51
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Valach M, Gonzalez Alcazar JA, Sarrasin M, Lang BF, Gray MW, Burger G. An Unexpectedly Complex Mitoribosome in Andalucia godoyi, a Protist with the Most Bacteria-like Mitochondrial Genome. Mol Biol Evol 2021; 38:788-804. [PMID: 32886790 PMCID: PMC7947838 DOI: 10.1093/molbev/msaa223] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The mitoribosome, as known from studies in model organisms, deviates considerably from its ancestor, the bacterial ribosome. Deviations include substantial reduction of the mitochondrial ribosomal RNA (mt-rRNA) structure and acquisition of numerous mitochondrion-specific (M) mitoribosomal proteins (mtRPs). A broadly accepted view assumes that M-mtRPs compensate for structural destabilization of mt-rRNA resulting from its evolutionary remodeling. Since most experimental information on mitoribosome makeup comes from eukaryotes having derived mitochondrial genomes and mt-rRNAs, we tested this assumption by investigating the mitochondrial translation machinery of jakobids, a lineage of unicellular protists with the most bacteria-like mitochondrial genomes. We report here proteomics analyses of the Andalucia godoyi small mitoribosomal subunit and in silico transcriptomic and comparative genome analyses of four additional jakobids. Jakobids have mt-rRNA structures that minimally differ from their bacterial counterparts. Yet, with at least 31 small subunit and 44 large subunit mtRPs, the mitoriboproteome of Andalucia is essentially as complex as that in animals or fungi. Furthermore, the relatively high conservation of jakobid sequences has helped to clarify the identity of several mtRPs, previously considered to be lineage-specific, as divergent homologs of conserved M-mtRPs, notably mS22 and mL61. The coexistence of bacteria-like mt-rRNAs and a complex mitoriboproteome refutes the view that M-mtRPs were ancestrally recruited to stabilize deviations of mt-rRNA structural elements. We postulate instead that the numerous M-mtRPs acquired in the last eukaryotic common ancestor allowed mt-rRNAs to pursue a broad range of evolutionary trajectories across lineages: from dramatic reduction to acquisition of novel elements to structural conservatism.
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Affiliation(s)
- Matus Valach
- Department of Biochemistry and Molecular Medicine, Robert-Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, Montreal, Quebec, Canada
| | - José Angel Gonzalez Alcazar
- Department of Biochemistry and Molecular Medicine, Robert-Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, Montreal, Quebec, Canada
| | - Matt Sarrasin
- Department of Biochemistry and Molecular Medicine, Robert-Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, Montreal, Quebec, Canada
| | - B Franz Lang
- Department of Biochemistry and Molecular Medicine, Robert-Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, Montreal, Quebec, Canada
| | - Michael W Gray
- Department of Biochemistry and Molecular Biology, Centre for Comparative Genomics and Evolutionary Bioinformatics, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Gertraud Burger
- Department of Biochemistry and Molecular Medicine, Robert-Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, Montreal, Quebec, Canada
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52
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Finger Y, Riemer J. Protein import by the mitochondrial disulfide relay in higher eukaryotes. Biol Chem 2021; 401:749-763. [PMID: 32142475 DOI: 10.1515/hsz-2020-0108] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 02/24/2020] [Indexed: 12/19/2022]
Abstract
The proteome of the mitochondrial intermembrane space (IMS) contains more than 100 proteins, all of which are synthesized on cytosolic ribosomes and consequently need to be imported by dedicated machineries. The mitochondrial disulfide relay is the major import machinery for soluble proteins in the IMS. Its major component, the oxidoreductase MIA40, interacts with incoming substrates, retains them in the IMS, and oxidatively folds them. After this reaction, MIA40 is reoxidized by the sulfhydryl oxidase augmenter of liver regeneration, which couples disulfide formation by this machinery to the activity of the respiratory chain. In this review, we will discuss the import of IMS proteins with a focus on recent findings showing the diversity of disulfide relay substrates, describing the cytosolic control of this import system and highlighting the physiological relevance of the disulfide relay machinery in higher eukaryotes.
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Affiliation(s)
- Yannik Finger
- Institute for Biochemistry, Redox Biochemistry, University of Cologne, Zülpicher Str. 47a/R. 3.49, D-50674 Cologne, Germany
| | - Jan Riemer
- Department of Chemistry, Institute for Biochemistry, Redox Biochemistry, University of Cologne, and Cologne Excellence Cluster on Cellular Stress Response in Aging-Associated Diseases, Zülpicher Str. 47a/R. 3.49, D-50674 Cologne, Germany
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53
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Alam J, Rahman FT, Sah-Teli SK, Venkatesan R, Koski MK, Autio KJ, Hiltunen JK, Kastaniotis AJ. Expression and analysis of the SAM-dependent RNA methyltransferase Rsm22 from Saccharomyces cerevisiae. Acta Crystallogr D Struct Biol 2021; 77:840-853. [PMID: 34076597 PMCID: PMC8171064 DOI: 10.1107/s2059798321004149] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 04/17/2021] [Indexed: 12/04/2022] Open
Abstract
Rsm22-family proteins are conserved putative SAM-dependent methyltransferases with important functions in mitochondrial translation. Here, the results of a comparative bioinformatics analysis of Rsm22-type proteins are presented, the expression, biophysical characterization and crystallization of Saccharomyces cerevisiae Rsm22 are reported, a low-resolution SAXS structure of the protein is revealed, and SAM-dependent RNA methyl transferase activity of the protein is demonstrated. The Saccharomyces cerevisiae Rsm22 protein (Sc-Rsm22), encoded by the nuclear RSM22 (systematic name YKL155c) gene, is a distant homologue of Rsm22 from Trypanosoma brucei (Tb-Rsm22) and METTL17 from mouse (Mm-METTL17). All three proteins have been shown to be associated with mitochondrial gene expression, and Sc-Rsm22 has been documented to be essential for mitochondrial respiration. The Sc-Rsm22 protein comprises a polypeptide of molecular weight 72.2 kDa that is predicted to harbor an N-terminal mitochondrial targeting sequence. The precise physiological function of Rsm22-family proteins is unknown, and no structural information has been available for Sc-Rsm22 to date. In this study, Sc-Rsm22 was expressed and purified in monomeric and dimeric forms, their folding was confirmed by circular-dichroism analyses and their low-resolution structures were determined using a small-angle X-ray scattering (SAXS) approach. The solution structure of the monomeric form of Sc-Rsm22 revealed an elongated three-domain arrangement, which differs from the shape of Tb-Rsm22 in its complex with the mitochondrial small ribosomal subunit in T. brucei (PDB entry 6sg9). A bioinformatic analysis revealed that the core domain in the middle (Leu117–Asp462 in Sc-Rsm22) resembles the corresponding region in Tb-Rsm22, including a Rossmann-like methyltransferase fold followed by a zinc-finger-like structure. The latter structure is not present in this position in other methyltransferases and is therefore a unique structural motif for this family. The first half of the C-terminal domain is likely to form an OB-fold, which is typically found in RNA-binding proteins and is also seen in the Tb-Rsm22 structure. In contrast, the N-terminal domain of Sc-Rsm22 is predicted to be fully α-helical and shares no sequence similarity with other family members. Functional studies demonstrated that the monomeric variant of Sc-Rsm22 methylates mitochondrial tRNAs in vitro. These data suggest that Sc-Rsm22 is a new and unique member of the RNA methyltransferases that is important for mitochondrial protein synthesis.
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Affiliation(s)
- Jahangir Alam
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Aapistie 7B, FIN-90220 Oulu, Finland
| | - Farah Tazkera Rahman
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Aapistie 7B, FIN-90220 Oulu, Finland
| | - Shiv K Sah-Teli
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Aapistie 7B, FIN-90220 Oulu, Finland
| | - Rajaram Venkatesan
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Aapistie 7B, FIN-90220 Oulu, Finland
| | | | - Kaija J Autio
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Aapistie 7B, FIN-90220 Oulu, Finland
| | - J Kalervo Hiltunen
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Aapistie 7B, FIN-90220 Oulu, Finland
| | - Alexander J Kastaniotis
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Aapistie 7B, FIN-90220 Oulu, Finland
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54
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Barbitoff YA, Matveenko AG, Matiiv AB, Maksiutenko EM, Moskalenko SE, Drozdova PB, Polev DE, Beliavskaia AY, Danilov LG, Predeus AV, Zhouravleva GA. Chromosome-level genome assembly and structural variant analysis of two laboratory yeast strains from the Peterhof Genetic Collection lineage. G3-GENES GENOMES GENETICS 2021; 11:6129118. [PMID: 33677552 PMCID: PMC8759820 DOI: 10.1093/g3journal/jkab029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 01/22/2021] [Indexed: 01/23/2023]
Abstract
Thousands of yeast genomes have been sequenced with both traditional and long-read technologies, and multiple observations about modes of genome evolution for both wild and laboratory strains have been drawn from these sequences. In our study, we applied Oxford Nanopore and Illumina technologies to assemble complete genomes of two widely used members of a distinct laboratory yeast lineage, the Peterhof Genetic Collection (PGC), and investigate the structural features of these genomes including transposable element content, copy number alterations, and structural rearrangements. We identified numerous notable structural differences between genomes of PGC strains and the reference S288C strain. We discovered a substantial enrichment of mid-length insertions and deletions within repetitive coding sequences, such as in the SCH9 gene or the NUP100 gene, with possible impact of these variants on protein amyloidogenicity. High contiguity of the final assemblies allowed us to trace back the history of reciprocal unbalanced translocations between chromosomes I, VIII, IX, XI, and XVI of the PGC strains. We show that formation of hybrid alleles of the FLO genes during such chromosomal rearrangements is likely responsible for the lack of invasive growth of yeast strains. Taken together, our results highlight important features of laboratory yeast strain evolution using the power of long-read sequencing.
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Affiliation(s)
- Yury A Barbitoff
- Department of Genetics and Biotechnology, St. Petersburg State University, St. Petersburg 199034, Russia.,Bioinformatics Institute, St. Petersburg 197342, Russia
| | - Andrew G Matveenko
- Department of Genetics and Biotechnology, St. Petersburg State University, St. Petersburg 199034, Russia.,Bioinformatics Institute, St. Petersburg 197342, Russia
| | - Anton B Matiiv
- Department of Genetics and Biotechnology, St. Petersburg State University, St. Petersburg 199034, Russia.,Bioinformatics Institute, St. Petersburg 197342, Russia
| | - Evgeniia M Maksiutenko
- Department of Genetics and Biotechnology, St. Petersburg State University, St. Petersburg 199034, Russia.,St. Petersburg Branch, Vavilov Institute of General Genetics of the Russian Academy of Sciences, St. Petersburg 199034, Russia
| | - Svetlana E Moskalenko
- Department of Genetics and Biotechnology, St. Petersburg State University, St. Petersburg 199034, Russia.,St. Petersburg Branch, Vavilov Institute of General Genetics of the Russian Academy of Sciences, St. Petersburg 199034, Russia
| | | | | | - Alexandra Y Beliavskaia
- Department of Invertebrate Zoology, St. Petersburg State University, 199034 St. Petersburg, Russia
| | - Lavrentii G Danilov
- Department of Genetics and Biotechnology, St. Petersburg State University, St. Petersburg 199034, Russia
| | - Alexander V Predeus
- Bioinformatics Institute, St. Petersburg 197342, Russia.,University of Liverpool, Liverpool, UK, L7 3EA
| | - Galina A Zhouravleva
- Department of Genetics and Biotechnology, St. Petersburg State University, St. Petersburg 199034, Russia
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55
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Liu S, Liu S, He B, Li L, Li L, Wang J, Cai T, Chen S, Jiang H. OXPHOS deficiency activates global adaptation pathways to maintain mitochondrial membrane potential. EMBO Rep 2021; 22:e51606. [PMID: 33655635 DOI: 10.15252/embr.202051606] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 01/18/2021] [Accepted: 01/27/2021] [Indexed: 12/19/2022] Open
Abstract
Reduction of mitochondrial membrane potential (Δψm ) is a hallmark of mitochondrial dysfunction. It activates adaptive responses in organisms from yeast to human to rewire metabolism, remove depolarized mitochondria, and degrade unimported precursor proteins. It remains unclear how cells maintain Δψm , which is critical for maintaining iron-sulfur cluster (ISC) synthesis, an indispensable function of mitochondria. Here, we show that yeast oxidative phosphorylation mutants deficient in complex III, IV, V, and mtDNA, respectively, exhibit activated stress responses and progressive reduction of Δψm . Extensive omics analyses of these mutants show that these mutants progressively activate adaptive responses, including transcriptional downregulation of ATP synthase inhibitor Inh1 and OXPHOS subunits, Puf3-mediated upregulation of import receptor Mia40 and global mitochondrial biogenesis, Snf1/AMPK-mediated upregulation of glycolysis and repression of ribosome biogenesis, and transcriptional upregulation of cytoplasmic chaperones. These adaptations disinhibit mitochondrial ATP hydrolysis, remodel mitochondrial proteome, and optimize ATP supply to mitochondria to convergently maintain Δψm , ISC biosynthesis, and cell proliferation.
