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Zgadzay Y, Mirabello C, Wanes G, Pánek T, Chauhan P, Nystedt B, Zíková A, Whitford PC, Gahura O, Amunts A. Mettl15-Mettl17 modulates the transition from early to late pre-mitoribosome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2025:2024.12.18.629302. [PMID: 39896671 PMCID: PMC11785013 DOI: 10.1101/2024.12.18.629302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2025]
Abstract
The assembly of the mitoribosomal small subunit involves folding and modification of rRNA, and its association with mitoribosomal proteins. This process is assisted by a dynamic network of assembly factors. Conserved methyltransferases Mettl15 and Mettl17 act on the solvent-exposed surface of rRNA. Binding of Mettl17 is associated with the early assembly stage, whereas Mettl15 is involved in the late stage, but the mechanism of transition between the two was unclear. Here, we integrate structural data from Trypanosoma brucei with mammalian homologs and molecular dynamics simulations. We reveal how the interplay of Mettl15 and Mettl17 in intermediate steps links the distinct stages of small subunit assembly. The analysis suggests a model wherein Mettl17 acts as a platform for Mettl15 recruitment. Subsequent release of Mettl17 allows a conformational change of Mettl15 for substrate recognition. Upon methylation, Mettl15 adopts a loosely bound state which ultimately leads to its replacement by initiation factors, concluding the assembly. Together, our results indicate that assembly factors Mettl15 and Mettl17 cooperate to regulate the biogenesis process, and present a structural data resource for understanding molecular adaptations of assembly factors in mitoribosome.
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Affiliation(s)
- Yury Zgadzay
- Department of Integrated Structural Biology, Institute of Genetics and Molecular and Cellular Biology, University of Strasbourg, Illkirch, France
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, 17165 Solna, Sweden
| | - Claudio Mirabello
- Dept of Physics, Chemistry and Biology, National Bioinformatics Infrastructure Sweden, Science for Life Laboratory, Linköping University, 581 83 Linköping, Sweden
| | - George Wanes
- Department of Physics, Northeastern University, Boston, MA, 02115, USA
- Center for Theoretical Biological Physics, Northeastern University, Boston, MA, 02115, USA
| | - Tomáš Pánek
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Prashant Chauhan
- Faculty of Science, University of South Bohemia, 37005 České Budějovice, Czech Republic
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 37005 České Budějovice, Czech Republic
| | - Björn Nystedt
- Dept of Cell and Molecular Biology, National Bioinformatics Infrastructure Sweden, Science for Life Laboratory, Uppsala University, Husargatan 3, SE-752 37 Uppsala, Sweden
| | - Alena Zíková
- Faculty of Science, University of South Bohemia, 37005 České Budějovice, Czech Republic
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 37005 České Budějovice, Czech Republic
| | - Paul C. Whitford
- Department of Physics, Northeastern University, Boston, MA, 02115, USA
- Center for Theoretical Biological Physics, Northeastern University, Boston, MA, 02115, USA
| | - Ondřej Gahura
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 37005 České Budějovice, Czech Republic
| | - Alexey Amunts
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, 17165 Solna, Sweden
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2
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Wu H, Zhu X, Zhou H, Sha M, Ye J, Yu H. Mitochondrial Ribosomal Proteins and Cancer. MEDICINA (KAUNAS, LITHUANIA) 2025; 61:96. [PMID: 39859078 PMCID: PMC11766452 DOI: 10.3390/medicina61010096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2024] [Revised: 12/19/2024] [Accepted: 01/07/2025] [Indexed: 01/27/2025]
Abstract
Mitochondria play key roles in maintaining cell life and cell function, and their dysfunction can lead to cell damage. Mitochondrial ribosomal proteins (MRPs) are encoded by nuclear genes and are assembled within the mitochondria. MRPs are pivotal components of the mitochondrial ribosomes, which are responsible for translating 13 mitochondrial DNA-encoded proteins essential for the mitochondrial respiratory chain. Recent studies have underscored the importance of MRPs in cancer biology, revealing their altered expression patterns in various types of cancer and their potential as both prognostic biomarkers and therapeutic targets. Herein, we review the current knowledge regarding the multiple functions of MRPs in maintaining the structure of the mitochondrial ribosome and apoptosis, their implications for cancer susceptibility and progression, and the innovative strategies being developed to target MRPs and mitoribosome biogenesis in cancer therapy. This comprehensive overview aims to provide insights into the role of MRPs in cancer biology and highlight promising strategies for future precision oncology.
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Affiliation(s)
- Huiyi Wu
- Department of Pathology, The Affiliated Taizhou People’s Hospital of Nanjing Medical University, Taizhou 225300, China; (H.W.); (X.Z.); (H.Z.)
| | - Xiaowei Zhu
- Department of Pathology, The Affiliated Taizhou People’s Hospital of Nanjing Medical University, Taizhou 225300, China; (H.W.); (X.Z.); (H.Z.)
| | - Huilin Zhou
- Department of Pathology, The Affiliated Taizhou People’s Hospital of Nanjing Medical University, Taizhou 225300, China; (H.W.); (X.Z.); (H.Z.)
| | - Min Sha
- Translational Medicine Center, The Affiliated Taizhou People’s Hospital of Nanjing Medical University, Taizhou 225300, China; (M.S.); (J.Y.)
| | - Jun Ye
- Translational Medicine Center, The Affiliated Taizhou People’s Hospital of Nanjing Medical University, Taizhou 225300, China; (M.S.); (J.Y.)
| | - Hong Yu
- Department of Pathology, The Affiliated Taizhou People’s Hospital of Nanjing Medical University, Taizhou 225300, China; (H.W.); (X.Z.); (H.Z.)
- Translational Medicine Center, The Affiliated Taizhou People’s Hospital of Nanjing Medical University, Taizhou 225300, China; (M.S.); (J.Y.)
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3
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Wang C, Kassem S, Rocha REO, Sun P, Nguyen TT, Kloehn J, Liu X, Brusini L, Bonavoglia A, Barua S, Boissier F, Lucia Del Cistia M, Peng H, Tang X, Xie F, Wang Z, Vadas O, Suo X, Hashem Y, Soldati-Favre D, Jia Y. Apicomplexan mitoribosome from highly fragmented rRNAs to a functional machine. Nat Commun 2024; 15:10689. [PMID: 39690155 PMCID: PMC11652630 DOI: 10.1038/s41467-024-55033-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2024] [Accepted: 11/28/2024] [Indexed: 12/19/2024] Open
Abstract
The phylum Apicomplexa comprises eukaryotic parasites that cause fatal diseases affecting millions of people and animals worldwide. Their mitochondrial genomes have been significantly reduced, leaving only three protein-coding genes and highly fragmented mitoribosomal rRNAs, raising challenging questions about mitoribosome composition, assembly and structure. Our study reveals how Toxoplasma gondii assembles over 40 mt-rRNA fragments using exclusively nuclear-encoded mitoribosomal proteins and three lineage-specific families of RNA-binding proteins. Among these are four proteins from the Apetala2/Ethylene Response Factor (AP2/ERF) family, originally known as transcription factors in plants and Apicomplexa, now repurposed as essential mitoribosome components. Cryo-EM analysis of the mitoribosome structure demonstrates how these AP2 proteins function as RNA binders to maintain mitoribosome integrity. The mitoribosome is also decorated with members of lineage-specific RNA-binding proteins belonging to RAP (RNA-binding domain abundant in Apicomplexa) proteins and HPR (heptatricopeptide repeat) families, highlighting the unique adaptations of these parasites. Solving the molecular puzzle of apicomplexan mitoribosome could inform the development of therapeutic strategies targeting organellar translation.
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Affiliation(s)
- Chaoyue Wang
- National Key Laboratory of Veterinary Public Health Security, Key Laboratory of Animal Epidemiology of the Ministry of Agriculture and Rural Affairs, National Animal Protozoa Laboratory & College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Sari Kassem
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Rafael Eduardo Oliveira Rocha
- INSERM U1212 Acides nucléiques: Régulations Naturelle et Artificielle (ARNA), Institut Européen de Chimie et Biologie, Université de Bordeaux, Pessac, 33607, France
| | - Pei Sun
- Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Institute of Zoology, Guangdong Academy of Science, Guangzhou, Guangdong Province, 510260, China
| | - Tan-Trung Nguyen
- INSERM U1212 Acides nucléiques: Régulations Naturelle et Artificielle (ARNA), Institut Européen de Chimie et Biologie, Université de Bordeaux, Pessac, 33607, France
| | - Joachim Kloehn
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Xianyong Liu
- National Key Laboratory of Veterinary Public Health Security, Key Laboratory of Animal Epidemiology of the Ministry of Agriculture and Rural Affairs, National Animal Protozoa Laboratory & College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Lorenzo Brusini
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Alessandro Bonavoglia
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Sramona Barua
- INSERM U1212 Acides nucléiques: Régulations Naturelle et Artificielle (ARNA), Institut Européen de Chimie et Biologie, Université de Bordeaux, Pessac, 33607, France
| | - Fanny Boissier
- INSERM U1212 Acides nucléiques: Régulations Naturelle et Artificielle (ARNA), Institut Européen de Chimie et Biologie, Université de Bordeaux, Pessac, 33607, France
| | - Mayara Lucia Del Cistia
- INSERM U1212 Acides nucléiques: Régulations Naturelle et Artificielle (ARNA), Institut Européen de Chimie et Biologie, Université de Bordeaux, Pessac, 33607, France
| | - Hongjuan Peng
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Diseases Research, School of Public Health; Key Laboratory of Infectious Diseases Research in South China (Ministry of Education), Southern Medical University, 1023-1063 South Shatai Rd, Guangzhou City, Guangdong Province, 510515, China
| | - Xinming Tang
- Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Fujie Xie
- National Key Laboratory of Veterinary Public Health Security, Key Laboratory of Animal Epidemiology of the Ministry of Agriculture and Rural Affairs, National Animal Protozoa Laboratory & College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Zixuan Wang
- National Key Laboratory of Veterinary Public Health Security, Key Laboratory of Animal Epidemiology of the Ministry of Agriculture and Rural Affairs, National Animal Protozoa Laboratory & College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Oscar Vadas
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Xun Suo
- National Key Laboratory of Veterinary Public Health Security, Key Laboratory of Animal Epidemiology of the Ministry of Agriculture and Rural Affairs, National Animal Protozoa Laboratory & College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China.
| | - Yaser Hashem
- INSERM U1212 Acides nucléiques: Régulations Naturelle et Artificielle (ARNA), Institut Européen de Chimie et Biologie, Université de Bordeaux, Pessac, 33607, France.
| | - Dominique Soldati-Favre
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland.
| | - Yonggen Jia
- Beijing Institute of Tropical Medicine, Beijing Friendship Hospital, Capital Medical University, Beijing, 100050, China.
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4
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Brischigliaro M, Sierra‐Magro A, Ahn A, Barrientos A. Mitochondrial ribosome biogenesis and redox sensing. FEBS Open Bio 2024; 14:1640-1655. [PMID: 38849194 PMCID: PMC11452305 DOI: 10.1002/2211-5463.13844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 05/06/2024] [Accepted: 05/29/2024] [Indexed: 06/09/2024] Open
Abstract
Mitoribosome biogenesis is a complex process involving RNA elements encoded in the mitochondrial genome and mitoribosomal proteins typically encoded in the nuclear genome. This process is orchestrated by extra-ribosomal proteins, nucleus-encoded assembly factors, which play roles across all assembly stages to coordinate ribosomal RNA processing and maturation with the sequential association of ribosomal proteins. Both biochemical studies and recent cryo-EM structures of mammalian mitoribosomes have provided insights into their assembly process. In this article, we will briefly outline the current understanding of mammalian mitoribosome biogenesis pathways and the factors involved. Special attention is devoted to the recent identification of iron-sulfur clusters as structural components of the mitoribosome and a small subunit assembly factor, the existence of redox-sensitive cysteines in mitoribosome proteins and assembly factors, and the role they may play as redox sensor units to regulate mitochondrial translation under stress.
