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Aoun M, Coelho A, Krämer A, Saxena A, Sabatier P, Beusch CM, Lönnblom E, Geng M, Do NN, Xu Z, Zhang J, He Y, Castillo LR, Abolhassani H, Xu B, Viljanen J, Rorbach J, Lahore GF, Gjertsson I, Kastbom A, Sjöwall C, Kihlberg J, Zubarev RA, Burkhardt H, Holmdahl R. Correction: Antigen-presenting autoreactive B cells activate regulatory T cells and suppress autoimmune arthritis in mice. J Exp Med 2023; 220:e2023010109212023c. [PMID: 37788218 PMCID: PMC10548394 DOI: 10.1084/jem.2023010109212023c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/05/2023] Open
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2
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Aoun M, Coelho A, Krämer A, Saxena A, Sabatier P, Beusch CM, Lönnblom E, Geng M, Do NN, Xu Z, Zhang J, He Y, Romero Castillo L, Abolhassani H, Xu B, Viljanen J, Rorbach J, Fernandez Lahore G, Gjertsson I, Kastbom A, Sjöwall C, Kihlberg J, Zubarev RA, Burkhardt H, Holmdahl R. Antigen-presenting autoreactive B cells activate regulatory T cells and suppress autoimmune arthritis in mice. J Exp Med 2023; 220:e20230101. [PMID: 37695523 PMCID: PMC10494526 DOI: 10.1084/jem.20230101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 05/31/2023] [Accepted: 08/16/2023] [Indexed: 09/12/2023] Open
Abstract
B cells undergo several rounds of selection to eliminate potentially pathogenic autoreactive clones, but in contrast to T cells, evidence of positive selection of autoreactive B cells remains moot. Using unique tetramers, we traced natural autoreactive B cells (C1-B) specific for a defined triple-helical epitope on collagen type-II (COL2), constituting a sizeable fraction of the physiological B cell repertoire in mice, rats, and humans. Adoptive transfer of C1-B suppressed arthritis independently of IL10, separating them from IL10-secreting regulatory B cells. Single-cell sequencing revealed an antigen processing and presentation signature, including induced expression of CD72 and CCR7 as surface markers. C1-B presented COL2 to T cells and induced the expansion of regulatory T cells in a contact-dependent manner. CD72 blockade impeded this effect suggesting a new downstream suppressor mechanism that regulates antigen-specific T cell tolerization. Thus, our results indicate that autoreactive antigen-specific naïve B cells tolerize infiltrating T cells against self-antigens to impede the development of tissue-specific autoimmune inflammation.
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Affiliation(s)
- Mike Aoun
- Division of Medical Inflammation Research, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Solna, Sweden
| | - Ana Coelho
- Division of Medical Inflammation Research, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Solna, Sweden
| | - Alexander Krämer
- Division of Medical Inflammation Research, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Solna, Sweden
| | - Amit Saxena
- Division of Medical Inflammation Research, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Solna, Sweden
| | - Pierre Sabatier
- Division of Physiological Chemistry I, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Solna, Sweden
| | - Christian Michel Beusch
- Division of Physiological Chemistry I, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Solna, Sweden
| | - Erik Lönnblom
- Division of Medical Inflammation Research, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Solna, Sweden
| | - Manman Geng
- Precision Medicine Institute, The Second Affiliated Hospital of Xi’an Jiaotong University, Xi’an, China
| | - Nhu-Nguyen Do
- Division of Medical Inflammation Research, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Solna, Sweden
- Fraunhofer Institute for Translational Medicine and Pharmacology, and Fraunhofer Cluster of Excellence for Immune-Mediated Diseases, Frankfurt am Main, Germany
| | - Zhongwei Xu
- Division of Medical Inflammation Research, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Solna, Sweden
| | - Jingdian Zhang
- Max Planck Institute Biology of Ageing—Karolinska Institute Laboratory, Karolinska Institute, Solna, Sweden
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Solna, Sweden
| | - Yibo He
- Division of Medical Inflammation Research, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Solna, Sweden
| | - Laura Romero Castillo
- Division of Medical Inflammation Research, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Solna, Sweden
| | - Hassan Abolhassani
- Division of Clinical Immunology, Department of Biosciences and Nutrition, Karolinska Institutet, Karolinska University Hospital, Neo Building, Solna, Sweden
| | - Bingze Xu
- Division of Medical Inflammation Research, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Solna, Sweden
| | - Johan Viljanen
- Department of Chemistry, Biomedical Center, Uppsala University, Uppsala, Sweden
| | - Joanna Rorbach
- Max Planck Institute Biology of Ageing—Karolinska Institute Laboratory, Karolinska Institute, Solna, Sweden
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Solna, Sweden
| | - Gonzalo Fernandez Lahore
- Division of Medical Inflammation Research, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Solna, Sweden
| | - Inger Gjertsson
- Department of Rheumatology and Inflammation Research, University of Gothenburg, Gothenburg, Sweden
| | - Alf Kastbom
- Division of Inflammation and Infection, Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Christopher Sjöwall
- Division of Inflammation and Infection, Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Jan Kihlberg
- Department of Chemistry, Biomedical Center, Uppsala University, Uppsala, Sweden
| | - Roman A. Zubarev
- Division of Physiological Chemistry I, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Solna, Sweden
- Department of Pharmacological and Technological Chemistry, I.M. Sechenov First Moscow State Medical University, Moscow, Russia
| | - Harald Burkhardt
- Fraunhofer Institute for Translational Medicine and Pharmacology, and Fraunhofer Cluster of Excellence for Immune-Mediated Diseases, Frankfurt am Main, Germany
- Division of Rheumatology, University Hospital Frankfurt, Goethe University, Frankfurt am Main, Germany
| | - Rikard Holmdahl
- Division of Medical Inflammation Research, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Solna, Sweden
- Precision Medicine Institute, The Second Affiliated Hospital of Xi’an Jiaotong University, Xi’an, China
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3
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Zhang J, Koolmeister C, Han J, Filograna R, Hanke L, Àdori M, Sheward DJ, Teifel S, Gopalakrishna S, Shao Q, Liu Y, Zhu K, Harris RA, McInerney G, Murrell B, Aoun M, Bäckdahl L, Holmdahl R, Pekalski M, Wedell A, Engvall M, Wredenberg A, Karlsson Hedestam GB, Castro Dopico X, Rorbach J. Antigen receptor stimulation induces purifying selection against pathogenic mitochondrial tRNA mutations. JCI Insight 2023; 8:e167656. [PMID: 37681412 PMCID: PMC10544217 DOI: 10.1172/jci.insight.167656] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 07/27/2023] [Indexed: 09/09/2023] Open
Abstract
Pathogenic mutations in mitochondrial (mt) tRNA genes that compromise oxidative phosphorylation (OXPHOS) exhibit heteroplasmy and cause a range of multisyndromic conditions. Although mitochondrial disease patients are known to suffer from abnormal immune responses, how heteroplasmic mtDNA mutations affect the immune system at the molecular level is largely unknown. Here, in mice carrying pathogenic C5024T in mt-tRNAAla and in patients with mitochondrial encephalomyopathy, lactic acidosis, stroke-like episodes (MELAS) syndrome carrying A3243G in mt-tRNALeu, we found memory T and B cells to have lower pathogenic mtDNA mutation burdens than their antigen-inexperienced naive counterparts, including after vaccination. Pathogenic burden reduction was less pronounced in myeloid compared with lymphoid lineages, despite C5024T compromising macrophage OXPHOS capacity. Rapid dilution of the C5024T mutation in T and B cell cultures could be induced by antigen receptor-triggered proliferation and was accelerated by metabolic stress conditions. Furthermore, we found C5024T to dysregulate CD8+ T cell metabolic remodeling and IFN-γ production after activation. Together, our data illustrate that the generation of memory lymphocytes shapes the mtDNA landscape, wherein pathogenic variants dysregulate the immune response.