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Affiliation(s)
- Siqi Liu
- Graduate School of Peking Union Medical College, Beijing, China.,National Institute of Biological Sciences, Beijing, China.,Beijing Key Laboratory of Cell Biology for Animal Aging, Beijing, China.,Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China
| | - Shanshan Liu
- Graduate School of Peking Union Medical College, Beijing, China.,National Institute of Biological Sciences, Beijing, China.,Beijing Key Laboratory of Cell Biology for Animal Aging, Beijing, China.,Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China
| | - Baiyu He
- National Institute of Biological Sciences, Beijing, China.,Beijing Key Laboratory of Cell Biology for Animal Aging, Beijing, China.,Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China.,College of Biological Sciences, China Agriculture University, Beijing, China
| | - Lanlan Li
- National Institute of Biological Sciences, Beijing, China.,Beijing Key Laboratory of Cell Biology for Animal Aging, Beijing, China.,Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China.,College of Life Sciences, Beijing Normal University, Beijing, China
| | - Lin Li
- National Institute of Biological Sciences, Beijing, China.,Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China
| | - Jiawen Wang
- National Institute of Biological Sciences, Beijing, China.,Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China
| | - Tao Cai
- National Institute of Biological Sciences, Beijing, China.,Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China
| | - She Chen
- National Institute of Biological Sciences, Beijing, China.,Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China
| | - Hui Jiang
- Graduate School of Peking Union Medical College, Beijing, China.,National Institute of Biological Sciences, Beijing, China.,Beijing Key Laboratory of Cell Biology for Animal Aging, Beijing, China.,Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China
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56
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Muñoz-Gómez SA, Bilolikar G, Wideman JG, Geiler-Samerotte K. Constructive Neutral Evolution 20 Years Later. J Mol Evol 2021; 89:172-182. [PMID: 33604782 PMCID: PMC7982386 DOI: 10.1007/s00239-021-09996-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Accepted: 01/13/2021] [Indexed: 12/29/2022]
Abstract
Evolution has led to a great diversity that ranges from elegant simplicity to ornate complexity. Many complex features are often assumed to be more functional or adaptive than their simpler alternatives. However, in 1999, Arlin Stolzfus published a paper in the Journal of Molecular Evolution that outlined a framework in which complexity can arise through a series of non-adaptive steps. He called this framework Constructive Neutral Evolution (CNE). Despite its two-decade-old roots, many evolutionary biologists still appear to be unaware of this explanatory framework for the origins of complexity. In this perspective piece, we explain the theory of CNE and how it changes the order of events in narratives that describe the evolution of complexity. We also provide an extensive list of cellular features that may have become more complex through CNE. We end by discussing strategies to determine whether complexity arose through neutral or adaptive processes.
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Affiliation(s)
- Sergio A Muñoz-Gómez
- School of Life Sciences, Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ, USA.
| | - Gaurav Bilolikar
- School of Life Sciences, Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ, USA
| | - Jeremy G Wideman
- School of Life Sciences, Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ, USA
| | - Kerry Geiler-Samerotte
- School of Life Sciences, Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ, USA.
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57
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Mechanisms and regulation of protein synthesis in mitochondria. Nat Rev Mol Cell Biol 2021; 22:307-325. [PMID: 33594280 DOI: 10.1038/s41580-021-00332-2] [Citation(s) in RCA: 147] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/13/2021] [Indexed: 02/06/2023]
Abstract
Mitochondria are cellular organelles responsible for generation of chemical energy in the process called oxidative phosphorylation. They originate from a bacterial ancestor and maintain their own genome, which is expressed by designated, mitochondrial transcription and translation machineries that differ from those operating for nuclear gene expression. In particular, the mitochondrial protein synthesis machinery is structurally and functionally very different from that governing eukaryotic, cytosolic translation. Despite harbouring their own genetic information, mitochondria are far from being independent of the rest of the cell and, conversely, cellular fitness is closely linked to mitochondrial function. Mitochondria depend heavily on the import of nuclear-encoded proteins for gene expression and function, and hence engage in extensive inter-compartmental crosstalk to regulate their proteome. This connectivity allows mitochondria to adapt to changes in cellular conditions and also mediates responses to stress and mitochondrial dysfunction. With a focus on mammals and yeast, we review fundamental insights that have been made into the biogenesis, architecture and mechanisms of the mitochondrial translation apparatus in the past years owing to the emergence of numerous near-atomic structures and a considerable amount of biochemical work. Moreover, we discuss how cellular mitochondrial protein expression is regulated, including aspects of mRNA and tRNA maturation and stability, roles of auxiliary factors, such as translation regulators, that adapt mitochondrial translation rates, and the importance of inter-compartmental crosstalk with nuclear gene expression and cytosolic translation and how it enables integration of mitochondrial translation into the cellular context.
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58
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Levitskii SA, Baleva MV, Chicherin IV, Krasheninnikov IA, Kamenski PA. Protein Biosynthesis in Mitochondria: Past Simple, Present Perfect, Future Indefinite. BIOCHEMISTRY (MOSCOW) 2021; 85:257-263. [PMID: 32564730 DOI: 10.1134/s0006297920030013] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Mitochondria are obligate organelles of most eukaryotic cells that perform many different functions important for cellular homeostasis. The main role of mitochondria is supplying cells with energy in a form of ATP, which is synthesized in a chain of oxidative phosphorylation reactions on the organelle inner membrane. It is commonly believed now that mitochondria have the endosymbiotic origin. In the course of evolution, they have lost most of their genetic material as a result of genome reduction and gene transfer to the nucleus. The majority of mitochondrial proteins are synthesized in the cytosol and then imported to the mitochondria. However, almost all known mitochondria still contain genomes that are maintained and expressed. The processes of protein biosynthesis in the mitochondria - mitochondrial translation - substantially differs from the analogous processes in bacteria and the cytosol of eukaryotic cells. Mitochondrial translation is characterized by a high degree of specialization and specific regulatory mechanisms. In this review, we analyze available information on the common principles of mitochondrial translation with emphasis on the molecular mechanisms of translation initiation in the mitochondria of yeast and mammalian cells.
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Affiliation(s)
- S A Levitskii
- Lomonosov Moscow State University, Faculty of Biology, Moscow, 119234, Russia
| | - M V Baleva
- Lomonosov Moscow State University, Faculty of Biology, Moscow, 119234, Russia
| | - I V Chicherin
- Lomonosov Moscow State University, Faculty of Biology, Moscow, 119234, Russia
| | - I A Krasheninnikov
- Lomonosov Moscow State University, Faculty of Biology, Moscow, 119234, Russia
| | - P A Kamenski
- Lomonosov Moscow State University, Faculty of Biology, Moscow, 119234, Russia.
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59
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Isokallio MA, Stewart JB. High-Throughput Detection of mtDNA Mutations Leading to tRNA Processing Errors. Methods Mol Biol 2021; 2192:117-132. [PMID: 33230770 DOI: 10.1007/978-1-0716-0834-0_10] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Some mutations in the tRNA genes of mitochondrial DNA (mtDNA) have been demonstrated to affect the processing of the mitochondrial transcriptome in human patients with mitochondrial disease. A recent analysis of mtDNA mutations in 527 human tumors revealed that approximately a quarter of the somatic mt-tRNA gene mutations lead to aberrant processing of the mitochondrial transcriptome in these tumors. Here, we describe a method, based on mtDNA mutations induced by the mtDNA mutator mouse, to map the sites that lead to transcript processing abnormalities. Mutations in the mtDNA are identified and quantified by amplicon-based mtDNA sequencing, and compared to the allelic ratios observed in matched RNASeq data. Strong deviation in the variant allele frequencies between the amplicon and RNASeq data suggests that such mutations lead to disruptions in mitochondrial transcript processing.
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60
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Ferrari A, Del'Olio S, Barrientos A. The Diseased Mitoribosome. FEBS Lett 2020; 595:1025-1061. [PMID: 33314036 DOI: 10.1002/1873-3468.14024] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 12/03/2020] [Accepted: 12/06/2020] [Indexed: 12/17/2022]
Abstract
Mitochondria control life and death in eukaryotic cells. Harboring a unique circular genome, a by-product of an ancient endosymbiotic event, mitochondria maintains a specialized and evolutionary divergent protein synthesis machinery, the mitoribosome. Mitoribosome biogenesis depends on elements encoded in both the mitochondrial genome (the RNA components) and the nuclear genome (all ribosomal proteins and assembly factors). Recent cryo-EM structures of mammalian mitoribosomes have illuminated their composition and provided hints regarding their assembly and elusive mitochondrial translation mechanisms. A growing body of literature involves the mitoribosome in inherited primary mitochondrial disorders. Mutations in genes encoding mitoribosomal RNAs, proteins, and assembly factors impede mitoribosome biogenesis, causing protein synthesis defects that lead to respiratory chain failure and mitochondrial disorders such as encephalo- and cardiomyopathy, deafness, neuropathy, and developmental delays. In this article, we review the current fundamental understanding of mitoribosome assembly and function, and the clinical landscape of mitochondrial disorders driven by mutations in mitoribosome components and assembly factors, to portray how basic and clinical studies combined help us better understand both mitochondrial biology and medicine.
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Affiliation(s)
- Alberto Ferrari
- Department of Neurology, University of Miami Miller School of Medicine, FL, USA
| | - Samuel Del'Olio
- Department of Neurology, University of Miami Miller School of Medicine, FL, USA.,Molecular and Cellular Pharmacology Graduate Program, University of Miami Miller School of Medicine, FL, USA
| | - Antoni Barrientos
- Department of Neurology, University of Miami Miller School of Medicine, FL, USA.,Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, FL, USA
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61
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Desai N, Yang H, Chandrasekaran V, Kazi R, Minczuk M, Ramakrishnan V. Elongational stalling activates mitoribosome-associated quality control. Science 2020; 370:1105-1110. [PMID: 33243891 PMCID: PMC7116630 DOI: 10.1126/science.abc7782] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 09/24/2020] [Indexed: 02/02/2023]
Abstract
The human mitochondrial ribosome (mitoribosome) and associated proteins regulate the synthesis of 13 essential subunits of the oxidative phosphorylation complexes. We report the discovery of a mitoribosome-associated quality control pathway that responds to interruptions during elongation, and we present structures at 3.1- to 3.3-angstrom resolution of mitoribosomal large subunits trapped during ribosome rescue. Release factor homolog C12orf65 (mtRF-R) and RNA binding protein C6orf203 (MTRES1) eject the nascent chain and peptidyl transfer RNA (tRNA), respectively, from stalled ribosomes. Recruitment of mitoribosome biogenesis factors to these quality control intermediates suggests additional roles for these factors during mitoribosome rescue. We also report related cryo-electron microscopy structures (3.7 to 4.4 angstrom resolution) of elongating mitoribosomes bound to tRNAs, nascent polypeptides, the guanosine triphosphatase elongation factors mtEF-Tu and mtEF-G1, and the Oxa1L translocase.
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Affiliation(s)
- Nirupa Desai
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Hanting Yang
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | | | - Razina Kazi
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Michal Minczuk
- MRC Mitochondrial Biology Unit, University of Cambridge, Hills Road, Cambridge CB2 0XY, UK
| | - V. Ramakrishnan
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK,Corresponding author.
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62
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Application of Cryo-EM for Visualization of Mitoribosomes. Methods Mol Biol 2020. [PMID: 33230775 DOI: 10.1007/978-1-0716-0834-0_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Mitochondrial ribosomes (mitoribosomes) are specialized machineries that carry out the synthesis of a limited number of proteins encoded in the mitochondrial genome, including components of the oxidative phosphorylation pathway. They have incorporated several structural features distinguishing them from bacterial and eukaryotic cytosolic counterparts. Our current understanding of the assembly and functioning of mitoribosomes is limited, and recent developments in cryo-EM provide promising directions for detailed investigation. Here we describe methods to purify mitoribosomes from human embryonic kidney cells for cryo-EM studies.
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63
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Matzov D, Taoka M, Nobe Y, Yamauchi Y, Halfon Y, Asis N, Zimermann E, Rozenberg H, Bashan A, Bhushan S, Isobe T, Gray MW, Yonath A, Shalev-Benami M. Cryo-EM structure of the highly atypical cytoplasmic ribosome of Euglena gracilis. Nucleic Acids Res 2020; 48:11750-11761. [PMID: 33091122 PMCID: PMC7672448 DOI: 10.1093/nar/gkaa893] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 09/21/2020] [Accepted: 10/21/2020] [Indexed: 12/11/2022] Open
Abstract
Ribosomal RNA is the central component of the ribosome, mediating its functional and architectural properties. Here, we report the cryo-EM structure of a highly divergent cytoplasmic ribosome from the single-celled eukaryotic alga Euglena gracilis. The Euglena large ribosomal subunit is distinct in that it contains 14 discrete rRNA fragments that are assembled non-covalently into the canonical ribosome structure. The rRNA is substantially enriched in post-transcriptional modifications that are spread far beyond the catalytic RNA core, contributing to the stabilization of this highly fragmented ribosome species. A unique cluster of five adenosine base methylations is found in an expansion segment adjacent to the protein exit tunnel, such that it is positioned for interaction with the nascent peptide. As well as featuring distinctive rRNA expansion segments, the Euglena ribosome contains four novel ribosomal proteins, localized to the ribosome surface, three of which do not have orthologs in other eukaryotes.
