed: 10/20/2022]
Abstract
As a legacy of their endosymbiotic eubacterial origin, mitochondria possess a residual genome, encoding only a few proteins and dependent on a variety of factors encoded by the nuclear genome for its maintenance and expression. As a facultative anaerobe with well understood genetics and molecular biology, Saccharomyces cerevisiae is the model system of choice for studying nucleo-mitochondrial genetic interactions. Maintenance of the mitochondrial genome is controlled by a set of nuclear-coded factors forming intricately interconnected circuits responsible for replication, recombination, repair and transmission to buds. Expression of the yeast mitochondrial genome is regulated mostly at the post-transcriptional level, and involves many general and gene-specific factors regulating splicing, RNA processing and stability and translation. A very interesting aspect of the yeast mitochondrial system is the relationship between genome maintenance and gene expression. Deletions of genes involved in many different aspects of mitochondrial gene expression, notably translation, result in an irreversible loss of functional mtDNA. The mitochondrial genetic system viewed from the systems biology perspective is therefore very fragile and lacks robustness compared to the remaining systems of the cell. This lack of robustness could be a legacy of the reductive evolution of the mitochondrial genome, but explanations involving selective advantages of increased evolvability have also been postulated.
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Affiliation(s)
- Kamil A Lipinski
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5A, 02-106, Warsaw, Poland
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41
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F1-dependent translation of mitochondrially encoded Atp6p and Atp8p subunits of yeast ATP synthase. Proc Natl Acad Sci U S A 2009; 106:18509-14. [PMID: 19841266 DOI: 10.1073/pnas.0910351106] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The ATP synthase of yeast mitochondria is composed of 17 different subunit polypeptides. We have screened a panel of ATP synthase mutants for impaired expression of Atp6p, Atp8p, and Atp9p, the only mitochondrially encoded subunits of ATP synthase. Our results show that translation of Atp6p and Atp8p is activated by F(1) ATPase (or assembly intermediates thereof). Mutants lacking the alpha or beta subunits of F(1), or the Atp11p and Atp12p chaperones that promote F(1) assembly, have normal levels of the bicistronic ATP8/ATP6 mRNAs but fail to synthesize Atp6p and Atp8p. F(1) mutants are also unable to express ARG8(m) when this normally nuclear gene is substituted for ATP6 or ATP8 in mitochondrial DNA. Translational activation by F(1) is also supported by the ability of ATP22, an Atp6p-specific translation factor, to restore Atp6p and to a lesser degree Atp8p synthesis in the absence of F(1). These results establish a mechanism by which expression of ATP6 and ATP8 is translationally regulated by F(1) to achieve a balanced output of two compartmentally separated sets of ATP synthase genes.
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TMEM70 protein — A novel ancillary factor of mammalian ATP synthase. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1787:529-32. [DOI: 10.1016/j.bbabio.2008.11.013] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2008] [Revised: 11/21/2008] [Accepted: 11/26/2008] [Indexed: 11/18/2022]
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43
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Current awareness on yeast. Yeast 2009. [DOI: 10.1002/yea.1619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Hess DC, Myers CL, Huttenhower C, Hibbs MA, Hayes AP, Paw J, Clore JJ, Mendoza RM, Luis BS, Nislow C, Giaever G, Costanzo M, Troyanskaya OG, Caudy AA. Computationally driven, quantitative experiments discover genes required for mitochondrial biogenesis. PLoS Genet 2009; 5:e1000407. [PMID: 19300474 PMCID: PMC2648979 DOI: 10.1371/journal.pgen.1000407] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2008] [Accepted: 02/05/2009] [Indexed: 01/09/2023] Open
Abstract
Mitochondria are central to many cellular processes including respiration, ion homeostasis, and apoptosis. Using computational predictions combined with traditional quantitative experiments, we have identified 100 proteins whose deficiency alters mitochondrial biogenesis and inheritance in Saccharomyces cerevisiae. In addition, we used computational predictions to perform targeted double-mutant analysis detecting another nine genes with synthetic defects in mitochondrial biogenesis. This represents an increase of about 25% over previously known participants. Nearly half of these newly characterized proteins are conserved in mammals, including several orthologs known to be involved in human disease. Mutations in many of these genes demonstrate statistically significant mitochondrial transmission phenotypes more subtle than could be detected by traditional genetic screens or high-throughput techniques, and 47 have not been previously localized to mitochondria. We further characterized a subset of these genes using growth profiling and dual immunofluorescence, which identified genes specifically required for aerobic respiration and an uncharacterized cytoplasmic protein required for normal mitochondrial motility. Our results demonstrate that by leveraging computational analysis to direct quantitative experimental assays, we have characterized mutants with subtle mitochondrial defects whose phenotypes were undetected by high-throughput methods. Mitochondria are the proverbial powerhouses of the cell, running the fundamental biochemical processes that produce energy from nutrients using oxygen. These processes are conserved in all eukaryotes, from humans to model organisms such as baker's yeast. In humans, mitochondrial dysfunction plays a role in a variety of diseases, including diabetes, neuromuscular disorders, and aging. In order to better understand fundamental mitochondrial biology, we studied genes involved in mitochondrial biogenesis in the yeast S. cerevisiae, discovering over 100 proteins with novel roles in this process. These experiments assigned function to 5% of the genes whose function was not known. In order to achieve this rapid rate of discovery, we developed a system incorporating highly quantitative experimental assays and an integrated, iterative process of computational protein function prediction. Beginning from relatively little prior knowledge, we found that computational predictions achieved about 60% accuracy and rapidly guided our laboratory work towards hundreds of promising candidate genes. Thus, in addition to providing a more thorough understanding of mitochondrial biology, this study establishes a framework for successfully integrating computation and experimentation to drive biological discovery. A companion manuscript, published in PLoS Computational Biology (doi:10.1371/journal.pcbi.1000322), discusses observations and conclusions important for the computational community.