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Affiliation(s)
- Jingdian Zhang
- Department of Medical Biochemistry and Biophysics, and
- Max Planck Institute Biology of Ageing-Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Camilla Koolmeister
- Department of Medical Biochemistry and Biophysics, and
- Max Planck Institute Biology of Ageing-Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Jinming Han
- Applied Immunology and Immunotherapy, Department of Clinical Neuroscience, Center for Molecular Medicine, Karolinska University Hospital, Stockholm, Sweden
| | - Roberta Filograna
- Department of Medical Biochemistry and Biophysics, and
- Max Planck Institute Biology of Ageing-Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Leo Hanke
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Monika Àdori
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Daniel J. Sheward
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
- Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Sina Teifel
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Shreekara Gopalakrishna
- Department of Medical Biochemistry and Biophysics, and
- Max Planck Institute Biology of Ageing-Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Qiuya Shao
- Department of Medical Biochemistry and Biophysics, and
- Max Planck Institute Biology of Ageing-Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Yong Liu
- Department of Medical Biochemistry and Biophysics, and
- Max Planck Institute Biology of Ageing-Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Keying Zhu
- Applied Immunology and Immunotherapy, Department of Clinical Neuroscience, Center for Molecular Medicine, Karolinska University Hospital, Stockholm, Sweden
| | - Robert A. Harris
- Applied Immunology and Immunotherapy, Department of Clinical Neuroscience, Center for Molecular Medicine, Karolinska University Hospital, Stockholm, Sweden
| | - Gerald McInerney
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Ben Murrell
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Mike Aoun
- Division of Medical Inflammation Research, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Liselotte Bäckdahl
- Division of Medical Inflammation Research, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Rikard Holmdahl
- Division of Medical Inflammation Research, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Marcin Pekalski
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Anna Wedell
- Max Planck Institute Biology of Ageing-Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Center for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden
| | - Martin Engvall
- Center for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden
| | - Anna Wredenberg
- Department of Medical Biochemistry and Biophysics, and
- Max Planck Institute Biology of Ageing-Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
- Center for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden
| | | | - Xaquin Castro Dopico
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Joanna Rorbach
- Department of Medical Biochemistry and Biophysics, and
- Max Planck Institute Biology of Ageing-Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
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4
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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: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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5
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Rodriguez L, Pou C, Lakshmikanth T, Zhang J, Mugabo CH, Wang J, Mikes J, Olin A, Chen Y, Rorbach J, Juto JE, Li TQ, Julin P, Brodin P. Achieving symptom relief in patients with myalgic encephalomyelitis by targeting the neuro-immune interface and optimizing disease tolerance. Oxf Open Immunol 2023; 4:iqad003. [PMID: 37255930 PMCID: PMC10148714 DOI: 10.1093/oxfimm/iqad003] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/05/2023] [Accepted: 03/24/2023] [Indexed: 06/01/2023] Open
Abstract
Myalgic encephalomyelitis (ME) previously also known as chronic fatigue syndrome is a heterogeneous, debilitating syndrome of unknown etiology responsible for long-lasting disability in millions of patients worldwide. The most well-known symptom of ME is post-exertional malaise, but many patients also experience autonomic dysregulation, cranial nerve dysfunction and signs of immune system activation. Many patients also report a sudden onset of disease following an infection. The brainstem is a suspected focal point in ME pathogenesis and patients with structural impairment to the brainstem often show ME-like symptoms. The brainstem is also where the vagus nerve originates, a critical neuro-immune interface and mediator of the inflammatory reflex which regulate systemic inflammation. Here, we report the results of a randomized, placebo-controlled trial using intranasal mechanical stimulation targeting nerve endings in the nasal cavity, likely from the trigeminal nerve, possibly activating additional centers in the brainstem of ME patients and correlating with a ∼30% reduction in overall symptom scores after 8 weeks of treatment. By performing longitudinal, systems-level monitoring of the blood immune system in these patients, we uncover signs of chronic immune activation in ME, as well as immunological correlates of improvement that center around gut-homing immune cells and reduced inflammation. The mechanisms of symptom relief remain to be determined, but transcriptional analyses suggest an upregulation of disease tolerance mechanisms. We believe that these results are suggestive of ME as a condition explained by a maladaptive disease tolerance response following infection.