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Affiliation(s)
| | - Ana Sierra‐Magro
- Department of NeurologyUniversity of Miami Miller School of MedicineFLUSA
| | - Ahram Ahn
- Department of Biochemistry and Molecular BiologyUniversity of Miami Miller School of MedicineFLUSA
| | - Antoni Barrientos
- Department of NeurologyUniversity of Miami Miller School of MedicineFLUSA
- Department of Biochemistry and Molecular BiologyUniversity of Miami Miller School of MedicineFLUSA
- Bruce W. Carter Department of Veterans Affairs VA Medical CenterMiamiFLUSA
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5
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Martín-Villanueva S, Galmozzi CV, Ruger-Herreros C, Kressler D, de la Cruz J. The Beak of Eukaryotic Ribosomes: Life, Work and Miracles. Biomolecules 2024; 14:882. [PMID: 39062596 PMCID: PMC11274626 DOI: 10.3390/biom14070882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2024] [Revised: 07/19/2024] [Accepted: 07/21/2024] [Indexed: 07/28/2024] Open
Abstract
Ribosomes are not totally globular machines. Instead, they comprise prominent structural protrusions and a myriad of tentacle-like projections, which are frequently made up of ribosomal RNA expansion segments and N- or C-terminal extensions of ribosomal proteins. This is more evident in higher eukaryotic ribosomes. One of the most characteristic protrusions, present in small ribosomal subunits in all three domains of life, is the so-called beak, which is relevant for the function and regulation of the ribosome's activities. During evolution, the beak has transitioned from an all ribosomal RNA structure (helix h33 in 16S rRNA) in bacteria, to an arrangement formed by three ribosomal proteins, eS10, eS12 and eS31, and a smaller h33 ribosomal RNA in eukaryotes. In this review, we describe the different structural and functional properties of the eukaryotic beak. We discuss the state-of-the-art concerning its composition and functional significance, including other processes apparently not related to translation, and the dynamics of its assembly in yeast and human cells. Moreover, we outline the current view about the relevance of the beak's components in human diseases, especially in ribosomopathies and cancer.
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Affiliation(s)
- Sara Martín-Villanueva
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, E-41013 Seville, Spain; (S.M.-V.); (C.V.G.); (C.R.-H.)
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, E-41012 Seville, Spain
| | - Carla V. Galmozzi
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, E-41013 Seville, Spain; (S.M.-V.); (C.V.G.); (C.R.-H.)
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, E-41012 Seville, Spain
| | - Carmen Ruger-Herreros
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, E-41013 Seville, Spain; (S.M.-V.); (C.V.G.); (C.R.-H.)
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, E-41012 Seville, Spain
| | - Dieter Kressler
- Department of Biology, University of Fribourg, CH-1700 Fribourg, Switzerland;
| | - Jesús de la Cruz
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, E-41013 Seville, Spain; (S.M.-V.); (C.V.G.); (C.R.-H.)
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, E-41012 Seville, Spain
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Hilander T, Awadhpersad R, Monteuuis G, Broda KL, Pohjanpelto M, Pyman E, Singh SK, Nyman TA, Crevel I, Taylor RW, Saada A, Balboa D, Battersby BJ, Jackson CB, Carroll CJ. Supernumerary proteins of the human mitochondrial ribosomal small subunit are integral for assembly and translation. iScience 2024; 27:110185. [PMID: 39015150 PMCID: PMC11251090 DOI: 10.1016/j.isci.2024.110185] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 03/28/2024] [Accepted: 06/01/2024] [Indexed: 07/18/2024] Open
Abstract
Mitochondrial ribosomes (mitoribosomes) have undergone substantial evolutionary structural remodeling accompanied by loss of ribosomal RNA, while acquiring unique protein subunits located on the periphery. We generated CRISPR-mediated knockouts of all 14 unique (mitochondria-specific/supernumerary) human mitoribosomal proteins (snMRPs) in the small subunit to study the effect on mitoribosome assembly and protein synthesis, each leading to a unique mitoribosome assembly defect with variable impact on mitochondrial protein synthesis. Surprisingly, the stability of mS37 was reduced in all our snMRP knockouts of the small and large ribosomal subunits and patient-derived lines with mitoribosome assembly defects. A redox-regulated CX9C motif in mS37 was essential for protein stability, suggesting a potential mechanism to regulate mitochondrial protein synthesis. Together, our findings support a modular assembly of the human mitochondrial small ribosomal subunit mediated by essential supernumerary subunits and identify a redox regulatory role involving mS37 in mitochondrial protein synthesis in health and disease.
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Affiliation(s)
- Taru Hilander
- Genetics Section, Cardiovascular and Genomics Research Institute, St George’s, University of London, London, UK
| | - Ryan Awadhpersad
- Department of Biochemistry and Developmental Biology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Geoffray Monteuuis
- Department of Biochemistry and Developmental Biology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Krystyna L. Broda
- Genetics Section, Cardiovascular and Genomics Research Institute, St George’s, University of London, London, UK
| | - Max Pohjanpelto
- Genetics Section, Cardiovascular and Genomics Research Institute, St George’s, University of London, London, UK
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland
| | - Elizabeth Pyman
- Genetics Section, Cardiovascular and Genomics Research Institute, St George’s, University of London, London, UK
| | - Sachin Kumar Singh
- Department of Immunology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway
| | - Tuula A. Nyman
- Department of Immunology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway
| | - Isabelle Crevel
- Core Facilities, St George’s, University of London, London, UK
| | - Robert W. Taylor
- Mitochondrial Research Group, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
- NHS Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne NE1 4LP, UK
| | - Ann Saada
- Department of Genetics, Hadassah Medical Center & Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 9112001 Israel
| | - Diego Balboa
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland
| | | | - Christopher B. Jackson
- Department of Biochemistry and Developmental Biology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Christopher J. Carroll
- Genetics Section, Cardiovascular and Genomics Research Institute, St George’s, University of London, London, UK
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7
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Zhong H, Barrientos A. The zinc finger motif in the mitochondrial large ribosomal subunit protein bL36m is essential for optimal yeast mitoribosome assembly and function. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119707. [PMID: 38493895 PMCID: PMC11009049 DOI: 10.1016/j.bbamcr.2024.119707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 03/08/2024] [Accepted: 03/11/2024] [Indexed: 03/19/2024]
Abstract
Ribosomes across species contain subsets of zinc finger proteins that play structural roles by binding to rRNA. While the majority of these zinc fingers belong to the C2-C2 type, the large subunit protein L36 in bacteria and mitochondria exhibits an atypical C2-CH motif. To comprehend the contribution of each coordinating residue in S. cerevisiae bL36m to mitoribosome assembly and function, we engineered and characterized strains carrying single and double mutations in the zinc coordinating residues. Our findings reveal that although all four residues markedly influence protein stability, C to A mutations in C66 and/or C69 have a more pronounced effect compared to those at C82 and H88. Importantly, protein stability directly correlates with the assembly and function of the mitoribosome and the growth rate of yeast in respiratory conditions. Mass spectrometry analysis of large subunit particles indicates that strains deleted for bL36m or expressing mutant variants have defective assembly of the L7/L12 stalk base, limiting their functional competence. Furthermore, we employed a synthetic bL36m protein collection, including both wild-type and mutant proteins, to elucidate their ability to bind zinc. Our data indicate that mutations in C82 and, particularly, H88 allow for some zinc binding albeit inefficient or unstable, explaining the residual accumulation and activity in mitochondria of bL36m variants carrying mutations in these residues. In conclusion, stable zinc binding by bL36m is essential for optimal mitoribosome assembly and function. MS data are available via ProteomeXchange with identifierPXD046465.
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Affiliation(s)
- Hui Zhong
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, 1600 NW 10th Ave., Miami, FL 33136, USA.
| | - Antoni Barrientos
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, 1600 NW 10th Ave., Miami, FL 33136, USA; Department of Neurology, University of Miami Miller School of Medicine, 1600 NW 10th Ave., Miami, FL 33136, USA; The Miami Veterans Affairs (VA) Medical System, 1201 NW 16th St, Miami, FL 33125, USA.
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8
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Ast T, Itoh Y, Sadre S, McCoy JG, Namkoong G, Wengrod JC, Chicherin I, Joshi PR, Kamenski P, Suess DLM, Amunts A, Mootha VK. METTL17 is an Fe-S cluster checkpoint for mitochondrial translation. Mol Cell 2024; 84:359-374.e8. [PMID: 38199006 PMCID: PMC11046306 DOI: 10.1016/j.molcel.2023.12.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 08/13/2023] [Accepted: 12/12/2023] [Indexed: 01/12/2024]
Abstract
Friedreich's ataxia (FA) is a debilitating, multisystemic disease caused by the depletion of frataxin (FXN), a mitochondrial iron-sulfur (Fe-S) cluster biogenesis factor. To understand the cellular pathogenesis of FA, we performed quantitative proteomics in FXN-deficient human cells. Nearly every annotated Fe-S cluster-containing protein was depleted, indicating that as a rule, cluster binding confers stability to Fe-S proteins. We also observed depletion of a small mitoribosomal assembly factor METTL17 and evidence of impaired mitochondrial translation. Using comparative sequence analysis, mutagenesis, biochemistry, and cryoelectron microscopy, we show that METTL17 binds to the mitoribosomal small subunit during late assembly and harbors a previously unrecognized [Fe4S4]2+ cluster required for its stability. METTL17 overexpression rescued the mitochondrial translation and bioenergetic defects, but not the cellular growth, of FXN-depleted cells. These findings suggest that METTL17 acts as an Fe-S cluster checkpoint, promoting translation of Fe-S cluster-rich oxidative phosphorylation (OXPHOS) proteins only when Fe-S cofactors are replete.
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Affiliation(s)
- Tslil Ast
- Broad Institute, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Yuzuru Itoh
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden
| | - Shayan Sadre
- Broad Institute, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Jason G McCoy
- Broad Institute, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Gil Namkoong
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jordan C Wengrod
- Broad Institute, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Ivan Chicherin
- Department of Biology, M.V.Lomonosov Moscow State University, Moscow 119234, Russia
| | - Pallavi R Joshi
- Broad Institute, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Piotr Kamenski
- Department of Biology, M.V.Lomonosov Moscow State University, Moscow 119234, Russia
| | - Daniel L M Suess
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Alexey Amunts
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden
| | - Vamsi K Mootha
- Broad Institute, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA.
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9
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Aeschlimann S, Stettler P, Schneider A. DNA segregation in mitochondria and beyond: insights from the trypanosomal tripartite attachment complex. Trends Biochem Sci 2023; 48:1058-1070. [PMID: 37775421 DOI: 10.1016/j.tibs.2023.08.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 08/13/2023] [Accepted: 08/28/2023] [Indexed: 10/01/2023]
Abstract
The tripartite attachment complex (TAC) of the single mitochondrion of trypanosomes allows precise segregation of its single nucleoid mitochondrial genome during cytokinesis. It couples the segregation of the duplicated mitochondrial genome to the segregation of the basal bodies of the flagella. Here, we provide a model of the molecular architecture of the TAC that explains how its eight essential subunits connect the basal body, across the mitochondrial membranes, with the mitochondrial genome. We also discuss how the TAC subunits are imported into the mitochondrion and how they assemble to form a new TAC. Finally, we present a comparative analysis of the trypanosomal TAC with open and closed mitotic spindles, which reveals conserved concepts between these diverse DNA segregation systems.
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Affiliation(s)
- Salome Aeschlimann
- Department of Chemistry, Biochemistry, and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, Bern CH-3012, Switzerland
| | - Philip Stettler
- Department of Chemistry, Biochemistry, and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, Bern CH-3012, Switzerland; Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern CH-3012, Switzerland
| | - André Schneider
- Department of Chemistry, Biochemistry, and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, Bern CH-3012, Switzerland; Institute for Advanced Study (Wissenschaftskolleg) Berlin, D-14193 Berlin, Germany.