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Affiliation(s)
- Donna Matzov
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Masato Taoka
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minami-osawa 1-1, Hachioji-shi, Tokyo 192-0397, Japan
| | - Yuko Nobe
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minami-osawa 1-1, Hachioji-shi, Tokyo 192-0397, Japan
| | - Yoshio Yamauchi
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minami-osawa 1-1, Hachioji-shi, Tokyo 192-0397, Japan
| | - Yehuda Halfon
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Nofar Asis
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Ella Zimermann
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Haim Rozenberg
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Anat Bashan
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Shashi Bhushan
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Toshiaki Isobe
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minami-osawa 1-1, Hachioji-shi, Tokyo 192-0397, Japan
| | - Michael W Gray
- Department of Biochemistry and Molecular Biology and Centre for Comparative Genomics and Evolutionary Bioinformatics, Dalhousie University, Halifax, Nova Scotia, Canada B3H 1X5
| | - Ada Yonath
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Moran Shalev-Benami
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 7610001, Israel
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64
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Structure of the mature kinetoplastids mitoribosome and insights into its large subunit biogenesis. Proc Natl Acad Sci U S A 2020; 117:29851-29861. [PMID: 33168716 PMCID: PMC7703582 DOI: 10.1073/pnas.2011301117] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Kinetoplastids is a group of flagellated unicellular eukaryotic parasites including human pathogens, such as Trypanosoma cruzi and Leishmania spp., etiologic agents of Chagas disease and leishmaniasis. They are potentially lethal, affecting more than 20 million people worldwide. Therapeutic strategies are extremely limited and highly toxic. The finding of new molecular targets represents one venue for the development of new therapeutic strategies. In this work, we present the structure of the full mitoribosomes from two kinetoplastids, Leishmania tarentolae and T. cruzi, thus far uncharacterized. We also reveal the structure of an large subunit assembly intermediate harboring 16 different factors. In addition to defining a subset of novel kinetoplastid-specific factors, our results shed light on the mitochondrial ribosomal RNA maturation process. Kinetoplastids are unicellular eukaryotic parasites responsible for such human pathologies as Chagas disease, sleeping sickness, and leishmaniasis. They have a single large mitochondrion, essential for the parasite survival. In kinetoplastid mitochondria, most of the molecular machineries and gene expression processes have significantly diverged and specialized, with an extreme example being their mitochondrial ribosomes. These large complexes are in charge of translating the few essential mRNAs encoded by mitochondrial genomes. Structural studies performed in Trypanosoma brucei already highlighted the numerous peculiarities of these mitoribosomes and the maturation of their small subunit. However, several important aspects mainly related to the large subunit (LSU) remain elusive, such as the structure and maturation of its ribosomal RNA. Here we present a cryo-electron microscopy study of the protozoans Leishmania tarentolae and Trypanosoma cruzi mitoribosomes. For both species, we obtained the structure of their mature mitoribosomes, complete rRNA of the LSU, as well as previously unidentified ribosomal proteins. In addition, we introduce the structure of an LSU assembly intermediate in the presence of 16 identified maturation factors. These maturation factors act on both the intersubunit and the solvent sides of the LSU, where they refold and chemically modify the rRNA and prevent early translation before full maturation of the LSU.
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65
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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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66
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Lafleur RPM, Herziger S, Schoenmakers SMC, Keizer ADA, Jahzerah J, Thota BNS, Su L, Bomans PHH, Sommerdijk NAJM, Palmans ARA, Haag R, Friedrich H, Böttcher C, Meijer EW. Supramolecular Double Helices from Small C 3-Symmetrical Molecules Aggregated in Water. J Am Chem Soc 2020; 142:17644-17652. [PMID: 32935541 PMCID: PMC7564094 DOI: 10.1021/jacs.0c08179] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
![]()
Supramolecular fibers
in water, micrometers long and several nanometers
in width, are among the most studied nanostructures for biomedical
applications. These supramolecular polymers are formed through a spontaneous
self-assembly process of small amphiphilic molecules by specific secondary
interactions. Although many compounds do not possess a stereocenter,
recent studies suggest the (co)existence of helical structures, albeit
in racemic form. Here, we disclose a series of supramolecular (co)polymers
based on water-soluble benzene-1,3,5-tricarboxamides (BTAs) that form
double helices, fibers that were long thought to be chains of single
molecules stacked in one dimension (1D). Detailed cryogenic transmission
electron microscopy (cryo-TEM) studies and subsequent three-dimensional-volume
reconstructions unveiled helical repeats, ranging from 15 to 30 nm.
Most remarkable, the pitch can be tuned through the composition of
the copolymers, where two different monomers with the same core but
different peripheries are mixed in various ratios. Like in lipid bilayers,
the hydrophobic shielding in the aggregates of these disc-shaped molecules
is proposed to be best obtained by dimer formation, promoting supramolecular
double helices. It is anticipated that many of the supramolecular
polymers in water will have a thermodynamic stable structure, such
as a double helix, although small structural changes can yield single
stacks as well. Hence, it is essential to perform detailed analyses
prior to sketching a molecular picture of these 1D fibers.
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Affiliation(s)
- René P M Lafleur
- Institute for Complex Molecular Systems, Eindhoven University of Technology, PO Box 513, Eindhoven 5600 MB, The Netherlands
| | - Svenja Herziger
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin 14195, Germany.,Research Center of Electron Microscopy and Core Facility BioSupraMol, Institute of Chemistry and Biochemistry, Freie Universität Berlin, Fabeckstraβe 36a, Berlin 14195, Germany
| | - Sandra M C Schoenmakers
- Institute for Complex Molecular Systems, Eindhoven University of Technology, PO Box 513, Eindhoven 5600 MB, The Netherlands
| | - Arthur D A Keizer
- Center of Multiscale Electron Microscopy, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, PO Box 513, Eindhoven 5600 MB, The Netherlands
| | - Jahaziel Jahzerah
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin 14195, Germany
| | - Bala N S Thota
- Institute for Complex Molecular Systems, Eindhoven University of Technology, PO Box 513, Eindhoven 5600 MB, The Netherlands.,Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin 14195, Germany
| | - Lu Su
- Institute for Complex Molecular Systems, Eindhoven University of Technology, PO Box 513, Eindhoven 5600 MB, The Netherlands
| | - Paul H H Bomans
- Institute for Complex Molecular Systems, Eindhoven University of Technology, PO Box 513, Eindhoven 5600 MB, The Netherlands.,Center of Multiscale Electron Microscopy, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, PO Box 513, Eindhoven 5600 MB, The Netherlands
| | - Nico A J M Sommerdijk
- Institute for Complex Molecular Systems, Eindhoven University of Technology, PO Box 513, Eindhoven 5600 MB, The Netherlands.,Center of Multiscale Electron Microscopy, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, PO Box 513, Eindhoven 5600 MB, The Netherlands
| | - Anja R A Palmans
- Institute for Complex Molecular Systems, Eindhoven University of Technology, PO Box 513, Eindhoven 5600 MB, The Netherlands
| | - Rainer Haag
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin 14195, Germany
| | - Heiner Friedrich
- Institute for Complex Molecular Systems, Eindhoven University of Technology, PO Box 513, Eindhoven 5600 MB, The Netherlands.,Center of Multiscale Electron Microscopy, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, PO Box 513, Eindhoven 5600 MB, The Netherlands
| | - Christoph Böttcher
- Research Center of Electron Microscopy and Core Facility BioSupraMol, Institute of Chemistry and Biochemistry, Freie Universität Berlin, Fabeckstraβe 36a, Berlin 14195, Germany
| | - E W Meijer
- Institute for Complex Molecular Systems, Eindhoven University of Technology, PO Box 513, Eindhoven 5600 MB, The Netherlands
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67
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Wiederstein M, Sippl MJ. TopMatch-web: pairwise matching of large assemblies of protein and nucleic acid chains in 3D. Nucleic Acids Res 2020; 48:W31-W35. [PMID: 32479639 PMCID: PMC7319569 DOI: 10.1093/nar/gkaa366] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 04/20/2020] [Accepted: 05/29/2020] [Indexed: 11/13/2022] Open
Abstract
Frequently, the complete functional units of biological molecules are assemblies of protein and nucleic acid chains. Stunning examples are the complex structures of ribosomes. Here, we present TopMatch-web, a computational tool for the study of the three-dimensional structure, function and evolution of such molecules. The unique feature of TopMatch is its ability to match the protein as well as nucleic acid chains of complete molecular assemblies simultaneously. The resulting structural alignments are visualized instantly using the high-performance molecular viewer NGL. We use the mitochondrial ribosomes of human and yeast as an example to demonstrate the capabilities of TopMatch-web. The service responds immediately, enabling the interactive study of many pairwise alignments of large molecular assemblies in a single session. TopMatch-web is freely accessible at https://topmatch.services.came.sbg.ac.at.
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Affiliation(s)
- Markus Wiederstein
- Paris-Lodron-University of Salzburg, Department of Biosciences, Hellbrunner Str. 34, 5020 Salzburg, Austria
| | - Manfred J Sippl
- Paris-Lodron-University of Salzburg, Department of Biosciences, Hellbrunner Str. 34, 5020 Salzburg, Austria
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68
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Laptev I, Dontsova O, Sergiev P. Epitranscriptomics of Mammalian Mitochondrial Ribosomal RNA. Cells 2020; 9:E2181. [PMID: 32992603 PMCID: PMC7600485 DOI: 10.3390/cells9102181] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 09/20/2020] [Accepted: 09/23/2020] [Indexed: 12/16/2022] Open
Abstract
Modified nucleotides are present in all ribosomal RNA molecules. Mitochondrial ribosomes are unique to have a set of methylated residues that includes universally conserved ones, those that could be found either in bacterial or in archaeal/eukaryotic cytosolic ribosomes and those that are present exclusively in mitochondria. A single pseudouridine within the mt-rRNA is located in the peptidyltransferase center at a position similar to that in bacteria. After recent completion of the list of enzymes responsible for the modification of mammalian mitochondrial rRNA it became possible to summarize an evolutionary history, functional role of mt-rRNA modification enzymes and an interplay of the mt-rRNA modification and mitoribosome assembly process, which is a goal of this review.
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Affiliation(s)
- Ivan Laptev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia; (I.L.); (O.D.)
| | - Olga Dontsova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia; (I.L.); (O.D.)
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Skolkovo, 143028 Moscow Region, Russia
- Department of Chemistry, Lomonosov Moscow State University, 119992 Moscow, Russia
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 117997 Moscow, Russia
| | - Petr Sergiev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia; (I.L.); (O.D.)
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Skolkovo, 143028 Moscow Region, Russia
- Department of Chemistry, Lomonosov Moscow State University, 119992 Moscow, Russia
- Institute of Functional Genomics, Lomonosov Moscow State University, 119992 Moscow, Russia
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69
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Poitevin F, Kushner A, Li X, Dao Duc K. Structural Heterogeneities of the Ribosome: New Frontiers and Opportunities for Cryo-EM. Molecules 2020; 25:E4262. [PMID: 32957592 PMCID: PMC7570653 DOI: 10.3390/molecules25184262] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 09/11/2020] [Accepted: 09/15/2020] [Indexed: 12/18/2022] Open
Abstract
The extent of ribosomal heterogeneity has caught increasing interest over the past few years, as recent studies have highlighted the presence of structural variations of the ribosome. More precisely, the heterogeneity of the ribosome covers multiple scales, including the dynamical aspects of ribosomal motion at the single particle level, specialization at the cellular and subcellular scale, or evolutionary differences across species. Upon solving the ribosome atomic structure at medium to high resolution, cryogenic electron microscopy (cryo-EM) has enabled investigating all these forms of heterogeneity. In this review, we present some recent advances in quantifying ribosome heterogeneity, with a focus on the conformational and evolutionary variations of the ribosome and their functional implications. These efforts highlight the need for new computational methods and comparative tools, to comprehensively model the continuous conformational transition pathways of the ribosome, as well as its evolution. While developing these methods presents some important challenges, it also provides an opportunity to extend our interpretation and usage of cryo-EM data, which would more generally benefit the study of molecular dynamics and evolution of proteins and other complexes.
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Affiliation(s)
- Frédéric Poitevin
- Department of LCLS Data Analytics, Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA;
| | - Artem Kushner
- Department of Mathematics, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; (A.K.); (X.L.)
- Department of Computer Science, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Xinpei Li
- Department of Mathematics, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; (A.K.); (X.L.)