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Affiliation(s)
- Lucie Rodriguez
- Department of Women’s and Children’s Health, Karolinska Institutet, Solna 17121, Sweden
| | | | | | - Jingdian Zhang
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Solna 17176, Sweden
- Max Planck Institute Biology of Ageing—Karolinska Institutet Laboratory, Karolinska Institutet, Solna 17176, Sweden
| | | | - Jun Wang
- Department of Women’s and Children’s Health, Karolinska Institutet, Solna 17121, Sweden
| | - Jaromir Mikes
- Department of Women’s and Children’s Health, Karolinska Institutet, Solna 17121, Sweden
| | - Axel Olin
- Department of Women’s and Children’s Health, Karolinska Institutet, Solna 17121, Sweden
| | - Yang Chen
- Department of Women’s and Children’s Health, Karolinska Institutet, Solna 17121, Sweden
| | - Joanna Rorbach
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Solna 17176, Sweden
- Max Planck Institute Biology of Ageing—Karolinska Institutet Laboratory, Karolinska Institutet, Solna 17176, Sweden
| | - Jan-Erik Juto
- Department of Clinical Sciences, Intervention and Technology, Karolinska Institutet, Solna 17177, Sweden
| | - Tie Qiang Li
- Department of Clinical Sciences, Intervention and Technology, Karolinska Institutet, Solna 17177, Sweden
- Department of Medical Radiation Physics and Nuclear Medicine, Karolinska University Hospital, Solna 17176, Sweden
| | - Per Julin
- Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Solna 17176, Sweden
- Neurological Rehabilitation Clinic, Stora Sköndal, Sköndal 12864, Sweden
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6
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Remes C, Khawaja A, Pearce SF, Dinan AM, Gopalakrishna S, Cipullo M, Kyriakidis V, Zhang J, Dopico XC, Yukhnovets O, Atanassov I, Firth AE, Cooperman B, Rorbach J. Translation initiation of leaderless and polycistronic transcripts in mammalian mitochondria. Nucleic Acids Res 2023; 51:891-907. [PMID: 36629253 PMCID: PMC9881170 DOI: 10.1093/nar/gkac1233] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 11/11/2022] [Accepted: 12/09/2022] [Indexed: 01/12/2023] Open
Abstract
The synthesis of mitochondrial OXPHOS complexes is central to cellular metabolism, yet many molecular details of mitochondrial translation remain elusive. It has been commonly held view that translation initiation in human mitochondria proceeded in a manner similar to bacterial systems, with the mitoribosomal small subunit bound to the initiation factors, mtIF2 and mtIF3, along with initiator tRNA and an mRNA. However, unlike in bacteria, most human mitochondrial mRNAs lack 5' leader sequences that can mediate small subunit binding, raising the question of how leaderless mRNAs are recognized by mitoribosomes. By using novel in vitro mitochondrial translation initiation assays, alongside biochemical and genetic characterization of cellular knockouts of mitochondrial translation factors, we describe unique features of translation initiation in human mitochondria. We show that in vitro, leaderless mRNA transcripts can be loaded directly onto assembled 55S mitoribosomes, but not onto the mitoribosomal small subunit (28S), in a manner that requires initiator fMet-tRNAMet binding. In addition, we demonstrate that in human cells and in vitro, mtIF3 activity is not required for translation of leaderless mitochondrial transcripts but is essential for translation of ATP6 in the case of the bicistronic ATP8/ATP6 transcript. Furthermore, we show that mtIF2 is indispensable for mitochondrial protein synthesis. Our results demonstrate an important evolutionary divergence of the mitochondrial translation system and further our fundamental understanding of a process central to eukaryotic metabolism.
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Affiliation(s)
- Cristina Remes
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Anas Khawaja
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Stockholm 17165, 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, Stockholm 17165, Sweden
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Adam M Dinan
- Department of Pathology, University of Cambridge, Cambridge, UK
| | - Shreekara Gopalakrishna
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Stockholm 17165, 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, Stockholm 17165, Sweden
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Vasileios Kyriakidis
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Stockholm 17165, Sweden
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Jingdian Zhang
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Stockholm 17165, Sweden
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Xaquin Castro Dopico
- Department of Microbiology, Tumor & Cell Biology, Karolinska Institutet, Stockholm 171 77, Sweden
| | - Olessya Yukhnovets
- RWTH Aachen, I. Physikalisches Institut (IA), Aachen, Germany
- Forschungszentrum Jülich, Institute of Complex Systems ICS-5, Jülich, Germany
| | - Ilian Atanassov
- Proteomics Core Facility, Max-Planck-Institute for Biology of Ageing, Joseph-Stelzmann-Str. 9b, 50931 Cologne, Germany
| | - Andrew E Firth
- Department of Pathology, University of Cambridge, Cambridge, UK
| | - Barry Cooperman
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Joanna Rorbach
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Stockholm 17165, Sweden
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
- STIAS: Stellenbosch Institute for Advanced Study at Stellenbosch University, Marais Rd, Stellenbosch 7600, South Africa
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7
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Sighel D, Battistini G, Rosatti EF, Vigna J, Pavan M, Belli R, Peroni D, Alessandrini F, Longhi S, Pancher M, Rorbach J, Moro S, Quattrone A, Mancini I. Streptogramin A derivatives as mitochondrial translation inhibitors to suppress glioblastoma stem cell growth. Eur J Med Chem 2023; 246:114979. [PMID: 36495628 DOI: 10.1016/j.ejmech.2022.114979] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 11/23/2022] [Accepted: 11/24/2022] [Indexed: 12/04/2022]
Abstract
New therapeutic strategies for glioblastoma treatment, especially tackling the tumour's glioblastoma stem cell (GSC) component, are an urgent medical need. Recently, mitochondrial translation inhibition has been shown to affect GSC growth, clonogenicity, and self-renewal capability, therefore becoming an attractive therapeutic target. The combination of streptogramins B and A antibiotics quinupristin/dalfopristin (Q/D), which inhibits mitochondrial ribosome function, affects GSCs more effectively in vitro than the standard of care temozolomide. Here, docking calculations based on the cryo-EM structure of the Q/D-bound mitochondrial ribosome have been used to develop a series of streptogramin A derivatives. We obtained twenty-two new and known molecules starting from the dalfopristin and virginiamycin M1 scaffolds. A structure-activity relationship refinement was performed to evaluate the capability of these compounds to suppress GSC growth and inhibit mitochondrial translation, either alone or in combination with quinupristin. Finally, quantitative ultra HPLC-mass spectrometry allowed us to assess the cell penetration of some of these derivatives. Among all, the fluorine derivatives of dalfopristin and virginiamycin M1, (16R)-1e and (16R)-2e, respectively, and flopristin resulted in being more potent than the corresponding lead compounds and penetrating to a greater extent into the cells. We, therefore, propose these three compounds for further evaluation in vivo as antineoplastic agents.
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Affiliation(s)
- Denise Sighel
- Laboratory of Translational Genomics, Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Via Sommarive 9, 38123, Povo, Trento, Italy.
| | - Giulia Battistini
- Laboratory of Bioorganic Chemistry, Department of Physics, University of Trento, Via Sommarive 14, 38123, Povo, Trento, Italy
| | - Emanuele Filiberto Rosatti
- Laboratory of Translational Genomics, Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Via Sommarive 9, 38123, Povo, Trento, Italy
| | - Jacopo Vigna
- Laboratory of Bioorganic Chemistry, Department of Physics, University of Trento, Via Sommarive 14, 38123, Povo, Trento, Italy
| | - Matteo Pavan
- Molecular Modeling Section (MMS), Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Via F. Marzolo 5, 35131, Padova, Italy
| | - Romina Belli
- Mass Spectrometry and Proteomics Core Facility, Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Via Sommarive 9, 38123, Povo, Trento, Italy
| | - Daniele Peroni
- Mass Spectrometry and Proteomics Core Facility, Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Via Sommarive 9, 38123, Povo, Trento, Italy
| | - Federica Alessandrini
- Laboratory of Translational Genomics, Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Via Sommarive 9, 38123, Povo, Trento, Italy
| | - Sara Longhi
- Laboratory of Translational Genomics, Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Via Sommarive 9, 38123, Povo, Trento, Italy
| | - Michael Pancher
- High Throughput Screening (HTS) and Validation Core Facility, Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Via Sommarive 9, 38123, Povo, Trento, Italy
| | - Joanna Rorbach
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Biomedicum, Solnavägen 9, 171 65, Solna, Stockholm, Sweden
| | - Stefano Moro
- Molecular Modeling Section (MMS), Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Via F. Marzolo 5, 35131, Padova, Italy
| | - Alessandro Quattrone
- Laboratory of Translational Genomics, Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Via Sommarive 9, 38123, Povo, Trento, Italy
| | - Ines Mancini
- Laboratory of Bioorganic Chemistry, Department of Physics, University of Trento, Via Sommarive 14, 38123, Povo, Trento, Italy.