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Affiliation(s)
- David C. Hess
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
| | - Chad L. Myers
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
- Department of Computer Science, Princeton University, Princeton, New Jersey, United States of America
- Department of Computer Science and Engineering, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Curtis Huttenhower
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
- Department of Computer Science, Princeton University, Princeton, New Jersey, United States of America
| | - Matthew A. Hibbs
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
- Department of Computer Science, Princeton University, Princeton, New Jersey, United States of America
| | - Alicia P. Hayes
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
| | - Jadine Paw
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - John J. Clore
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
| | - Rosa M. Mendoza
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
| | - Bryan San Luis
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Corey Nislow
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Guri Giaever
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Michael Costanzo
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Olga G. Troyanskaya
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
- Department of Computer Science, Princeton University, Princeton, New Jersey, United States of America
- * E-mail: (OGT); (AAC)
| | - Amy A. Caudy
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
- * E-mail: (OGT); (AAC)
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Rak M, Zeng X, Brière JJ, Tzagoloff A. Assembly of F0 in Saccharomyces cerevisiae. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1793:108-16. [PMID: 18672007 DOI: 10.1016/j.bbamcr.2008.07.001] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2008] [Revised: 06/26/2008] [Accepted: 07/01/2008] [Indexed: 11/30/2022]
Abstract
Respiratory deficient mutants of Saccharomyces cerevisiae have been instrumental in identifying an increasing number of nuclear gene products that promote pre- and post-translational steps of the pathway responsible for biogenesis of the mitochondrial ATP synthase. In this article we have attempted to marshal current information about the functions of such accessory factors and the roles they play in expression and assembly of the mitochondrially encoded subunits of the ATP synthase. We also discuss evidence that the ATP synthase may be built up from three separate modules corresponding to the F1 ATPase, the stator and F0.
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Affiliation(s)
- Malgorzata Rak
- Department of Biological Sciences, Columbia University New York, NY 10027, USA
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Kucharczyk R, Zick M, Bietenhader M, Rak M, Couplan E, Blondel M, Caubet SD, di Rago JP. Mitochondrial ATP synthase disorders: molecular mechanisms and the quest for curative therapeutic approaches. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1793:186-99. [PMID: 18620007 DOI: 10.1016/j.bbamcr.2008.06.012] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2008] [Revised: 06/06/2008] [Accepted: 06/11/2008] [Indexed: 01/09/2023]
Abstract
In mammals, the majority of cellular ATP is produced by the mitochondrial F1F(O)-ATP synthase through an elaborate catalytic mechanism. While most subunits of this enzymatic complex are encoded by the nuclear genome, a few essential components are encoded in the mitochondrial genome. The biogenesis of this multi-subunit enzyme is a sophisticated multi-step process that is regulated on levels of transcription, translation and assembly. Defects that result in diminished abundance or functional impairment of the F1F(O)-ATP synthase can cause a variety of severe neuromuscular disorders. Underlying mutations have been identified in both the nuclear and the mitochondrial DNA. The pathogenic mechanisms are only partially understood. Currently, the therapeutic options are extremely limited. Alternative methods of treatment have however been proposed, but still encounter several technical difficulties. The application of novel scientific approaches promises to deepen our understanding of the molecular mechanisms of the ATP synthase, unravel novel therapeutic pathways and improve the unfortunate situation of the patients suffering from such diseases.
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Affiliation(s)
- Roza Kucharczyk
- Institut de Biochimie et Génétique Cellulaires, CNRS-Université Bordeaux2, Bordeaux 33077, France
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