- Department of Computer Science, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Khanh Dao Duc
- Department of Mathematics, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; (A.K.); (X.L.)
- Department of Computer Science, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
- Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
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70
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Singh AP, Salvatori R, Aftab W, Kohler A, Carlström A, Forne I, Imhof A, Ott M. Molecular Connectivity of Mitochondrial Gene Expression and OXPHOS Biogenesis. Mol Cell 2020; 79:1051-1065.e10. [PMID: 32877643 DOI: 10.1016/j.molcel.2020.07.024] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 07/20/2020] [Accepted: 07/21/2020] [Indexed: 01/05/2023]
Abstract
Mitochondria contain their own gene expression systems, including membrane-bound ribosomes dedicated to synthesizing a few hydrophobic subunits of the oxidative phosphorylation (OXPHOS) complexes. We used a proximity-dependent biotinylation technique, BioID, coupled with mass spectrometry to delineate in baker's yeast a comprehensive network of factors involved in biogenesis of mitochondrial encoded proteins. This mitochondrial gene expression network (MiGENet) encompasses proteins involved in transcription, RNA processing, translation, or protein biogenesis. Our analyses indicate the spatial organization of these processes, thereby revealing basic mechanistic principles and the proteins populating strategically important sites. For example, newly synthesized proteins are directly handed over to ribosomal tunnel exit-bound factors that mediate membrane insertion, co-factor acquisition, or their mounting into OXPHOS complexes in a special early assembly hub. Collectively, the data reveal the connectivity of mitochondrial gene expression, reflecting a unique tailoring of the mitochondrial gene expression system.
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Affiliation(s)
- Abeer Prakash Singh
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden; Department of Medical Biochemistry and Cell Biology, University of Gothenburg, 40530 Gothenburg, Sweden
| | - Roger Salvatori
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden; Department of Medical Biochemistry and Cell Biology, University of Gothenburg, 40530 Gothenburg, Sweden
| | - Wasim Aftab
- BioMedical Center, Faculty of Medicine, Ludwig Maximilians University of Munich, 82152 Planegg-Martinsried, Germany; Graduate School for Quantitative Biosciences (QBM), Ludwig Maximilians University of Munich, 81377 Munich, Germany
| | - Andreas Kohler
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden
| | - Andreas Carlström
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden
| | - Ignasi Forne
- BioMedical Center, Faculty of Medicine, Ludwig Maximilians University of Munich, 82152 Planegg-Martinsried, Germany
| | - Axel Imhof
- BioMedical Center, Faculty of Medicine, Ludwig Maximilians University of Munich, 82152 Planegg-Martinsried, Germany
| | - Martin Ott
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden; Department of Medical Biochemistry and Cell Biology, University of Gothenburg, 40530 Gothenburg, Sweden.
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71
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Seshadri SR, Banarjee C, Barros MH, Fontanesi F. The translational activator Sov1 coordinates mitochondrial gene expression with mitoribosome biogenesis. Nucleic Acids Res 2020; 48:6759-6774. [PMID: 32449921 PMCID: PMC7337963 DOI: 10.1093/nar/gkaa424] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 05/06/2020] [Accepted: 05/07/2020] [Indexed: 02/07/2023] Open
Abstract
Mitoribosome biogenesis is an expensive metabolic process that is essential to maintain cellular respiratory capacity and requires the stoichiometric accumulation of rRNAs and proteins encoded in two distinct genomes. In yeast, the ribosomal protein Var1, alias uS3m, is mitochondrion-encoded. uS3m is a protein universally present in all ribosomes, where it forms part of the small subunit (SSU) mRNA entry channel and plays a pivotal role in ribosome loading onto the mRNA. However, despite its critical functional role, very little is known concerning VAR1 gene expression. Here, we demonstrate that the protein Sov1 is an in bona fide VAR1 mRNA translational activator and additionally interacts with newly synthesized Var1 polypeptide. Moreover, we show that Sov1 assists the late steps of mtSSU biogenesis involving the incorporation of Var1, an event necessary for uS14 and mS46 assembly. Notably, we have uncovered a translational regulatory mechanism by which Sov1 fine-tunes Var1 synthesis with its assembly into the mitoribosome.
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Affiliation(s)
- Suhas R Seshadri
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Chitra Banarjee
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Mario H Barros
- Departamento de Microbiologia, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, Sao Paulo 05508-900, Brazil
| | - Flavia Fontanesi
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
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72
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Piątkowski J, Golik P. Yeast pentatricopeptide protein Dmr1 (Ccm1) binds a repetitive AU-rich motif in the small subunit mitochondrial ribosomal RNA. RNA (NEW YORK, N.Y.) 2020; 26:1268-1282. [PMID: 32467310 PMCID: PMC7430664 DOI: 10.1261/rna.074880.120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 05/23/2020] [Indexed: 06/11/2023]
Abstract
PPR proteins are a diverse family of RNA binding factors found in all Eukaryotic lineages. They perform multiple functions in the expression of organellar genes, mostly on the post-transcriptional level. PPR proteins are also significant determinants of evolutionary nucleo-organellar compatibility. Plant PPR proteins recognize their RNA substrates using a simple modular code. No target sequences recognized by animal or yeast PPR proteins were identified prior to the present study, making it impossible to assess whether this plant PPR code is conserved in other organisms. Dmr1p (Ccm1p, Ygr150cp) is a S. cerevisiae PPR protein essential for mitochondrial gene expression and involved in the stability of 15S ribosomal RNA. We demonstrate that in vitro Dmr1p specifically binds a motif composed of multiple AUA repeats occurring twice in the 15S rRNA sequence as the minimal 14 nt (AUA)4AU or longer (AUA)7 variant. Short RNA fragments containing this motif are protected by Dmr1p from exoribonucleolytic activity in vitro. Presence of the identified motif in mtDNA of different yeast species correlates with the compatibility between their Dmr1p orthologs and S. cerevisiae mtDNA. RNA recognition by Dmr1p is likely based on a rudimentary form of a PPR code specifying U at every third position, and depends on other factors, like RNA structure.
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Affiliation(s)
- Jakub Piątkowski
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, 02-106, Poland
| | - Paweł Golik
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, 02-106, Poland
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, 02-106, Poland
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73
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Rudler DL, Hughes LA, Viola HM, Hool LC, Rackham O, Filipovska A. Fidelity and coordination of mitochondrial protein synthesis in health and disease. J Physiol 2020; 599:3449-3462. [PMID: 32710561 DOI: 10.1113/jp280359] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 07/07/2020] [Indexed: 12/12/2022] Open
Abstract
The evolutionary acquisition of mitochondria has given rise to the diversity of eukaryotic life. Mitochondria have retained their ancestral α-proteobacterial traits through the maintenance of double membranes and their own circular genome. Their genome varies in size from very large in plants to the smallest in animals and their parasites. The mitochondrial genome encodes essential genes for protein synthesis and has to coordinate its expression with the nuclear genome from which it sources most of the proteins required for mitochondrial biogenesis and function. The mitochondrial protein synthesis machinery is unique because it is encoded by both the nuclear and mitochondrial genomes thereby requiring tight regulation to produce the respiratory complexes that drive oxidative phosphorylation for energy production. The fidelity and coordination of mitochondrial protein synthesis are essential for ATP production. Here we compare and contrast the mitochondrial translation mechanisms in mammals and fungi to bacteria and reveal that their diverse regulation can have unusual impacts on the health and disease of these organisms. We highlight that in mammals the rate of protein synthesis is more important than the fidelity of translation, enabling coordinated biogenesis of the mitochondrial respiratory chain with respiratory chain proteins synthesised by cytoplasmic ribosomes. Changes in mitochondrial protein fidelity can trigger the activation of the diverse cellular signalling networks in fungi and mammals to combat dysfunction in energy conservation. The physiological consequences of altered fidelity of protein synthesis can range from liver regeneration to the onset and development of cardiomyopathy.
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Affiliation(s)
- Danielle L Rudler
- Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia, 6009, Australia.,ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, Nedlands, Western Australia, 6009, Australia.,Centre for Medical Research, The University of Western Australia, QEII Medical Centre, Nedlands, Western Australia, 6009, Australia
| | - Laetitia A Hughes
- Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia, 6009, Australia.,ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, Nedlands, Western Australia, 6009, Australia.,Centre for Medical Research, The University of Western Australia, QEII Medical Centre, Nedlands, Western Australia, 6009, Australia
| | - Helena M Viola
- School of Human Sciences, University of Western Australia, 35 Stirling Highway, Nedlands, Western Australia, 6009, Australia
| | - Livia C Hool
- School of Human Sciences, University of Western Australia, 35 Stirling Highway, Nedlands, Western Australia, 6009, Australia.,Victor Chang Cardiac Research Institute, Sydney, NSW, Australia
| | - Oliver Rackham
- Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia, 6009, Australia.,ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, Nedlands, Western Australia, 6009, Australia.,School of Pharmacy and Biomedical Sciences, Curtin University, Bentley, Western Australia, 6102, Australia.,Curtin Health Innovation Research Institute, Curtin University, Bentley, Western Australia, 6102, Australia.,Telethon Kids Institute, Northern Entrance, Perth Children's Hospital, 15 Hospital Avenue, Nedlands, Western Australia, Australia
| | - Aleksandra Filipovska
- Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia, 6009, Australia.,ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, Nedlands, Western Australia, 6009, Australia.,Centre for Medical Research, The University of Western Australia, QEII Medical Centre, Nedlands, Western Australia, 6009, Australia.,Telethon Kids Institute, Northern Entrance, Perth Children's Hospital, 15 Hospital Avenue, Nedlands, Western Australia, Australia.,School of Molecular Sciences, University of Western Australia, Crawley, Western Australia, 6009, Australia
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74
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Koripella RK, Sharma MR, Bhargava K, Datta PP, Kaushal PS, Keshavan P, Spremulli LL, Banavali NK, Agrawal RK. Structures of the human mitochondrial ribosome bound to EF-G1 reveal distinct features of mitochondrial translation elongation. Nat Commun 2020; 11:3830. [PMID: 32737313 PMCID: PMC7395135 DOI: 10.1038/s41467-020-17715-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 07/15/2020] [Indexed: 02/06/2023] Open
Abstract
The mammalian mitochondrial ribosome (mitoribosome) and its associated translational factors have evolved to accommodate greater participation of proteins in mitochondrial translation. Here we present the 2.68-3.96 Å cryo-EM structures of the human 55S mitoribosome in complex with the human mitochondrial elongation factor G1 (EF-G1mt) in three distinct conformational states, including an intermediate state and a post-translocational state. These structures reveal the role of several mitochondria-specific (mito-specific) mitoribosomal proteins (MRPs) and a mito-specific segment of EF-G1mt in mitochondrial tRNA (tRNAmt) translocation. In particular, the mito-specific C-terminal extension in EF-G1mt is directly involved in translocation of the acceptor arm of the A-site tRNAmt. In addition to the ratchet-like and independent head-swiveling motions exhibited by the small mitoribosomal subunit, we discover significant conformational changes in MRP mL45 at the nascent polypeptide-exit site within the large mitoribosomal subunit that could be critical for tethering of the elongating mitoribosome onto the inner-mitochondrial membrane.
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MESH Headings
- Amino Acid Sequence
- Binding Sites
- Cryoelectron Microscopy
- HEK293 Cells
- Humans
- Mitochondria/metabolism
- Mitochondria/ultrastructure
- Mitochondrial Membranes/metabolism
- Mitochondrial Membranes/ultrastructure
- Mitochondrial Proteins/chemistry
- Mitochondrial Proteins/genetics
- Mitochondrial Proteins/metabolism
- Models, Molecular
- Nucleic Acid Conformation
- Peptide Chain Elongation, Translational
- Peptide Elongation Factor G/chemistry
- Peptide Elongation Factor G/genetics
- Peptide Elongation Factor G/metabolism
- Protein Binding
- Protein Conformation, alpha-Helical
- Protein Conformation, beta-Strand
- Protein Interaction Domains and Motifs
- RNA, Mitochondrial/chemistry
- RNA, Mitochondrial/genetics
- RNA, Mitochondrial/metabolism
- RNA, Transfer/chemistry
- RNA, Transfer/genetics
- RNA, Transfer/metabolism
- Recombinant Proteins/chemistry
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Ribosomal Proteins/chemistry
- Ribosomal Proteins/genetics
- Ribosomal Proteins/metabolism
- Ribosomes/metabolism
- Ribosomes/ultrastructure
- Sequence Alignment
- Sequence Homology, Amino Acid
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Affiliation(s)
- Ravi Kiran Koripella
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY, 12201, USA
| | - Manjuli R Sharma
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY, 12201, USA
| | - Kalpana Bhargava
- Department of Chemistry, Campus Box 3290, University of North Carolina, Chapel Hill, NC, USA
- High Energy Material Research Lab, Defense Research and Development Organization, Sutarwadi, Pashan, Pune, Maharashtra, 411021, India
| | - Partha P Datta
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY, 12201, USA
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, 741246, India
| | - Prem S Kaushal
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY, 12201, USA
- Regional Centre for Biotechnology, 3rd Milestone, Faridabad-Gurgaon Expressway, PO Box # 3, Faridabad, Haryana, 121001, India
| | - Pooja Keshavan
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY, 12201, USA
| | - Linda L Spremulli
- Department of Chemistry, Campus Box 3290, University of North Carolina, Chapel Hill, NC, USA
| | - Nilesh K Banavali
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY, 12201, USA
- Department of Biomedical Sciences, University at Albany, SUNY, Albany, NY, 12201-0509, USA
| | - Rajendra K Agrawal
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY, 12201, USA.