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10
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Zhong H, Janer A, Khalimonchuk O, Antonicka H, Shoubridge E, Barrientos A. BOLA3 and NFU1 link mitoribosome iron-sulfur cluster assembly to multiple mitochondrial dysfunctions syndrome. Nucleic Acids Res 2023; 51:11797-11812. [PMID: 37823603 PMCID: PMC10681725 DOI: 10.1093/nar/gkad842] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Revised: 09/08/2023] [Accepted: 09/20/2023] [Indexed: 10/13/2023] Open
Abstract
The human mitochondrial ribosome contains three [2Fe-2S] clusters whose assembly pathway, role, and implications for mitochondrial and metabolic diseases are unknown. Here, structure-function correlation studies show that the clusters play a structural role during mitoribosome assembly. To uncover the assembly pathway, we have examined the effect of silencing the expression of Fe-S cluster biosynthetic and delivery factors on mitoribosome stability. We find that the mitoribosome receives its [2Fe-2S] clusters from the GLRX5-BOLA3 node. Additionally, the assembly of the small subunit depends on the mitoribosome biogenesis factor METTL17, recently reported containing a [4Fe-4S] cluster, which we propose is inserted via the ISCA1-NFU1 node. Consistently, fibroblasts from subjects suffering from 'multiple mitochondrial dysfunction' syndrome due to mutations in BOLA3 or NFU1 display previously unrecognized attenuation of mitochondrial protein synthesis that contributes to their cellular and pathophysiological phenotypes. Finally, we report that, in addition to their structural role, one of the mitoribosomal [2Fe-2S] clusters and the [4Fe-4S] cluster in mitoribosome assembly factor METTL17 sense changes in the redox environment, thus providing a way to regulate organellar protein synthesis accordingly.
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Affiliation(s)
- Hui Zhong
- Department of Biochemistry and Molecular Biology. University of Miami Miller School of Medicine, 1600 NW 10Ave. Miami, FL 33136, USA
| | - Alexandre Janer
- The Neuro and Department of Human Genetics, McGill University, Montreal, QC, Canada
| | - Oleh Khalimonchuk
- Department of Biochemistry. University of Nebraska-Lincoln; 1901 Vine St. Beadle Center, Lincoln, NE 68588, USA
- Nebraska Redox Biology Center. University of Nebraska-Lincoln; 1901 Vine St. Beadle Center, Lincoln, NE 68588, USA
| | - Hana Antonicka
- The Neuro and Department of Human Genetics, McGill University, Montreal, QC, Canada
| | - Eric A Shoubridge
- The Neuro and Department of Human Genetics, McGill University, Montreal, QC, Canada
| | - Antoni Barrientos
- Department of Biochemistry and Molecular Biology. University of Miami Miller School of Medicine, 1600 NW 10Ave. Miami, FL 33136, USA
- Department of Neurology. University of Miami Miller School of Medicine; 1600 NW 10 Ave., Miami, FL 33136, USA
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11
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Valach M, Benz C, Aguilar LC, Gahura O, Faktorová D, Zíková A, Oeffinger M, Burger G, Gray MW, Lukeš J. Miniature RNAs are embedded in an exceptionally protein-rich mitoribosome via an elaborate assembly pathway. Nucleic Acids Res 2023; 51:6443-6460. [PMID: 37207340 PMCID: PMC10325924 DOI: 10.1093/nar/gkad422] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 04/20/2023] [Accepted: 05/08/2023] [Indexed: 05/21/2023] Open
Abstract
The mitochondrial ribosome (mitoribosome) has diverged drastically from its evolutionary progenitor, the bacterial ribosome. Structural and compositional diversity is particularly striking in the phylum Euglenozoa, with an extraordinary protein gain in the mitoribosome of kinetoplastid protists. Here we report an even more complex mitoribosome in diplonemids, the sister-group of kinetoplastids. Affinity pulldown of mitoribosomal complexes from Diplonema papillatum, the diplonemid type species, demonstrates that they have a mass of > 5 MDa, contain as many as 130 integral proteins, and exhibit a protein-to-RNA ratio of 11:1. This unusual composition reflects unprecedented structural reduction of ribosomal RNAs, increased size of canonical mitoribosomal proteins, and accretion of three dozen lineage-specific components. In addition, we identified >50 candidate assembly factors, around half of which contribute to early mitoribosome maturation steps. Because little is known about early assembly stages even in model organisms, our investigation of the diplonemid mitoribosome illuminates this process. Together, our results provide a foundation for understanding how runaway evolutionary divergence shapes both biogenesis and function of a complex molecular machine.
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Affiliation(s)
- Matus Valach
- Department of Biochemistry and Robert-Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, Montréal, Quebec, Canada
| | - Corinna Benz
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic
| | - Lisbeth C Aguilar
- Center for Genetic and Neurological Diseases, Institut de recherches cliniques de Montréal (IRCM), Montréal, Quebec, Canada
| | - Ondřej Gahura
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic
| | - Drahomíra Faktorová
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic
- Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Alena Zíková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic
- Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Marlene Oeffinger
- Department of Biochemistry and Robert-Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, Montréal, Quebec, Canada
- Center for Genetic and Neurological Diseases, Institut de recherches cliniques de Montréal (IRCM), Montréal, Quebec, Canada
- Division of Experimental Medicine, McGill University, Montréal, Quebec, Canada
| | - Gertraud Burger
- Department of Biochemistry and Robert-Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, Montréal, Quebec, Canada
| | - Michael W Gray
- Department of Biochemistry and Molecular Biology and Institute of Comparative Genomics, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic
- Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
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12
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Wenger C, Harsman A, Niemann M, Oeljeklaus S, von Känel C, Calderaro S, Warscheid B, Schneider A. The Mba1 homologue of Trypanosoma brucei is involved in the biogenesis of oxidative phosphorylation complexes. Mol Microbiol 2023; 119:537-550. [PMID: 36829306 DOI: 10.1111/mmi.15048] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 02/16/2023] [Accepted: 02/21/2023] [Indexed: 02/26/2023]
Abstract
Consistent with other eukaryotes, the Trypanosoma brucei mitochondrial genome encodes mainly hydrophobic core subunits of the oxidative phosphorylation system. These proteins must be co-translationally inserted into the inner mitochondrial membrane and are synthesized by the highly unique trypanosomal mitoribosomes, which have a much higher protein to RNA ratio than any other ribosome. Here, we show that the trypanosomal orthologue of the mitoribosome receptor Mba1 (TbMba1) is essential for normal growth of procyclic trypanosomes but redundant in the bloodstream form, which lacks an oxidative phosphorylation system. Proteomic analyses of TbMba1-depleted mitochondria from procyclic cells revealed reduced levels of many components of the oxidative phosphorylation system, most of which belong to the cytochrome c oxidase (Cox) complex, three subunits of which are mitochondrially encoded. However, the integrity of the mitoribosome and its interaction with the inner membrane were not affected. Pull-down experiments showed that TbMba1 forms a dynamic interaction network that includes the trypanosomal Mdm38/Letm1 orthologue and a trypanosome-specific factor that stabilizes the CoxI and CoxII mRNAs. In summary, our study suggests that the function of Mba1 in the biogenesis of membrane subunits of OXPHOS complexes is conserved among yeast, mammals and trypanosomes, which belong to two eukaryotic supergroups.
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Affiliation(s)
- Christoph Wenger
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Anke Harsman
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Moritz Niemann
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Silke Oeljeklaus
- Faculty of Chemistry and Pharmacy, Biochemistry II, Theodor Boveri-Institute, University of Würzburg, Würzburg, Germany
| | - Corinne von Känel
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Salvatore Calderaro
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Bettina Warscheid
- Faculty of Chemistry and Pharmacy, Biochemistry II, Theodor Boveri-Institute, University of Würzburg, Würzburg, Germany.,CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - André Schneider
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland.,Institute for Advanced Study (Wissenschaftskolleg) Berlin, Berlin, Germany
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13
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AlphaFold2 reveals commonalities and novelties in protein structure space for 21 model organisms. Commun Biol 2023; 6:160. [PMID: 36755055 PMCID: PMC9908985 DOI: 10.1038/s42003-023-04488-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 01/16/2023] [Indexed: 02/10/2023] Open
Abstract
Deep-learning (DL) methods like DeepMind's AlphaFold2 (AF2) have led to substantial improvements in protein structure prediction. We analyse confident AF2 models from 21 model organisms using a new classification protocol (CATH-Assign) which exploits novel DL methods for structural comparison and classification. Of ~370,000 confident models, 92% can be assigned to 3253 superfamilies in our CATH domain superfamily classification. The remaining cluster into 2367 putative novel superfamilies. Detailed manual analysis on 618 of these, having at least one human relative, reveal extremely remote homologies and further unusual features. Only 25 novel superfamilies could be confirmed. Although most models map to existing superfamilies, AF2 domains expand CATH by 67% and increases the number of unique 'global' folds by 36% and will provide valuable insights on structure function relationships. CATH-Assign will harness the huge expansion in structural data provided by DeepMind to rationalise evolutionary changes driving functional divergence.
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14
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Harper NJ, Burnside C, Klinge S. Principles of mitoribosomal small subunit assembly in eukaryotes. Nature 2023; 614:175-181. [PMID: 36482135 PMCID: PMC9892005 DOI: 10.1038/s41586-022-05621-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 12/02/2022] [Indexed: 12/13/2022]
Abstract
Mitochondrial ribosomes (mitoribosomes) synthesize proteins encoded within the mitochondrial genome that are assembled into oxidative phosphorylation complexes. Thus, mitoribosome biogenesis is essential for ATP production and cellular metabolism1. Here we used cryo-electron microscopy to determine nine structures of native yeast and human mitoribosomal small subunit assembly intermediates, illuminating the mechanistic basis for how GTPases are used to control early steps of decoding centre formation, how initial rRNA folding and processing events are mediated, and how mitoribosomal proteins have active roles during assembly. Furthermore, this series of intermediates from two species with divergent mitoribosomal architecture uncovers both conserved principles and species-specific adaptations that govern the maturation of mitoribosomal small subunits in eukaryotes. By revealing the dynamic interplay between assembly factors, mitoribosomal proteins and rRNA that are required to generate functional subunits, our structural analysis provides a vignette for how molecular complexity and diversity can evolve in large ribonucleoprotein assemblies.
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Affiliation(s)
- Nathan J Harper
- Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, NY, USA
- Tri-Institutional Training Program in Chemical Biology, The Rockefeller University, New York, NY, USA
| | - Chloe Burnside
- Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, NY, USA
- Tri-Institutional Training Program in Chemical Biology, The Rockefeller University, New York, NY, USA
| | - Sebastian Klinge
- Laboratory of Protein and Nucleic Acid Chemistry, The Rockefeller University, New York, NY, USA.
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15
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Abstract
Mitoribosome biogenesis is a complex and energetically costly process that involves RNA elements encoded in the mitochondrial genome and mitoribosomal proteins most frequently encoded in the nuclear genome. The process is catalyzed by extra-ribosomal proteins, nucleus-encoded assembly factors that act in all stages of the assembly process to coordinate the processing and maturation of ribosomal RNAs with the hierarchical association of ribosomal proteins. Biochemical studies and recent cryo-EM structures of mammalian mitoribosomes have provided hints regarding their assembly. In this general concept chapter, we will briefly describe the current knowledge, mainly regarding the mammalian mitoribosome biogenesis pathway and factors involved, and will emphasize the biological sources and approaches that have been applied to advance the field.
