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Matsumoto E, Sasaki T, Higashiyama T, Sasaki N. Human RCC1L is involved in the maintenance of mitochondrial nucleoids and mtDNA. Sci Rep 2025; 15:13811. [PMID: 40259011 PMCID: PMC12012109 DOI: 10.1038/s41598-025-98397-y] [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: 12/12/2024] [Accepted: 04/11/2025] [Indexed: 04/23/2025] Open
Abstract
Mitochondrial DNA (mtDNA) is organized with proteins into mitochondrial nucleoid (mt-nucleoid). The mt-nucleoid is a unit for the maintenance and function of mtDNA. The regulator of chromosome condensation 1-like protein (RCC1L) performs various functions in mitochondria, including translation, but its involvement in regulating mt-nucleoid maintenance is unknown. Herein, we found that human RCC1L was required to maintain mt-nucleoids and mtDNA. Human RCC1L has three splicing isoforms: RCC1LV1, RCC1LV2, and RCC1LV3. Knockout (KO) cells lacking all RCC1L isoforms, which were lethal without pyruvate and uridine, exhibited a decrease in mt-nucleoids and mtDNA, along with swollen and fragmented mitochondria. Among the three RCC1L isoforms, only RCC1LV1 recovered all phenotypes observed in RCC1L KO cells. As the treatment of wild-type cells with chloramphenicol, a mitochondrial translation inhibitor, did not lead to the decrease in mt-nucleoids accompanied by mtDNA depletion, the decrease in mt-nucleoids and mtDNA in RCC1L KO cells was not solely attributed to impaired mitochondrial translation. Using conditional RCC1L KO cells, we observed a rapid decrease in mt-nucleoids and mtDNA during a specific period following RCC1L loss. Our findings indicate that RCC1L regulates the maintenance of mt-nucleoids and mtDNA besides its role in mitochondrial translational regulation.
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Affiliation(s)
- Emi Matsumoto
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Taeko Sasaki
- Laboratory of Molecular Membrane Biology, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi, Gunma, 371-8512, Japan
- Laboratory of Molecular Traffic, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi, Gunma, 371-8512, Japan
| | - Tetsuya Higashiyama
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Narie Sasaki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
- Center for Diversity, Equity & Inclusion, Tohoku University, 2-1-1 Katahira Aoba-ku, Sendai, Miyagi, 980-8577, Japan.
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2
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Heinrichs M, Finke AF, Aibara S, Krempler A, Boshnakovska A, Rehling P, Hillen HS, Richter-Dennerlein R. Coupling of ribosome biogenesis and translation initiation in human mitochondria. Nat Commun 2025; 16:3641. [PMID: 40240327 PMCID: PMC12003892 DOI: 10.1038/s41467-025-58827-x] [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: 08/12/2024] [Accepted: 04/02/2025] [Indexed: 04/18/2025] Open
Abstract
Biogenesis of mitoribosomes requires dedicated chaperones, RNA-modifying enzymes, and GTPases, and defects in mitoribosome assembly lead to severe mitochondriopathies in humans. Here, we characterize late-step assembly states of the small mitoribosomal subunit (mtSSU) by combining genetic perturbation and mutagenesis analysis with biochemical and structural approaches. Isolation of native mtSSU biogenesis intermediates via a FLAG-tagged variant of the GTPase MTG3 reveals three distinct assembly states, which show how factors cooperate to mature the 12S rRNA. In addition, we observe four distinct primed initiation mtSSU states with an incompletely matured rRNA, suggesting that biogenesis and translation initiation are not mutually exclusive processes but can occur simultaneously. Together, these results provide insights into mtSSU biogenesis and suggest a functional coupling between ribosome biogenesis and translation initiation in human mitochondria.
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Affiliation(s)
- Marleen Heinrichs
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
| | - Anna Franziska Finke
- Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany
- Research Group Structure and Function of Molecular Machines, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Shintaro Aibara
- Department of Molecular Biology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Angelique Krempler
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany
| | - Angela Boshnakovska
- Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Peter Rehling
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
- Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany
- Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Translational Neuroinflammation and Automated Microscopy, Göttingen, Germany
- Göttingen Center for Molecular Biosciences, University of Göttingen, Göttingen, Germany
| | - Hauke S Hillen
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany.
- Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany.
- Research Group Structure and Function of Molecular Machines, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.
- Göttingen Center for Molecular Biosciences, University of Göttingen, Göttingen, Germany.
| | - Ricarda Richter-Dennerlein
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany.
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany.
- Göttingen Center for Molecular Biosciences, University of Göttingen, Göttingen, Germany.
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3
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Kapila R, Mehra U, Kaur J, Verma Y, Jakar S, Datta K. Insights into Mtg3-mitochondrial ribosome association in Saccharomyces cerevisiae. Biochem Biophys Res Commun 2024; 737:150502. [PMID: 39180962 DOI: 10.1016/j.bbrc.2024.150502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2024] [Revised: 07/27/2024] [Accepted: 08/02/2024] [Indexed: 08/27/2024]
Abstract
Ribosome biogenesis is a highly regulated multistep process aided by energy-consuming auxiliary factors. GTPases form the largest class of auxiliary factors used by bacterial, cytosolic, and mitochondrial ribosomes for their maturation. Mtg3, a circularly permuted YqeH family of GTPase, is implicated in the mitoribosome small subunit biogenesis. However, its precise mechanistic role has yet to be characterized. Mtg3 is likely to bind precursor mitoribosome molecules during subunit maturation in vivo. However, this interaction has yet to be observed with mitoribosomes biochemically. In this study, we delineate the specific conditions necessary for preserving the association of Mtg3 with mitoribosomes on a sucrose density gradient. We show that the C-terminal domain of Mtg3 is required for robust binding to the mitoribosome. Furthermore, point mutants likely to abrogate GTP/GDP binding and GTPase activity compromise protein function in vivo. Surprisingly, the association with the mitoribosome was not compromised in mutants likely to be deficient for nucleotide binding/hydrolysis. Thus, our finding supports a model wherein Mtg3 binds to a precursor mitoribosome through its C-terminus to facilitate a conformational change or validate a folding intermediate driven by the GTP/GDP binding and hydrolysis cycle.
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Affiliation(s)
- Ritika Kapila
- Department of Genetics, University of Delhi South Campus, New Delhi, India
| | - Upasana Mehra
- Department of Genetics, University of Delhi South Campus, New Delhi, India
| | - Jaswinder Kaur
- Department of Genetics, University of Delhi South Campus, New Delhi, India
| | - Yash Verma
- Department of Genetics, University of Delhi South Campus, New Delhi, India
| | - Shweta Jakar
- Department of Genetics, University of Delhi South Campus, New Delhi, India
| | - Kaustuv Datta
- Department of Genetics, University of Delhi South Campus, New Delhi, India.
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4
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Besnard F, Guintard A, Grohs C, Guzylack-Piriou L, Cano M, Escouflaire C, Hozé C, Leclerc H, Buronfosse T, Dutheil L, Jourdain J, Barbat A, Fritz S, Deloche MC, Remot A, Gaussères B, Clément A, Bouchier M, Contat E, Relun A, Plassard V, Rivière J, Péchoux C, Vilotte M, Eche C, Kuchly C, Charles M, Boulling A, Viard G, Minéry S, Barbey S, Birbes C, Danchin-Burge C, Launay F, Mattalia S, Allais-Bonnet A, Ravary B, Millemann Y, Guatteo R, Klopp C, Gaspin C, Iampietro C, Donnadieu C, Milan D, Arcangioli MA, Boussaha M, Foucras G, Boichard D, Capitan A. Massive detection of cryptic recessive genetic defects in dairy cattle mining millions of life histories. Genome Biol 2024; 25:248. [PMID: 39343954 PMCID: PMC11441225 DOI: 10.1186/s13059-024-03384-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 08/30/2024] [Indexed: 10/01/2024] Open
Abstract
BACKGROUND Dairy cattle breeds are populations of limited effective size, subject to recurrent outbreaks of recessive defects that are commonly studied using positional cloning. However, this strategy, based on the observation of animals with characteristic features, may overlook a number of conditions, such as immune or metabolic genetic disorders, which may be confused with pathologies of environmental etiology. RESULTS We present a data mining framework specifically designed to detect recessive defects in livestock that have been previously missed due to a lack of specific signs, incomplete penetrance, or incomplete linkage disequilibrium. This approach leverages the massive data generated by genomic selection. Its basic principle is to compare the observed and expected numbers of homozygotes for sliding haplotypes in animals with different life histories. Within three cattle breeds, we report 33 new loci responsible for increased risk of juvenile mortality and present a series of validations based on large-scale genotyping, clinical examination, and functional studies for candidate variants affecting the NOA1, RFC5, and ITGB7 genes. In particular, we describe disorders associated with NOA1 and RFC5 mutations for the first time in vertebrates. CONCLUSIONS The discovery of these many new defects will help to characterize the genetic basis of inbreeding depression, while their management will improve animal welfare and reduce losses to the industry.
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Affiliation(s)
- Florian Besnard
- Université Paris-Saclay, INRAE, AgroParisTech, GABI, 78350, Jouy-en-Josas, France.
- IDELE, 149 Rue de Bercy, 75012, Paris, France.
| | - Ana Guintard
- Université Paris-Saclay, INRAE, AgroParisTech, GABI, 78350, Jouy-en-Josas, France
- ELIANCE, 75012, Paris, France
| | - Cécile Grohs
- Université Paris-Saclay, INRAE, AgroParisTech, GABI, 78350, Jouy-en-Josas, France
| | | | - Margarita Cano
- Université Paris-Saclay, INRAE, AgroParisTech, GABI, 78350, Jouy-en-Josas, France
| | - Clémentine Escouflaire
- Université Paris-Saclay, INRAE, AgroParisTech, GABI, 78350, Jouy-en-Josas, France
- ELIANCE, 75012, Paris, France
| | - Chris Hozé
- Université Paris-Saclay, INRAE, AgroParisTech, GABI, 78350, Jouy-en-Josas, France
- ELIANCE, 75012, Paris, France
| | - Hélène Leclerc
- Université Paris-Saclay, INRAE, AgroParisTech, GABI, 78350, Jouy-en-Josas, France
- ELIANCE, 75012, Paris, France
| | | | - Lucie Dutheil
- IHAP, Université de Toulouse, INRAE, ENVT, 31076, Toulouse, France
| | - Jeanlin Jourdain
- Université Paris-Saclay, INRAE, AgroParisTech, GABI, 78350, Jouy-en-Josas, France
- ELIANCE, 75012, Paris, France
| | - Anne Barbat
- Université Paris-Saclay, INRAE, AgroParisTech, GABI, 78350, Jouy-en-Josas, France
| | - Sébastien Fritz
- Université Paris-Saclay, INRAE, AgroParisTech, GABI, 78350, Jouy-en-Josas, France
- ELIANCE, 75012, Paris, France
| | - Marie-Christine Deloche
- Université Paris-Saclay, INRAE, AgroParisTech, GABI, 78350, Jouy-en-Josas, France
- ELIANCE, 75012, Paris, France
| | - Aude Remot
- INRAE, Université de Tours, ISP, 37380, Nouzilly, France
| | | | - Adèle Clément
- IHAP, Université de Toulouse, INRAE, ENVT, 31076, Toulouse, France
| | - Marion Bouchier
- VetAgro Sup, Université Lyon1, 69280, Marcy-L'Etoile, France
| | - Elise Contat
- VetAgro Sup, Université Lyon1, 69280, Marcy-L'Etoile, France
| | - Anne Relun
- Oniris, INRAE, BIOEPAR, 44300, Nantes, France
| | | | - Julie Rivière
- Université Paris-Saclay, INRAE, AgroParisTech, GABI, 78350, Jouy-en-Josas, France
- Université Paris-Saclay, INRAE, AgroParisTech, MICALIS, 78350, Jouy-en-Josas, France
| | - Christine Péchoux
- Université Paris-Saclay, INRAE, AgroParisTech, GABI, 78350, Jouy-en-Josas, France
| | - Marthe Vilotte
- Université Paris-Saclay, INRAE, AgroParisTech, GABI, 78350, Jouy-en-Josas, France
| | - Camille Eche
- INRAE, US 1426, GeT-PlaGe, Genotoul, France Génomique, Université Fédérale de Toulouse, 31320, Castanet-Tolosan, France
| | - Claire Kuchly
- INRAE, US 1426, GeT-PlaGe, Genotoul, France Génomique, Université Fédérale de Toulouse, 31320, Castanet-Tolosan, France
| | - Mathieu Charles
- Université Paris-Saclay, INRAE, AgroParisTech, GABI, 78350, Jouy-en-Josas, France
| | - Arnaud Boulling
- Université Paris-Saclay, INRAE, AgroParisTech, GABI, 78350, Jouy-en-Josas, France
| | - Guillaume Viard
- ELIANCE, 75012, Paris, France
- Université Paris-Saclay, INRAE, Ecole Nationale Vétérinaire d'Alfort, BREED, 78350, Jouy-en-Josas, France
| | | | - Sarah Barbey
- UE326, Unité Expérimentale du Pin, INRAE, 61310, Le Pin Au Haras, France
| | - Clément Birbes
- Université Fédérale de Toulouse, INRAE, BioinfOmics, GenoToul Bioinformatics Facility, 31320, Castanet-Tolosan, France
| | | | - Frédéric Launay
- UE326, Unité Expérimentale du Pin, INRAE, 61310, Le Pin Au Haras, France
| | | | - Aurélie Allais-Bonnet
- ELIANCE, 75012, Paris, France
- Université Paris-Saclay, INRAE, Ecole Nationale Vétérinaire d'Alfort, BREED, 78350, Jouy-en-Josas, France
| | | | | | | | - Christophe Klopp
- Université Fédérale de Toulouse, INRAE, BioinfOmics, GenoToul Bioinformatics Facility, 31320, Castanet-Tolosan, France
| | - Christine Gaspin
- Université Fédérale de Toulouse, INRAE, BioinfOmics, GenoToul Bioinformatics Facility, 31320, Castanet-Tolosan, France
| | - Carole Iampietro
- INRAE, US 1426, GeT-PlaGe, Genotoul, France Génomique, Université Fédérale de Toulouse, 31320, Castanet-Tolosan, France
| | - Cécile Donnadieu
- INRAE, US 1426, GeT-PlaGe, Genotoul, France Génomique, Université Fédérale de Toulouse, 31320, Castanet-Tolosan, France
| | - Denis Milan
- GenPhySE, Université Fédérale de Toulouse, INRAE, INPT, ENVT, 31320, Castanet-Tolosan, France
| | | | - Mekki Boussaha
- Université Paris-Saclay, INRAE, AgroParisTech, GABI, 78350, Jouy-en-Josas, France
| | - Gilles Foucras
- IHAP, Université de Toulouse, INRAE, ENVT, 31076, Toulouse, France
| | - Didier Boichard
- Université Paris-Saclay, INRAE, AgroParisTech, GABI, 78350, Jouy-en-Josas, France
| | - Aurélien Capitan
- Université Paris-Saclay, INRAE, AgroParisTech, GABI, 78350, Jouy-en-Josas, France.