- Department of Biomedical Sciences, University at Albany, SUNY, Albany, NY, 12201-0509, USA.
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75
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Lu XJ. DSSR-enabled innovative schematics of 3D nucleic acid structures with PyMOL. Nucleic Acids Res 2020; 48:e74. [PMID: 32442277 PMCID: PMC7367123 DOI: 10.1093/nar/gkaa426] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 04/26/2020] [Accepted: 05/07/2020] [Indexed: 12/11/2022] Open
Abstract
Sophisticated analysis and simplified visualization are crucial for understanding complicated structures of biomacromolecules. DSSR (Dissecting the Spatial Structure of RNA) is an integrated computational tool that has streamlined the analysis and annotation of 3D nucleic acid structures. The program creates schematic block representations in diverse styles that can be seamlessly integrated into PyMOL and complement its other popular visualization options. In addition to portraying individual base blocks, DSSR can draw Watson-Crick pairs as long blocks and highlight the minor-groove edges. Notably, DSSR can dramatically simplify the depiction of G-quadruplexes by automatically detecting G-tetrads and treating them as large square blocks. The DSSR-enabled innovative schematics with PyMOL are aesthetically pleasing and highly informative: the base identity, pairing geometry, stacking interactions, double-helical stems, and G-quadruplexes are immediately obvious. These features can be accessed via four interfaces: the command-line interface, the DSSR plugin for PyMOL, the web application, and the web application programming interface. The supplemental PDF serves as a practical guide, with complete and reproducible examples. Thus, even beginners or occasional users can get started quickly, especially via the web application at http://skmatic.x3dna.org.
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Affiliation(s)
- Xiang-Jun Lu
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
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76
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Bertgen L, Mühlhaus T, Herrmann JM. Clingy genes: Why were genes for ribosomal proteins retained in many mitochondrial genomes? BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148275. [PMID: 32712152 DOI: 10.1016/j.bbabio.2020.148275] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 07/14/2020] [Accepted: 07/19/2020] [Indexed: 11/18/2022]
Abstract
Why mitochondria still retain their own genome is a puzzle given the enormous effort to maintain a mitochondrial translation machinery. Most mitochondrially encoded proteins are membrane-embedded subunits of the respiratory chain. Their hydrophobicity presumably impedes their import into mitochondria. However, many mitochondrial genomes also encode protein subunits of the mitochondrial ribosome. These proteins lack transmembrane domains and hydrophobicity cannot explain why their genes remained in mitochondria. In this review, we provide an overview about mitochondrially encoded subunits of mitochondrial ribosomes of fungi, plants and protists. Moreover, we discuss and evaluate different hypotheses which were put forward to explain why (ribosomal) proteins remained mitochondrially encoded. It seems likely that the synthesis of ribosomal proteins in the mitochondrial matrix is used to regulate the assembly of the mitochondrial ribosome within mitochondria and to avoid problems that mitochondrial proteins might pose for cytosolic proteostasis and for the assembly of cytosolic ribosomes.
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Affiliation(s)
- Lea Bertgen
- Cell Biology, University of Kaiserslautern, Erwin-Schrödinger-Straße 13, 67663 Kaiserslautern, Germany
| | - Timo Mühlhaus
- Computational Systems Biology, University of Kaiserslautern, Erwin-Schrödinger-Straße 23, 67663 Kaiserslautern, Germany
| | - Johannes M Herrmann
- Cell Biology, University of Kaiserslautern, Erwin-Schrödinger-Straße 13, 67663 Kaiserslautern, Germany.
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77
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Jaskolowski M, Ramrath DJF, Bieri P, Niemann M, Mattei S, Calderaro S, Leibundgut M, Horn EK, Boehringer D, Schneider A, Ban N. Structural Insights into the Mechanism of Mitoribosomal Large Subunit Biogenesis. Mol Cell 2020; 79:629-644.e4. [PMID: 32679035 DOI: 10.1016/j.molcel.2020.06.030] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 05/04/2020] [Accepted: 06/11/2020] [Indexed: 12/19/2022]
Abstract
In contrast to the bacterial translation machinery, mitoribosomes and mitochondrial translation factors are highly divergent in terms of composition and architecture. There is increasing evidence that the biogenesis of mitoribosomes is an intricate pathway, involving many assembly factors. To better understand this process, we investigated native assembly intermediates of the mitoribosomal large subunit from the human parasite Trypanosoma brucei using cryo-electron microscopy. We identify 28 assembly factors, 6 of which are homologous to bacterial and eukaryotic ribosome assembly factors. They interact with the partially folded rRNA by specifically recognizing functionally important regions such as the peptidyltransferase center. The architectural and compositional comparison of the assembly intermediates indicates a stepwise modular assembly process, during which the rRNA folds toward its mature state. During the process, several conserved GTPases and a helicase form highly intertwined interaction networks that stabilize distinct assembly intermediates. The presented structures provide general insights into mitoribosomal maturation.
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Affiliation(s)
| | | | - Philipp Bieri
- Department of Biology, ETH Zurich, Zurich 8093, Switzerland
| | - Moritz Niemann
- Department of Chemistry and Biochemistry, University of Bern, Bern 3012, Switzerland
| | - Simone Mattei
- Department of Biology, ETH Zurich, Zurich 8093, Switzerland
| | - Salvatore Calderaro
- Department of Chemistry and Biochemistry, University of Bern, Bern 3012, Switzerland
| | | | - Elke K Horn
- Department of Chemistry and Biochemistry, University of Bern, Bern 3012, Switzerland
| | | | - André Schneider
- Department of Chemistry and Biochemistry, University of Bern, Bern 3012, Switzerland.
| | - Nenad Ban
- Department of Biology, ETH Zurich, Zurich 8093, Switzerland.
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78
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Kostinski S, Reuveni S. Ribosome Composition Maximizes Cellular Growth Rates in E. coli. PHYSICAL REVIEW LETTERS 2020; 125:028103. [PMID: 32701325 DOI: 10.1103/physrevlett.125.028103] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 05/14/2020] [Indexed: 06/11/2023]
Abstract
Bacterial ribosomes are composed of one-third protein and two-thirds RNA by mass. The predominance of RNA is often attributed to a primordial RNA world, but why exactly two-thirds remains a long-standing mystery. Here we present a quantitative analysis, based on the kinetics of ribosome self-replication, demonstrating that the 1∶2 protein-to-RNA mass ratio uniquely maximizes cellular growth rates in E. coli. A previously unrecognized growth law, and an invariant of bacterial growth, also follow from our analysis. The growth law reveals that the ratio between the number of ribosomes and the number of polymerases making ribosomal RNA is proportional to the cellular doubling time. The invariant is conserved across growth conditions and specifies how key microscopic parameters in the cell, such as transcription and translation rates, are coupled to cellular physiology. Quantitative predictions from the growth law and invariant are shown to be in excellent agreement with E. coli data despite having no fitting parameters. Our analysis can be readily extended to other bacteria once data become available.
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Affiliation(s)
- Sarah Kostinski
- School of Chemistry, Center for the Physics & Chemistry of Living Systems, Tel Aviv University, 6997801 Tel Aviv, Israel
| | - Shlomi Reuveni
- School of Chemistry, Center for the Physics & Chemistry of Living Systems, Tel Aviv University, 6997801 Tel Aviv, Israel
- Sackler Center for Computational Molecular & Materials Science, Ratner Institute for Single Molecule Chemistry, Tel Aviv University, 6997801 Tel Aviv, Israel
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79
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Sun C, Gonzalez B, Vago FS, Jiang W. High resolution single particle Cryo-EM refinement using JSPR. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2020; 160:37-42. [PMID: 32622834 DOI: 10.1016/j.pbiomolbio.2020.05.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 05/06/2020] [Accepted: 05/09/2020] [Indexed: 11/30/2022]
Abstract
JSPR is a single particle cryo-EM image processing and 3D reconstruction software developed in the Jiang laboratory at Purdue University. It began as a few refinement scripts for symmetric and asymmetric reconstructions of icosahedral viruses, but has grown into a comprehensive suite of tools for building ab initio reconstructions, high resolution refinements of viruses, protein complexes of arbitrary symmetries including helical tubes/filaments, and image file handling utilities. In this review, we will present examples achieved using JSPR and demonstrate recently implemented features of JSPR such as multi-aberration "alignments" and automatic optimization of masking for the assessment of map resolution using "true" FSC.
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Affiliation(s)
- Chen Sun
- Department of Biological Sciences, Markey Center for Structural Biology, Purdue University, West Lafayette, IN, 47906, USA
| | - Brenda Gonzalez
- Department of Biological Sciences, Markey Center for Structural Biology, Purdue University, West Lafayette, IN, 47906, USA
| | - Frank S Vago
- Department of Biological Sciences, Markey Center for Structural Biology, Purdue University, West Lafayette, IN, 47906, USA
| | - Wen Jiang
- Department of Biological Sciences, Markey Center for Structural Biology, Purdue University, West Lafayette, IN, 47906, USA.
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80
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Černý J, Božíková P, Svoboda J, Schneider B. A unified dinucleotide alphabet describing both RNA and DNA structures. Nucleic Acids Res 2020; 48:6367-6381. [PMID: 32406923 PMCID: PMC7293047 DOI: 10.1093/nar/gkaa383] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 04/11/2020] [Accepted: 04/30/2020] [Indexed: 12/13/2022] Open
Abstract
By analyzing almost 120 000 dinucleotides in over 2000 nonredundant nucleic acid crystal structures, we define 96+1 diNucleotide Conformers, NtCs, which describe the geometry of RNA and DNA dinucleotides. NtC classes are grouped into 15 codes of the structural alphabet CANA (Conformational Alphabet of Nucleic Acids) to simplify symbolic annotation of the prominent structural features of NAs and their intuitive graphical display. The search for nontrivial patterns of NtCs resulted in the identification of several types of RNA loops, some of them observed for the first time. Over 30% of the nearly six million dinucleotides in the PDB cannot be assigned to any NtC class but we demonstrate that up to a half of them can be re-refined with the help of proper refinement targets. A statistical analysis of the preferences of NtCs and CANA codes for the 16 dinucleotide sequences showed that neither the NtC class AA00, which forms the scaffold of RNA structures, nor BB00, the DNA most populated class, are sequence neutral but their distributions are significantly biased. The reported automated assignment of the NtC classes and CANA codes available at dnatco.org provides a powerful tool for unbiased analysis of nucleic acid structures by structural and molecular biologists.
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Affiliation(s)
- Jiří Černý
- Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, CZ-252 50 Vestec, Prague-West, Czech Republic
| | - Paulína Božíková
- Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, CZ-252 50 Vestec, Prague-West, Czech Republic
| | - Jakub Svoboda
- Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, CZ-252 50 Vestec, Prague-West, Czech Republic
| | - Bohdan Schneider
- Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, CZ-252 50 Vestec, Prague-West, Czech Republic
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81
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Tobiasson V, Amunts A. Ciliate mitoribosome illuminates evolutionary steps of mitochondrial translation. eLife 2020; 9:59264. [PMID: 32553108 PMCID: PMC7326499 DOI: 10.7554/elife.59264] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 06/08/2020] [Indexed: 12/23/2022] Open
Abstract
To understand the steps involved in the evolution of translation, we used Tetrahymena thermophila, a ciliate with high coding capacity of the mitochondrial genome, as the model organism and characterized its mitochondrial ribosome (mitoribosome) using cryo-EM. The structure of the mitoribosome reveals an assembly of 94-ribosomal proteins and four-rRNAs with an additional protein mass of ~700 kDa on the small subunit, while the large subunit lacks 5S rRNA. The structure also shows that the small subunit head is constrained, tRNA binding sites are formed by mitochondria-specific protein elements, conserved protein bS1 is excluded, and bacterial RNA polymerase binding site is blocked. We provide evidence for anintrinsic protein targeting system through visualization of mitochondria-specific mL105 by the exit tunnel that would facilitate the recruitment of a nascent polypeptide. Functional protein uS3m is encoded by three complementary genes from the nucleus and mitochondrion, establishing a link between genetic drift and mitochondrial translation. Finally, we reannotated nine open reading frames in the mitochondrial genome that code for mitoribosomal proteins.