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Affiliation(s)
- J Conor Moran
- Department of Biochemistry and Molecular Biology, University of Miami, Miller School of Medicine, Miami, FL, USA
| | - Samuel Del'Olio
- Department of Molecular and Cellular Pharmacology, University of Miami, Miller School of Medicine, Miami, FL, USA
| | - Austin Choi
- Department of Neurology, University of Miami, Miller School of Medicine, Miami, FL, USA
| | - Hui Zhong
- Department of Biochemistry and Molecular Biology, University of Miami, Miller School of Medicine, Miami, FL, USA
| | - Antoni Barrientos
- Department of Neurology and Department of Biochemistry and Molecular Biology, University of Miami, Miller School of Medicine, Miami, FL, USA.
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16
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Del'Olio S, Barrientos A. Systematic Analysis of Assembly Intermediates in Yeast to Decipher the Mitoribosome Assembly Pathway. Methods Mol Biol 2023; 2661:163-191. [PMID: 37166638 PMCID: PMC10654547 DOI: 10.1007/978-1-0716-3171-3_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Studies of yeast mitoribosome assembly have been historically hampered by the difficulty of generating mitoribosome protein-coding gene deletion strains with a stable mitochondrial genome. The identification of mitochondrial DNA-stabilizing approaches allows for the generation of a complete set of yeast deletion strains covering all mitoribosome proteins and known assembly factors. These strains can be used to analyze the integrity and assembly state of mitoribosomes by determining the sedimentation profile of these structures by sucrose gradient centrifugation of mitochondrial extracts, coupled to mass spectrometry analysis of mitoribosome composition. Subsequent hierarchical cluster analysis of mitoribosome subassemblies accumulated in mutant strains reveals details regarding the order of protein association during the mitoribosome biogenetic process. These strains also allow the expression of truncated protein variants to probe the role of mitochondrion-specific protein extensions, the relevance of protein cofactors, or the importance of RNA-protein interactions in functional sites of the mitoribosome. In this chapter, we will detail the methodology involved in these studies.
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Affiliation(s)
- Samuel Del'Olio
- Department of Molecular and Cellular Pharmacology, University of Miami, Miller School of Medicine, Miami, FL, USA
| | - Antoni Barrientos
- Department of Neurology and Department of Biochemistry and Molecular Biology, University of Miami, Miller School of Medicine, Miami, FL, USA.
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17
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Mechanisms and players of mitoribosomal biogenesis revealed in trypanosomatids. Trends Parasitol 2022; 38:1053-1067. [PMID: 36075844 DOI: 10.1016/j.pt.2022.08.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 07/29/2022] [Accepted: 08/16/2022] [Indexed: 01/13/2023]
Abstract
Translation in mitochondria is mediated by mitochondrial ribosomes, or mitoribosomes, complex ribonucleoprotein machines with dual genetic origin. Mitoribosomes in trypanosomatid parasites diverged markedly from their bacterial ancestors and other eukaryotic lineages in terms of protein composition, rRNA content, and overall architecture, yet their core functional elements remained conserved. Recent cryo-electron microscopy studies provided atomic models of trypanosomatid large and small mitoribosomal subunits and their precursors, making these parasites the organisms with the best-understood biogenesis of mitoribosomes. The structures revealed molecular mechanisms and players involved in the assembly of mitoribosomes not only in the parasites, but also in eukaryotes in general.
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18
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Mitochondrial RNA editing in Trypanoplasma borreli: new tools, new revelations. Comput Struct Biotechnol J 2022; 20:6388-6402. [DOI: 10.1016/j.csbj.2022.11.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 11/09/2022] [Accepted: 11/09/2022] [Indexed: 11/16/2022] Open
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19
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Dass S, Mather MW, Morrisey JM, Ling L, Vaidya AB, Ke H. Transcriptional changes in Plasmodium falciparum upon conditional knock down of mitochondrial ribosomal proteins RSM22 and L23. PLoS One 2022; 17:e0274993. [PMID: 36201550 PMCID: PMC9536634 DOI: 10.1371/journal.pone.0274993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 09/07/2022] [Indexed: 11/23/2022] Open
Abstract
The mitochondrion of malaria parasites is an attractive antimalarial drug target, which require mitoribosomes to translate genes encoded in the mitochondrial (mt) DNA. Plasmodium mitoribosomes are composed of highly fragmented ribosomal RNA (rRNA) encoded in the mtDNA. All mitoribosomal proteins (MRPs) and other assembly factors are encoded in the nuclear genome. Here, we have studied one putative assembly factor, RSM22 (Pf3D7_1027200) and one large subunit (LSU) MRP, L23 (Pf3D7_1239100) in Plasmodium falciparum. We show that both proteins localize to the mitochondrion. Conditional knock down (KD) of PfRSM22 or PfMRPL23 leads to reduced cytochrome bc1 complex activity and increased sensitivity to bc1 inhibitors such as atovaquone and ELQ-300. Using RNA sequencing as a tool, we reveal the transcriptomic changes of nuclear and mitochondrial genomes upon KD of these two proteins. In the early phase of KD, while most mt rRNAs and transcripts of putative MRPs were downregulated in the absence of PfRSM22, many mt rRNAs and several MRPs were upregulated after KD of PfMRPL23. The contrast effects in the early phase of KD likely suggests non-redundant roles of PfRSM22 and PfMRPL23 in the assembly of P. falciparum mitoribosomes. At the late time points of KD, loss of PfRSM22 and PfMRPL23 caused defects in many essential metabolic pathways and transcripts related to essential mitochondrial functions, leading to parasite death. In addition, we enlist mitochondrial proteins of unknown function that are likely novel Plasmodium MRPs based on their structural similarity to known MRPs as well as their expression profiles in KD parasites.
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Affiliation(s)
- Swati Dass
- Center for Molecular Parasitology, Department of Microbiology and Immunology Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Michael W. Mather
- Center for Molecular Parasitology, Department of Microbiology and Immunology Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Joanne M. Morrisey
- Center for Molecular Parasitology, Department of Microbiology and Immunology Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Liqin Ling
- Center for Molecular Parasitology, Department of Microbiology and Immunology Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Akhil B. Vaidya
- Center for Molecular Parasitology, Department of Microbiology and Immunology Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Hangjun Ke
- Center for Molecular Parasitology, Department of Microbiology and Immunology Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
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20
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Jeilani M, Billington K, Sunter JD, Dean S, Wheeler RJ. Nucleolar targeting in an early-branching eukaryote suggests a general mechanism for ribosome protein sorting. J Cell Sci 2022; 135:jcs259701. [PMID: 36052646 PMCID: PMC9659390 DOI: 10.1242/jcs.259701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Accepted: 08/24/2022] [Indexed: 11/20/2022] Open
Abstract
The compartmentalised eukaryotic cell demands accurate targeting of proteins to the organelles in which they function, whether membrane-bound (like the nucleus) or non-membrane-bound (like the nucleolus). Nucleolar targeting relies on positively charged localisation signals and has received rejuvenated interest since the widespread recognition of liquid-liquid phase separation (LLPS) as a mechanism contributing to nucleolus formation. Here, we exploit a new genome-wide analysis of protein localisation in the early-branching eukaryote Trypanosoma brucei to analyse general nucleolar protein properties. T. brucei nucleolar proteins have similar properties to those in common model eukaryotes, specifically basic amino acids. Using protein truncations and addition of candidate targeting sequences to proteins, we show both homopolymer runs and distributed basic amino acids give nucleolar partition, further aided by a nuclear localisation signal (NLS). These findings are consistent with phase separation models of nucleolar formation and physical protein properties being a major contributing mechanism for eukaryotic nucleolar targeting, conserved from the last eukaryotic common ancestor. Importantly, cytoplasmic ribosome proteins, unlike mitochondrial ribosome proteins, have more basic residues - pointing to adaptation of physicochemical properties to assist segregation.
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Affiliation(s)
- Milad Jeilani
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Karen Billington
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
| | - Jack Daniel Sunter
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
| | - Samuel Dean
- Warwick Medical School, Warwick University, Warwick CV4 7AL, UK
| | - Richard John Wheeler
- Peter Medawar Building for Pathogen Research, Nuffield Department of Medicine, University of Oxford, Oxford OX1 3SY, UK
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21
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Grüttner S, Nguyen TT, Bruhs A, Mireau H, Kempken F. The P-type pentatricopeptide repeat protein DWEORG1 is a non-previously reported rPPR protein of Arabidopsis mitochondria. Sci Rep 2022; 12:12492. [PMID: 35864185 PMCID: PMC9304396 DOI: 10.1038/s41598-022-16812-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 07/15/2022] [Indexed: 11/17/2022] Open
Abstract
Gene expression in plant mitochondria is mainly regulated by nuclear-encoded proteins on a post-transcriptional level. Pentatricopeptide repeat (PPR) proteins play a major role by participating in mRNA stability, splicing, RNA editing, and translation initiation. PPR proteins were also shown to be part of the mitochondrial ribosome (rPPR proteins), which may act as regulators of gene expression in plants. In this study, we focus on a mitochondrial-located P-type PPR protein—DWEORG1—from Arabidopsis thaliana. Its abundance in mitochondria is high, and it has a similar expression pattern as rPPR proteins. Mutant dweorg1 plants exhibit a slow-growth phenotype. Using ribosome profiling, a decrease in translation efficiency for cox2, rps4, rpl5, and ccmFN2 was observed in dweorg1 mutants, correlating with a reduced accumulation of the Cox2 protein in these plants. In addition, the mitochondrial rRNA levels are significantly reduced in dweorg1 compared with the wild type. DWEORG1 co-migrates with the ribosomal proteins Rps4 and Rpl16 in sucrose gradients, suggesting an association of DWEORG1 with the mitoribosome. Collectively, this data suggests that DWEORG1 encodes a novel rPPR protein that is needed for the translation of cox2, rps4, rpl5, and ccmFN2 and provides a stabilizing function for mitochondrial ribosomes.
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Affiliation(s)
- Stefanie Grüttner
- Abteilung Botanische Genetik und Molekularbiologie, Botanisches Institut und Botanischer Garten, Christian-Albrechts-Universität zu Kiel, Olshausenstraße 40, 24098, Kiel, Germany
| | - Tan-Trung Nguyen
- Institut Jean-Pierre Bourgin INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles, France
| | - Anika Bruhs
- Abteilung Botanische Genetik und Molekularbiologie, Botanisches Institut und Botanischer Garten, Christian-Albrechts-Universität zu Kiel, Olshausenstraße 40, 24098, Kiel, Germany
| | - Hakim Mireau
- Institut Jean-Pierre Bourgin INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles, France.
| | - Frank Kempken
- Abteilung Botanische Genetik und Molekularbiologie, Botanisches Institut und Botanischer Garten, Christian-Albrechts-Universität zu Kiel, Olshausenstraße 40, 24098, Kiel, Germany.
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22
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Fatkhullin BF, Gabdulkhakov AG, Yusupov MM. Is RsfS a Hibernation Factor or a Ribosome Biogenesis Factor? BIOCHEMISTRY. BIOKHIMIIA 2022; 87:500-510. [PMID: 35790407 DOI: 10.1134/s0006297922060025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 04/20/2022] [Accepted: 04/20/2022] [Indexed: 06/15/2023]
Abstract
Solving the structures of bacterial, archaeal, and eukaryotic ribosomes by crystallography and cryo-electron microscopy has given an impetus for studying intracellular regulatory proteins affecting various stages of protein translation. Among them are ribosome hibernation factors, which have been actively investigated during the last decade. These factors are involved in the regulation of protein biosynthesis under stressful conditions. The main role of hibernation factors is the reduction of energy consumption for protein biosynthesis and preservation of existing functional ribosomes from degradation, which increases cell survival under unfavorable conditions. Despite a broad interest in this topic, only a few articles have been published on the ribosomal silencing factor S (RsfS). According to the results of these studies, RsfS can be assigned to the group of hibernation factors. However, recent structural studies of the 50S ribosomal subunit maturation demonstrated that RsfS has the features inherent to biogenesis factors for example, ability to bind to the immature ribosomal subunit (similar to the RsfS mitochondrial ortholog MALSU1, mitochondrial assembly of ribosomal large subunit 1). In this review, we summarized the information on the function and structural features RsfS, as well as compared RsfS with MALSU1 in order to answer the emerging question on whether RsfS is a hibernation factor or a ribosome biogenesis factor. We believe that this review might promote future studies of the RsfS-involving molecular mechanisms, which so far remain completely unknown.