- ELIANCE, 75012, Paris, France.
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5
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Cipullo M, Valentín Gesé G, Gopalakrishna S, Krueger A, Lobo V, Pirozhkova MA, Marks J, Páleníková P, Shiriaev D, Liu Y, Misic J, Cai Y, Nguyen MD, Abdelbagi A, Li X, Minczuk M, Hafner M, Benhalevy D, Sarshad AA, Atanassov I, Hällberg BM, Rorbach J. GTPBP8 plays a role in mitoribosome formation in human mitochondria. Nat Commun 2024; 15:5664. [PMID: 38969660 PMCID: PMC11229512 DOI: 10.1038/s41467-024-50011-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 06/26/2024] [Indexed: 07/07/2024] Open
Abstract
Mitochondrial gene expression relies on mitoribosomes to translate mitochondrial mRNAs. The biogenesis of mitoribosomes is an intricate process involving multiple assembly factors. Among these factors, GTP-binding proteins (GTPBPs) play important roles. In bacterial systems, numerous GTPBPs are required for ribosome subunit maturation, with EngB being a GTPBP involved in the ribosomal large subunit assembly. In this study, we focus on exploring the function of GTPBP8, the human homolog of EngB. We find that ablation of GTPBP8 leads to the inhibition of mitochondrial translation, resulting in significant impairment of oxidative phosphorylation. Structural analysis of mitoribosomes from GTPBP8 knock-out cells shows the accumulation of mitoribosomal large subunit assembly intermediates that are incapable of forming functional monosomes. Furthermore, fPAR-CLIP analysis reveals that GTPBP8 is an RNA-binding protein that interacts specifically with the mitochondrial ribosome large subunit 16 S rRNA. Our study highlights the role of GTPBP8 as a component of the mitochondrial gene expression machinery involved in mitochondrial large subunit maturation.
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Affiliation(s)
- Miriam Cipullo
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, 17165, Sweden
| | - Genís Valentín Gesé
- Department of Cell and Molecular Biology, Karolinska Institutet, Solnavägen 9, Stockholm, 17165, Sweden
| | - Shreekara Gopalakrishna
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, 17165, Sweden
| | - Annika Krueger
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, 17165, Sweden
| | - Vivian Lobo
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, SE-40530, Gothenburg, Sweden
- Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, SE-40530, Gothenburg, Sweden
| | - Maria A Pirozhkova
- Lab for Cellular RNA Biology, Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - James Marks
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Petra Páleníková
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, CB2 0XY, UK
| | - Dmitrii Shiriaev
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, 17165, Sweden
| | - Yong Liu
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, 17165, Sweden
| | - Jelena Misic
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, 17165, Sweden
| | - Yu Cai
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, 17165, Sweden
| | - Minh Duc Nguyen
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, 17165, Sweden
| | - Abubakar Abdelbagi
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, 17165, Sweden
| | - Xinping Li
- Proteomics Core Facility, Max-Planck-Institute for Biology of Ageing, Joseph-Stelzmann-Str. 9b, 50931, Cologne, Germany
| | - Michal Minczuk
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, CB2 0XY, UK
| | - Markus Hafner
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Daniel Benhalevy
- Lab for Cellular RNA Biology, Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Aishe A Sarshad
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, SE-40530, Gothenburg, Sweden
- Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, SE-40530, Gothenburg, Sweden
| | - Ilian Atanassov
- Proteomics Core Facility, Max-Planck-Institute for Biology of Ageing, Joseph-Stelzmann-Str. 9b, 50931, Cologne, Germany
| | - B Martin Hällberg
- Department of Cell and Molecular Biology, Karolinska Institutet, Solnavägen 9, Stockholm, 17165, Sweden
| | - Joanna Rorbach
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, 17165, Sweden.
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6
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Key J, Gispert S, Auburger G. Knockout Mouse Studies Show That Mitochondrial CLPP Peptidase and CLPX Unfoldase Act in Matrix Condensates near IMM, as Fast Stress Response in Protein Assemblies for Transcript Processing, Translation, and Heme Production. Genes (Basel) 2024; 15:694. [PMID: 38927630 PMCID: PMC11202940 DOI: 10.3390/genes15060694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Revised: 05/23/2024] [Accepted: 05/24/2024] [Indexed: 06/28/2024] Open
Abstract
LONP1 is the principal AAA+ unfoldase and bulk protease in the mitochondrial matrix, so its deletion causes embryonic lethality. The AAA+ unfoldase CLPX and the peptidase CLPP also act in the matrix, especially during stress periods, but their substrates are poorly defined. Mammalian CLPP deletion triggers infertility, deafness, growth retardation, and cGAS-STING-activated cytosolic innate immunity. CLPX mutations impair heme biosynthesis and heavy metal homeostasis. CLPP and CLPX are conserved from bacteria to humans, despite their secondary role in proteolysis. Based on recent proteomic-metabolomic evidence from knockout mice and patient cells, we propose that CLPP acts on phase-separated ribonucleoprotein granules and CLPX on multi-enzyme condensates as first-aid systems near the inner mitochondrial membrane. Trimming within assemblies, CLPP rescues stalled processes in mitoribosomes, mitochondrial RNA granules and nucleoids, and the D-foci-mediated degradation of toxic double-stranded mtRNA/mtDNA. Unfolding multi-enzyme condensates, CLPX maximizes PLP-dependent delta-transamination and rescues malformed nascent peptides. Overall, their actions occur in granules with multivalent or hydrophobic interactions, separated from the aqueous phase. Thus, the role of CLPXP in the matrix is compartment-selective, as other mitochondrial peptidases: MPPs at precursor import pores, m-AAA and i-AAA at either IMM face, PARL within the IMM, and OMA1/HTRA2 in the intermembrane space.
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Affiliation(s)
| | | | - Georg Auburger
- Experimental Neurology, Clinic of Neurology, University Hospital, Goethe University Frankfurt, Heinrich Hoffmann Str. 7, 60590 Frankfurt am Main, Germany; (J.K.); (S.G.)
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7
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Antolínez-Fernández Á, Esteban-Ramos P, Fernández-Moreno MÁ, Clemente P. Molecular pathways in mitochondrial disorders due to a defective mitochondrial protein synthesis. Front Cell Dev Biol 2024; 12:1410245. [PMID: 38855161 PMCID: PMC11157125 DOI: 10.3389/fcell.2024.1410245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Accepted: 05/09/2024] [Indexed: 06/11/2024] Open
Abstract
Mitochondria play a central role in cellular metabolism producing the necessary ATP through oxidative phosphorylation. As a remnant of their prokaryotic past, mitochondria contain their own genome, which encodes 13 subunits of the oxidative phosphorylation system, as well as the tRNAs and rRNAs necessary for their translation in the organelle. Mitochondrial protein synthesis depends on the import of a vast array of nuclear-encoded proteins including the mitochondrial ribosome protein components, translation factors, aminoacyl-tRNA synthetases or assembly factors among others. Cryo-EM studies have improved our understanding of the composition of the mitochondrial ribosome and the factors required for mitochondrial protein synthesis and the advances in next-generation sequencing techniques have allowed for the identification of a growing number of genes involved in mitochondrial pathologies with a defective translation. These disorders are often multisystemic, affecting those tissues with a higher energy demand, and often present with neurodegenerative phenotypes. In this article, we review the known proteins required for mitochondrial translation, the disorders that derive from a defective mitochondrial protein synthesis and the animal models that have been established for their study.
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Affiliation(s)
- Álvaro Antolínez-Fernández
- Instituto de Investigaciones Biomédicas Sols-Morreale (IIBM), Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, Madrid, Spain
- Departamento de Bioquímica, Universidad Autónoma de Madrid, Madrid, Spain
| | - Paula Esteban-Ramos
- Instituto de Investigaciones Biomédicas Sols-Morreale (IIBM), Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, Madrid, Spain
- Departamento de Bioquímica, Universidad Autónoma de Madrid, Madrid, Spain
| | - Miguel Ángel Fernández-Moreno
- Instituto de Investigaciones Biomédicas Sols-Morreale (IIBM), Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, Madrid, Spain
- Departamento de Bioquímica, Universidad Autónoma de Madrid, Madrid, Spain
| | - Paula Clemente
- Instituto de Investigaciones Biomédicas Sols-Morreale (IIBM), Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, Madrid, Spain
- Departamento de Bioquímica, Universidad Autónoma de Madrid, Madrid, Spain
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8
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Wang L, Hilander T, Liu X, Tsang HY, Eriksson O, Jackson CB, Varjosalo M, Zhao H. GTPBP8 is required for mitoribosomal biogenesis and mitochondrial translation. Cell Mol Life Sci 2023; 80:361. [PMID: 37971521 PMCID: PMC10654211 DOI: 10.1007/s00018-023-05014-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 09/28/2023] [Accepted: 10/25/2023] [Indexed: 11/19/2023]
Abstract
Mitochondrial translation occurs on the mitochondrial ribosome, also known as the mitoribosome. The assembly of mitoribosomes is a highly coordinated process. During mitoribosome biogenesis, various assembly factors transiently associate with the nascent ribosome, facilitating the accurate and efficient construction of the mitoribosome. However, the specific factors involved in the assembly process, the precise mechanisms, and the cellular compartments involved in this vital process are not yet fully understood. In this study, we discovered a crucial role for GTP-binding protein 8 (GTPBP8) in the assembly of the mitoribosomal large subunit (mt-LSU) and mitochondrial translation. GTPBP8 is identified as a novel GTPase located in the matrix and peripherally bound to the inner mitochondrial membrane. Importantly, GTPBP8 is specifically associated with the mt-LSU during its assembly. Depletion of GTPBP8 leads to an abnormal accumulation of mt-LSU, indicating that GTPBP8 is critical for proper mt-LSU assembly. Furthermore, the absence of GTPBP8 results in reduced levels of fully assembled 55S monosomes. This impaired assembly leads to compromised mitochondrial translation and, consequently, impaired mitochondrial function. The identification of GTPBP8 as an important player in these processes provides new insights into the molecular mechanisms underlying mitochondrial protein synthesis and its regulation.