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Affiliation(s)
- Victor Tobiasson
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden.,Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Solna, Sweden
| | - Alexey Amunts
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden.,Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Solna, Sweden
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82
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Ribosome engineering reveals the importance of 5S rRNA autonomy for ribosome assembly. Nat Commun 2020; 11:2900. [PMID: 32518240 PMCID: PMC7283268 DOI: 10.1038/s41467-020-16694-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 05/11/2020] [Indexed: 12/11/2022] Open
Abstract
5S rRNA is an indispensable component of cytoplasmic ribosomes in all species. The functions of 5S rRNA and the reasons for its evolutionary preservation as an independent molecule remain unclear. Here we used ribosome engineering to investigate whether 5S rRNA autonomy is critical for ribosome function and cell survival. By linking circularly permutated 5S rRNA with 23S rRNA we generated a bacterial strain devoid of free 5S rRNA. Viability of the engineered cells demonstrates that autonomous 5S rRNA is dispensable for cell growth under standard conditions and is unlikely to have essential functions outside the ribosome. The fully assembled ribosomes carrying 23S-5S rRNA are highly active in translation. However, the engineered cells accumulate aberrant 50S subunits unable to form stable 70S ribosomes. Cryo-EM analysis revealed a malformed peptidyl transferase center in the misassembled 50S subunits. Our results argue that the autonomy of 5S rRNA is preserved due to its role in ribosome biogenesis.
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83
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Ling L, Mulaka M, Munro J, Dass S, Mather MW, Riscoe MK, Llinás M, Zhou J, Ke H. Genetic ablation of the mitoribosome in the malaria parasite Plasmodium falciparum sensitizes it to antimalarials that target mitochondrial functions. J Biol Chem 2020; 295:7235-7248. [PMID: 32273345 PMCID: PMC7247301 DOI: 10.1074/jbc.ra120.012646] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 04/04/2020] [Indexed: 02/05/2023] Open
Abstract
The mitochondrion of malaria parasites contains several clinically validated drug targets. Within Plasmodium spp., the causative agents of malaria, the mitochondrial DNA (mtDNA) is only 6 kb long, being the smallest mitochondrial genome among all eukaryotes. The mtDNA encodes only three proteins of the mitochondrial electron transport chain and ∼27 small, fragmented rRNA genes having lengths of 22-195 nucleotides. The rRNA fragments are thought to form a mitochondrial ribosome (mitoribosome), together with ribosomal proteins imported from the cytosol. The mitoribosome of Plasmodium falciparum is essential for maintenance of the mitochondrial membrane potential and parasite viability. However, the role of the mitoribosome in sustaining the metabolic status of the parasite mitochondrion remains unclear. The small ribosomal subunit in P. falciparum has 14 annotated mitoribosomal proteins, and employing a CRISPR/Cas9-based conditional knockdown tool, here we verified the location and tested the essentiality of three candidates (PfmtRPS12, PfmtRPS17, and PfmtRPS18). Using immuno-EM, we provide evidence that the P. falciparum mitoribosome is closely associated with the mitochondrial inner membrane. Upon knockdown of the mitoribosome, parasites became hypersensitive to inhibitors targeting mitochondrial Complex III (bc1), dihydroorotate dehydrogenase (DHOD), and the F1F0-ATP synthase complex. Furthermore, the mitoribosome knockdown blocked the pyrimidine biosynthesis pathway and reduced the cellular pool of pyrimidine nucleotides. These results suggest that disruption of the P. falciparum mitoribosome compromises the metabolic capacity of the mitochondrion, rendering the parasite hypersensitive to a panel of inhibitors that target mitochondrial functions.
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Affiliation(s)
- Liqin Ling
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129; Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Maruthi Mulaka
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129
| | - Justin Munro
- Department of Chemistry and Huck Center for Malaria Research, Pennsylvania State University, University Park, Pennsylvania 16802
| | - Swati Dass
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129
| | - Michael W Mather
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129
| | - Michael K Riscoe
- Portland Veterans Affairs Medical Center, Portland, Oregon 97239
| | - Manuel Llinás
- Department of Chemistry and Huck Center for Malaria Research, Pennsylvania State University, University Park, Pennsylvania 16802; Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16802
| | - Jing Zhou
- Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu 610041, China.
| | - Hangjun Ke
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129.
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84
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Yeast Mitochondrial Translation Initiation Factor 3 Interacts with Pet111p to Promote COX2 mRNA Translation. Int J Mol Sci 2020; 21:ijms21103414. [PMID: 32408541 PMCID: PMC7279496 DOI: 10.3390/ijms21103414] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 05/08/2020] [Accepted: 05/11/2020] [Indexed: 11/17/2022] Open
Abstract
Mitochondrial genomes code for several core components of respiratory chain complexes. Thus, mitochondrial translation is of great importance for the organelle as well as for the whole cell. In yeast, mitochondrial translation initiation factor 3, Aim23p, is not essential for the organellar protein synthesis; however, its absence leads to a significant quantitative imbalance of the mitochondrial translation products. This fact points to a possible specific action of Aim23p on the biosynthesis of some mitochondrial protein species. In this work, we examined such peculiar effects of Aim23p in relation to yeast mitochondrial COX2 mRNA translation. We show that Aim23p is indispensable to this process. According to our data, this is mediated by Aimp23p interaction with the known specific factor of the COX2 mRNA translation, Pet111p. If there is no Aim23p in the yeast cells, an increased amount of Pet111p ensures proper COX2 mRNA translation. Our results demonstrate the additional non-canonical function of initiation factor 3 in yeast mitochondrial translation.
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85
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Bowman JC, Petrov AS, Frenkel-Pinter M, Penev PI, Williams LD. Root of the Tree: The Significance, Evolution, and Origins of the Ribosome. Chem Rev 2020; 120:4848-4878. [PMID: 32374986 DOI: 10.1021/acs.chemrev.9b00742] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The ribosome is an ancient molecular fossil that provides a telescope to the origins of life. Made from RNA and protein, the ribosome translates mRNA to coded protein in all living systems. Universality, economy, centrality and antiquity are ingrained in translation. The translation machinery dominates the set of genes that are shared as orthologues across the tree of life. The lineage of the translation system defines the universal tree of life. The function of a ribosome is to build ribosomes; to accomplish this task, ribosomes make ribosomal proteins, polymerases, enzymes, and signaling proteins. Every coded protein ever produced by life on Earth has passed through the exit tunnel, which is the birth canal of biology. During the root phase of the tree of life, before the last common ancestor of life (LUCA), exit tunnel evolution is dominant and unremitting. Protein folding coevolved with evolution of the exit tunnel. The ribosome shows that protein folding initiated with intrinsic disorder, supported through a short, primitive exit tunnel. Folding progressed to thermodynamically stable β-structures and then to kinetically trapped α-structures. The latter were enabled by a long, mature exit tunnel that partially offset the general thermodynamic tendency of all polypeptides to form β-sheets. RNA chaperoned the evolution of protein folding from the very beginning. The universal common core of the ribosome, with a mass of nearly 2 million Daltons, was finalized by LUCA. The ribosome entered stasis after LUCA and remained in that state for billions of years. Bacterial ribosomes never left stasis. Archaeal ribosomes have remained near stasis, except for the superphylum Asgard, which has accreted rRNA post LUCA. Eukaryotic ribosomes in some lineages appear to be logarithmically accreting rRNA over the last billion years. Ribosomal expansion in Asgard and Eukarya has been incremental and iterative, without substantial remodeling of pre-existing basal structures. The ribosome preserves information on its history.
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Affiliation(s)
- Jessica C Bowman
- Center for the Origins of Life, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Anton S Petrov
- Center for the Origins of Life, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Moran Frenkel-Pinter
- Center for the Origins of Life, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Petar I Penev
- Center for the Origins of Life, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Loren Dean Williams
- Center for the Origins of Life, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
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86
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Waltz F, Corre N, Hashem Y, Giegé P. Specificities of the plant mitochondrial translation apparatus. Mitochondrion 2020; 53:30-37. [PMID: 32334144 DOI: 10.1016/j.mito.2020.04.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 04/14/2020] [Accepted: 04/21/2020] [Indexed: 12/16/2022]
Abstract
Mitochondria are endosymbiotic organelles responsible for energy production in most eukaryotic cells. They host a genome and a fully functional gene expression machinery. In plants this machinery involves hundreds of pentatricopeptide repeat (PPR) proteins. Translation, the final step of mitochondrial gene expression is performed by mitochondrial ribosomes (mitoribosomes). The nature of these molecular machines remained elusive for a very long time. Because of their bacterial origin, it was expected that mitoribosomes would closely resemble bacterial ribosomes. However, recent advances in cryo-electron microscopy have revealed the extraordinary diversity of mitoribosome structure and composition. The plant mitoribosome was characterized for Arabidopsis. In plants, in contrast to other species such as mammals and kinetoplastids where rRNA has been largely reduced, the mitoribosome could be described as a protein/RNA-augmented bacterial ribosome. It has an oversized small subunit formed by expanded ribosomal RNAs and additional protein components when compared to bacterial ribosomes. The same holds true for the large subunit. The small subunit is characterized by a new elongated domain on the head. Among its additional proteins, several PPR proteins are core mitoribosome proteins. They mainly act at the structural level to stabilize and maintain the plant-specific ribosomal RNA expansions but could also be involved in translation initiation. Recent advances in plant mitoribosome composition and structure, its specialization for membrane protein synthesis, translation initiation, the regulation and dynamics of mitochondrial translation are reviewed here and put in perspective with the diversity of mitochondrial translation processes in the green lineage and in the wider context of eukaryote evolution.
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Affiliation(s)
- Florent Waltz
- Institut Européen de Chimie et Biologie, U1212 Inserm, Université de Bordeaux, 2 rue R. Escarpit, F 33600 Pessac, France
| | - Nicolas Corre
- Institut de biologie de moléculaire des plantes, CNRS, Université de Strasbourg, 12 rue du général Zimmer, F 67084 Strasbourg, France
| | - Yaser Hashem
- Institut Européen de Chimie et Biologie, U1212 Inserm, Université de Bordeaux, 2 rue R. Escarpit, F 33600 Pessac, France
| | - Philippe Giegé
- Institut de biologie de moléculaire des plantes, CNRS, Université de Strasbourg, 12 rue du général Zimmer, F 67084 Strasbourg, France.
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87
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Waltz F, Soufari H, Bochler A, Giegé P, Hashem Y. Cryo-EM structure of the RNA-rich plant mitochondrial ribosome. NATURE PLANTS 2020; 6:377-383. [PMID: 32251374 DOI: 10.1038/s41477-020-0631-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 03/02/2020] [Indexed: 05/25/2023]
Abstract
The vast majority of eukaryotic cells contain mitochondria, essential powerhouses and metabolic hubs1. These organelles have a bacterial origin and were acquired during an early endosymbiosis event2. Mitochondria possess specialized gene expression systems composed of various molecular machines, including the mitochondrial ribosomes (mitoribosomes). Mitoribosomes are in charge of translating the few essential mRNAs still encoded by mitochondrial genomes3. While chloroplast ribosomes strongly resemble those of bacteria4,5, mitoribosomes have diverged significantly during evolution and present strikingly different structures across eukaryotic species6-10. In contrast to animals and trypanosomatids, plant mitoribosomes have unusually expanded ribosomal RNAs and have conserved the short 5S rRNA, which is usually missing in mitoribosomes11. We have previously characterized the composition of the plant mitoribosome6, revealing a dozen plant-specific proteins in addition to the common conserved mitoribosomal proteins. In spite of the tremendous recent advances in the field, plant mitoribosomes remained elusive to high-resolution structural investigations and the plant-specific ribosomal features of unknown structures. Here, we present a cryo-electron microscopy study of the plant 78S mitoribosome from cauliflower at near-atomic resolution. We show that most of the plant-specific ribosomal proteins are pentatricopeptide repeat proteins (PPRs) that deeply interact with the plant-specific rRNA expansion segments. These additional rRNA segments and proteins reshape the overall structure of the plant mitochondrial ribosome, and we discuss their involvement in the membrane association and mRNA recruitment prior to translation initiation. Finally, our structure unveils an rRNA-constructive phase of mitoribosome evolution across eukaryotes.
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Affiliation(s)
- Florent Waltz
- Institut Européen de Chimie et Biologie, U1212 Inserm, Université de Bordeaux, Pessac, France
| | - Heddy Soufari
- Institut Européen de Chimie et Biologie, U1212 Inserm, Université de Bordeaux, Pessac, France
| | - Anthony Bochler
- Institut Européen de Chimie et Biologie, U1212 Inserm, Université de Bordeaux, Pessac, France
| | - Philippe Giegé
- Institut de biologie de moléculaire des plantes, UPR 2357 du CNRS, Université de Strasbourg, Strasbourg, France.
| | - Yaser Hashem
- Institut Européen de Chimie et Biologie, U1212 Inserm, Université de Bordeaux, Pessac, France.