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Affiliation(s)
- Bulat F Fatkhullin
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
- Institute of Genetics and Molecular and Cellular Biology, Illkirsch-Graffenstaden, F-67400, France
| | - Azat G Gabdulkhakov
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
| | - Marat M Yusupov
- Institute of Genetics and Molecular and Cellular Biology, Illkirsch-Graffenstaden, F-67400, France
- Laboratory of Structural Analyze of Biomacromolecules, Federal Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Kazan, 420111, Russia
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23
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Durrieu-Gaillard S, Sissler M, Hashem Y. Purification of Mitochondrial Ribosomal Complexes from Trypanosoma cruzi and Leishmania tarentolae for Cryo-EM Analysis. Bio Protoc 2022; 12:e4425. [PMID: 35865117 PMCID: PMC9183961 DOI: 10.21769/bioprotoc.4425] [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: 12/06/2021] [Revised: 04/05/2022] [Accepted: 04/11/2022] [Indexed: 12/29/2022] Open
Abstract
Kinetoplastids are unicellular eukaryotic parasites responsible for human pathologies such as Chagas disease, sleeping sickness or Leishmaniasis, caused by Trypanosoma cruzi, Trypanosoma brucei, and various Leishmania spp., respectively. They harbor a single large mitochondrion that is essential for the survival of the parasite. Interestingly, most of the mitochondrial gene expression machineries and processes present significant differences from their nuclear and cytosolic counterparts. A striking example concerns their mitochondrial ribosomes, in charge of translating the few essential mRNAs encoded by mitochondrial genomes. Here, we present a detailed protocol including the specific procedures to isolate mitochondria from two species of kinetoplastids, T. cruzi and L. tarentolae, by differential centrifugations. Then, we detail the protocol to purify mitochondrial ribosomal complexes from these two species of parasites (including ribosomal maturating complexes) by a sucrose gradient approach. Finally, we describe how to prepare cryo-electron microscopy (cryo-EM) grids from these two sorts of samples. This protocol will be useful for further studies aiming at analyzing mitochondrial translation regulation.
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Affiliation(s)
| | - Marie Sissler
- Institut Europeen de Chimie et Biologie, U1212 Inserm/UMR5320 CNRS, Universite,
*For correspondence: ;
| | - Yaser Hashem
- Institut Europeen de Chimie et Biologie, U1212 Inserm/UMR5320 CNRS, Universite,
*For correspondence: ;
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24
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Scaltsoyiannes V, Corre N, Waltz F, Giegé P. Types and Functions of Mitoribosome-Specific Ribosomal Proteins across Eukaryotes. Int J Mol Sci 2022; 23:ijms23073474. [PMID: 35408834 PMCID: PMC8998825 DOI: 10.3390/ijms23073474] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 03/17/2022] [Accepted: 03/21/2022] [Indexed: 02/04/2023] Open
Abstract
Mitochondria are key organelles that combine features inherited from their bacterial endosymbiotic ancestor with traits that arose during eukaryote evolution. These energy producing organelles have retained a genome and fully functional gene expression machineries including specific ribosomes. Recent advances in cryo-electron microscopy have enabled the characterization of a fast-growing number of the low abundant membrane-bound mitochondrial ribosomes. Surprisingly, mitoribosomes were found to be extremely diverse both in terms of structure and composition. Still, all of them drastically increased their number of ribosomal proteins. Interestingly, among the more than 130 novel ribosomal proteins identified to date in mitochondria, most of them are composed of a-helices. Many of them belong to the nuclear encoded super family of helical repeat proteins. Here we review the diversity of functions and the mode of action held by the novel mitoribosome proteins and discuss why these proteins that share similar helical folds were independently recruited by mitoribosomes during evolution in independent eukaryote clades.
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Affiliation(s)
- Vassilis Scaltsoyiannes
- CNRS, Institut de Biologie Moléculaire des Plantes, Université de Strasbourg, 67084 Strasbourg, France; (V.S.); (N.C.)
| | - Nicolas Corre
- CNRS, Institut de Biologie Moléculaire des Plantes, Université de Strasbourg, 67084 Strasbourg, France; (V.S.); (N.C.)
| | - Florent Waltz
- CNRS, Institut de Biologie Moléculaire des Plantes, Université de Strasbourg, 67084 Strasbourg, France; (V.S.); (N.C.)
- Helmholtz Pioneer Campus, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764 Munich, Germany
- Correspondence: (F.W.); (P.G.); Tel.: +33-3-6715-5363 (P.G.); Fax: +33-3-8861-4442 (P.G.)
| | - Philippe Giegé
- CNRS, Institut de Biologie Moléculaire des Plantes, Université de Strasbourg, 67084 Strasbourg, France; (V.S.); (N.C.)
- Correspondence: (F.W.); (P.G.); Tel.: +33-3-6715-5363 (P.G.); Fax: +33-3-8861-4442 (P.G.)
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25
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Lenarčič T, Niemann M, Ramrath DJF, Calderaro S, Flügel T, Saurer M, Leibundgut M, Boehringer D, Prange C, Horn EK, Schneider A, Ban N. Mitoribosomal small subunit maturation involves formation of initiation-like complexes. Proc Natl Acad Sci U S A 2022; 119:e2114710118. [PMID: 35042777 PMCID: PMC8784144 DOI: 10.1073/pnas.2114710118] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 10/29/2021] [Indexed: 01/02/2023] Open
Abstract
Mitochondrial ribosomes (mitoribosomes) play a central role in synthesizing mitochondrial inner membrane proteins responsible for oxidative phosphorylation. Although mitoribosomes from different organisms exhibit considerable structural variations, recent insights into mitoribosome assembly suggest that mitoribosome maturation follows common principles and involves a number of conserved assembly factors. To investigate the steps involved in the assembly of the mitoribosomal small subunit (mt-SSU) we determined the cryoelectron microscopy structures of middle and late assembly intermediates of the Trypanosoma brucei mitochondrial small subunit (mt-SSU) at 3.6- and 3.7-Å resolution, respectively. We identified five additional assembly factors that together with the mitochondrial initiation factor 2 (mt-IF-2) specifically interact with functionally important regions of the rRNA, including the decoding center, thereby preventing premature mRNA or large subunit binding. Structural comparison of assembly intermediates with mature mt-SSU combined with RNAi experiments suggests a noncanonical role of mt-IF-2 and a stepwise assembly process, where modular exchange of ribosomal proteins and assembly factors together with mt-IF-2 ensure proper 9S rRNA folding and protein maturation during the final steps of assembly.
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Affiliation(s)
- Tea Lenarčič
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Moritz Niemann
- Department of Chemistry, Biochemistry, and Pharmaceutical Sciences, University of Bern, CH-3012 Bern, Switzerland
| | - David J F Ramrath
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Salvatore Calderaro
- Department of Chemistry, Biochemistry, and Pharmaceutical Sciences, University of Bern, CH-3012 Bern, Switzerland
| | - Timo Flügel
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Martin Saurer
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Marc Leibundgut
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Daniel Boehringer
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Céline Prange
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Elke K Horn
- Department of Chemistry, Biochemistry, and Pharmaceutical Sciences, University of Bern, CH-3012 Bern, Switzerland
| | - André Schneider
- Department of Chemistry, Biochemistry, and Pharmaceutical Sciences, University of Bern, CH-3012 Bern, Switzerland
| | - Nenad Ban
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, CH-8093 Zurich, Switzerland;
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26
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Jüttner M, Ferreira-Cerca S. A Comparative Perspective on Ribosome Biogenesis: Unity and Diversity Across the Tree of Life. Methods Mol Biol 2022; 2533:3-22. [PMID: 35796979 PMCID: PMC9761495 DOI: 10.1007/978-1-0716-2501-9_1] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
Ribosomes are universally conserved ribonucleoprotein complexes involved in the decoding of the genetic information contained in messenger RNAs into proteins. Accordingly, ribosome biogenesis is a fundamental cellular process required for functional ribosome homeostasis and to preserve satisfactory gene expression capability.Although the ribosome is universally conserved, its biogenesis shows an intriguing degree of variability across the tree of life . These differences also raise yet unresolved questions. Among them are (a) what are, if existing, the remaining ancestral common principles of ribosome biogenesis ; (b) what are the molecular impacts of the evolution history and how did they contribute to (re)shape the ribosome biogenesis pathway across the tree of life ; (c) what is the extent of functional divergence and/or convergence (functional mimicry), and in the latter case (if existing) what is the molecular basis; (d) considering the universal ribosome conservation, what is the capability of functional plasticity and cellular adaptation of the ribosome biogenesis pathway?In this review, we provide a brief overview of ribosome biogenesis across the tree of life and try to illustrate some potential and/or emerging answers to these unresolved questions.
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Affiliation(s)
- Michael Jüttner
- Biochemistry III-Regensburg Center for Biochemistry-Institute for Biochemistry, Genetics and Microbiology, University of Regensburg, Regensburg, Germany
| | - Sébastien Ferreira-Cerca
- Biochemistry III-Regensburg Center for Biochemistry-Institute for Biochemistry, Genetics and Microbiology, University of Regensburg, Regensburg, Germany.
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27
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Waltz F, Salinas-Giegé T, Englmeier R, Meichel H, Soufari H, Kuhn L, Pfeffer S, Förster F, Engel BD, Giegé P, Drouard L, Hashem Y. How to build a ribosome from RNA fragments in Chlamydomonas mitochondria. Nat Commun 2021; 12:7176. [PMID: 34887394 PMCID: PMC8660880 DOI: 10.1038/s41467-021-27200-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 11/08/2021] [Indexed: 01/12/2023] Open
Abstract
Mitochondria are the powerhouse of eukaryotic cells. They possess their own gene expression machineries where highly divergent and specialized ribosomes, named hereafter mitoribosomes, translate the few essential messenger RNAs still encoded by mitochondrial genomes. Here, we present a biochemical and structural characterization of the mitoribosome in the model green alga Chlamydomonas reinhardtii, as well as a functional study of some of its specific components. Single particle cryo-electron microscopy resolves how the Chlamydomonas mitoribosome is assembled from 13 rRNA fragments encoded by separate non-contiguous gene pieces. Additional proteins, mainly OPR, PPR and mTERF helical repeat proteins, are found in Chlamydomonas mitoribosome, revealing the structure of an OPR protein in complex with its RNA binding partner. Targeted amiRNA silencing indicates that these ribosomal proteins are required for mitoribosome integrity. Finally, we use cryo-electron tomography to show that Chlamydomonas mitoribosomes are attached to the inner mitochondrial membrane via two contact points mediated by Chlamydomonas-specific proteins. Our study expands our understanding of mitoribosome diversity and the various strategies these specialized molecular machines adopt for membrane tethering.
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Affiliation(s)
- Florent Waltz
- Institut Européen de Chimie et Biologie, U1212 Inserm, Université de Bordeaux, 2 rue R. Escarpit, 33600, Pessac, France
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, 12 rue du général Zimmer, 67084, Strasbourg, France
- Helmholtz Pioneer Campus, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany
| | - Thalia Salinas-Giegé
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, 12 rue du général Zimmer, 67084, Strasbourg, France
| | - Robert Englmeier
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht, The Netherlands
| | - Herrade Meichel
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, 12 rue du général Zimmer, 67084, Strasbourg, France
| | - Heddy Soufari
- Institut Européen de Chimie et Biologie, U1212 Inserm, Université de Bordeaux, 2 rue R. Escarpit, 33600, Pessac, France
| | - Lauriane Kuhn
- Plateforme protéomique Strasbourg Esplanade FRC1589 du CNRS, Université de Strasbourg, 67084, Strasbourg, France
| | - Stefan Pfeffer
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, 69120, Heidelberg, Germany
| | - Friedrich Förster
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht, The Netherlands
| | - Benjamin D Engel
- Helmholtz Pioneer Campus, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany
- Department of Chemistry, Technical University of Munich, Lichtenbergstraße 4, 85748, Garching, Germany
| | - Philippe Giegé
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, 12 rue du général Zimmer, 67084, Strasbourg, France.
| | - Laurence Drouard
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, 12 rue du général Zimmer, 67084, Strasbourg, France.
| | - Yaser Hashem
- Institut Européen de Chimie et Biologie, U1212 Inserm, Université de Bordeaux, 2 rue R. Escarpit, 33600, Pessac, France.