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Affiliation(s)
- Liang Wang
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00014, Helsinki, Finland
- National Chengdu Center for Safety Evaluation of Drugs, State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, West China Hospital, West China Medical School, Sichuan University, #1 Keyuan Road, Gaopeng Street, High-Tech Development Zone, West China, Chengdu, 610041, China
| | - Taru Hilander
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00014, Helsinki, Finland
| | - Xiaonan Liu
- Institute of Biotechnology and Helsinki Institute of Life Science, University of Helsinki, 00014, Helsinki, Finland
| | - Hoi Ying Tsang
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00014, Helsinki, Finland
| | - Ove Eriksson
- Department of Biochemistry and Developmental Biology, Faculty of Medicine, University of Helsinki, 00014, Helsinki, Finland
| | - Christopher B Jackson
- Department of Biochemistry and Developmental Biology, Faculty of Medicine, University of Helsinki, 00014, Helsinki, Finland
| | - Markku Varjosalo
- Institute of Biotechnology and Helsinki Institute of Life Science, University of Helsinki, 00014, Helsinki, Finland
| | - Hongxia Zhao
- Faculty of Biological and Environmental Sciences, University of Helsinki, 00014, Helsinki, Finland.
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9
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Khawaja A, Cipullo M, Krüger A, Rorbach J. Insights into mitoribosomal biogenesis from recent structural studies. Trends Biochem Sci 2023; 48:629-641. [PMID: 37169615 DOI: 10.1016/j.tibs.2023.04.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 04/03/2023] [Accepted: 04/04/2023] [Indexed: 05/13/2023]
Abstract
The mitochondrial ribosome (mitoribosome) is a multicomponent machine that has unique structural features. Biogenesis of the human mitoribosome includes correct maturation and folding of the mitochondria-encoded RNA components (12S and 16S mt-rRNAs, and mt-tRNAVal) and their assembly together with 82 nucleus-encoded mitoribosomal proteins. This complex process requires the coordinated action of multiple assembly factors. Recent advances in single-particle cryo-electron microscopy (cryo-EM) have provided detailed insights into the specific functions of several mitoribosome assembly factors and have defined their timing. In this review we summarize mitoribosomal small (mtSSU) and large subunit (mtLSU) biogenesis based on structural findings, and we discuss potential crosstalk between mtSSU and mtLSU assembly pathways as well as coordination between mitoribosome biogenesis and other processes involved in mitochondrial gene expression.
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Affiliation(s)
- Anas Khawaja
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Biomedicum, 171 65 Solna, Sweden; Max Planck Institute Biology of Ageing, Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Miriam Cipullo
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Biomedicum, 171 65 Solna, Sweden; Max Planck Institute Biology of Ageing, Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Annika Krüger
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Biomedicum, 171 65 Solna, Sweden; Max Planck Institute Biology of Ageing, Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Joanna Rorbach
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Biomedicum, 171 65 Solna, Sweden; Max Planck Institute Biology of Ageing, Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden.
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10
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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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11
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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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12
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Mitochondrial Genetic Background May Impact Statins Side Effects and Atherosclerosis Development in Familial Hypercholesterolemia. Int J Mol Sci 2022; 24:ijms24010471. [PMID: 36613915 PMCID: PMC9820128 DOI: 10.3390/ijms24010471] [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: 11/30/2022] [Revised: 12/21/2022] [Accepted: 12/22/2022] [Indexed: 12/30/2022] Open
Abstract
Heredity of familial hypercholesterolemia (FH) can present as a dominant monogenic disorder of polygenic origin or with no known genetic cause. In addition, the variability of the symptoms among individuals or within the same families evidence the potential contribution of additional factors than monogenic mutations that could modulate the development and severity of the disease. In addition, statins, the lipid-lowering drugs which constitute the first-line therapy for the disease, cause associated muscular symptoms in a certain number of individuals. Here, we analyze the evidence of the mitochondrial genetic variation with a special emphasis on the role of CoQ10 to explain this variability found in both disease symptoms and statins side effects. We propose to use mtDNA variants and copy numbers as markers for the cardiovascular disease development of FH patients and to predict potential statin secondary effects and explore new mechanisms to identify new markers of disease or implement personalized medicine strategies for FH therapy.
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13
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Li J, Yu C, Ni S, Duan Y. Identification of Core Genes and Screening of Potential Targets in Intervertebral Disc Degeneration Using Integrated Bioinformatics Analysis. Front Genet 2022; 13:864100. [PMID: 35711934 PMCID: PMC9196128 DOI: 10.3389/fgene.2022.864100] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 04/22/2022] [Indexed: 12/27/2022] Open
Abstract
Background: Intervertebral disc degeneration (IDD), characterized by diverse pathological changes, causes low back pain (LBP). However, prophylactic and delaying treatments for IDD are limited. The aim of our study was to investigate the gene network and biomarkers of IDD and suggest potential therapeutic targets. Methods: Differentially expressed genes (DEGs) associated with IDD were identified by analyzing the mRNA, miRNA, and lncRNA expression profiles of IDD cases from the Gene Expression Omnibus (GEO). The protein–protein interaction (PPI) network, Gene Ontology (GO) enrichment, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis as well as miRNA–lncRNA–mRNA networks were conducted. Moreover, we obtained 71 hub genes and performed a comprehensive analysis including GO, KEGG, gene set enrichment analysis (GSEA), gene set variation analysis (GSVA), Disease Ontology (DO), methylation analysis, receiver operating characteristic (ROC) curve analysis, immune infiltration analysis, and potential drug identification. We finally used qRT-PCR to verify 13 significant DEGs in normal and degenerative nucleus pulposus cells (NPCs). Results: We identified 305 DEGs closely related to IDD. The GO and KEGG analyses indicated that changes in IDD are significantly associated with enrichment of the inflammatory and immune response. GSEA analysis suggested that cell activation involved in the inflammatory immune response amide biosynthetic process was the key for the development of IDD. The GSVA suggested that DNA repair, oxidative phosphorylation, peroxisome, IL-6-JAK-STAT3 signaling, and apoptosis were crucial in the development of IDD. Among the 71 hub genes, the methylation levels of 11 genes were increased in IDD. A total of twenty genes showed a high functional similarity and diagnostic value in IDD. The result of the immune cell infiltration analysis indicated that seven genes were closely related to active natural killer cells. The most relevant targeted hub genes for potential drug or molecular compounds were MET and PIK3CD. Also, qRT-PCR results showed that ARHGAP27, C15orf39, DEPDC1, DHRSX, MGAM, SLC11A1, SMC4, and LINC00887 were significantly downregulated in degenerative NPCs; H19, LINC00685, mir-185-5p, and mir-4306 were upregulated in degenerative NPCs; and the expression level of mir-663a did not change significantly in normal and degenerative NPCs. Conclusion: Our findings may provide new insights into the functional characteristics and mechanism of IDD and aid the development of IDD therapeutics.
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Affiliation(s)
- Jianjun Li
- Department of Spine Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Cheng Yu
- Department of Spine Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Songjia Ni
- Department of Orthopaedic Trauma, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Yang Duan
- Department of Spine Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou, China
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14
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Illigmann A, Thoma Y, Pan S, Reinhardt L, Brötz-Oesterhelt H. Contribution of the Clp Protease to Bacterial Survival and Mitochondrial Homoeostasis. Microb Physiol 2021; 31:260-279. [PMID: 34438398 DOI: 10.1159/000517718] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 06/07/2021] [Indexed: 11/19/2022]
Abstract
Fast adaptation to environmental changes ensures bacterial survival, and proteolysis represents a key cellular process in adaptation. The Clp protease system is a multi-component machinery responsible for protein homoeostasis, protein quality control, and targeted proteolysis of transcriptional regulators in prokaryotic cells and prokaryote-derived organelles of eukaryotic cells. A functional Clp protease complex consists of the tetradecameric proteolytic core ClpP and a hexameric ATP-consuming Clp-ATPase, several of which can associate with the same proteolytic core. Clp-ATPases confer substrate specificity by recognising specific degradation tags, and further selectivity is conferred by adaptor proteins, together allowing for a fine-tuned degradation process embedded in elaborate regulatory networks. This review focuses on the contribution of the Clp protease system to prokaryotic survival and summarises the current state of knowledge for exemplary bacteria in an increasing degree of interaction with eukaryotic cells. Starting from free-living bacteria as exemplified by a non-pathogenic and a pathogenic member of the Firmicutes, i.e., Bacillus subtilis and Staphylococcus aureus, respectively, we turn our attention to facultative and obligate intracellular bacterial pathogens, i.e., Mycobacterium tuberculosis, Listeria monocytogenes, and Chlamydia trachomatis, and conclude with mitochondria. Under stress conditions, the Clp protease system exerts its pivotal role in the degradation of damaged proteins and controls the timing and extent of the heat-shock response by regulatory proteolysis. Key regulators of developmental programmes like natural competence, motility, and sporulation are also under Clp proteolytic control. In many pathogenic species, the Clp system is required for the expression of virulence factors and essential for colonising the host. In accordance with its evolutionary origin, the human mitochondrial Clp protease strongly resembles its bacterial counterparts, taking a central role in protein quality control and homoeostasis, energy metabolism, and apoptosis in eukaryotic cells, and several cancer cell types depend on it for proliferation.
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Affiliation(s)
- Astrid Illigmann
- Department of Microbial Bioactive Compounds, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Yvonne Thoma
- Department of Microbial Bioactive Compounds, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Stefan Pan
- Department of Microbial Bioactive Compounds, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Laura Reinhardt
- Department of Microbial Bioactive Compounds, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Heike Brötz-Oesterhelt
- Department of Microbial Bioactive Compounds, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany.,Cluster of Excellence Controlling Microbes to Fight Infection, University of Tübingen, Tübingen, Germany
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15
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Hilander T, Jackson CB, Robciuc M, Bashir T, Zhao H. The roles of assembly factors in mammalian mitoribosome biogenesis. Mitochondrion 2021; 60:70-84. [PMID: 34339868 DOI: 10.1016/j.mito.2021.07.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 07/27/2021] [Accepted: 07/28/2021] [Indexed: 02/08/2023]
Abstract
As ancient bacterial endosymbionts of eukaryotic cells, mitochondria have retained their own circular DNA as well as protein translation system including mitochondrial ribosomes (mitoribosomes). In recent years, methodological advancements in cryoelectron microscopy and mass spectrometry have revealed the extent of the evolutionary divergence of mitoribosomes from their bacterial ancestors and their adaptation to the synthesis of 13 mitochondrial DNA encoded oxidative phosphorylation complex subunits. In addition to the structural data, the first assembly pathway maps of mitoribosomes have started to emerge and concomitantly also the assembly factors involved in this process to achieve fully translational competent particles. These transiently associated factors assist in the intricate assembly process of mitoribosomes by enhancing protein incorporation, ribosomal RNA folding and modification, and by blocking premature or non-native protein binding, for example. This review focuses on summarizing the current understanding of the known mammalian mitoribosome assembly factors and discussing their possible roles in the assembly of small or large mitoribosomal subunits.
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Affiliation(s)
- Taru Hilander
- Faculty of Biological and Environmental Sciences, University of Helsinki, Finland.
| | - Christopher B Jackson
- Department of Biochemistry and Developmental Biology, Faculty of Medicine, University of Helsinki, Finland.
| | - Marius Robciuc
- Faculty of Biological and Environmental Sciences, University of Helsinki, Finland
| | - Tanzeela Bashir
- Faculty of Biological and Environmental Sciences, University of Helsinki, Finland
| | - Hongxia Zhao
- Faculty of Biological and Environmental Sciences, University of Helsinki, Finland; Key Laboratory of Stem Cell and Biopharmaceutical Technology, School of Life Sciences, Guangxi Normal University, Guangxi, China.