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88
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Gray MW, Burger G, Derelle R, Klimeš V, Leger MM, Sarrasin M, Vlček Č, Roger AJ, Eliáš M, Lang BF. The draft nuclear genome sequence and predicted mitochondrial proteome of Andalucia godoyi, a protist with the most gene-rich and bacteria-like mitochondrial genome. BMC Biol 2020; 18:22. [PMID: 32122349 PMCID: PMC7050145 DOI: 10.1186/s12915-020-0741-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 01/21/2020] [Indexed: 01/02/2023] Open
Abstract
Background Comparative analyses have indicated that the mitochondrion of the last eukaryotic common ancestor likely possessed all the key core structures and functions that are widely conserved throughout the domain Eucarya. To date, such studies have largely focused on animals, fungi, and land plants (primarily multicellular eukaryotes); relatively few mitochondrial proteomes from protists (primarily unicellular eukaryotic microbes) have been examined. To gauge the full extent of mitochondrial structural and functional complexity and to identify potential evolutionary trends in mitochondrial proteomes, more comprehensive explorations of phylogenetically diverse mitochondrial proteomes are required. In this regard, a key group is the jakobids, a clade of protists belonging to the eukaryotic supergroup Discoba, distinguished by having the most gene-rich and most bacteria-like mitochondrial genomes discovered to date. Results In this study, we assembled the draft nuclear genome sequence for the jakobid Andalucia godoyi and used a comprehensive in silico approach to infer the nucleus-encoded portion of the mitochondrial proteome of this protist, identifying 864 candidate mitochondrial proteins. The A. godoyi mitochondrial proteome has a complexity that parallels that of other eukaryotes, while exhibiting an unusually large number of ancestral features that have been lost particularly in opisthokont (animal and fungal) mitochondria. Notably, we find no evidence that the A. godoyi nuclear genome has or had a gene encoding a single-subunit, T3/T7 bacteriophage-like RNA polymerase, which functions as the mitochondrial transcriptase in all eukaryotes except the jakobids. Conclusions As genome and mitochondrial proteome data have become more widely available, a strikingly punctuate phylogenetic distribution of different mitochondrial components has been revealed, emphasizing that the pathways of mitochondrial proteome evolution are likely complex and lineage-specific. Unraveling this complexity will require comprehensive comparative analyses of mitochondrial proteomes from a phylogenetically broad range of eukaryotes, especially protists. The systematic in silico approach described here offers a valuable adjunct to direct proteomic analysis (e.g., via mass spectrometry), particularly in cases where the latter approach is constrained by sample limitation or other practical considerations.
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Affiliation(s)
- Michael W Gray
- Department of Biochemistry and Molecular Biology and Centre for Comparative Genomics and Evolutionary Bioinformatics, Sir Charles Tupper Medical Building, Dalhousie University, 5850 College Street, Halifax, Nova Scotia, B3H 4R2, Canada.
| | - Gertraud Burger
- Département de Biochimie and Robert-Cedergren Center for Bioinformatics and Genomics, Université de Montréal, Montréal, QC, Canada
| | - Romain Derelle
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Vladimír Klimeš
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Michelle M Leger
- Department of Biochemistry and Molecular Biology and Centre for Comparative Genomics and Evolutionary Bioinformatics, Sir Charles Tupper Medical Building, Dalhousie University, 5850 College Street, Halifax, Nova Scotia, B3H 4R2, Canada.,Institute of Evolutionary Biology (CSIC-UPF), Barcelona, Spain
| | - Matt Sarrasin
- Département de Biochimie and Robert-Cedergren Center for Bioinformatics and Genomics, Université de Montréal, Montréal, QC, Canada
| | - Čestmír Vlček
- Current address: Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Andrew J Roger
- Department of Biochemistry and Molecular Biology and Centre for Comparative Genomics and Evolutionary Bioinformatics, Sir Charles Tupper Medical Building, Dalhousie University, 5850 College Street, Halifax, Nova Scotia, B3H 4R2, Canada
| | - Marek Eliáš
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - B Franz Lang
- Département de Biochimie and Robert-Cedergren Center for Bioinformatics and Genomics, Université de Montréal, Montréal, QC, Canada
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89
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Salvatori R, Kehrein K, Singh AP, Aftab W, Möller-Hergt BV, Forne I, Imhof A, Ott M. Molecular Wiring of a Mitochondrial Translational Feedback Loop. Mol Cell 2020; 77:887-900.e5. [DOI: 10.1016/j.molcel.2019.11.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 09/03/2019] [Accepted: 11/25/2019] [Indexed: 11/16/2022]
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90
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Integrative Structural Biology of Protein-RNA Complexes. Structure 2020; 28:6-28. [DOI: 10.1016/j.str.2019.11.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 11/17/2019] [Accepted: 11/27/2019] [Indexed: 12/16/2022]
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91
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Benjin X, Ling L. Developments, applications, and prospects of cryo-electron microscopy. Protein Sci 2019; 29:872-882. [PMID: 31854478 PMCID: PMC7096719 DOI: 10.1002/pro.3805] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 12/12/2019] [Accepted: 12/16/2019] [Indexed: 12/30/2022]
Abstract
Cryo‐electron microscopy (cryo‐EM) is a structural biological method that is used to determine the 3D structures of biomacromolecules. After years of development, cryo‐EM has made great achievements, which has led to a revolution in structural biology. In this article, the principle, characteristics, history, current situation, workflow, and common problems of cryo‐EM are systematically reviewed. In addition, the new development direction of cryo‐EM—cryo‐electron tomography (cryo‐ET), is discussed in detail. Also, cryo‐EM is prospected from the following aspects: the structural analysis of small proteins, the improvement of resolution and efficiency, and the relationship between cryo‐EM and drug development. This review is dedicated to giving readers a comprehensive understanding of the development and application of cryo‐EM, and to bringing them new insights.
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Affiliation(s)
- Xu Benjin
- Laboratory Medicine Department in Fenyang College of Shanxi Medical University, Shanxi, Fenyang, China
| | - Liu Ling
- Laboratory Medicine Department in Fenyang College of Shanxi Medical University, Shanxi, Fenyang, China
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92
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Ferreira N, Perks KL, Rossetti G, Rudler DL, Hughes LA, Ermer JA, Scott LH, Kuznetsova I, Richman TR, Narayana VK, Abudulai LN, Shearwood AJ, Cserne Szappanos H, Tull D, Yeoh GC, Hool LC, Filipovska A, Rackham O. Stress signaling and cellular proliferation reverse the effects of mitochondrial mistranslation. EMBO J 2019; 38:e102155. [PMID: 31721250 PMCID: PMC6912024 DOI: 10.15252/embj.2019102155] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 09/17/2019] [Accepted: 09/20/2019] [Indexed: 12/12/2022] Open
Abstract
Translation fidelity is crucial for prokaryotes and eukaryotic nuclear-encoded proteins; however, little is known about the role of mistranslation in mitochondria and its potential effects on metabolism. We generated yeast and mouse models with error-prone and hyper-accurate mitochondrial translation, and found that translation rate is more important than translational accuracy for cell function in mammals. Specifically, we found that mitochondrial mistranslation causes reduced overall mitochondrial translation and respiratory complex assembly rates. In mammals, this effect is compensated for by increased mitochondrial protein stability and upregulation of the citric acid cycle. Moreover, this induced mitochondrial stress signaling, which enables the recovery of mitochondrial translation via mitochondrial biogenesis, telomerase expression, and cell proliferation, and thereby normalizes metabolism. Conversely, we show that increased fidelity of mitochondrial translation reduces the rate of protein synthesis without eliciting a mitochondrial stress response. Consequently, the rate of translation cannot be recovered and this leads to dilated cardiomyopathy in mice. In summary, our findings reveal mammalian-specific signaling pathways that respond to changes in the fidelity of mitochondrial protein synthesis and affect metabolism.
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Affiliation(s)
- Nicola Ferreira
- Harry Perkins Institute of Medical ResearchNedlandsWAAustralia
- The University of Western Australia Centre for Medical ResearchCrawleyWAAustralia
| | - Kara L Perks
- Harry Perkins Institute of Medical ResearchNedlandsWAAustralia
- The University of Western Australia Centre for Medical ResearchCrawleyWAAustralia
| | - Giulia Rossetti
- Harry Perkins Institute of Medical ResearchNedlandsWAAustralia
- The University of Western Australia Centre for Medical ResearchCrawleyWAAustralia
| | - Danielle L Rudler
- Harry Perkins Institute of Medical ResearchNedlandsWAAustralia
- The University of Western Australia Centre for Medical ResearchCrawleyWAAustralia
| | - Laetitia A Hughes
- Harry Perkins Institute of Medical ResearchNedlandsWAAustralia
- The University of Western Australia Centre for Medical ResearchCrawleyWAAustralia
| | - Judith A Ermer
- Harry Perkins Institute of Medical ResearchNedlandsWAAustralia
- The University of Western Australia Centre for Medical ResearchCrawleyWAAustralia
| | - Louis H Scott
- Harry Perkins Institute of Medical ResearchNedlandsWAAustralia
- The University of Western Australia Centre for Medical ResearchCrawleyWAAustralia
| | - Irina Kuznetsova
- Harry Perkins Institute of Medical ResearchNedlandsWAAustralia
- The University of Western Australia Centre for Medical ResearchCrawleyWAAustralia
| | - Tara R Richman
- Harry Perkins Institute of Medical ResearchNedlandsWAAustralia
- The University of Western Australia Centre for Medical ResearchCrawleyWAAustralia
| | - Vinod K Narayana
- Metabolomics AustraliaBio21 Institute of Molecular Science and BiotechnologyUniversity of MelbourneParkvilleVic.Australia
| | - Laila N Abudulai
- Centre for Microscopy, Characterisation and AnalysisThe University of Western AustraliaPerthWAAustralia
- School of Molecular SciencesThe University of Western Australia, CrawleyWAAustralia
- The School of Biomedical SciencesThe University of Western AustraliaNedlandsWAAustralia
| | - Anne‐Marie J Shearwood
- Harry Perkins Institute of Medical ResearchNedlandsWAAustralia
- The University of Western Australia Centre for Medical ResearchCrawleyWAAustralia
| | | | - Dedreia Tull
- Metabolomics AustraliaBio21 Institute of Molecular Science and BiotechnologyUniversity of MelbourneParkvilleVic.Australia
| | - George C Yeoh
- Harry Perkins Institute of Medical ResearchNedlandsWAAustralia
| | - Livia C Hool
- School of Human Sciences (Physiology)The University of Western AustraliaCrawleyWAAustralia
- Victor Chang Cardiac Research InstituteDarlinghurstNSWAustralia
| | - Aleksandra Filipovska
- Harry Perkins Institute of Medical ResearchNedlandsWAAustralia
- The University of Western Australia Centre for Medical ResearchCrawleyWAAustralia
- School of Molecular SciencesThe University of Western Australia, CrawleyWAAustralia
| | - Oliver Rackham
- Harry Perkins Institute of Medical ResearchNedlandsWAAustralia
- School of Pharmacy and Biomedical SciencesCurtin UniversityBentleyWAAustralia
- Curtin Health Innovation Research InstituteCurtin UniversityBentleyWAAustralia
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93
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Tomal A, Kwasniak-Owczarek M, Janska H. An Update on Mitochondrial Ribosome Biology: The Plant Mitoribosome in the Spotlight. Cells 2019; 8:E1562. [PMID: 31816993 PMCID: PMC6953067 DOI: 10.3390/cells8121562] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 11/28/2019] [Accepted: 12/01/2019] [Indexed: 02/06/2023] Open
Abstract
Contrary to the widely held belief that mitochondrial ribosomes (mitoribosomes) are highly similar to bacterial ones, recent experimental evidence reveals that mitoribosomes do differ significantly from their bacterial counterparts. This review is focused on plant mitoribosomes, but we also highlight the most striking similarities and differences between the plant and non-plant mitoribosomes. An analysis of the composition and structure of mitoribosomes in trypanosomes, yeast, mammals and plants uncovers numerous organism-specific features. For the plant mitoribosome, the most striking feature is the enormous size of the small subunit compared to the large one. Apart from the new structural information, possible functional peculiarities of different types of mitoribosomes are also discussed. Studies suggest that the protein composition of mitoribosomes is dynamic, especially during development, giving rise to a heterogeneous populations of ribosomes fulfilling specific functions. Moreover, convincing data shows that mitoribosomes interact with components involved in diverse mitochondrial gene expression steps, forming large expressosome-like structures.
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Affiliation(s)
| | | | - Hanna Janska
- Department of Cellular Molecular Biology, Faculty of Biotechnology, University of Wroclaw, 50-383 Wroclaw, Poland; (A.T.); (M.K.-O.)