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28
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Herbert CJ, Labarre-Mariotte S, Cornu D, Sophie C, Panozzo C, Michel T, Dujardin G, Bonnefoy N. Translational activators and mitoribosomal isoforms cooperate to mediate mRNA-specific translation in Schizosaccharomyces pombe mitochondria. Nucleic Acids Res 2021; 49:11145-11166. [PMID: 34634819 PMCID: PMC8565316 DOI: 10.1093/nar/gkab789] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 08/24/2021] [Accepted: 10/05/2021] [Indexed: 11/12/2022] Open
Abstract
Mitochondrial mRNAs encode key subunits of the oxidative phosphorylation complexes that produce energy for the cell. In Saccharomyces cerevisiae, mitochondrial translation is under the control of translational activators, specific to each mRNA. In Schizosaccharomyces pombe, which more closely resembles the human system by its mitochondrial DNA structure and physiology, most translational activators appear to be either lacking, or recruited for post-translational functions. By combining bioinformatics, genetic and biochemical approaches we identified two interacting factors, Cbp7 and Cbp8, controlling Cytb production in S. pombe. We show that their absence affects cytb mRNA stability and impairs the detection of the Cytb protein. We further identified two classes of Cbp7/Cbp8 partners and showed that they modulated Cytb or Cox1 synthesis. First, two isoforms of bS1m, a protein of the small mitoribosomal subunit, that appear mutually exclusive and confer translational specificity. Second, a complex of four proteins dedicated to Cox1 synthesis, which includes an RNA helicase that interacts with the mitochondrial ribosome. Our results suggest that S. pombe contains, in addition to complexes of translational activators, a heterogeneous population of mitochondrial ribosomes that could specifically modulate translation depending on the mRNA translated, in order to optimally balance the production of different respiratory complex subunits.
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Affiliation(s)
- Christopher J Herbert
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Sylvie Labarre-Mariotte
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - David Cornu
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Cyrielle Sophie
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Cristina Panozzo
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Thomas Michel
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Geneviève Dujardin
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Nathalie Bonnefoy
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
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29
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Tartakoff AM, Chen L, Raghavachari S, Gitiforooz D, Dhinakaran A, Ni CL, Pasadyn C, Mahabeleshwar GH, Pasadyn V, Woolford JL. The nucleolus as a polarized coaxial cable in which the rDNA axis is surrounded by dynamic subunit-specific phases. Curr Biol 2021; 31:2507-2519.e4. [PMID: 33862007 PMCID: PMC8222187 DOI: 10.1016/j.cub.2021.03.041] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 01/18/2021] [Accepted: 03/11/2021] [Indexed: 12/24/2022]
Abstract
In ribosomal DNA (rDNA) repeats, sequences encoding small-subunit (SSU) rRNA precede those encoding large-subunit (LSU) rRNAs. Processing the composite transcript and subunit assembly requires >100 subunit-specific nucleolar assembly factors (AFs). To investigate the functional organization of the nucleolus, we localized AFs in S. cerevisiae in which the rDNA axis was "linearized" to reduce its dimensionality, thereby revealing its coaxial organization. In this situation, rRNA synthesis and processing continue. The axis is embedded in an inner layer/phase of SSU AFs that is surrounded by an outer layer/phase of LSU AFs. When subunit production is inhibited, subsets of AFs differentially relocate between the inner and outer layers, as expected if there is a cycle of repeated relocation whereby "latent" AFs become "operative" when recruited to nascent subunits. Recognition of AF cycling and localization of segments of rRNA make it possible to infer the existence of assembly intermediates that span between the inner and outer layers and to chart the cotranscriptional assembly of each subunit. AF cycling also can explain how having more than one protein phase in the nucleolus makes possible "vectorial 2-phase partitioning" as a driving force for relocation of nascent rRNPs. Because nucleoplasmic AFs are also present in the outer layer, we propose that critical surface remodeling occurs at this site, thereby partitioning subunit precursors into the nucleoplasm for post-transcriptional maturation. Comparison to observations on higher eukaryotes shows that the coaxial paradigm is likely to be applicable for the many other organisms that have rDNA repeats.
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Affiliation(s)
- Alan M Tartakoff
- Department of Pathology and Cell Biology Program, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH 44106, USA.
| | - Lan Chen
- Department of Pathology and Cell Biology Program, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH 44106, USA
| | - Shashank Raghavachari
- Department of Pathology and Cell Biology Program, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH 44106, USA
| | - Daria Gitiforooz
- Department of Pathology and Cell Biology Program, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH 44106, USA
| | - Akshyasri Dhinakaran
- Department of Pathology and Cell Biology Program, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH 44106, USA
| | - Chun-Lun Ni
- Department of Pathology and Cell Biology Program, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH 44106, USA
| | | | - Ganapati H Mahabeleshwar
- Department of Pathology and Cell Biology Program, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH 44106, USA
| | - Vanessa Pasadyn
- Department of Pathology and Cell Biology Program, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH 44106, USA
| | - John L Woolford
- Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA
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30
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Cipullo M, Gesé GV, Khawaja A, Hällberg BM, Rorbach J. Structural basis for late maturation steps of the human mitoribosomal large subunit. Nat Commun 2021; 12:3673. [PMID: 34135318 PMCID: PMC8209036 DOI: 10.1038/s41467-021-23617-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 05/07/2021] [Indexed: 01/29/2023] Open
Abstract
Mitochondrial ribosomes (mitoribosomes) synthesize a critical set of proteins essential for oxidative phosphorylation. Therefore, mitoribosomal function is vital to the cellular energy supply. Mitoribosome biogenesis follows distinct molecular pathways that remain poorly understood. Here, we determine the cryo-EM structures of mitoribosomes isolated from human cell lines with either depleted or overexpressed mitoribosome assembly factor GTPBP5, allowing us to capture consecutive steps during mitoribosomal large subunit (mt-LSU) biogenesis. Our structures provide essential insights into the last steps of 16S rRNA folding, methylation and peptidyl transferase centre (PTC) completion, which require the coordinated action of nine assembly factors. We show that mammalian-specific MTERF4 contributes to the folding of 16S rRNA, allowing 16 S rRNA methylation by MRM2, while GTPBP5 and NSUN4 promote fine-tuning rRNA rearrangements leading to PTC formation. Moreover, our data reveal an unexpected involvement of the elongation factor mtEF-Tu in mt-LSU assembly, where mtEF-Tu interacts with GTPBP5, similar to its interaction with tRNA during translational elongation.
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Affiliation(s)
- Miriam Cipullo
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Solna, Sweden
- Max Planck Institute Biology of Ageing-Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Genís Valentín Gesé
- Department of Cell and Molecular Biology, Karolinska Institutet, Solna, Sweden
| | - Anas Khawaja
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Solna, Sweden
- Max Planck Institute Biology of Ageing-Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - B Martin Hällberg
- Department of Cell and Molecular Biology, Karolinska Institutet, Solna, Sweden.
- Centre for Structural Systems Biology (CSSB) and Karolinska Institutet VR-RÅC, Hamburg, Germany.
| | - Joanna Rorbach
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Solna, Sweden.
- Max Planck Institute Biology of Ageing-Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden.
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31
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Lenarčič T, Jaskolowski M, Leibundgut M, Scaiola A, Schönhut T, Saurer M, Lee RG, Rackham O, Filipovska A, Ban N. Stepwise maturation of the peptidyl transferase region of human mitoribosomes. Nat Commun 2021; 12:3671. [PMID: 34135320 PMCID: PMC8208988 DOI: 10.1038/s41467-021-23811-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 05/07/2021] [Indexed: 02/08/2023] Open
Abstract
Mitochondrial ribosomes are specialized for the synthesis of membrane proteins responsible for oxidative phosphorylation. Mammalian mitoribosomes have diverged considerably from the ancestral bacterial ribosomes and feature dramatically reduced ribosomal RNAs. The structural basis of the mammalian mitochondrial ribosome assembly is currently not well understood. Here we present eight distinct assembly intermediates of the human large mitoribosomal subunit involving seven assembly factors. We discover that the NSUN4-MTERF4 dimer plays a critical role in the process by stabilizing the 16S rRNA in a conformation that exposes the functionally important regions of rRNA for modification by the MRM2 methyltransferase and quality control interactions with the conserved mitochondrial GTPase MTG2 that contacts the sarcin-ricin loop and the immature active site. The successive action of these factors leads to the formation of the peptidyl transferase active site of the mitoribosome and the folding of the surrounding rRNA regions responsible for interactions with tRNAs and the small ribosomal subunit.
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Affiliation(s)
- Tea Lenarčič
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Mateusz Jaskolowski
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Marc Leibundgut
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Alain Scaiola
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Tanja Schönhut
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Martin Saurer
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Richard G Lee
- Harry Perkins Institute of Medical Research, QEII Medical Centre, University of Western Australia, Nedlands, WA, Australia
- ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, University of Western Australia, Nedlands, WA, Australia
| | - Oliver Rackham
- Harry Perkins Institute of Medical Research, QEII Medical Centre, University of Western Australia, Nedlands, WA, Australia
- ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, University of Western Australia, Nedlands, WA, Australia
- Curtin Health Innovation Research Institute and Curtin Medical School, Curtin University, Bentley, WA, Australia
- Telethon Kids Institute, Northern Entrance, Perth Children's Hospital, Nedlands, WA, Australia
| | - Aleksandra Filipovska
- Harry Perkins Institute of Medical Research, QEII Medical Centre, University of Western Australia, Nedlands, WA, Australia
- ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, University of Western Australia, Nedlands, WA, Australia
- Telethon Kids Institute, Northern Entrance, Perth Children's Hospital, Nedlands, WA, Australia
| | - Nenad Ban
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland.
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32
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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: 5] [Impact Index Per Article: 1.3] [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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Ribosome Biogenesis and Cancer: Overview on Ribosomal Proteins. Int J Mol Sci 2021; 22:ijms22115496. [PMID: 34071057 PMCID: PMC8197113 DOI: 10.3390/ijms22115496] [Citation(s) in RCA: 108] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/16/2021] [Accepted: 05/19/2021] [Indexed: 12/11/2022] Open
Abstract
Cytosolic ribosomes (cytoribosomes) are macromolecular ribonucleoprotein complexes that are assembled from ribosomal RNA and ribosomal proteins, which are essential for protein biosynthesis. Mitochondrial ribosomes (mitoribosomes) perform translation of the proteins essential for the oxidative phosphorylation system. The biogenesis of cytoribosomes and mitoribosomes includes ribosomal RNA processing, modification and binding to ribosomal proteins and is assisted by numerous biogenesis factors. This is a major energy-consuming process in the cell and, therefore, is highly coordinated and sensitive to several cellular stressors. In mitochondria, the regulation of mitoribosome biogenesis is essential for cellular respiration, a process linked to cell growth and proliferation. This review briefly overviews the key stages of cytosolic and mitochondrial ribosome biogenesis; summarizes the main steps of ribosome biogenesis alterations occurring during tumorigenesis, highlighting the changes in the expression level of cytosolic ribosomal proteins (CRPs) and mitochondrial ribosomal proteins (MRPs) in different types of tumors; focuses on the currently available information regarding the extra-ribosomal functions of CRPs and MRPs correlated to cancer; and discusses the role of CRPs and MRPs as biomarkers and/or molecular targets in cancer treatment.