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16
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D’Souza AR, Van Haute L, Powell CA, Mutti CD, Páleníková P, Rebelo-Guiomar P, Rorbach J, Minczuk M. YbeY is required for ribosome small subunit assembly and tRNA processing in human mitochondria. Nucleic Acids Res 2021; 49:5798-5812. [PMID: 34037799 PMCID: PMC8191802 DOI: 10.1093/nar/gkab404] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 04/20/2021] [Accepted: 05/06/2021] [Indexed: 12/12/2022] Open
Abstract
Mitochondria contain their own translation apparatus which enables them to produce the polypeptides encoded in their genome. The mitochondrially-encoded RNA components of the mitochondrial ribosome require various post-transcriptional processing steps. Additional protein factors are required to facilitate the biogenesis of the functional mitoribosome. We have characterized a mitochondrially-localized protein, YbeY, which interacts with the assembling mitoribosome through the small subunit. Loss of YbeY leads to a severe reduction in mitochondrial translation and a loss of cell viability, associated with less accurate mitochondrial tRNASer(AGY) processing from the primary transcript and a defect in the maturation of the mitoribosomal small subunit. Our results suggest that YbeY performs a dual, likely independent, function in mitochondria being involved in precursor RNA processing and mitoribosome biogenesis. Issue Section: Nucleic Acid Enzymes.
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Affiliation(s)
- Aaron R D’Souza
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Hills Road, Cambridge CB2 0XY, UK
| | - Lindsey Van Haute
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Hills Road, Cambridge CB2 0XY, UK
| | - Christopher A Powell
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Hills Road, Cambridge CB2 0XY, UK
| | - Christian D Mutti
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Hills Road, Cambridge CB2 0XY, UK
| | - Petra Páleníková
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Hills Road, Cambridge CB2 0XY, UK
| | - Pedro Rebelo-Guiomar
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Hills Road, Cambridge CB2 0XY, UK
| | - Joanna Rorbach
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Hills Road, Cambridge CB2 0XY, UK
| | - Michal Minczuk
- To whom correspondence should be addressed. Tel: +44 122 325 2750;
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17
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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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18
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Genetic Adaptations in Mudskipper and Tetrapod Give Insights into Their Convergent Water-to-Land Transition. Animals (Basel) 2021; 11:ani11020584. [PMID: 33672418 PMCID: PMC7926366 DOI: 10.3390/ani11020584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 02/13/2021] [Accepted: 02/20/2021] [Indexed: 11/17/2022] Open
Abstract
Water-to-land transition has been independently evolved in multiple vertebrate lineages including the most recent common ancestor of tetrapod and multiple fish clades, and among them, mudskippers uniquely adapted to the mudflat. Even though physiological and morphological adaptation of mudskippers is thought to resemble that of the ancestral tetrapod, it is unclear if they share genome-wide evolutionary signatures. To detect potential signatures of positive selection in mudskipper and tetrapods, we analyzed 4118 singleton orthologues of terrestrial tetrapods, coelacanth, mudskipper, and fully aquatic fishes. Among positively selected genes identified in mudskipper and tetrapod lineages, genes involved in immune responses, mitochondrial oxidative phosphorylation, and kidney development were detected. On the other hand, tetrapod-specific and mudskipper-specific positively selected genes were functionally enriched for DNA repair processes, which could be associated with higher exposure to UV light. We also performed gene family analysis and discovered convergent contraction of eight gene families, including βγ-crystallin coding genes in both tetrapod and mudskipper lineages. Findings of this study suggest the similar genetic adaptation against environmental constraints between the ancient tetrapod and mudskippers for their land adaptation.
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19
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Cipullo M, Pearce SF, Lopez Sanchez IG, Gopalakrishna S, Krüger A, Schober F, Busch JD, Li X, Wredenberg A, Atanassov I, Rorbach J. Human GTPBP5 is involved in the late stage of mitoribosome large subunit assembly. Nucleic Acids Res 2021; 49:354-370. [PMID: 33283228 PMCID: PMC7797037 DOI: 10.1093/nar/gkaa1131] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 11/02/2020] [Accepted: 11/10/2020] [Indexed: 12/12/2022] Open
Abstract
Human mitoribosomes are macromolecular complexes essential for translation of 11 mitochondrial mRNAs. The large and the small mitoribosomal subunits undergo a multistep maturation process that requires the involvement of several factors. Among these factors, GTP-binding proteins (GTPBPs) play an important role as GTP hydrolysis can provide energy throughout the assembly stages. In bacteria, many GTPBPs are needed for the maturation of ribosome subunits and, of particular interest for this study, ObgE has been shown to assist in the 50S subunit assembly. Here, we characterize the role of a related human Obg-family member, GTPBP5. We show that GTPBP5 interacts specifically with the large mitoribosomal subunit (mt-LSU) proteins and several late-stage mitoribosome assembly factors, including MTERF4:NSUN4 complex, MRM2 methyltransferase, MALSU1 and MTG1. Interestingly, we find that interaction of GTPBP5 with the mt-LSU is compromised in the presence of a non-hydrolysable analogue of GTP, implying a different mechanism of action of this protein in contrast to that of other Obg-family GTPBPs. GTPBP5 ablation leads to severe impairment in the oxidative phosphorylation system, concurrent with a decrease in mitochondrial translation and reduced monosome formation. Overall, our data indicate an important role of GTPBP5 in mitochondrial function and suggest its involvement in the late-stage of mt-LSU maturation.
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Affiliation(s)
- Miriam Cipullo
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Solnavägen 9, 171 65 Solna, Sweden.,Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Sarah F Pearce
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Solnavägen 9, 171 65 Solna, Sweden.,Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Isabel G Lopez Sanchez
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Solnavägen 9, 171 65 Solna, Sweden.,Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, 32 Gisborne Street, East Melbourne, 3002 Victoria, Australia
| | - Shreekara Gopalakrishna
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Solnavägen 9, 171 65 Solna, Sweden.,Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Annika Krüger
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Solnavägen 9, 171 65 Solna, Sweden.,Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Florian Schober
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden.,Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital, Solna (L1:00), 171 76 Stockholm, Sweden
| | - Jakob D Busch
- Department of Mitochondrial Biology, Max-Planck-Institute for Biology of Ageing, Joseph-Stelzmann-Str. 9b, 50931 Cologne, Germany
| | - Xinping Li
- Proteomics Core Facility, Max-Planck-Institute for Biology of Ageing, Joseph-Stelzmann-Str. 9b, 50931 Cologne, Germany
| | - Anna Wredenberg
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Solnavägen 9, 171 65 Solna, Sweden.,Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Ilian Atanassov
- Proteomics Core Facility, Max-Planck-Institute for Biology of Ageing, Joseph-Stelzmann-Str. 9b, 50931 Cologne, Germany
| | - Joanna Rorbach
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Solnavägen 9, 171 65 Solna, Sweden.,Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
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20
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Lavdovskaia E, Denks K, Nadler F, Steube E, Linden A, Urlaub H, Rodnina MV, Richter-Dennerlein R. Dual function of GTPBP6 in biogenesis and recycling of human mitochondrial ribosomes. Nucleic Acids Res 2021; 48:12929-12942. [PMID: 33264405 PMCID: PMC7736812 DOI: 10.1093/nar/gkaa1132] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 10/19/2020] [Accepted: 11/09/2020] [Indexed: 01/01/2023] Open
Abstract
Translation and ribosome biogenesis in mitochondria require auxiliary factors that ensure rapid and accurate synthesis of mitochondrial proteins. Defects in translation are associated with oxidative phosphorylation deficiency and cause severe human diseases, but the exact roles of mitochondrial translation-associated factors are not known. Here we identify the functions of GTPBP6, a homolog of the bacterial ribosome-recycling factor HflX, in human mitochondria. Similarly to HflX, GTPBP6 facilitates the dissociation of ribosomes in vitro and in vivo. In contrast to HflX, GTPBP6 is also required for the assembly of mitochondrial ribosomes. GTPBP6 ablation leads to accumulation of late assembly intermediate(s) of the large ribosomal subunit containing ribosome biogenesis factors MTERF4, NSUN4, MALSU1 and the GTPases GTPBP5, GTPBP7 and GTPBP10. Our data show that GTPBP6 has a dual function acting in ribosome recycling and biogenesis. These findings contribute to our understanding of large ribosomal subunit assembly as well as ribosome recycling pathway in mitochondria.
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Affiliation(s)
- Elena Lavdovskaia
- Department of Cellular Biochemistry, University Medical Center Goettingen, D-37073 Goettingen, Germany.,Cluster of Excellence 'Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells' (MBExC), University of Goettingen, Goettingen, Germany
| | - Kärt Denks
- Cluster of Excellence 'Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells' (MBExC), University of Goettingen, Goettingen, Germany.,Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, D-37077 Goettingen, Germany
| | - Franziska Nadler
- Department of Cellular Biochemistry, University Medical Center Goettingen, D-37073 Goettingen, Germany
| | - Emely Steube
- Department of Cellular Biochemistry, University Medical Center Goettingen, D-37073 Goettingen, Germany
| | - Andreas Linden
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, D-37077 Goettingen, Germany.,Bioanalytics, Institute for Clinical Chemistry, University Medical Center Goettingen, D-37073 Goettingen, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, D-37077 Goettingen, Germany.,Bioanalytics, Institute for Clinical Chemistry, University Medical Center Goettingen, D-37073 Goettingen, Germany
| | - Marina V Rodnina
- Cluster of Excellence 'Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells' (MBExC), University of Goettingen, Goettingen, Germany.,Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, D-37077 Goettingen, Germany
| | - Ricarda Richter-Dennerlein
- Department of Cellular Biochemistry, University Medical Center Goettingen, D-37073 Goettingen, Germany.,Cluster of Excellence 'Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells' (MBExC), University of Goettingen, Goettingen, Germany
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21
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Role of GTPases in Driving Mitoribosome Assembly. Trends Cell Biol 2021; 31:284-297. [PMID: 33419649 DOI: 10.1016/j.tcb.2020.12.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 12/01/2020] [Accepted: 12/11/2020] [Indexed: 01/08/2023]
Abstract
Mitoribosomes catalyze essential protein synthesis within mitochondria. Mitoribosome biogenesis is assisted by an increasing number of assembly factors, among which guanosine triphosphate hydrolases (GTPases) are the most abundant class. Here, we review recent progress in our understanding of mitoribosome assembly GTPases. We describe their shared and specific features and mechanisms of action, compare them with their bacterial counterparts, and discuss their possible roles in the assembly of small or large mitoribosomal subunits and the formation of the monosome by establishing quality-control checkpoints during these processes. Furthermore, following the recent unification of the nomenclature for the mitoribosomal proteins, we also propose a unified nomenclature for mitoribosome assembly GTPases.