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8
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Krüger A, Remes C, Shiriaev DI, Liu Y, Spåhr H, Wibom R, Atanassov I, Nguyen MD, Cooperman BS, Rorbach J. Human mitochondria require mtRF1 for translation termination at non-canonical stop codons. Nat Commun 2023; 14:30. [PMID: 36596788 PMCID: PMC9810596 DOI: 10.1038/s41467-022-35684-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 12/19/2022] [Indexed: 01/04/2023] Open
Abstract
The mitochondrial translation machinery highly diverged from its bacterial counterpart. This includes deviation from the universal genetic code, with AGA and AGG codons lacking cognate tRNAs in human mitochondria. The locations of these codons at the end of COX1 and ND6 open reading frames, respectively, suggest they might function as stop codons. However, while the canonical stop codons UAA and UAG are known to be recognized by mtRF1a, the release mechanism at AGA and AGG codons remains a debated issue. Here, we show that upon the loss of another member of the mitochondrial release factor family, mtRF1, mitoribosomes accumulate specifically at AGA and AGG codons. Stalling of mitoribosomes alters COX1 transcript and protein levels, but not ND6 synthesis. In addition, using an in vitro reconstituted mitochondrial translation system, we demonstrate the specific peptide release activity of mtRF1 at the AGA and AGG codons. Together, our results reveal the role of mtRF1 in translation termination at non-canonical stop codons in mitochondria.
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Affiliation(s)
- 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
| | - Cristina Remes
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Dmitrii Igorevich Shiriaev
- 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
| | - Yong Liu
- 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
| | - Henrik Spåhr
- 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
| | - Rolf Wibom
- Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Ilian Atanassov
- Proteomics Core Facility, Max-Planck-Institute for Biology of Ageing, Joseph-Stelzmann-Str. 9b, 50931, Cologne, Germany
| | - Minh Duc Nguyen
- 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
| | - Barry S Cooperman
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - 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. .,S.T.I.A.S: Stellenbosch Institute for Advanced Study, Marais Rd, Mostertsdrift, Stellenbosch, 7600, South Africa.
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9
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Remes C, Nguyen MD, Spahr H, Ng M, Fritsch C, Bhattacharya A, Li H, Cooperman B, Rorbach J. Assembly of the Mitochondrial Translation Initiation Complex. Methods Mol Biol 2023; 2661:217-232. [PMID: 37166640 DOI: 10.1007/978-1-0716-3171-3_13] [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
Mitochondria maintain their own translational machinery that is responsible for the synthesis of essential components of the oxidative phosphorylation system. The mammalian mitochondrial translation system differs significantly from its cytosolic and bacterial counterparts. Here, we describe detailed protocols for efficient in vitro reconstitution of the mammalian mitochondrial translation initiation complex, which can be further used for mechanistic analyses of different aspects of mitochondrial translation.
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Affiliation(s)
- Cristina Remes
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, USA.
| | - Minh Duc Nguyen
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Solna, Sweden
| | - Henrik Spahr
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Solna, Sweden
| | - Martin Ng
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, USA
| | - Clark Fritsch
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Arpan Bhattacharya
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, USA
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Hong Li
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, USA
| | - Barry Cooperman
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, USA
| | - Joanna Rorbach
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Solna, Sweden
- Max Planck Institute Biology of Ageing, Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
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10
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Itoh Y, Khawaja A, Laptev I, Cipullo M, Atanassov I, Sergiev P, Rorbach J, Amunts A. Mechanism of mitoribosomal small subunit biogenesis and preinitiation. Nature 2022; 606:603-608. [PMID: 35676484 PMCID: PMC9200640 DOI: 10.1038/s41586-022-04795-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Accepted: 04/22/2022] [Indexed: 12/27/2022]
Abstract
Mitoribosomes are essential for the synthesis and maintenance of bioenergetic proteins. Here we use cryo-electron microscopy to determine a series of the small mitoribosomal subunit (SSU) intermediates in complex with auxiliary factors, revealing a sequential assembly mechanism. The methyltransferase TFB1M binds to partially unfolded rRNA h45 that is promoted by RBFA, while the mRNA channel is blocked. This enables binding of METTL15 that promotes further rRNA maturation and a large conformational change of RBFA. The new conformation allows initiation factor mtIF3 to already occupy the subunit interface during the assembly. Finally, the mitochondria-specific ribosomal protein mS37 (ref. 1) outcompetes RBFA to complete the assembly with the SSU-mS37-mtIF3 complex2 that proceeds towards mtIF2 binding and translation initiation. Our results explain how the action of step-specific factors modulate the dynamic assembly of the SSU, and adaptation of a unique protein, mS37, links the assembly to initiation to establish the catalytic human mitoribosome.
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Affiliation(s)
- Yuzuru Itoh
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden
| | - Anas Khawaja
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
- Max Planck Institute for Biology of Ageing-Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Ivan Laptev
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
- Department of Chemistry, Lomonosov Moscow State University, Moscow, Russia
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Miriam Cipullo
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, 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, Cologne, Germany
| | - Petr Sergiev
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
- Department of Chemistry, Lomonosov Moscow State University, Moscow, Russia
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
- Institute of Functional Genomics, Lomonosov Moscow State University, Moscow, Russia
| | - Joanna Rorbach
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden.
- Max Planck Institute for Biology of Ageing-Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden.
| | - Alexey Amunts
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden.