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34
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Záhonová K, Lax G, Sinha SD, Leonard G, Richards TA, Lukeš J, Wideman JG. Single-cell genomics unveils a canonical origin of the diverse mitochondrial genomes of euglenozoans. BMC Biol 2021; 19:103. [PMID: 34001130 PMCID: PMC8130358 DOI: 10.1186/s12915-021-01035-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 04/22/2021] [Indexed: 12/28/2022] Open
Abstract
Background The supergroup Euglenozoa unites heterotrophic flagellates from three major clades, kinetoplastids, diplonemids, and euglenids, each of which exhibits extremely divergent mitochondrial characteristics. Mitochondrial genomes (mtDNAs) of euglenids comprise multiple linear chromosomes carrying single genes, whereas mitochondrial chromosomes are circular non-catenated in diplonemids, but circular and catenated in kinetoplastids. In diplonemids and kinetoplastids, mitochondrial mRNAs require extensive and diverse editing and/or trans-splicing to produce mature transcripts. All known euglenozoan mtDNAs exhibit extremely short mitochondrial small (rns) and large (rnl) subunit rRNA genes, and absence of tRNA genes. How these features evolved from an ancestral bacteria-like circular mitochondrial genome remains unanswered. Results We sequenced and assembled 20 euglenozoan single-cell amplified genomes (SAGs). In our phylogenetic and phylogenomic analyses, three SAGs were placed within kinetoplastids, 14 within diplonemids, one (EU2) within euglenids, and two SAGs with nearly identical small subunit rRNA gene (18S) sequences (EU17/18) branched as either a basal lineage of euglenids, or as a sister to all euglenozoans. Near-complete mitochondrial genomes were identified in EU2 and EU17/18. Surprisingly, both EU2 and EU17/18 mitochondrial contigs contained multiple genes and one tRNA gene. Furthermore, EU17/18 mtDNA possessed several features unique among euglenozoans including full-length rns and rnl genes, six mitoribosomal genes, and nad11, all likely on a single chromosome. Conclusions Our data strongly suggest that EU17/18 is an early-branching euglenozoan with numerous ancestral mitochondrial features. Collectively these data contribute to untangling the early evolution of euglenozoan mitochondria. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01035-y.
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Affiliation(s)
- Kristína Záhonová
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic.,Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic
| | - Gordon Lax
- Department of Botany, University of British Columbia, Vancouver, Canada
| | - Savar D Sinha
- Center for Mechanisms of Evolution, Biodesign Institute, School of Life Sciences, Arizona State University, Tempe, USA
| | - Guy Leonard
- Department of Zoology, University of Oxford, Oxford, UK
| | | | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic. .,Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic.
| | - Jeremy G Wideman
- Center for Mechanisms of Evolution, Biodesign Institute, School of Life Sciences, Arizona State University, Tempe, USA.
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35
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Aphasizheva I, Aphasizhev R. Mitochondrial RNA quality control in trypanosomes. WILEY INTERDISCIPLINARY REVIEWS. RNA 2021; 12:e1638. [PMID: 33331073 PMCID: PMC9805618 DOI: 10.1002/wrna.1638] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/27/2020] [Accepted: 11/29/2020] [Indexed: 01/04/2023]
Abstract
Unicellular parasites Trypanosoma brucei spp. cause African human and animal trypanosomiasis, a spectrum of diseases that jeopardize public health and afflict the economy in sub-Saharan Africa. These hemoflagellates are distinguished by a single mitochondrion, which contains a kinetoplast nucleoid composed of DNA and histone-like proteins. Kinetoplast DNA (kDNA) represents a densely packed network of interlinked relaxed circular molecules: a few ~23-kb maxicircles encoding ribosomal RNAs (rRNAs) and proteins, and approximately 5,000 1-kb minicircles bearing guide RNA (gRNA) genes. The transcription start site defines the mRNA's 5' terminus while the primary RNA is remodeled into a monocistronic messenger by 3'-5' exonucleolytic trimming, 5' and 3' end modifications, and, in most cases, by internal U-insertion/deletion editing. Ribosomal and guide RNA precursors are also trimmed, and the processed molecules are uridylated. For 35 years, mRNA editing has attracted a major effort, but more recently the essential pre- and postediting processing and turnover events have been discovered and the key effectors have been identified. Among these, pentatricopeptide repeat (PPR) RNA binding proteins emerged as conduits coupling modifications of mRNA termini with internal sequence changes introduced by editing. Among 39 annotated PPRs, 20 belong to ribosomal subunits or assembly intermediates, four function as polyadenylation factors, a single factor directs 5' mRNA modification, and one protein is found in F1-ATPase. Nuclear and mitochondrial RNases P consist of a single PPR polypeptide, PRORP1 and PROP2, respectively. Here, we review PPR-mediated mitochondrial processes and discuss their potential roles in mRNA maturation, quality control, translational activation, and decay. This article is categorized under: RNA Processing > Capping and 5' End Modifications RNA Processing > 3' End Processing RNA Processing > RNA Editing and Modification.
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Affiliation(s)
- Inna Aphasizheva
- Department of Molecular and Cell Biology, Boston University Medical Campus, Boston, Massachusetts
| | - Ruslan Aphasizhev
- Department of Molecular and Cell Biology, Boston University Medical Campus, Boston, Massachusetts,Department of Biochemistry, Boston University Medical Campus, Boston, Massachusetts
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36
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Human Mitoribosome Biogenesis and Its Emerging Links to Disease. Int J Mol Sci 2021; 22:ijms22083827. [PMID: 33917098 PMCID: PMC8067846 DOI: 10.3390/ijms22083827] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 03/23/2021] [Accepted: 03/24/2021] [Indexed: 12/20/2022] Open
Abstract
Mammalian mitochondrial ribosomes (mitoribosomes) synthesize a small subset of proteins, which are essential components of the oxidative phosphorylation machinery. Therefore, their function is of fundamental importance to cellular metabolism. The assembly of mitoribosomes is a complex process that progresses through numerous maturation and protein-binding events coordinated by the actions of several assembly factors. Dysregulation of mitoribosome production is increasingly recognized as a contributor to metabolic and neurodegenerative diseases. In recent years, mutations in multiple components of the mitoribosome assembly machinery have been associated with a range of human pathologies, highlighting their importance to cell function and health. Here, we provide a review of our current understanding of mitoribosome biogenesis, highlighting the key factors involved in this process and the growing number of mutations in genes encoding mitoribosomal RNAs, proteins, and assembly factors that lead to human disease.
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Huang H, Ghalei H, Karbstein K. Quality control of 40S ribosome head assembly ensures scanning competence. J Cell Biol 2021; 219:152152. [PMID: 33007085 PMCID: PMC7534925 DOI: 10.1083/jcb.202004161] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 06/25/2020] [Accepted: 08/13/2020] [Indexed: 11/22/2022] Open
Abstract
During translation initiation, 40S ribosomes scan the mRNA until they encounter the start codon, where conformational changes produce a translation-competent 80S complex. Destabilizing the scanning complex results in misinitiation at non-AUG codons, demonstrating its importance for fidelity. Here, we use a combination of biochemical and genetic analyses to demonstrate that the ability of the nascent subunit to adopt the scanning complex is tested during assembly via structural mimicry. Specifically, formation of the 80S-like assembly intermediate, which structurally resembles scanning complexes, requires the correct folding of two rRNA elements in the subunit head and the proper positioning of the universally conserved head proteins Rps3, Rps15, Rps20, and Rps29. rRNA misfolding impairs the formation of 80S-like ribosomes, and bypass of individual checkpoints using cancer-associated mutations produces ribosomes defective in accurate start-site selection. Thus, the formation of 80S-like assembly intermediates is a quality control step that ensures scanning competence of the nascent subunit.
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Affiliation(s)
- Haina Huang
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, FL
| | - Homa Ghalei
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, FL
| | - Katrin Karbstein
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, Jupiter, FL.,Howard Hughes Medical Institute, Chevy Chase, MD
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38
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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: 188] [Impact Index Per Article: 47.0] [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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39
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Tobiasson V, Gahura O, Aibara S, Baradaran R, Zíková A, Amunts A. Interconnected assembly factors regulate the biogenesis of mitoribosomal large subunit. EMBO J 2021; 40:e106292. [PMID: 33576519 PMCID: PMC7957421 DOI: 10.15252/embj.2020106292] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 12/18/2020] [Accepted: 12/23/2020] [Indexed: 12/11/2022] Open
Abstract
Mitoribosomes consist of ribosomal RNA and protein components, coordinated assembly of which is critical for function. We used mitoribosomes from Trypanosoma brucei with reduced RNA and increased protein mass to provide insights into the biogenesis of the mitoribosomal large subunit. Structural characterization of a stable assembly intermediate revealed 22 assembly factors, some of which have orthologues/counterparts/homologues in mammalian genomes. These assembly factors form a protein network that spans a distance of 180 Å, shielding the ribosomal RNA surface. The central protuberance and L7/L12 stalk are not assembled entirely and require removal of assembly factors and remodeling of the mitoribosomal proteins to become functional. The conserved proteins GTPBP7 and mt‐EngA are bound together at the subunit interface in proximity to the peptidyl transferase center. A mitochondrial acyl‐carrier protein plays a role in docking the L1 stalk, which needs to be repositioned during maturation. Additional enzymatically deactivated factors scaffold the assembly while the exit tunnel is blocked. Together, this extensive network of accessory factors stabilizes the immature sites and connects the functionally important regions of the mitoribosomal large subunit.
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Affiliation(s)
- Victor Tobiasson
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden
| | - Ondřej Gahura
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Ceske Budejovice, Czech Republic
| | - Shintaro Aibara
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden
| | - Rozbeh Baradaran
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden
| | - Alena Zíková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Ceske Budejovice, Czech Republic.,Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic
| | - Alexey Amunts
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden
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40
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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: 49] [Impact Index Per Article: 9.8] [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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41
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Summer S, Smirnova A, Gabriele A, Toth U, Fasemore AM, Förstner KU, Kuhn L, Chicher J, Hammann P, Mitulović G, Entelis N, Tarassov I, Rossmanith W, Smirnov A. YBEY is an essential biogenesis factor for mitochondrial ribosomes. Nucleic Acids Res 2020; 48:9762-9786. [PMID: 32182356 PMCID: PMC7515705 DOI: 10.1093/nar/gkaa148] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 02/24/2020] [Accepted: 02/26/2020] [Indexed: 12/11/2022] Open
Abstract
Ribosome biogenesis requires numerous trans-acting factors, some of which are deeply conserved. In Bacteria, the endoribonuclease YbeY is believed to be involved in 16S rRNA 3′-end processing and its loss was associated with ribosomal abnormalities. In Eukarya, YBEY appears to generally localize to mitochondria (or chloroplasts). Here we show that the deletion of human YBEY results in a severe respiratory deficiency and morphologically abnormal mitochondria as an apparent consequence of impaired mitochondrial translation. Reduced stability of 12S rRNA and the deficiency of several proteins of the small ribosomal subunit in YBEY knockout cells pointed towards a defect in mitochondrial ribosome biogenesis. The specific interaction of mitoribosomal protein uS11m with YBEY suggests that the latter helps to properly incorporate uS11m into the nascent small subunit in its late assembly stage. This scenario shows similarities with final stages of cytosolic ribosome biogenesis, and may represent a late checkpoint before the mitoribosome engages in translation.