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22
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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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23
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Busch JD, Cipullo M, Atanassov I, Bratic A, Silva Ramos E, Schöndorf T, Li X, Pearce SF, Milenkovic D, Rorbach J, Larsson NG. MitoRibo-Tag Mice Provide a Tool for In Vivo Studies of Mitoribosome Composition. Cell Rep 2019; 29:1728-1738.e9. [PMID: 31693908 PMCID: PMC6859486 DOI: 10.1016/j.celrep.2019.09.080] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 08/14/2019] [Accepted: 09/26/2019] [Indexed: 11/16/2022] Open
Abstract
Mitochondria harbor specialized ribosomes (mitoribosomes) necessary for the synthesis of key membrane proteins of the oxidative phosphorylation (OXPHOS) machinery located in the mitochondrial inner membrane. To date, no animal model exists to study mitoribosome composition and mitochondrial translation coordination in mammals in vivo. Here, we create MitoRibo-Tag mice as a tool enabling affinity purification and proteomics analyses of mitoribosomes and their interactome in different tissues. We also define the composition of an assembly intermediate formed in the absence of MTERF4, necessary for a late step in mitoribosomal biogenesis. We identify the orphan protein PUSL1, which interacts with a large subunit assembly intermediate, and demonstrate that it is an inner-membrane-associated mitochondrial matrix protein required for efficient mitochondrial translation. This work establishes MitoRibo-Tag mice as a powerful tool to study mitoribosomes in vivo, enabling future studies on the mitoribosome interactome under different physiological states, as well as in disease and aging. MitoRibo-Tag mice with a tag on mL62 were generated to study mitoribosomes in vivo The mitoribosome interactome of different mouse tissues was defined with proteomics PUSL1 was identified as a mitoribosome-interacting protein using MitoRibo-Tag mice MitoRibo-Tag mice allow mitoribosome analysis under different conditions and setups
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Affiliation(s)
- Jakob D Busch
- Department of Mitochondrial Biology, Max-Planck-Institute for Biology of Ageing, Joseph-Stelzmann-Str. 9b, 50931 Cologne, Germany; Faculty of Mathematics and Natural Sciences, University of Cologne, Albertus-Magnus-Platz, 50923 Cologne, Germany
| | - Miriam Cipullo
- Department of Medical Biochemistry and Biophysics, Research Division of Molecular Metabolism, Karolinska Institutet, Solnavägen 9, 171 65 Solna, Sweden; Max-Planck-Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Ilian Atanassov
- Proteomics Core Facility, Max-Planck-Institute for Biology of Ageing, Joseph-Stelzmann-Str. 9b, 50931 Cologne, Germany
| | - Ana Bratic
- Department of Mitochondrial Biology, Max-Planck-Institute for Biology of Ageing, Joseph-Stelzmann-Str. 9b, 50931 Cologne, Germany
| | - Eduardo Silva Ramos
- Department of Mitochondrial Biology, Max-Planck-Institute for Biology of Ageing, Joseph-Stelzmann-Str. 9b, 50931 Cologne, Germany
| | - Thomas Schöndorf
- Department of Mitochondrial Biology, Max-Planck-Institute for Biology of Ageing, Joseph-Stelzmann-Str. 9b, 50931 Cologne, Germany; Faculty of Mathematics and Natural Sciences, University of Cologne, Albertus-Magnus-Platz, 50923 Cologne, Germany
| | - Xinping Li
- Proteomics Core Facility, Max-Planck-Institute for Biology of Ageing, Joseph-Stelzmann-Str. 9b, 50931 Cologne, Germany
| | - Sarah F Pearce
- Department of Medical Biochemistry and Biophysics, Research Division of Molecular Metabolism, Karolinska Institutet, Solnavägen 9, 171 65 Solna, Sweden; Max-Planck-Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Dusanka Milenkovic
- Department of Mitochondrial Biology, Max-Planck-Institute for Biology of Ageing, Joseph-Stelzmann-Str. 9b, 50931 Cologne, Germany
| | - Joanna Rorbach
- Department of Medical Biochemistry and Biophysics, Research Division of Molecular Metabolism, Karolinska Institutet, Solnavägen 9, 171 65 Solna, Sweden; Max-Planck-Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden.
| | - Nils-Göran Larsson
- Department of Mitochondrial Biology, Max-Planck-Institute for Biology of Ageing, Joseph-Stelzmann-Str. 9b, 50931 Cologne, Germany; Department of Medical Biochemistry and Biophysics, Research Division of Molecular Metabolism, Karolinska Institutet, Solnavägen 9, 171 65 Solna, Sweden; Max-Planck-Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden.
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24
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Maiti P, Kim HJ, Tu YT, Barrientos A. Human GTPBP10 is required for mitoribosome maturation. Nucleic Acids Res 2018; 46:11423-11437. [PMID: 30321378 PMCID: PMC6265488 DOI: 10.1093/nar/gky938] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Revised: 09/18/2018] [Accepted: 10/05/2018] [Indexed: 01/07/2023] Open
Abstract
Most steps on the biogenesis of the mitochondrial ribosome (mitoribosome) occur near the mitochondrial DNA nucleoid, in RNA granules, which contain dedicated RNA metabolism and mitoribosome assembly factors. Here, analysis of the RNA granule proteome identified the presence of a set of small GTPases that belong to conserved families of ribosome assembly factors. We show that GTPBP10, a member of the conserved Obg family of P-loop small G proteins, is a mitochondrial protein and have used gene-editing technologies to create a HEK293T cell line KO for GTPBP10. The absence of GTPBP10 leads to attenuated mtLSU and mtSSU levels and the virtual absence of the 55S monosome, which entirely prevents mitochondrial protein synthesis. We show that a fraction of GTPBP10 cosediments with the large mitoribosome subunit and the monosome. GTPBP10 physically interacts with the 16S rRNA, but not with the 12S rRNA, and crosslinks with several mtLSU proteins. Additionally, GTPBP10 is indirectly required for efficient processing of the 12S-16S rRNA precursor transcript, which could explain the mtSSU accumulation defect. We propose that GTPBP10 primarily ensures proper mtLSU maturation and ultimately serves to coordinate mtSSU and mtLSU accumulation then providing a quality control check-point function during mtLSU assembly that minimizes premature subunit joining.
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Affiliation(s)
- Priyanka Maiti
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Hyun-Jung Kim
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Ya-Ting Tu
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Antoni Barrientos
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
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25
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Kim HJ, Barrientos A. MTG1 couples mitoribosome large subunit assembly with intersubunit bridge formation. Nucleic Acids Res 2018; 46:8435-8453. [PMID: 30085276 PMCID: PMC6144824 DOI: 10.1093/nar/gky672] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 07/11/2018] [Accepted: 07/13/2018] [Indexed: 02/06/2023] Open
Abstract
Mammalian mitochondrial ribosomes (mitoribosomes) synthesize 13 proteins, essential components of the oxidative phosphorylation system. They are linked to mitochondrial disorders, often involving cardiomyopathy. Mitoribosome biogenesis is assisted by multiple cofactors whose specific functions remain largely uncharacterized. Here, we examined the role of human MTG1, a conserved ribosome assembly guanosine triphosphatase. MTG1-silencing in human cardiomyocytes and developing zebrafish revealed early cardiovascular lesions. A combination of gene-editing and biochemical approaches using HEK293T cells demonstrated that MTG1 binds to the large subunit (mtLSU) 16S ribosomal RNA to facilitate incorporation of late-assembly proteins. Furthermore, MTG1 interacts with mtLSU uL19 protein and mtSSU mS27, a putative guanosine triphosphate-exchange factor (GEF), to enable MTG1 release and the formation of the mB6 intersubunit bridge. In this way, MTG1 establishes a quality control checkpoint in mitoribosome assembly. In conclusion, MTG1 controls mitochondrial translation by coupling mtLSU assembly with intersubunit bridge formation using the intrinsic GEF activity acquired by the mtSSU through mS27, a unique occurrence in translational systems.
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Affiliation(s)
- Hyun-Jung Kim
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Antoni Barrientos
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
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26
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He H, Yang Q, Shen B, Zhang S, Peng X. OsNOA1 functions in a threshold-dependent manner to regulate chloroplast proteins in rice at lower temperatures. BMC PLANT BIOLOGY 2018; 18:44. [PMID: 29548275 PMCID: PMC5857130 DOI: 10.1186/s12870-018-1258-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 03/01/2018] [Indexed: 05/22/2023]
Abstract
BACKGROUND Although decreased protein expressions have been observed in NOA1 (Nitric Oxide Associated protein 1) deficient plants, the molecular mechanisms of how NOA1 regulates protein metabolism remain poorly understood. In this study, we have used a global comparative proteomic approach for both OsNOA1 suppression and overexpression transgenic lines under two different temperatures, in combination with physiological and biochemical analyses to explore the regulatory mechanisms of OsNOA1 in rice. RESULTS In OsNOA1-silenced or highly overexpressed rice, considerably different expression patterns of both chlorophyll and Rubisco as well as distinct phenotypes were observed between the growth temperatures at 22 °C and 30 °C. These observations led us to hypothesize there appears a narrow abundance threshold for OsNOA1 to function properly at lower temperatures, while higher temperatures seem to partially compensate for the changes of OsNOA1 abundance. Quantitative proteomic analyses revealed higher temperatures could restore 90% of the suppressed proteins to normal levels, whereas almost all of the remaining suppressed proteins were chloroplast ribosomal proteins. Additionally, our data showed 90% of the suppressed proteins in both types of transgenic plants at lower temperatures were located in the chloroplast, suggesting a primary effect of OsNOA1 on chloroplast proteins. Transcript analyses, along with in vitro pull-down experiments further demonstrated OsNOA1 is associated with the function of chloroplast ribosomes. CONCLUSIONS Our results suggest OsNOA1 functions in a threshold-dependent manner for regulation of chloroplast proteins at lower temperatures, which may be mediated by interactions between OsNOA1 and chloroplast ribosomes.
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Affiliation(s)
- Han He
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou, China
| | - Qiaosong Yang
- Institute of Fruit Tree Research, Guangdong Academy of Agricultural Sciences, Guangzhou, China
| | - Boran Shen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou, China
| | - Sheng Zhang
- Institute of Biotechnology, Cornell University, Ithaca, USA
| | - Xinxiang Peng
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou, China
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27
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The human RNA-binding protein RBFA promotes the maturation of the mitochondrial ribosome. Biochem J 2017; 474:2145-2158. [PMID: 28512204 PMCID: PMC5468982 DOI: 10.1042/bcj20170256] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 05/09/2017] [Accepted: 05/15/2017] [Indexed: 11/17/2022]
Abstract
Accurate assembly and maturation of human mitochondrial ribosomes is essential for synthesis of the 13 polypeptides encoded by the mitochondrial genome. This process requires the correct integration of 80 proteins, 1 mt (mitochondrial)-tRNA and 2 mt-rRNA species, the latter being post-transcriptionally modified at many sites. Here, we report that human ribosome-binding factor A (RBFA) is a mitochondrial RNA-binding protein that exerts crucial roles in mitoribosome biogenesis. Unlike its bacterial orthologue, RBFA associates mainly with helices 44 and 45 of the 12S rRNA in the mitoribosomal small subunit to promote dimethylation of two highly conserved consecutive adenines. Characterization of RBFA-depleted cells indicates that this dimethylation is not a prerequisite for assembly of the small ribosomal subunit. However, the RBFA-facilitated modification is necessary for completing mt-rRNA maturation and regulating association of the small and large subunits to form a functional monosome implicating RBFA in the quality control of mitoribosome formation.
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28
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Ertl NG, O'Connor WA, Brooks P, Keats M, Elizur A. Combined exposure to pyrene and fluoranthene and their molecular effects on the Sydney rock oyster, Saccostrea glomerata. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2016; 177:136-145. [PMID: 27286571 DOI: 10.1016/j.aquatox.2016.05.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 05/15/2016] [Accepted: 05/20/2016] [Indexed: 06/06/2023]
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitously detected in the water column, associated with particulate matter or in the tissue of marine organisms such as molluscs. PAH exposure and their resultant bioaccumulation in molluscs can cause a range of serious physiological effects in the affected animals. To examine the molecular response of these xenobiotics in bivalves, Sydney rock oysters (Saccostrea glomerata) were exposed to pyrene and fluoranthene for seven days. Chemical analysis of the soft-tissue of PAH stressed S. glomerata confirmed that pyrene and fluoranthene could be bioaccumulated by these oysters. RNA-Seq analysis of PAH-exposed S. glomerata showed a total of 765 transcripts differentially expressed between control and PAH-stressed oysters. Closer examination of the transcripts revealed a range genes encoding enzymes involved in PAH detoxification (e.g. cytochrome P450), innate immune responses (e.g. pathogen recognition, phagocytosis) and protein synthesis. Overall, pyrene and fluoranthene exposure appears to have resulted in a suppression of pathogen recognition and some protein synthesis processes, whereas transcripts of genes encoding proteins involved in clearance of cell debris and some transcripts of genes involved in PAH detoxification were induced in response to the stressors. Pyrene and fluoranthene exposure thus invoked a complex molecular response in S. glomerata, with results suggesting that oysters focus on removing the stressors from their system and dealing with the downstream effects of PAH exposure, potentially at the exclusion of other, less immediate concerns (e.g. protection from infection).
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Affiliation(s)
- Nicole G Ertl
- University of the Sunshine Coast, Sippy Downs, Queensland, Australia; Australian Seafood Cooperative Research Centre, South Australia, Australia.
| | - Wayne A O'Connor
- University of the Sunshine Coast, Sippy Downs, Queensland, Australia; Department of Primary Industries, New South Wales, Australia. wayne.o'
| | - Peter Brooks
- University of the Sunshine Coast, Sippy Downs, Queensland, Australia.
| | - Michael Keats
- University of the Sunshine Coast, Sippy Downs, Queensland, Australia.
| | - Abigail Elizur
- University of the Sunshine Coast, Sippy Downs, Queensland, Australia.