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11
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Erikson E, Ádori M, Khoenkhoen S, Zhang J, Rorbach J, Castro Dopico X, Karlsson Hedestam GB. Impaired plasma cell differentiation associates with increased oxidative metabolism in IκBNS-deficient B cells. Cell Immunol 2022; 375:104516. [DOI: 10.1016/j.cellimm.2022.104516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Revised: 03/30/2022] [Accepted: 03/30/2022] [Indexed: 11/03/2022]
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12
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Itoh Y, Singh V, Khawaja A, Naschberger A, Nguyen MD, Rorbach J, Amunts A. Structure of the mitoribosomal small subunit with streptomycin reveals Fe-S clusters and physiological molecules. eLife 2022; 11:77460. [PMID: 36480258 PMCID: PMC9731571 DOI: 10.7554/elife.77460] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 10/27/2022] [Indexed: 12/13/2022] Open
Abstract
The mitoribosome regulates cellular energy production, and its dysfunction is associated with aging. Inhibition of the mitoribosome can be caused by off-target binding of antimicrobial drugs and was shown to be coupled with a bilateral decreased visual acuity. Previously, we reported mitochondria-specific protein aspects of the mitoribosome, and in this article we present a 2.4-Å resolution structure of the small subunit in a complex with the anti-tuberculosis drug streptomycin that reveals roles of non-protein components. We found iron-sulfur clusters that are coordinated by different mitoribosomal proteins, nicotinamide adenine dinucleotide (NAD) associated with rRNA insertion, and posttranslational modifications. This is the first evidence of inter-protein coordination of iron-sulfur, and the finding of iron-sulfur clusters and NAD as fundamental building blocks of the mitoribosome directly links to mitochondrial disease and aging. We also report details of streptomycin interactions, suggesting that the mitoribosome-bound streptomycin is likely to be in hydrated gem-diol form and can be subjected to other modifications by the cellular milieu. The presented approach of adding antibiotics to cultured cells can be used to define their native structures in a bound form under more physiological conditions, and since streptomycin is a widely used drug for treatment, the newly resolved features can serve as determinants for targeting.
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Affiliation(s)
- Yuzuru Itoh
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm UniversityStockholmSweden
| | - Vivek Singh
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm UniversityStockholmSweden
| | - Anas Khawaja
- Department of Medical Biochemistry and Biophysics, Karolinska InstituteStockholmSweden,Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska InstitutetStockholmSweden
| | - Andreas Naschberger
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm UniversityStockholmSweden
| | - Minh Duc Nguyen
- Department of Medical Biochemistry and Biophysics, Karolinska InstituteStockholmSweden,Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska InstitutetStockholmSweden
| | - Joanna Rorbach
- Department of Medical Biochemistry and Biophysics, Karolinska InstituteStockholmSweden,Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska InstitutetStockholmSweden
| | - Alexey Amunts
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm UniversityStockholmSweden
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13
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Castro Dopico X, Muschiol S, Christian M, Hanke L, Sheward DJ, Grinberg NF, Rorbach J, Bogdanovic G, Mcinerney GM, Allander T, Wallace C, Murrell B, Albert J, Karlsson Hedestam GB. Seropositivity in blood donors and pregnant women during the first year of SARS-CoV-2 transmission in Stockholm, Sweden. J Intern Med 2021; 290:666-676. [PMID: 34008203 PMCID: PMC8242905 DOI: 10.1111/joim.13304] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 03/25/2021] [Accepted: 04/07/2021] [Indexed: 12/26/2022]
Abstract
BACKGROUND In Sweden, social restrictions to contain SARS-CoV-2 have primarily relied upon voluntary adherence to a set of recommendations. Strict lockdowns have not been enforced, potentially affecting viral dissemination. To understand the levels of past SARS-CoV-2 infection in the Stockholm population before the start of mass vaccinations, healthy blood donors and pregnant women (n = 5,100) were sampled at random between 14 March 2020 and 28 February 2021. METHODS In this cross-sectional prospective study, otherwise-healthy blood donors (n = 2,600) and pregnant women (n = 2,500) were sampled for consecutive weeks (at four intervals) throughout the study period. Sera from all participants and a cohort of historical (negative) controls (n = 595) were screened for IgG responses against stabilized trimers of the SARS-CoV-2 spike (S) glycoprotein and the smaller receptor-binding domain (RBD). As a complement to standard analytical approaches, a probabilistic (cut-off independent) Bayesian framework that assigns likelihood of past infection was used to analyse data over time. SETTING Healthy participant samples were randomly selected from their respective pools through Karolinska University Hospital. The study was carried out in accordance with Swedish Ethical Review Authority: registration number 2020-01807. PARTICIPANTS No participants were symptomatic at sampling, and blood donors were all over the age of 18. No additional metadata were available from the participants. RESULTS Blood donors and pregnant women showed a similar seroprevalence. After a steep rise at the start of the pandemic, the seroprevalence trajectory increased steadily in approach to the winter second wave of infections, approaching 15% of all individuals surveyed by 13 December 2020. By the end of February 2021, 19% of the population tested seropositive. Notably, 96% of seropositive healthy donors screened (n = 56) developed neutralizing antibody responses at titres comparable to or higher than those observed in clinical trials of SARS-CoV-2 spike mRNA vaccination, supporting that mild infection engenders a competent B-cell response. CONCLUSIONS These data indicate that in the first year since the start of community transmission, seropositivity levels in metropolitan in Stockholm had reached approximately one in five persons, providing important baseline seroprevalence information prior to the start of vaccination.
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Affiliation(s)
- X. Castro Dopico
- From theDepartment of Microbiology, Tumor and Cell BiologyKarolinska InstitutetStockholmSweden
| | - S. Muschiol
- From theDepartment of Microbiology, Tumor and Cell BiologyKarolinska InstitutetStockholmSweden
- Department of Clinical MicrobiologyKarolinska University HospitalStockholmSweden
| | - M. Christian
- From theDepartment of Microbiology, Tumor and Cell BiologyKarolinska InstitutetStockholmSweden
| | - L. Hanke
- From theDepartment of Microbiology, Tumor and Cell BiologyKarolinska InstitutetStockholmSweden
| | - D. J. Sheward
- From theDepartment of Microbiology, Tumor and Cell BiologyKarolinska InstitutetStockholmSweden
| | - N. F. Grinberg
- Cambridge Institute of Therapeutic Immunology & Infectious DiseaseUniversity of CambridgeCambridgeUK
| | - J. Rorbach
- Department of Medical Biochemistry and BiophysicsKarolinska InstitutetStockholmSweden
- Max Planck Institute Biology of Ageing‐Karolinska Institutet LaboratoryKarolinska InstitutetStockholmSweden
| | - G. Bogdanovic
- Department of Clinical MicrobiologyKarolinska University HospitalStockholmSweden
| | - G. M. Mcinerney
- From theDepartment of Microbiology, Tumor and Cell BiologyKarolinska InstitutetStockholmSweden
| | - T. Allander
- From theDepartment of Microbiology, Tumor and Cell BiologyKarolinska InstitutetStockholmSweden
- Department of Clinical MicrobiologyKarolinska University HospitalStockholmSweden
| | - C. Wallace
- Cambridge Institute of Therapeutic Immunology & Infectious DiseaseUniversity of CambridgeCambridgeUK
- Biostatistics Unit, Cambridge Institute of Public HealthUniversity of CambridgeCambridgeUK
| | - B. Murrell
- From theDepartment of Microbiology, Tumor and Cell BiologyKarolinska InstitutetStockholmSweden
| | - J. Albert
- From theDepartment of Microbiology, Tumor and Cell BiologyKarolinska InstitutetStockholmSweden
- Department of Clinical MicrobiologyKarolinska University HospitalStockholmSweden
| | - G. B. Karlsson Hedestam
- From theDepartment of Microbiology, Tumor and Cell BiologyKarolinska InstitutetStockholmSweden
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14
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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: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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15
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Cipullo M, Gesé GV, Khawaja A, Hällberg BM, Rorbach J. Structural basis for late maturation steps of the human mitoribosomal large subunit. Nat Commun 2021; 12:3673. [PMID: 34135318 PMCID: PMC8209036 DOI: 10.1038/s41467-021-23617-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 05/07/2021] [Indexed: 01/29/2023] Open
Abstract
Mitochondrial ribosomes (mitoribosomes) synthesize a critical set of proteins essential for oxidative phosphorylation. Therefore, mitoribosomal function is vital to the cellular energy supply. Mitoribosome biogenesis follows distinct molecular pathways that remain poorly understood. Here, we determine the cryo-EM structures of mitoribosomes isolated from human cell lines with either depleted or overexpressed mitoribosome assembly factor GTPBP5, allowing us to capture consecutive steps during mitoribosomal large subunit (mt-LSU) biogenesis. Our structures provide essential insights into the last steps of 16S rRNA folding, methylation and peptidyl transferase centre (PTC) completion, which require the coordinated action of nine assembly factors. We show that mammalian-specific MTERF4 contributes to the folding of 16S rRNA, allowing 16 S rRNA methylation by MRM2, while GTPBP5 and NSUN4 promote fine-tuning rRNA rearrangements leading to PTC formation. Moreover, our data reveal an unexpected involvement of the elongation factor mtEF-Tu in mt-LSU assembly, where mtEF-Tu interacts with GTPBP5, similar to its interaction with tRNA during translational elongation.