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Affiliation(s)
- Sabrina Summer
- Center for Anatomy & Cell Biology, Medical University of Vienna, Vienna A-1090, Austria
| | - Anna Smirnova
- UMR7156 - Molecular Genetics, Genomics, Microbiology, University of Strasbourg, CNRS, Strasbourg F-67000, France
| | - Alessandro Gabriele
- UMR7156 - Molecular Genetics, Genomics, Microbiology, University of Strasbourg, CNRS, Strasbourg F-67000, France
| | - Ursula Toth
- Center for Anatomy & Cell Biology, Medical University of Vienna, Vienna A-1090, Austria
| | | | - Konrad U Förstner
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg 97080, Germany.,TH Köln - University of Applied Sciences, Faculty of Information Science and Communication Studies, Institute of Information Science, Cologne D-50678, Germany.,ZB MED - Information Centre for Life Sciences, Cologne D-50931, Germany
| | - Lauriane Kuhn
- Proteomics Platform Strasbourg-Esplanade, FRC1589, IBMC, CNRS, Strasbourg F-67000, France
| | - Johana Chicher
- Proteomics Platform Strasbourg-Esplanade, FRC1589, IBMC, CNRS, Strasbourg F-67000, France
| | - Philippe Hammann
- Proteomics Platform Strasbourg-Esplanade, FRC1589, IBMC, CNRS, Strasbourg F-67000, France
| | - Goran Mitulović
- Proteomics Core Facility, Clinical Department for Laboratory Medicine, Medical University of Vienna, Vienna A-1090, Austria
| | - Nina Entelis
- UMR7156 - Molecular Genetics, Genomics, Microbiology, University of Strasbourg, CNRS, Strasbourg F-67000, France
| | - Ivan Tarassov
- UMR7156 - Molecular Genetics, Genomics, Microbiology, University of Strasbourg, CNRS, Strasbourg F-67000, France
| | - Walter Rossmanith
- Center for Anatomy & Cell Biology, Medical University of Vienna, Vienna A-1090, Austria
| | - Alexandre Smirnov
- UMR7156 - Molecular Genetics, Genomics, Microbiology, University of Strasbourg, CNRS, Strasbourg F-67000, France
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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: 31] [Impact Index Per Article: 6.2] [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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43
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Aphasizheva I, Yu T, Suematsu T, Liu Q, Mesitov MV, Yu C, Huang L, Zhang L, Aphasizhev R. Poly(A) binding KPAF4/5 complex stabilizes kinetoplast mRNAs in Trypanosoma brucei. Nucleic Acids Res 2020; 48:8645-8662. [PMID: 32614436 PMCID: PMC7470953 DOI: 10.1093/nar/gkaa575] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 06/22/2020] [Accepted: 06/24/2020] [Indexed: 12/23/2022] Open
Abstract
In Trypanosoma brucei, mitochondrial pre-mRNAs undergo 3′-5′ exonucleolytic processing, 3′ adenylation and uridylation, 5′ pyrophosphate removal, and, often, U-insertion/deletion editing. The 3′ modifications are modulated by pentatricopeptide repeat (PPR) Kinetoplast Polyadenylation Factors (KPAFs). We have shown that KPAF3 binding to the 3′ region stabilizes properly trimmed transcripts and stimulates their A-tailing by KPAP1 poly(A) polymerase. Conversely, poly(A) binding KPAF4 shields the nascent A-tail from uridylation and decay thereby protecting pre-mRNA upon KPAF3 displacement by editing. While editing concludes in the 5′ region, KPAF1/2 dimer induces A/U-tailing to activate translation. Remarkably, 5′ end recognition and pyrophosphate hydrolysis by the PPsome complex also contribute to mRNA stabilization. Here, we demonstrate that KPAF4 functions as a heterodimer with KPAF5, a protein lacking discernable motifs. We show that KPAF5 stabilizes KPAF4 to enable poly(A) tail recognition, which likely leads to mRNA stabilization during the editing process and impedes spontaneous translational activation of partially-edited transcripts. Thus, KPAF4/5 represents a poly(A) binding element of the mitochondrial polyadenylation complex. We present evidence that RNA editing substrate binding complex bridges the 5′ end-bound PPsome and 3′ end-bound polyadenylation complexes. This interaction may enable mRNA circularization, an apparently critical element of mitochondrial mRNA stability and quality control.
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Affiliation(s)
- Inna Aphasizheva
- Department of Molecular and Cell Biology, Boston University Medical Campus, Boston, MA 02118, USA
| | - Tian Yu
- Department of Molecular and Cell Biology, Boston University Medical Campus, Boston, MA 02118, USA
| | - Takuma Suematsu
- Department of Molecular and Cell Biology, Boston University Medical Campus, Boston, MA 02118, USA
| | - Qiushi Liu
- Department of Molecular and Cell Biology, Boston University Medical Campus, Boston, MA 02118, USA
| | - Mikhail V Mesitov
- Department of Molecular and Cell Biology, Boston University Medical Campus, Boston, MA 02118, USA
| | - Clinton Yu
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA 92697, USA
| | - Lan Huang
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA 92697, USA
| | - Liye Zhang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Ruslan Aphasizhev
- Department of Molecular and Cell Biology, Boston University Medical Campus, Boston, MA 02118, USA.,Department of Biochemistry, Boston University Medical Campus, Boston, MA 02118, USA
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44
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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: 16] [Impact Index Per Article: 3.2] [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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45
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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: 18] [Impact Index Per Article: 3.6] [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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46
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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: 8] [Impact Index Per Article: 1.6] [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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47
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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: 48] [Impact Index Per Article: 9.6] [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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48
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Cupo RR, Shorter J. Skd3 (human ClpB) is a potent mitochondrial protein disaggregase that is inactivated by 3-methylglutaconic aciduria-linked mutations. eLife 2020; 9:e55279. [PMID: 32573439 PMCID: PMC7343390 DOI: 10.7554/elife.55279] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Accepted: 06/22/2020] [Indexed: 12/14/2022] Open
Abstract
Cells have evolved specialized protein disaggregases to reverse toxic protein aggregation and restore protein functionality. In nonmetazoan eukaryotes, the AAA+ disaggregase Hsp78 resolubilizes and reactivates proteins in mitochondria. Curiously, metazoa lack Hsp78. Hence, whether metazoan mitochondria reactivate aggregated proteins is unknown. Here, we establish that a mitochondrial AAA+ protein, Skd3 (human ClpB), couples ATP hydrolysis to protein disaggregation and reactivation. The Skd3 ankyrin-repeat domain combines with conserved AAA+ elements to enable stand-alone disaggregase activity. A mitochondrial inner-membrane protease, PARL, removes an autoinhibitory peptide from Skd3 to greatly enhance disaggregase activity. Indeed, PARL-activated Skd3 solubilizes α-synuclein fibrils connected to Parkinson's disease. Human cells lacking Skd3 exhibit reduced solubility of various mitochondrial proteins, including anti-apoptotic Hax1. Importantly, Skd3 variants linked to 3-methylglutaconic aciduria, a severe mitochondrial disorder, display diminished disaggregase activity (but not always reduced ATPase activity), which predicts disease severity. Thus, Skd3 is a potent protein disaggregase critical for human health.
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Affiliation(s)
- Ryan R Cupo
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of PennsylvaniaPhiladelphiaUnited States
- Pharmacology Graduate Group, Perelman School of Medicine at the University of PennsylvaniaPhiladelphiaUnited States
| | - James Shorter
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of PennsylvaniaPhiladelphiaUnited States
- Pharmacology Graduate Group, Perelman School of Medicine at the University of PennsylvaniaPhiladelphiaUnited States
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49
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Aphasizheva I, Alfonzo J, Carnes J, Cestari I, Cruz-Reyes J, Göringer HU, Hajduk S, Lukeš J, Madison-Antenucci S, Maslov DA, McDermott SM, Ochsenreiter T, Read LK, Salavati R, Schnaufer A, Schneider A, Simpson L, Stuart K, Yurchenko V, Zhou ZH, Zíková A, Zhang L, Zimmer S, Aphasizhev R. Lexis and Grammar of Mitochondrial RNA Processing in Trypanosomes. Trends Parasitol 2020; 36:337-355. [PMID: 32191849 PMCID: PMC7083771 DOI: 10.1016/j.pt.2020.01.006] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 01/19/2020] [Accepted: 01/22/2020] [Indexed: 12/15/2022]
Abstract
Trypanosoma brucei spp. cause African human and animal trypanosomiasis, a burden on health and economy in Africa. These hemoflagellates are distinguished by a kinetoplast nucleoid containing mitochondrial DNAs of two kinds: maxicircles encoding ribosomal RNAs (rRNAs) and proteins and minicircles bearing guide RNAs (gRNAs) for mRNA editing. All RNAs are produced by a phage-type RNA polymerase as 3' extended precursors, which undergo exonucleolytic trimming. Most pre-mRNAs proceed through 3' adenylation, uridine insertion/deletion editing, and 3' A/U-tailing. The rRNAs and gRNAs are 3' uridylated. Historically, RNA editing has attracted major research effort, and recently essential pre- and postediting processing events have been discovered. Here, we classify the key players that transform primary transcripts into mature molecules and regulate their function and turnover.
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Affiliation(s)
- Inna Aphasizheva
- Department of Molecular and Cell Biology, Boston University Medical Campus, Boston, MA 02118, USA.
| | - Juan Alfonzo
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
| | - Jason Carnes
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA 98109, USA
| | - Igor Cestari
- Institute of Parasitology, McGill University, 21,111 Lakeshore Road, Ste-Anne-de-Bellevue, H9X3V9, Québec, Canada
| | - Jorge Cruz-Reyes
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - H Ulrich Göringer
- Department of Molecular Genetics, Darmstadt University of Technology, 64287 Darmstadt, Germany
| | - Stephen Hajduk
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences and Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Susan Madison-Antenucci
- Parasitology Laboratory, Wadsworth Center, New York State Department of Health, Albany, NY 12201, USA
| | - Dmitri A Maslov
- Department of Molecular, Cell, and Systems Biology, University of California - Riverside, Riverside, CA 92521, USA
| | - Suzanne M McDermott
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA 98109, USA
| | - Torsten Ochsenreiter
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, Bern CH-3012, Switzerland
| | - Laurie K Read
- Department of Microbiology and Immunology, University at Buffalo, Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY 14203, USA
| | - Reza Salavati
- Institute of Parasitology, McGill University, 21,111 Lakeshore Road, Ste-Anne-de-Bellevue, H9X3V9, Québec, Canada
| | - Achim Schnaufer
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - André Schneider
- Department of Chemistry and Biochemistry, University of Bern, Bern CH-3012, Switzerland
| | - Larry Simpson
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA90095, USA
| | - Kenneth Stuart
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA 98109, USA
| | - Vyacheslav Yurchenko
- Life Science Research Centre, Faculty of Science, University of Ostrava, Ostrava, Czech Republic; Martsinovsky Institute of Medical Parasitology, Sechenov University, Moscow, Russia
| | - Z Hong Zhou
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA90095, USA
| | - Alena Zíková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences and Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Liye Zhang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Sara Zimmer
- University of Minnesota Medical School, Duluth campus, Duluth, MN 55812, USA
| | - Ruslan Aphasizhev
- Department of Molecular and Cell Biology, Boston University Medical Campus, Boston, MA 02118, USA
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50
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Abstract
The ribosome and RNase P are cellular ribonucleoprotein complexes that perform peptide bond synthesis and phosphodiester bond cleavage, respectively. Both are ancient biological assemblies that were already present in the last universal common ancestor of all life. The large subunit rRNA in the ribosome and the RNA subunit of RNase P are the ribozyme components required for catalysis. Here, we explore the idea that these two large ribozymes may have begun their evolutionary odyssey as an assemblage of RNA "fragments" smaller than the contemporary full-length versions and that they transitioned through distinct stages along a pathway that may also be relevant for the evolution of other non-coding RNAs.
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Affiliation(s)
- Michael W Gray
- Department of Biochemistry and Molecular Biology and Centre for Comparative Genomics and Evolutionary Bioinformatics, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada.
| | - Venkat Gopalan
- Department of Chemistry and Biochemistry and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210.
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