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Chrzanowska-Lightowlers ZM, Lightowlers RN. Translation in Mitochondrial Ribosomes. Methods Mol Biol 2023; 2661:53-72. [PMID: 37166631 DOI: 10.1007/978-1-0716-3171-3_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Mitochondrial protein synthesis is essential for the life of aerobic eukaryotes. Without it, oxidative phosphorylation cannot be coupled. Evolution has shaped a battery of factors and machinery that are key to production of just a handful of critical proteins. In this general concept chapter, we attempt to briefly summarize our current knowledge of the overall process in mitochondria from a variety of species, breaking this down to the four parts of translation: initiation, elongation, termination, and recycling. Where appropriate, we highlight differences between species and emphasize gaps in our understanding. Excitingly, with the current revolution in cryoelectron microscopy and mitochondrial genome editing, it is highly likely that many of these gaps will be resolved in the near future. However, the absence of a faithful in vitro reconstituted system to study mitochondrial translation is still problematic.
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Affiliation(s)
- Zofia M Chrzanowska-Lightowlers
- Wellcome Centre for Mitochondrial Research, Newcastle University Biosciences Institute, Faculty of Medical Sciences, Newcastle upon Tyne, UK.
| | - Robert N Lightowlers
- Wellcome Centre for Mitochondrial Research, Newcastle University Biosciences Institute, Faculty of Medical Sciences, Newcastle upon Tyne, UK
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Di Nottia M, Marchese M, Verrigni D, Mutti CD, Torraco A, Oliva R, Fernandez-Vizarra E, Morani F, Trani G, Rizza T, Ghezzi D, Ardissone A, Nesti C, Vasco G, Zeviani M, Minczuk M, Bertini E, Santorelli FM, Carrozzo R. A homozygous MRPL24 mutation causes a complex movement disorder and affects the mitoribosome assembly. Neurobiol Dis 2020; 141:104880. [PMID: 32344152 DOI: 10.1016/j.nbd.2020.104880] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 03/04/2020] [Accepted: 04/23/2020] [Indexed: 01/31/2023] Open
Abstract
Mitochondrial ribosomal protein large 24 (MRPL24) is 1 of the 82 protein components of mitochondrial ribosomes, playing an essential role in the mitochondrial translation process. We report here on a baby girl with cerebellar atrophy, choreoathetosis of limbs and face, intellectual disability and a combined defect of complexes I and IV in muscle biopsy, caused by a homozygous missense mutation identified in MRPL24. The variant predicts a Leu91Pro substitution at an evolutionarily conserved site. Using human mutant cells and the zebrafish model, we demonstrated the pathological role of the identified variant. In fact, in fibroblasts we observed a significant reduction of MRPL24 protein and of mitochondrial respiratory chain complex I and IV subunits, as well a markedly reduced synthesis of the mtDNA-encoded peptides. In zebrafish we demonstrated that the orthologue gene is expressed in metabolically active tissues, and that gene knockdown induced locomotion impairment, structural defects and low ATP production. The motor phenotype was complemented by human WT but not mutant cRNA. Moreover, sucrose density gradient fractionation showed perturbed assembly of large subunit mitoribosomal proteins, suggesting that the mutation leads to a conformational change in MRPL24, which is expected to cause an aberrant interaction of the protein with other components of the 39S mitoribosomal subunit.
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Affiliation(s)
- Michela Di Nottia
- Unit of Muscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Maria Marchese
- Molecular Medicine & Neurogenetics, IRCCS Fondazione Stella Maris, Pisa, Italy
| | - Daniela Verrigni
- Unit of Muscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | | | - Alessandra Torraco
- Unit of Muscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Romina Oliva
- Department of Sciences and Technologies, University Parthenope of Naples, Naples, Italy
| | | | - Federica Morani
- Molecular Medicine & Neurogenetics, IRCCS Fondazione Stella Maris, Pisa, Italy
| | - Giulia Trani
- Unit of Muscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Teresa Rizza
- Unit of Muscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Daniele Ghezzi
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy; Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Anna Ardissone
- Child Neurology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy; Department of Molecular and Translational Medicine DIMET, University of Milan-Bicocca, Milan, Italy
| | - Claudia Nesti
- Molecular Medicine & Neurogenetics, IRCCS Fondazione Stella Maris, Pisa, Italy
| | - Gessica Vasco
- Department of Neurosciences, IRCCS Bambino Gesù Children Hospital, Rome, Italy
| | - Massimo Zeviani
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Michal Minczuk
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Enrico Bertini
- Unit of Muscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | | | - Rosalba Carrozzo
- Unit of Muscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.
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Ayyub SA, Gao F, Lightowlers RN, Chrzanowska-Lightowlers ZM. Rescuing stalled mammalian mitoribosomes - what can we learn from bacteria? J Cell Sci 2020; 133:133/1/jcs231811. [PMID: 31896602 DOI: 10.1242/jcs.231811] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
In the canonical process of translation, newly completed proteins escape from the ribosome following cleavage of the ester bond that anchors the polypeptide to the P-site tRNA, after which the ribosome can be recycled to initiate a new round of translation. Not all protein synthesis runs to completion as various factors can impede the progression of ribosomes. Rescuing of stalled ribosomes in mammalian mitochondria, however, does not share the same mechanisms that many bacteria use. The classic method for rescuing bacterial ribosomes is trans-translation. The key components of this system are absent from mammalian mitochondria; however, four members of a translation termination factor family are present, with some evidence of homology to members of a bacterial back-up rescue system. To date, there is no definitive demonstration of any other member of this family functioning in mitoribosome rescue. Here, we provide an overview of the processes and key players of canonical translation termination in both bacteria and mammalian mitochondria, followed by a perspective of the bacterial systems used to rescue stalled ribosomes. We highlight any similarities or differences with the mitochondrial translation release factors, and suggest potential roles for these proteins in ribosome rescue in mammalian mitochondria.
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Affiliation(s)
- Shreya Ahana Ayyub
- The Wellcome Centre for Mitochondrial Research, Newcastle University, The Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Fei Gao
- The Wellcome Centre for Mitochondrial Research, Newcastle University, The Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Robert N Lightowlers
- The Wellcome Centre for Mitochondrial Research, Newcastle University, The Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Zofia M Chrzanowska-Lightowlers
- The Wellcome Centre for Mitochondrial Research, Newcastle University, The Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
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