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Affiliation(s)
- Miriam Cipullo
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Solna, Sweden
- Max Planck Institute Biology of Ageing-Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Genís Valentín Gesé
- Department of Cell and Molecular Biology, Karolinska Institutet, Solna, Sweden
| | - Anas Khawaja
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Solna, Sweden
- Max Planck Institute Biology of Ageing-Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - B Martin Hällberg
- Department of Cell and Molecular Biology, Karolinska Institutet, Solna, Sweden.
- Centre for Structural Systems Biology (CSSB) and Karolinska Institutet VR-RÅC, Hamburg, Germany.
| | - Joanna Rorbach
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Solna, Sweden.
- Max Planck Institute Biology of Ageing-Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden.
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16
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Sighel D, Notarangelo M, Aibara S, Re A, Ricci G, Guida M, Soldano A, Adami V, Ambrosini C, Broso F, Rosatti EF, Longhi S, Buccarelli M, D'Alessandris QG, Giannetti S, Pacioni S, Ricci-Vitiani L, Rorbach J, Pallini R, Roulland S, Amunts A, Mancini I, Modelska A, Quattrone A. Inhibition of mitochondrial translation suppresses glioblastoma stem cell growth. Cell Rep 2021; 35:109024. [PMID: 33910005 PMCID: PMC8097689 DOI: 10.1016/j.celrep.2021.109024] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 02/27/2021] [Accepted: 04/01/2021] [Indexed: 12/13/2022] Open
Abstract
Glioblastoma stem cells (GSCs) resist current glioblastoma (GBM) therapies. GSCs rely highly on oxidative phosphorylation (OXPHOS), whose function requires mitochondrial translation. Here we explore the therapeutic potential of targeting mitochondrial translation and report the results of high-content screening with putative blockers of mitochondrial ribosomes. We identify the bacterial antibiotic quinupristin/dalfopristin (Q/D) as an effective suppressor of GSC growth. Q/D also decreases the clonogenicity of GSCs in vitro, consequently dysregulating the cell cycle and inducing apoptosis. Cryoelectron microscopy (cryo-EM) reveals that Q/D binds to the large mitoribosomal subunit, inhibiting mitochondrial protein synthesis and functionally dysregulating OXPHOS complexes. These data suggest that targeting mitochondrial translation could be explored to therapeutically suppress GSC growth in GBM and that Q/D could potentially be repurposed for cancer treatment. Screen of putative mitoribosome inhibitors identifies Q/D as effective on GSCs Q/D selectively inhibits growth of GSCs Treatment with Q/D decreases clonogenicity, blocks cell cycle, and induces apoptosis Q/D binds to mitoribosomes and inhibits mitochondrial translation and therefore OXPHOS
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Affiliation(s)
- Denise Sighel
- Department CIBIO, University of Trento, Trento 38123, Italy.
| | | | - Shintaro Aibara
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Stockholm 171 65, Sweden
| | - Angela Re
- Department CIBIO, University of Trento, Trento 38123, Italy; Centre for Sustainable Future Technologies, Fondazione Istituto Italiano di Tecnologia, Torino 10144, Italy
| | - Gianluca Ricci
- Department CIBIO, University of Trento, Trento 38123, Italy
| | | | | | | | | | | | | | - Sara Longhi
- Department CIBIO, University of Trento, Trento 38123, Italy
| | - Mariachiara Buccarelli
- Department of Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome 00161, Italy
| | - Quintino G D'Alessandris
- Institute of Neurosurgery, Università Cattolica del Sacro Cuore, IRCCS Fondazione Policlinico A. Gemelli, Rome 00168, Italy
| | - Stefano Giannetti
- Institute of Biology, Università Cattolica del Sacro Cuore, Rome 00168, Italy
| | - Simone Pacioni
- Institute of Neurosurgery, Università Cattolica del Sacro Cuore, IRCCS Fondazione Policlinico A. Gemelli, Rome 00168, Italy
| | - Lucia Ricci-Vitiani
- Department of Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome 00161, Italy
| | - Joanna Rorbach
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Division of Metabolic Diseases, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm 171 65, Sweden
| | - Roberto Pallini
- Institute of Neurosurgery, Università Cattolica del Sacro Cuore, IRCCS Fondazione Policlinico A. Gemelli, Rome 00168, Italy
| | - Sandrine Roulland
- Aix Marseille University, CNRS, INSERM, Centre d'Immunologie de Marseille-Luminy, Marseille, France
| | - Alexey Amunts
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Stockholm 171 65, Sweden
| | - Ines Mancini
- Department of Physics, University of Trento, Trento 38123, Italy
| | - Angelika Modelska
- Department CIBIO, University of Trento, Trento 38123, Italy; Aix Marseille University, CNRS, INSERM, Centre d'Immunologie de Marseille-Luminy, Marseille, France.