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29
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Manikas RG, Thomson E, Thoms M, Hurt E. The K⁺-dependent GTPase Nug1 is implicated in the association of the helicase Dbp10 to the immature peptidyl transferase centre during ribosome maturation. Nucleic Acids Res 2016; 44:1800-12. [PMID: 26823502 PMCID: PMC4770245 DOI: 10.1093/nar/gkw045] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 01/14/2016] [Indexed: 12/16/2022] Open
Abstract
Ribosome synthesis employs a number of energy-consuming enzymes in both eukaryotes and prokaryotes. One such enzyme is the conserved circularly permuted GTPase Nug1 (nucleostemin in human). Nug1 is essential for 60S subunit assembly and nuclear export, but its role and time of action during maturation remained unclear. Based on in vitro enzymatic assays using the Chaetomium thermophilum (Ct) orthologue, we show that Nug1 exhibits a low intrinsic GTPase activity that is stimulated by potassium ions, rendering Nug1 a cation-dependent GTPase. In vivo we observe 60S biogenesis defects upon depletion of yeast Nug1 or expression of a Nug1 nucleotide-binding mutant. Most prominently, the RNA helicase Dbp10 was lost from early pre-60S particles, which suggested a physical interaction that could be reconstituted in vitro using CtNug1 and CtDbp10. In vivo rRNA-protein crosslinking revealed that Nug1 and Dbp10 bind at proximal and partially overlapping sites on the 60S pre-ribosome, most prominently to H89 that will constitute part of the peptidyl transferase center (PTC). The binding sites of Dbp10 are the same as those identified for the prokaryotic helicase DbpA bound to the 50S subunit. We suggest that Dbp10 and DbpA are performing a conserved role during PTC formation in all organisms.
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Affiliation(s)
- Rizos-Georgios Manikas
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, Heidelberg D-69120, Germany
| | - Emma Thomson
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, Heidelberg D-69120, Germany
| | - Matthias Thoms
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, Heidelberg D-69120, Germany
| | - Ed Hurt
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 328, Heidelberg D-69120, Germany
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30
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Richter-Dennerlein R, Dennerlein S, Rehling P. Integrating mitochondrial translation into the cellular context. Nat Rev Mol Cell Biol 2015; 16:586-92. [PMID: 26535422 DOI: 10.1038/nrm4051] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mitochondrial-encoded subunits of the oxidative phosphorylation system assemble with nuclear-encoded subunits into enzymatic complexes. Recent findings showed that mitochondrial translation is linked to other mitochondrial functions, as well as to cellular processes. The supply of mitochondrial-encoded proteins is coordinated by the coupling of mitochondrial protein synthesis with assembly of respiratory chain complexes. MicroRNAs imported from the cytoplasm into mitochondria were, surprisingly, found to act as regulators of mitochondrial translation. In turn, translation in mitochondria controls cellular proliferation, and mitochondrial ribosomal subunits contribute to the cytoplasmic stress response. Thus, translation in mitochondria is apparently integrated into cellular processes.
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31
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Al-Furoukh N, Ianni A, Nolte H, Hölper S, Krüger M, Wanrooij S, Braun T. ClpX stimulates the mitochondrial unfolded protein response (UPRmt) in mammalian cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:2580-91. [DOI: 10.1016/j.bbamcr.2015.06.016] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 06/09/2015] [Accepted: 06/27/2015] [Indexed: 02/06/2023]
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32
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Elson JL, Smith PM, Greaves LC, Lightowlers RN, Chrzanowska-Lightowlers ZMA, Taylor RW, Vila-Sanjurjo A. The presence of highly disruptive 16S rRNA mutations in clinical samples indicates a wider role for mutations of the mitochondrial ribosome in human disease. Mitochondrion 2015; 25:17-27. [PMID: 26349026 PMCID: PMC4665369 DOI: 10.1016/j.mito.2015.08.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 08/19/2015] [Accepted: 08/27/2015] [Indexed: 11/16/2022]
Abstract
Mitochondrial DNA mutations are well recognized as an important cause of disease, with over two hundred variants in the protein encoding and mt-tRNA genes associated with human disorders. In contrast, the two genes encoding the mitochondrial rRNAs (mt-rRNAs) have been studied in far less detail. This is because establishing the pathogenicity of mt-rRNA mutations is a major diagnostic challenge. Only two disease causing mutations have been identified at these loci, both mapping to the small subunit (SSU). On the large subunit (LSU), however, the evidence for the presence of pathogenic LSU mt-rRNA changes is particularly sparse. We have previously expanded the list of deleterious SSU mt-rRNA mutations by identifying highly disruptive base changes capable of blocking the activity of the mitoribosomal SSU. To do this, we used a new methodology named heterologous inferential analysis (HIA). The recent arrival of near-atomic-resolution structures of the human mitoribosomal LSU, has enhanced the power of our approach by permitting the analysis of the corresponding sites of mutation within their natural structural context. Here, we have used these tools to determine whether LSU mt-rRNA mutations found in the context of human disease and/or ageing could disrupt the function of the mitoribosomal LSU. Our results clearly show that, much like the for SSU mt-rRNA, LSU mt-rRNAs mutations capable of compromising the function of the mitoribosomal LSU are indeed present in clinical samples. Thus, our work constitutes an important contribution to an emerging view of the mitoribosome as an important element in human health. Identification of pathogenic mutations of mitochondrial rRNAs is problematic. We analysed 64 rare 16S rRNA mutations obtained from clinical samples. The mutations underwent heterologous inferential analysis (HIA). We show that highly disruptive 16S rRNA mutations are present in clinical samples.
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Affiliation(s)
- Joanna L Elson
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, United Kingdom; Centre for Human Metabonomics, North-West University, Potchefstroom, South Africa
| | - Paul M Smith
- Institute of Medical Sciences, Ninewells Hospital and Medical School, Dundee University, Dundee DD1 9SY, Scotland, UK; Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, The Medical School, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Laura C Greaves
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, The Medical School, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Robert N Lightowlers
- Newcastle University Institute for Cell and Molecular Biosciences, Newcastle University, The Medical School, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Zofia M A Chrzanowska-Lightowlers
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, The Medical School, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Robert W Taylor
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, The Medical School, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Antón Vila-Sanjurjo
- Grupo GIBE, Bioloxía Celular e Molecular, Facultade de Ciencias, Universidade da Coruña (UDC), Campus Zapateira s/n, 15071 A Coruña, Spain.
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Scuotto M, Rivieccio E, Varone A, Corda D, Bucci M, Vellecco V, Cirino G, Virgilio A, Esposito V, Galeone A, Borbone N, Varra M, Mayol L. Site specific replacements of a single loop nucleoside with a dibenzyl linker may switch the activity of TBA from anticoagulant to antiproliferative. Nucleic Acids Res 2015; 43:7702-16. [PMID: 26250112 PMCID: PMC4652776 DOI: 10.1093/nar/gkv789] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 07/23/2015] [Indexed: 12/20/2022] Open
Abstract
Many antiproliferative G-quadruplexes (G4s) arise from the folding of GT-rich strands. Among these, the Thrombin Binding Aptamer (TBA), as a rare example, adopts a monomolecular well-defined G4 structure. Nevertheless, the potential anticancer properties of TBA are severely hampered by its anticoagulant action and, consequently, no related studies have appeared so far in the literature. We wish to report here that suitable chemical modifications in the TBA sequence can preserve its antiproliferative over anticoagulant activity. Particularly, we replaced one residue of the TT or TGT loops with a dibenzyl linker to develop seven new quadruplex-forming TBA based sequences (TBA-bs), which were studied for their structural (CD, CD melting, 1D NMR) and biological (fibrinogen, PT and MTT assays) properties. The three-dimensional structures of the TBA-bs modified at T13 (TBA-bs13) or T12 (TBA-bs12), the former endowed with selective antiproliferative activity, and the latter acting as potently as TBA in both coagulation and MTT assays, were further studied by 2D NMR restrained molecular mechanics. The comparative structural analyses indicated that neither the stability, nor the topology of the G4s, but the different localization of the two benzene rings of the linker was responsible for the loss of the antithrombin activity for TBA-bs13.
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Affiliation(s)
- Maria Scuotto
- Department of Pharmacy, University of Naples Federico II, Via Domenico Montesano 49, Naples, Italy
| | - Elisa Rivieccio
- Department of Pharmacy, University of Naples Federico II, Via Domenico Montesano 49, Naples, Italy
| | - Alessia Varone
- Institute of Protein Biochemistry, National Research Council, Via Pietro Castellino 111, 80131 Naples, Italy
| | - Daniela Corda
- Institute of Protein Biochemistry, National Research Council, Via Pietro Castellino 111, 80131 Naples, Italy
| | - Mariarosaria Bucci
- Department of Pharmacy, University of Naples Federico II, Via Domenico Montesano 49, Naples, Italy
| | - Valentina Vellecco
- Department of Pharmacy, University of Naples Federico II, Via Domenico Montesano 49, Naples, Italy
| | - Giuseppe Cirino
- Department of Pharmacy, University of Naples Federico II, Via Domenico Montesano 49, Naples, Italy
| | - Antonella Virgilio
- Department of Pharmacy, University of Naples Federico II, Via Domenico Montesano 49, Naples, Italy
| | - Veronica Esposito
- Department of Pharmacy, University of Naples Federico II, Via Domenico Montesano 49, Naples, Italy
| | - Aldo Galeone
- Department of Pharmacy, University of Naples Federico II, Via Domenico Montesano 49, Naples, Italy
| | - Nicola Borbone
- Department of Pharmacy, University of Naples Federico II, Via Domenico Montesano 49, Naples, Italy
| | - Michela Varra
- Department of Pharmacy, University of Naples Federico II, Via Domenico Montesano 49, Naples, Italy
| | - Luciano Mayol
- Department of Pharmacy, University of Naples Federico II, Via Domenico Montesano 49, Naples, Italy
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Baggio F, Bratic A, Mourier A, Kauppila TES, Tain LS, Kukat C, Habermann B, Partridge L, Larsson NG. Drosophila melanogaster LRPPRC2 is involved in coordination of mitochondrial translation. Nucleic Acids Res 2014; 42:13920-38. [PMID: 25428350 PMCID: PMC4267620 DOI: 10.1093/nar/gku1132] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Members of the pentatricopeptide repeat domain (PPR) protein family bind RNA and are important for post-transcriptional control of organelle gene expression in unicellular eukaryotes, metazoans and plants. They also have a role in human pathology, as mutations in the leucine-rich PPR-containing (LRPPRC) gene cause severe neurodegeneration. We have previously shown that the mammalian LRPPRC protein and its Drosophila melanogaster homolog DmLRPPRC1 (also known as bicoid stability factor) are necessary for mitochondrial translation by controlling stability and polyadenylation of mRNAs. We here report characterization of DmLRPPRC2, a second fruit fly homolog of LRPPRC, and show that it has a predominant mitochondrial localization and interacts with a stem-loop interacting RNA binding protein (DmSLIRP2). Ubiquitous downregulation of DmLrpprc2 expression causes respiratory chain dysfunction, developmental delay and shortened lifespan. Unexpectedly, decreased DmLRPPRC2 expression does not globally affect steady-state levels or polyadenylation of mitochondrial transcripts. However, some mitochondrial transcripts abnormally associate with the mitochondrial ribosomes and some products are dramatically overproduced and other ones decreased, which, in turn, results in severe deficiency of respiratory chain complexes. The function of DmLRPPRC2 thus seems to be to ensure that mitochondrial transcripts are presented to the mitochondrial ribosomes in an orderly fashion to avoid poorly coordinated translation.