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94
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Mays JN, Camacho-Villasana Y, Garcia-Villegas R, Perez-Martinez X, Barrientos A, Fontanesi F. The mitoribosome-specific protein mS38 is preferentially required for synthesis of cytochrome c oxidase subunits. Nucleic Acids Res 2019; 47:5746-5760. [PMID: 30968120 PMCID: PMC6582356 DOI: 10.1093/nar/gkz266] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 03/26/2019] [Accepted: 04/02/2019] [Indexed: 12/20/2022] Open
Abstract
Message-specific translational regulation mechanisms shape the biogenesis of multimeric oxidative phosphorylation (OXPHOS) enzyme in mitochondria from the yeast Saccharomyces cerevisiae. These mechanisms, driven mainly by the action of mRNA-specific translational activators, help to coordinate synthesis of OXPHOS catalytic subunits by the mitoribosomes with both the import of their nucleus-encoded partners and their assembly to form the holocomplexes. However, little is known regarding the role that the mitoribosome itself may play in mRNA-specific translational regulation. Here, we show that the mitoribosome small subunit protein Cox24/mS38, known to be necessary for mitoribosome-specific intersubunit bridge formation and 15S rRNA H44 stabilization, is required for efficient mitoribogenesis. Consequently, mS38 is necessary to sustain the overall mitochondrial protein synthesis rate, despite an adaptive ∼2-fold increase in mitoribosome abundance in mS38-deleted cells. Additionally, the absence of mS38 preferentially disturbs translation initiation of COX1, COX2, and COX3 mRNAs, without affecting the levels of mRNA-specific translational activators. We propose that mS38 confers the mitochondrial ribosome an intrinsic capacity of translational regulation, probably acquired during evolution from bacterial ribosomes to facilitate the translation of mitochondrial mRNAs, which lack typical anti-Shine-Dalgarno sequences.
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Affiliation(s)
- Jeffri-Noelle Mays
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Yolanda Camacho-Villasana
- Departamento de Genetica Molecular, Instituto de Fisiologiía Celular, Universidad Nacional Autonoma de Mexico, Mexico City 04510, Mexico
| | - Rodolfo Garcia-Villegas
- Departamento de Genetica Molecular, Instituto de Fisiologiía Celular, Universidad Nacional Autonoma de Mexico, Mexico City 04510, Mexico
| | - Xochitl Perez-Martinez
- Departamento de Genetica Molecular, Instituto de Fisiologiía Celular, Universidad Nacional Autonoma de Mexico, Mexico City 04510, Mexico
| | - Antoni Barrientos
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA.,Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Flavia Fontanesi
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
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95
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Waltz F, Giegé P. Striking Diversity of Mitochondria-Specific Translation Processes across Eukaryotes. Trends Biochem Sci 2019; 45:149-162. [PMID: 31780199 DOI: 10.1016/j.tibs.2019.10.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 10/03/2019] [Accepted: 10/08/2019] [Indexed: 12/13/2022]
Abstract
Mitochondria are essential organelles that act as energy conversion powerhouses and metabolic hubs. Their gene expression machineries combine traits inherited from prokaryote ancestors and specific features acquired during eukaryote evolution. Mitochondrial research has wide implications ranging from human health to agronomy. We highlight recent advances in mitochondrial translation. Functional, biochemical, and structural data have revealed an unexpected diversity of mitochondrial translation systems, particularly of their key players, the mitochondrial ribosomes (mitoribosomes). Ribosome assembly and translation mechanisms, such as initiation, are discussed and put in perspective with the prevalence of eukaryote-specific families of mitochondrial translation factors such as pentatricopeptide repeat (PPR) proteins.
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Affiliation(s)
- Florent Waltz
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg, France; Institut Européen de Chimie et de Biologie, l'Institut National de la Santé et de la Recherche Médicale (INSERM), Université de Bordeaux, 2 rue Robert Escarpit, 33607 Pessac, France.
| | - Philippe Giegé
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg, 12 rue du Général Zimmer, 67084 Strasbourg, France.
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96
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Ayyub SA, Varshney U. Translation initiation in mammalian mitochondria- a prokaryotic perspective. RNA Biol 2019; 17:165-175. [PMID: 31696767 DOI: 10.1080/15476286.2019.1690099] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
ATP is generated in mitochondria of eukaryotic cells by oxidative phosphorylation (OXPHOS). The OXPHOS complex, which is crucial for cellular metabolism, comprises of both nuclear and mitochondrially encoded subunits. Also, the occurrence of several pathologies because of mutations in the mitochondrial translation apparatus indicates the importance of mitochondrial translation and its regulation. The mitochondrial translation apparatus is similar to its prokaryotic counterpart due to a common origin of evolution. However, mitochondrial translation has diverged from prokaryotic translation in many ways by reductive evolution. In this review, we focus on mammalian mitochondrial translation initiation, a highly regulated step of translation, and present a comparison with prokaryotic translation.
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Affiliation(s)
- Shreya Ahana Ayyub
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Umesh Varshney
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India.,Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
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97
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Ma C, Bendory T, Boumal N, Sigworth F, Singer A. Heterogeneous multireference alignment for images with application to 2-D classification in single particle reconstruction. IEEE TRANSACTIONS ON IMAGE PROCESSING : A PUBLICATION OF THE IEEE SIGNAL PROCESSING SOCIETY 2019; 29:1699-1710. [PMID: 31613760 DOI: 10.1109/tip.2019.2945686] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Motivated by the task of 2-D classification in single particle reconstruction by cryo-electron microscopy (cryo-EM), we consider the problem of heterogeneous multireference alignment of images. In this problem, the goal is to estimate a (typically small) set of target images from a (typically large) collection of observations. Each observation is a rotated, noisy version of one of the target images. For each individual observation, neither the rotation nor which target image has been rotated are known. As the noise level in cryo-EM data is high, clustering the observations and estimating individual rotations is challenging. We propose a framework to estimate the target images directly from the observations, completely bypassing the need to cluster or register the images. The framework consists of two steps. First, we estimate rotation-invariant features of the images, such as the bispectrum. These features can be estimated to any desired accuracy, at any noise level, provided sufficiently many observations are collected. Then, we estimate the images from the invariant features. Numerical experiments on synthetic cryo-EM datasets demonstrate the effectiveness of the method. Ultimately, we outline future developments required to apply this method to experimental data.
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98
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Ndi M, Masuyer G, Dawitz H, Carlström A, Michel M, Elofsson A, Rapp M, Stenmark P, Ott M. Structural basis for the interaction of the chaperone Cbp3 with newly synthesized cytochrome b during mitochondrial respiratory chain assembly. J Biol Chem 2019; 294:16663-16671. [PMID: 31537648 DOI: 10.1074/jbc.ra119.010483] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Revised: 09/04/2019] [Indexed: 11/06/2022] Open
Abstract
Assembly of the mitochondrial respiratory chain requires the coordinated synthesis of mitochondrial and nuclear encoded subunits, redox co-factor acquisition, and correct joining of the subunits to form functional complexes. The conserved Cbp3-Cbp6 chaperone complex binds newly synthesized cytochrome b and supports the ordered acquisition of the heme co-factors. Moreover, it functions as a translational activator by interacting with the mitoribosome. Cbp3 consists of two distinct domains: an N-terminal domain present in mitochondrial Cbp3 homologs and a highly conserved C-terminal domain comprising a ubiquinol-cytochrome c chaperone region. Here, we solved the crystal structure of this C-terminal domain from a bacterial homolog at 1.4 Å resolution, revealing a unique all-helical fold. This structure allowed mapping of the interaction sites of yeast Cbp3 with Cbp6 and cytochrome b via site-specific photo-cross-linking. We propose that mitochondrial Cbp3 homologs carry an N-terminal extension that positions the conserved C-terminal domain at the ribosomal tunnel exit for an efficient interaction with its substrate, the newly synthesized cytochrome b protein.
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Affiliation(s)
- Mama Ndi
- Department of Biochemistry and Biophysics, Stockholm University SE-10691 Stockholm, Sweden
| | - Geoffrey Masuyer
- Department of Biochemistry and Biophysics, Stockholm University SE-10691 Stockholm, Sweden.,Department of Pharmacy and Pharmacology, University of Bath, Bath BA2 7AY, United Kingdom
| | - Hannah Dawitz
- Department of Biochemistry and Biophysics, Stockholm University SE-10691 Stockholm, Sweden
| | - Andreas Carlström
- Department of Biochemistry and Biophysics, Stockholm University SE-10691 Stockholm, Sweden
| | - Mirco Michel
- Department of Biochemistry and Biophysics, Stockholm University SE-10691 Stockholm, Sweden.,Science for Life Laboratories, Stockholm University, SE-171 21 Solna, Sweden
| | - Arne Elofsson
- Department of Biochemistry and Biophysics, Stockholm University SE-10691 Stockholm, Sweden.,Science for Life Laboratories, Stockholm University, SE-171 21 Solna, Sweden
| | - Mikaela Rapp
- Department of Biochemistry and Biophysics, Stockholm University SE-10691 Stockholm, Sweden
| | - Pål Stenmark
- Department of Biochemistry and Biophysics, Stockholm University SE-10691 Stockholm, Sweden .,Department of Experimental Medical Science, Lund University, SE-221 84 Lund, Sweden
| | - Martin Ott
- Department of Biochemistry and Biophysics, Stockholm University SE-10691 Stockholm, Sweden
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Sahu PK, Salim S, Pp M, Chauhan S, Tomar RS. Reverse genetic analysis of yeast YPR099C/MRPL51 reveals a critical role of both overlapping ORFs in respiratory growth and MRPL51 in mitochondrial DNA maintenance. FEMS Yeast Res 2019; 19:5543219. [PMID: 31374566 DOI: 10.1093/femsyr/foz056] [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: 05/29/2019] [Accepted: 08/01/2019] [Indexed: 11/14/2022] Open
Abstract
The Saccharomyces cerevisiae genome contains 6572 ORFs, of which 680 ORFs are classified as dubious ORFs. A dubious ORF is a small, noncoding, nonconserved ORF that overlaps with another ORF of the complementary strand. Our study characterizes a dubious/nondubious ORF pair, YPR099C/MRPL51, and shows the transcript and protein level expression of YPR099C. Its subcellular localization was observed in the mitochondria. The overlapping ORF, MRPL51, encodes a mitochondrial ribosomal protein of large subunit. Deletion of any ORF from YPR099C/MRPL51 pair induces common phenotypes, i.e. loss of mtDNA, lack of mitochondrial fusion and lack of respiratory growth, due to the double deletion (ypr099cΔ/Δmrpl51Δ/Δ) caused by sequence overlap. Hence, we created the single deletions of each ORF of the YPR099C/MRPL51 pair by an alternative approach to distinguish their phenotypes and identify the specific functions. Both the ORFs were found essential for the functional mitochondria and respiratory growth, but MRPL51 showed its specific requirement in mtDNA stability. The mechanism of mtDNA maintenance by Mrpl51 is probably Mhr1 dependent that physically interacts with Mrpl51 and also regulates mtDNA repair. Overall, our study provides strong evidence for the protein level expression of a dubious ORF YPR099C and the bifunctional role of Mrpl51 in mtDNA maintenance.
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Affiliation(s)
- Pushpendra Kumar Sahu
- Laboratory of Chromatin Biology, Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal 462066, Madhya Pradesh, India
| | - Sagar Salim
- Laboratory of Chromatin Biology, Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal 462066, Madhya Pradesh, India
| | - Mubthasima Pp
- Laboratory of Chromatin Biology, Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal 462066, Madhya Pradesh, India
| | - Sakshi Chauhan
- Laboratory of Chromatin Biology, Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal 462066, Madhya Pradesh, India
| | - Raghuvir Singh Tomar
- Laboratory of Chromatin Biology, Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal 462066, Madhya Pradesh, India
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Masud AJ, Kastaniotis AJ, Rahman MT, Autio KJ, Hiltunen JK. Mitochondrial acyl carrier protein (ACP) at the interface of metabolic state sensing and mitochondrial function. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1866:118540. [PMID: 31473256 DOI: 10.1016/j.bbamcr.2019.118540] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 08/23/2019] [Accepted: 08/27/2019] [Indexed: 12/20/2022]
Abstract
Acyl carrier protein (ACP) is a principal partner in the cytosolic and mitochondrial fatty acid synthesis (FAS) pathways. The active form holo-ACP serves as FAS platform, using its 4'-phosphopantetheine group to present covalently attached FAS intermediates to the enzymes responsible for the acyl chain elongation process. Mitochondrial unacylated holo-ACP is a component of mammalian mitoribosomes, and acylated ACP species participate as interaction partners in several ACP-LYRM (leucine-tyrosine-arginine motif)-protein heterodimers that act either as assembly factors or subunits of the electron transport chain and Fe-S cluster assembly complexes. Moreover, octanoyl-ACP provides the C8 backbone for endogenous lipoic acid synthesis. Accumulating evidence suggests that mtFAS-generated acyl-ACPs act as signaling molecules in an intramitochondrial metabolic state sensing circuit, coordinating mitochondrial acetyl-CoA levels with mitochondrial respiration, Fe-S cluster biogenesis and protein lipoylation.
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Affiliation(s)
- Ali J Masud
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | | | - M Tanvir Rahman
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Kaija J Autio
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - J Kalervo Hiltunen
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland.
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