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17
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Shi Y, Yuan J, Rraklli V, Maxymovitz E, Cipullo M, Liu M, Li S, Westerlund I, Bedoya-Reina OC, Bullova P, Rorbach J, Juhlin CC, Stenman A, Larsson C, Kogner P, O’Sullivan MJ, Schlisio S, Holmberg J. Aberrant splicing in neuroblastoma generates RNA-fusion transcripts and provides vulnerability to spliceosome inhibitors. Nucleic Acids Res 2021; 49:2509-2521. [PMID: 33555349 PMCID: PMC7969022 DOI: 10.1093/nar/gkab054] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 01/14/2021] [Accepted: 01/21/2021] [Indexed: 11/12/2022] Open
Abstract
The paucity of recurrent mutations has hampered efforts to understand and treat neuroblastoma. Alternative splicing and splicing-dependent RNA-fusions represent mechanisms able to increase the gene product repertoire but their role in neuroblastoma remains largely unexplored. Here we investigate the presence and possible roles of aberrant splicing and splicing-dependent RNA-fusion transcripts in neuroblastoma. In addition, we attend to establish whether the spliceosome can be targeted to treat neuroblastoma. Through analysis of RNA-sequenced neuroblastoma we show that elevated expression of splicing factors is a strong predictor of poor clinical outcome. Furthermore, we identified >900 primarily intrachromosomal fusions containing canonical splicing sites. Fusions included transcripts from well-known oncogenes, were enriched for proximal genes and in chromosomal regions commonly gained or lost in neuroblastoma. As a proof-of-principle that these fusions can generate altered gene products, we characterized a ZNF451-BAG2 fusion, producing a truncated BAG2-protein which inhibited retinoic acid induced differentiation. Spliceosome inhibition impeded neuroblastoma fusion expression, induced apoptosis and inhibited xenograft tumor growth. Our findings elucidate a splicing-dependent mechanism generating altered gene products in neuroblastoma and show that the spliceosome is a potential target for clinical intervention.
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Affiliation(s)
- Yao Shi
- Department of Cell and Molecular Biology, Karolinska Institutet, Solnavägen 9, SE-171 65 Stockholm, Sweden
| | - Juan Yuan
- Department of Cell and Molecular Biology, Karolinska Institutet, Solnavägen 9, SE-171 65 Stockholm, Sweden
| | - Vilma Rraklli
- Department of Cell and Molecular Biology, Karolinska Institutet, Solnavägen 9, SE-171 65 Stockholm, Sweden
| | - Eva Maxymovitz
- Department of Cell and Molecular Biology, Karolinska Institutet, Solnavägen 9, SE-171 65 Stockholm, Sweden
| | - Miriam Cipullo
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Solnavägen 9, SE-171-65 Solna, Sweden
| | - Mingzhi Liu
- Department of Cell and Molecular Biology, Karolinska Institutet, Solnavägen 9, SE-171 65 Stockholm, Sweden
| | - Shuijie Li
- Department of Microbiology, Tumor- and Cellbiology, Karolinska Institutet, Solnavägen 9, SE-171 65 Solna, Sweden
| | - Isabelle Westerlund
- Department of Cell and Molecular Biology, Karolinska Institutet, Solnavägen 9, SE-171 65 Stockholm, Sweden
| | - Oscar C Bedoya-Reina
- Department of Microbiology, Tumor- and Cellbiology, Karolinska Institutet, Solnavägen 9, SE-171 65 Solna, Sweden
| | - Petra Bullova
- Department of Microbiology, Tumor- and Cellbiology, Karolinska Institutet, Solnavägen 9, SE-171 65 Solna, Sweden
| | - Joanna Rorbach
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Solnavägen 9, SE-171-65 Solna, Sweden
| | - C Christofer Juhlin
- Department of Oncology-Pathology, Karolinska Institutet, Cancer Center Karolinska (CCK), Karolinska University Hospital, SE-171 76 Stockholm, Sweden
| | - Adam Stenman
- Department of Oncology-Pathology, Karolinska Institutet, Cancer Center Karolinska (CCK), Karolinska University Hospital, SE-171 76 Stockholm, Sweden
| | - Catharina Larsson
- Department of Oncology-Pathology, Karolinska Institutet, Cancer Center Karolinska (CCK), Karolinska University Hospital, SE-171 76 Stockholm, Sweden
| | - Per Kogner
- Department of Women's and Children's Health, Karolinska Institutet, Karolinska University Hospital, SE-171 76 Stockholm, Sweden
| | - Maureen J O’Sullivan
- Department of Histopathology, Our Lady's Children's Hospital, Dublin, Ireland
- Trinity Translational Medicine Institute, Trinity College, Dublin, Ireland
| | - Susanne Schlisio
- Department of Microbiology, Tumor- and Cellbiology, Karolinska Institutet, Solnavägen 9, SE-171 65 Solna, Sweden
| | - Johan Holmberg
- Department of Cell and Molecular Biology, Karolinska Institutet, Solnavägen 9, SE-171 65 Stockholm, Sweden
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18
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Páleníková P, Harbour ME, Ding S, Fearnley IM, Van Haute L, Rorbach J, Scavetta R, Minczuk M, Rebelo-Guiomar P. Quantitative density gradient analysis by mass spectrometry (qDGMS) and complexome profiling analysis (ComPrAn) R package for the study of macromolecular complexes. Biochim Biophys Acta Bioenerg 2021; 1862:148399. [PMID: 33592209 PMCID: PMC8047798 DOI: 10.1016/j.bbabio.2021.148399] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 02/05/2021] [Accepted: 02/07/2021] [Indexed: 11/28/2022]
Abstract
Many cellular processes involve the participation of large macromolecular assemblies. Understanding their function requires methods allowing to study their dynamic and mechanistic properties. Here we present a method for quantitative analysis of native protein or ribonucleoprotein complexes by mass spectrometry following their separation by density – qDGMS. Mass spectrometric quantitation is enabled through stable isotope labelling with amino acids in cell culture (SILAC). We provide a complete guide, from experimental design to preparation of publication-ready figures, using a purposely-developed R package – ComPrAn. As specific examples, we present the use of sucrose density gradients to inspect the assembly and dynamics of the human mitochondrial ribosome (mitoribosome), its interacting proteins, the small subunit of the cytoplasmic ribosome, cytoplasmic aminoacyl-tRNA synthetase complex and the mitochondrial PDH complex. ComPrAn provides tools for analysis of peptide-level data as well as normalization and clustering tools for protein-level data, dedicated visualization functions and graphical user interface. Although, it has been developed for the analysis of qDGMS samples, it can also be used for other proteomics experiments that involve 2-state labelled samples separated into fractions. We show that qDGMS and ComPrAn can be used to study macromolecular complexes in their native state, accounting for the dynamics inherent to biological systems and benefiting from its proteome-wide quantitative and qualitative capability. qDGMS is a novel method to study macromolecular complex composition and assembly. Complexes are separated in near-native form by density gradient ultracentrifugation. SILAC enables simultaneous quantitative proteomic analysis of two biological samples. R package ComPrAn allows analysis of SILAC complexome profiling and qDGMS data sets.
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Affiliation(s)
- Petra Páleníková
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - Michael E Harbour
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - Shujing Ding
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - Ian M Fearnley
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - Lindsey Van Haute
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - Joanna Rorbach
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | | | - Michal Minczuk
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, United Kingdom.
| | - Pedro Rebelo-Guiomar
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, United Kingdom.