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Affiliation(s)
- Francesca Baggio
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, Cologne 50931, Germany
| | - Ana Bratic
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, Cologne 50931, Germany
| | - Arnaud Mourier
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, Cologne 50931, Germany
| | - Timo E S Kauppila
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, Cologne 50931, Germany
| | - Luke S Tain
- Department of the Biological Mechanisms of Ageing, Max Planck Institute for Biology of Ageing, Cologne 50931, Germany
| | - Christian Kukat
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, Cologne 50931, Germany FACS & Imaging Core Facility, Max Planck Institute for Biology of Ageing, Cologne 50931, Germany
| | - Bianca Habermann
- Department of Computational Biology, Max Planck Institute of Biochemistry, Martinsried 82152, Germany
| | - Linda Partridge
- Department of the Biological Mechanisms of Ageing, Max Planck Institute for Biology of Ageing, Cologne 50931, Germany
| | - Nils-Göran Larsson
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, Cologne 50931, Germany Department of Laboratory Medicine, Karolinska Institutet, Stockholm 17177, Sweden
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35
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Lee KW, Bogenhagen DF. Assignment of 2'-O-methyltransferases to modification sites on the mammalian mitochondrial large subunit 16 S ribosomal RNA (rRNA). J Biol Chem 2014; 289:24936-24942. [PMID: 25074936 DOI: 10.21074/jbc.c24114.581868] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023] Open
Abstract
Advances in proteomics and large scale studies of potential mitochondrial proteins have led to the identification of many novel mitochondrial proteins in need of further characterization. Among these novel proteins are three mammalian rRNA methyltransferase family members RNMTL1, MRM1, and MRM2. MRM1 and MRM2 have bacterial and yeast homologs, whereas RNMTL1 appears to have evolved later in higher eukaryotes. We recently confirmed the localization of the three proteins to mitochondria, specifically in the vicinity of mtDNA nucleoids. In this study, we took advantage of the ability of 2'-O-ribose modification to block site-specific cleavage of RNA by DNAzymes to show that MRM1, MRM2, and RNMTL1 are responsible for modification of human large subunit rRNA at residues G(1145), U(1369), and G(1370), respectively.
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Affiliation(s)
- Ken-Wing Lee
- From the Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York 11794-8651
| | - Daniel F Bogenhagen
- From the Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York 11794-8651
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36
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Lee KW, Bogenhagen DF. Assignment of 2'-O-methyltransferases to modification sites on the mammalian mitochondrial large subunit 16 S ribosomal RNA (rRNA). J Biol Chem 2014; 289:24936-42. [PMID: 25074936 DOI: 10.1074/jbc.c114.581868] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Advances in proteomics and large scale studies of potential mitochondrial proteins have led to the identification of many novel mitochondrial proteins in need of further characterization. Among these novel proteins are three mammalian rRNA methyltransferase family members RNMTL1, MRM1, and MRM2. MRM1 and MRM2 have bacterial and yeast homologs, whereas RNMTL1 appears to have evolved later in higher eukaryotes. We recently confirmed the localization of the three proteins to mitochondria, specifically in the vicinity of mtDNA nucleoids. In this study, we took advantage of the ability of 2'-O-ribose modification to block site-specific cleavage of RNA by DNAzymes to show that MRM1, MRM2, and RNMTL1 are responsible for modification of human large subunit rRNA at residues G(1145), U(1369), and G(1370), respectively.
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Affiliation(s)
- Ken-Wing Lee
- From the Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York 11794-8651
| | - Daniel F Bogenhagen
- From the Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York 11794-8651
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37
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Al-Furoukh N, Kardon JR, Krüger M, Szibor M, Baker TA, Braun T. NOA1, a novel ClpXP substrate, takes an unexpected nuclear detour prior to mitochondrial import. PLoS One 2014; 9:e103141. [PMID: 25072814 PMCID: PMC4114565 DOI: 10.1371/journal.pone.0103141] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 06/26/2014] [Indexed: 11/25/2022] Open
Abstract
The mitochondrial matrix GTPase NOA1 is a nuclear encoded protein, essential for mitochondrial protein synthesis, oxidative phosphorylation and ATP production. Here, we demonstrate that newly translated NOA1 protein is imported into the nucleus, where it localizes to the nucleolus and interacts with UBF1 before nuclear export and import into mitochondria. Mutation of the nuclear localization signal (NLS) prevented both nuclear and mitochondrial import while deletion of the N-terminal mitochondrial targeting sequence (MTS) or the C-terminal RNA binding domain of NOA1 impaired mitochondrial import. Absence of the MTS resulted in accumulation of NOA1 in the nucleus and increased caspase-dependent apoptosis. We also found that export of NOA1 from the nucleus requires a leptomycin-B sensitive, Crm1-dependent nuclear export signal (NES). Finally, we show that NOA1 is a new substrate of the mitochondrial matrix protease complex ClpXP. Our results uncovered an unexpected, mandatory detour of NOA1 through the nucleolus before uptake into mitochondria. We propose that nucleo-mitochondrial translocation of proteins is more widespread than previously anticipated providing additional means to control protein bioavailability as well as cellular communication between both compartments.
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Affiliation(s)
- Natalie Al-Furoukh
- Department of Cardiac Development and Remodeling, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Julia R. Kardon
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Boston, Massachusetts, United States of America
| | - Marcus Krüger
- Department of Cardiac Development and Remodeling, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Marten Szibor
- Department of Cardiac Development and Remodeling, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Tania A. Baker
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Boston, Massachusetts, United States of America
| | - Thomas Braun
- Department of Cardiac Development and Remodeling, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
- * E-mail:
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38
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Smith PM, Elson JL, Greaves LC, Wortmann SB, Rodenburg RJT, Lightowlers RN, Chrzanowska-Lightowlers ZMA, Taylor RW, Vila-Sanjurjo A. The role of the mitochondrial ribosome in human disease: searching for mutations in 12S mitochondrial rRNA with high disruptive potential. Hum Mol Genet 2013; 23:949-67. [PMID: 24092330 PMCID: PMC3900107 DOI: 10.1093/hmg/ddt490] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Mutations of mitochondrial DNA are linked to many human diseases. Despite the identification of a large number of variants in the mitochondrially encoded rRNA (mt-rRNA) genes, the evidence supporting their pathogenicity is, at best, circumstantial. Establishing the pathogenicity of these variations is of major diagnostic importance. Here, we aim to estimate the disruptive effect of mt-rRNA variations on the function of the mitochondrial ribosome. In the absence of direct biochemical methods to study the effect of mt-rRNA variations, we relied on the universal conservation of the rRNA fold to infer their disruptive potential. Our method, named heterologous inferential analysis or HIA, combines conservational information with functional and structural data obtained from heterologous ribosomal sources. Thus, HIA's predictive power is superior to the traditional reliance on simple conservation indexes. By using HIA, we have been able to evaluate the disruptive potential for a subset of uncharacterized 12S mt-rRNA variations. Our analysis revealed the existence of variations in the rRNA component of the human mitoribosome with different degrees of disruptive power. In cases where sufficient information regarding the genetic and pathological manifestation of the mitochondrial phenotype is available, HIA data can be used to predict the pathogenicity of mt-rRNA mutations. In other cases, HIA analysis will allow the prioritization of variants for additional investigation. Eventually, HIA-inspired analysis of potentially pathogenic mt-rRNA variations, in the context of a scoring system specifically designed for these variants, could lead to a powerful diagnostic tool.
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Affiliation(s)
- Paul M Smith
- Institute of Medical Sciences, Ninewells Hospital and Medical School, Dundee University, Dundee DD1 9SY, Scotland, UK
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Rackham O, Filipovska A. Supernumerary proteins of mitochondrial ribosomes. Biochim Biophys Acta Gen Subj 2013; 1840:1227-32. [PMID: 23958563 DOI: 10.1016/j.bbagen.2013.08.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 08/08/2013] [Accepted: 08/13/2013] [Indexed: 01/13/2023]
Abstract
BACKGROUND Messenger RNAs encoded by mitochondrial genomes are translated on mitochondrial ribosomes that have unique structure and protein composition compared to prokaryotic and cytoplasmic ribosomes. Mitochondrial ribosomes are a patchwork of core proteins that share homology with prokaryotic ribosomal proteins and new, supernumerary proteins that can be unique to different organisms. In mammals, there are specific supernumerary ribosomal proteins that are not present in other eukaryotes. SCOPE OF REVIEW Here we discuss the roles of supernumerary proteins in the regulation of mitochondrial gene expression and compare them among different eukaryotic systems. Furthermore, we consider if differences in the structure and organization of mitochondrial genomes may have contributed to the acquisition of mitochondrial ribosomal proteins with new functions. MAJOR CONCLUSIONS The distinct and diverse compositions of mitochondrial ribosomes illustrate the high evolutionary divergence found between mitochondrial genetic systems. GENERAL SIGNIFICANCE Elucidating the role of the organism-specific supernumerary proteins may provide a window into the regulation of mitochondrial gene expression through evolution in response to distinct evolutionary paths taken by mitochondria in different organisms. This article is part of a Special Issue entitled Frontiers of Mitochondrial Research.
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Affiliation(s)
- Oliver Rackham
- Western Australian Institute for Medical Research, Western Australia 6000, Australia; School of Chemistry and Biochemistry, The University of Western Australia, Western Australia 6009, Australia
| | - Aleksandra Filipovska
- Western Australian Institute for Medical Research, Western Australia 6000, Australia; School of Chemistry and Biochemistry, The University of Western Australia, Western Australia 6009, Australia.
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40
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Al-Furoukh N, Goffart S, Szibor M, Wanrooij S, Braun T. Binding to G-quadruplex RNA activates the mitochondrial GTPase NOA1. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:2933-2942. [PMID: 23933583 DOI: 10.1016/j.bbamcr.2013.07.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 07/26/2013] [Accepted: 07/29/2013] [Indexed: 11/19/2022]
Abstract
NOA1 is an evolutionary conserved, nuclear encoded GTPase essential for mitochondrial function and cellular survival. The function of NOA1 for assembly of mitochondrial ribosomes and regulation of OXPHOS activity depends on its GTPase activity, but so far no ligands have been identified that regulate the GTPase activity of NOA1. To identify nucleic acids that bind to the RNA-binding domain of NOA1 we employed SELEX (Systemic Evolution of Ligands by EXponential Enrichment) using recombinant mouse wildtype NOA1 and the GTPase mutant NOA1-K353R. We found that NOA1 binds specifically to oligonucleotides that fold into guanine tetrads (G-quadruplexes). Binding of G-quadruplex oligonucleotides stimulated the GTPase activity of NOA1 suggesting a regulatory link between G-quadruplex containing RNAs, NOA1 function and assembly of mitochondrial ribosomes.
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Affiliation(s)
- Natalie Al-Furoukh
- Max-Planck-Institute for Heart and Lung Research, Ludwigstrasse 43, 61231 Bad Nauheim, Germany.
| | - Steffi Goffart
- Max-Planck-Institute for Heart and Lung Research, Ludwigstrasse 43, 61231 Bad Nauheim, Germany; University of Eastern Finland, Department of Biology, Yliopistokatu 7, 80101 Joensuu, Finland.
| | - Marten Szibor
- Max-Planck-Institute for Heart and Lung Research, Ludwigstrasse 43, 61231 Bad Nauheim, Germany.
| | - Sjoerd Wanrooij
- University of Gothenburg, Department of Medical Biochemistry and Cell Biology, Box 440, SE-40530, Göteborg, Sweden; Burgers Lab, Department of Biochemistry and Biophysics, Washington University, Campus Box 8231, 4566 Scott Avenue, MO 63110, St. Louis, USA.
| | - Thomas Braun
- Max-Planck-Institute for Heart and Lung Research, Ludwigstrasse 43, 61231 Bad Nauheim, Germany.
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41
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Chen GL, Miller GM. Extensive alternative splicing of the repressor element silencing transcription factor linked to cancer. PLoS One 2013; 8:e62217. [PMID: 23614038 PMCID: PMC3628349 DOI: 10.1371/journal.pone.0062217] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Accepted: 03/18/2013] [Indexed: 12/15/2022] Open
Abstract
The repressor element silencing transcription factor (REST) is a coordinate transcriptional and epigenetic regulator which functions as a tumor suppressor or an oncogene depending on cellular context, and a truncated splice variant REST4 has been linked to various types of cancer. We performed a comprehensive analysis of alternative splicing (AS) of REST by rapid amplification of cDNA ends and PCR amplification of cDNAs from various tissues and cell lines with specific primers. We identified 8 novel alternative exons including an alternate last exon which doubles the REST gene boundary, along with numerous 5'/3' splice sites and ends in the constitutive exons. With the combination of various splicing patterns (e.g. exon skipping and alternative usage of the first and last exons) that are predictive of altered REST activity, at least 45 alternatively spliced variants of coding and non-coding mRNA were expressed in a species- and cell-type/tissue-specific manner with individual differences. By examining the repertoire of REST pre-mRNA splicing in 27 patients with kidney, liver and lung cancer, we found that all patients without exception showed differential expression of various REST splice variants between paired tumor and adjacent normal tissues, with striking cell-type/tissue and individual differences. Moreover, we revealed that exon 3 skipping, which causes no frame shift but loss of a domain essential for nuclear translocation, was affected by pioglitazone, a highly selective activator of the peroxisome proliferator-activated receptor gamma (PPARγ) which contributes to cell differentiation and tumorigenesis besides its metabolic actions. Accordingly, this study demonstrates an extensive AS of REST pre-mRNA which redefines REST gene boundary and structure, along with a general but differential link between REST pre-mRNA splicing and various types of cancer. These findings advance our understanding of the complex, context-dependent regulation of REST gene expression and function, and provide potential biomarkers and therapeutic targets for cancer.
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Affiliation(s)
- Guo-Lin Chen
- Division of Neuroscience, New England Primate Research Center, Harvard Medical School, Southborough, Massachusetts, United States of America.
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42
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Almajan ER, Richter R, Paeger L, Martinelli P, Barth E, Decker T, Larsson NG, Kloppenburg P, Langer T, Rugarli EI. AFG3L2 supports mitochondrial protein synthesis and Purkinje cell survival. J Clin Invest 2012; 122:4048-58. [PMID: 23041622 DOI: 10.1172/jci64604] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Accepted: 08/13/2012] [Indexed: 12/11/2022] Open
Abstract
Mutations in the AFG3L2 gene have been linked to spinocerebellar ataxia type 28 and spastic ataxia-neuropathy syndrome in humans; however, the pathogenic mechanism is still unclear. AFG3L2 encodes a subunit of the mitochondrial m-AAA protease, previously implicated in quality control of misfolded inner mitochondrial membrane proteins and in regulatory functions via processing of specific substrates. Here, we used a conditional Afg3l2 mouse model that allows restricted deletion of the gene in Purkinje cells (PCs) to shed light on the pathogenic cascade in the neurons mainly affected in the human diseases. We demonstrate a cell-autonomous requirement of AFG3L2 for survival of PCs. Examination of PCs prior to neurodegeneration revealed fragmentation and altered distribution of mitochondria in the dendritic tree, indicating that abnormal mitochondrial dynamics is an early event in the pathogenic process. Moreover, PCs displayed features pointing to defects in mitochondrially encoded respiratory chain subunits at early stages. To unravel the underlying mechanism, we examined a constitutive knockout of Afg3l2, which revealed a decreased rate of mitochondrial protein synthesis associated with impaired mitochondrial ribosome assembly. We therefore propose that defective mitochondrial protein synthesis, leading to early-onset fragmentation of the mitochondrial network, is a central causative factor in AFG3L2-related neurodegeneration.
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Affiliation(s)
- Eva R Almajan
- Institute of Zoology, University of Cologne, Cologne, Germany
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43
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Abstract
Mammalian mitochondria contain their own genome that encodes mRNAs for thirteen essential subunits of the complexes performing oxidative phosphorylation as well as the RNA components (two rRNAs and 22 tRNAs) needed for their translation in mitochondria. All RNA species are produced from single polycistronic precursor RNAs, yet the relative concentrations of various RNAs differ significantly. This underscores the essential role of post-transcriptional mechanisms that control the maturation, stability and translation of mitochondrial RNAs. The present review provides a detailed summary on the role of RNA maturation in the regulation of mitochondrial gene expression, focusing mainly on messenger RNA polyadenylation and stability control. Furthermore, the role of mitochondrial ribosomal RNA stability, processing and modifications in the biogenesis of the mitochondrial ribosome is discussed.
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44
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Rackham O, Mercer TR, Filipovska A. The human mitochondrial transcriptome and the RNA-binding proteins that regulate its expression. WILEY INTERDISCIPLINARY REVIEWS-RNA 2012; 3:675-95. [DOI: 10.1002/wrna.1128] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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45
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Ash MR, Maher MJ, Mitchell Guss J, Jormakka M. The cation-dependent G-proteins: in a class of their own. FEBS Lett 2012; 586:2218-24. [PMID: 22750478 DOI: 10.1016/j.febslet.2012.06.030] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Revised: 06/14/2012] [Accepted: 06/19/2012] [Indexed: 12/31/2022]
Abstract
G-proteins are some of the most important and abundant enzymes, yet their intrinsic nucleotide hydrolysis reaction is notoriously slow and must be accelerated in vivo. Recent experiments on dynamin and GTPases involved in ribosome assembly have demonstrated that their hydrolysis activities are stimulated by potassium ions. This article presents the hypothesis that cation-mediated activation of G-proteins is more common than currently realised, and that such GTPases represent a structurally and functionally unique class of G-proteins. Based on sequence analysis we provide a list of predicted cation-dependent GTPases, which encompasses almost all members of the TEES, Obg-HflX, YqeH-like and dynamin superfamilies. The results from this analysis effectively re-define the conditions under which many of these G-proteins should be studied in vitro.
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Affiliation(s)
- Miriam-Rose Ash
- School of Molecular Bioscience, The University of Sydney, Australia.
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46
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He J, Cooper HM, Reyes A, Di Re M, Kazak L, Wood SR, Mao CC, Fearnley IM, Walker JE, Holt IJ. Human C4orf14 interacts with the mitochondrial nucleoid and is involved in the biogenesis of the small mitochondrial ribosomal subunit. Nucleic Acids Res 2012; 40:6097-108. [PMID: 22447445 PMCID: PMC3401442 DOI: 10.1093/nar/gks257] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The bacterial homologue of C4orf14, YqeH, has been linked to assembly of the small ribosomal subunit. Here, recombinant C4orf14 isolated from human cells, co-purified with the small, 28S subunit of the mitochondrial ribosome and the endogenous protein co-fractionated with the 28S subunit in sucrose gradients. Gene silencing of C4orf14 specifically affected components of the small subunit, leading to decreased protein synthesis in the organelle. The GTPase of C4orf14 was critical to its interaction with the 28S subunit, as was GTP. Therefore, we propose that C4orf14, with bound GTP, binds to components of the 28S subunit facilitating its assembly, and GTP hydrolysis acts as the release mechanism. C4orf14 was also found to be associated with human mitochondrial nucleoids, and C4orf14 gene silencing caused mitochondrial DNA depletion. In vitro C4orf14 is capable of binding to DNA. The association of C4orf14 with mitochondrial translation factors and the mitochondrial nucleoid suggests that the 28S subunit is assembled at the mitochondrial nucleoid, enabling the direct transfer of messenger RNA from the nucleoid to the ribosome in the organelle.
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Affiliation(s)
- J He
- MRC-Mitochondrial Biology Unit, Wellcome Trust-MRC Building, Hills Road Cambridge, CB2 0XY, UK
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47
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Wanschers BFJ, Szklarczyk R, Pajak A, van den Brand MAM, Gloerich J, Rodenburg RJT, Lightowlers RN, Nijtmans LG, Huynen MA. C7orf30 specifically associates with the large subunit of the mitochondrial ribosome and is involved in translation. Nucleic Acids Res 2012; 40:4040-51. [PMID: 22238375 PMCID: PMC3351149 DOI: 10.1093/nar/gkr1271] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In a comparative genomics study for mitochondrial ribosome-associated proteins, we identified C7orf30, the human homolog of the plant protein iojap. Gene order conservation among bacteria and the observation that iojap orthologs cannot be transferred between bacterial species predict this protein to be associated with the mitochondrial ribosome. Here, we show colocalization of C7orf30 with the large subunit of the mitochondrial ribosome using isokinetic sucrose gradient and 2D Blue Native polyacrylamide gel electrophoresis (BN-PAGE) analysis. We co-purified C7orf30 with proteins of the large subunit, and not with proteins of the small subunit, supporting interaction that is specific to the large mitoribosomal complex. Consistent with this physical association, a mitochondrial translation assay reveals negative effects of C7orf30 siRNA knock-down on mitochondrial gene expression. Based on our data we propose that C7orf30 is involved in ribosomal large subunit function. Sequencing the gene in 35 patients with impaired mitochondrial translation did not reveal disease-causing mutations in C7orf30.
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Affiliation(s)
- Bas F J Wanschers
- Centre for Molecular and Biomolecular Informatics, Radboud University Nijmegen Medical Centre, The Netherlands
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Rorbach J, Gammage PA, Minczuk M. C7orf30 is necessary for biogenesis of the large subunit of the mitochondrial ribosome. Nucleic Acids Res 2012; 40:4097-109. [PMID: 22238376 PMCID: PMC3351152 DOI: 10.1093/nar/gkr1282] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Defects of the translation apparatus in human mitochondria are known to cause disease, yet details of how protein synthesis is regulated in this organelle remain to be unveiled. Here, we characterize a novel human protein, C7orf30 that contributes critically to mitochondrial translation and specifically associates with the large subunit of the mitochondrial ribosome (mt-LSU). Inactivation of C7orf30 in human cells by RNA interference results in respiratory incompetence owing to reduced mitochondrial translation rates without any appreciable effects on the steady-state levels of mitochondrial mRNAs and rRNAs. Ineffective translation in C7orf30-depleted cells or cells overexpressing a dominant-negative mutant of the protein results from aberrant assembly of mt-LSU and consequently reduced formation of the monosome. These findings lead us to propose that C7orf30 is a human assembly and/or stability factor involved in the biogenesis of the large subunit of the mitochondrial ribosome.
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Affiliation(s)
- Joanna Rorbach
- MRC Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
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Christian BE, Spremulli LL. Mechanism of protein biosynthesis in mammalian mitochondria. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2011; 1819:1035-54. [PMID: 22172991 DOI: 10.1016/j.bbagrm.2011.11.009] [Citation(s) in RCA: 144] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Revised: 11/03/2011] [Accepted: 11/08/2011] [Indexed: 01/25/2023]
Abstract
Protein synthesis in mammalian mitochondria produces 13 proteins that are essential subunits of the oxidative phosphorylation complexes. This review provides a detailed outline of each phase of mitochondrial translation including initiation, elongation, termination, and ribosome recycling. The roles of essential proteins involved in each phase are described. All of the products of mitochondrial protein synthesis in mammals are inserted into the inner membrane. Several proteins that may help bind ribosomes to the membrane during translation are described, although much remains to be learned about this process. Mutations in mitochondrial or nuclear genes encoding components of the translation system often lead to severe deficiencies in oxidative phosphorylation, and a summary of these mutations is provided. This article is part of a Special Issue entitled: Mitochondrial Gene Expression.
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Affiliation(s)
- Brooke E Christian
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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Ruzzenente B, Metodiev MD, Wredenberg A, Bratic A, Park CB, Cámara Y, Milenkovic D, Zickermann V, Wibom R, Hultenby K, Erdjument-Bromage H, Tempst P, Brandt U, Stewart JB, Gustafsson CM, Larsson NG. LRPPRC is necessary for polyadenylation and coordination of translation of mitochondrial mRNAs. EMBO J 2011; 31:443-56. [PMID: 22045337 DOI: 10.1038/emboj.2011.392] [Citation(s) in RCA: 265] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Accepted: 09/30/2011] [Indexed: 11/09/2022] Open
Abstract
Regulation of mtDNA expression is critical for maintaining cellular energy homeostasis and may, in principle, occur at many different levels. The leucine-rich pentatricopeptide repeat containing (LRPPRC) protein regulates mitochondrial mRNA stability and an amino-acid substitution of this protein causes the French-Canadian type of Leigh syndrome (LSFC), a neurodegenerative disorder characterized by complex IV deficiency. We have generated conditional Lrpprc knockout mice and show here that the gene is essential for embryonic development. Tissue-specific disruption of Lrpprc in heart causes mitochondrial cardiomyopathy with drastic reduction in steady-state levels of most mitochondrial mRNAs. LRPPRC forms an RNA-dependent protein complex that is necessary for maintaining a pool of non-translated mRNAs in mammalian mitochondria. Loss of LRPPRC does not only decrease mRNA stability, but also leads to loss of mRNA polyadenylation and the appearance of aberrant mitochondrial translation. The translation pattern without the presence of LRPPRC is misregulated with excessive translation of some transcripts and no translation of others. Our findings point to the existence of an elaborate machinery that regulates mammalian mtDNA expression at the post-transcriptional level.
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Affiliation(s)
- Benedetta Ruzzenente
- Department of Mitochondrial Genetics, Max Planck Institute for Biology of Ageing, Cologne, Germany
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