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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: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Pearce SF, Cipullo M, Chung B, Brierley I, Rorbach J. Mitoribosome Profiling from Human Cell Culture: A High Resolution View of Mitochondrial Translation. Methods Mol Biol 2021; 2192:183-196. [PMID: 33230774 DOI: 10.1007/978-1-0716-0834-0_14] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 01/04/2023]
Abstract
Ribosome profiling (Ribo-Seq) is a technique that allows genome-wide, quantitative analysis of translation. In recent years, it has found multiple applications in studies of translation in diverse organisms, tracking protein synthesis with single codon resolution. Traditional protocols applied for generating Ribo-Seq libraries from mammalian cell cultures are not suitable to study mitochondrial translation due to differences between eukaryotic cytosolic and mitochondrial ribosomes. Here, we present an adapted protocol enriching for mitoribosome footprints. In addition, we describe the preparation of small RNA sequencing libraries from the resultant mitochondrial ribosomal protected fragments (mtRPFs).
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Affiliation(s)
- Sarah F Pearce
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Solna, Sweden.,Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Miriam Cipullo
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Solna, Sweden.,Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Betty Chung
- Department of Pathology, University of Cambridge, Cambridge, UK
| | - Ian Brierley
- Department of Pathology, University of Cambridge, Cambridge, UK
| | - Joanna Rorbach
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Solna, Sweden. .,Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden.
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21
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Abshire ET, Hughes KL, Diao R, Pearce S, Gopalakrishna S, Trievel RC, Rorbach J, Freddolino PL, Goldstrohm AC. Differential processing and localization of human Nocturnin controls metabolism of mRNA and nicotinamide adenine dinucleotide cofactors. J Biol Chem 2020; 295:15112-15133. [PMID: 32839274 PMCID: PMC7606674 DOI: 10.1074/jbc.ra120.012618] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [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: 01/10/2020] [Revised: 08/06/2020] [Indexed: 01/02/2023] Open
Abstract
Nocturnin (NOCT) is a eukaryotic enzyme that belongs to a superfamily of exoribonucleases, endonucleases, and phosphatases. In this study, we analyze the expression, processing, localization, and cellular functions of human NOCT. We find that NOCT protein is differentially expressed and processed in a cell and tissue type-specific manner to control its localization to the cytoplasm or mitochondrial exterior or interior. The N terminus of NOCT is necessary and sufficient to confer import and processing in the mitochondria. We measured the impact of cytoplasmic NOCT on the transcriptome and observed that it affects mRNA levels of hundreds of genes that are significantly enriched in osteoblast, neuronal, and mitochondrial functions. Recent biochemical data indicate that NOCT dephosphorylates NADP(H) metabolites, and thus we measured the effect of NOCT on these cofactors in cells. We find that NOCT increases NAD(H) and decreases NADP(H) levels in a manner dependent on its intracellular localization. Collectively, our data indicate that NOCT can regulate levels of both mRNAs and NADP(H) cofactors in a manner specified by its location in cells.
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Affiliation(s)
- Elizabeth T Abshire
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota, USA; Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Kelsey L Hughes
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota, USA
| | - Rucheng Diao
- Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Sarah Pearce
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institute, Solna, Sweden; Max Planck Institute Biology of Ageing - Karolinska Institute Laboratory, Karolinska Institute, Stockholm, Sweden
| | - Shreekara Gopalakrishna
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institute, Solna, Sweden
| | - Raymond C Trievel
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Joanna Rorbach
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institute, Solna, Sweden; Max Planck Institute Biology of Ageing - Karolinska Institute Laboratory, Karolinska Institute, Stockholm, Sweden
| | - Peter L Freddolino
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan, USA; Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Aaron C Goldstrohm
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota, USA.
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22
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Lopez Sanchez MIG, Cipullo M, Gopalakrishna S, Khawaja A, Rorbach J. Methylation of Ribosomal RNA: A Mitochondrial Perspective. Front Genet 2020; 11:761. [PMID: 32765591 PMCID: PMC7379855 DOI: 10.3389/fgene.2020.00761] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Accepted: 06/26/2020] [Indexed: 01/02/2023] Open
Abstract
Ribosomal RNA (rRNA) from all organisms undergoes post-transcriptional modifications that increase the diversity of its composition and activity. In mitochondria, specialized mitochondrial ribosomes (mitoribosomes) are responsible for the synthesis of 13 oxidative phosphorylation proteins encoded by the mitochondrial genome. Mitoribosomal RNA is also modified, with 10 modifications thus far identified and all corresponding modifying enzymes described. This form of epigenetic regulation of mitochondrial gene expression affects mitoribosome biogenesis and function. Here, we provide an overview on rRNA methylation and highlight critical work that is beginning to elucidate its role in mitochondrial gene expression. Given the similarities between bacterial and mitochondrial ribosomes, we focus on studies involving Escherichia coli and human models. Furthermore, we highlight the use of state-of-the-art technologies, such as cryoEM in the study of rRNA methylation and its biological relevance. Understanding the mechanisms and functional relevance of this process represents an exciting frontier in the RNA biology and mitochondrial fields.
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Affiliation(s)
- M Isabel G Lopez Sanchez
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Solna, Sweden.,Centre for Eye Research Australia, Melbourne, VIC, Australia
| | - Miriam Cipullo
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Solna, Sweden.,Max Planck Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Shreekara Gopalakrishna
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Solna, Sweden.,Max Planck Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Anas Khawaja
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Solna, Sweden.,Max Planck Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Joanna Rorbach
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Solna, Sweden.,Max Planck Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
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23
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Gopalakrishna S, Pearce SF, Dinan AM, Schober FA, Cipullo M, Spåhr H, Khawaja A, Maffezzini C, Freyer C, Wredenberg A, Atanassov I, Firth AE, Rorbach J. C6orf203 is an RNA-binding protein involved in mitochondrial protein synthesis. Nucleic Acids Res 2019; 47:9386-9399. [PMID: 31396629 PMCID: PMC6755124 DOI: 10.1093/nar/gkz684] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 07/22/2019] [Accepted: 07/26/2019] [Indexed: 01/17/2023] Open
Abstract
In all biological systems, RNAs are associated with RNA-binding proteins (RBPs), forming complexes that control gene regulatory mechanisms, from RNA synthesis to decay. In mammalian mitochondria, post-transcriptional regulation of gene expression is conducted by mitochondrial RBPs (mt-RBPs) at various stages of mt-RNA metabolism, including polycistronic transcript production, its processing into individual transcripts, mt-RNA modifications, stability, translation and degradation. To date, only a handful of mt-RBPs have been characterized. Here, we describe a putative human mitochondrial protein, C6orf203, that contains an S4-like domain-an evolutionarily conserved RNA-binding domain previously identified in proteins involved in translation. Our data show C6orf203 to bind highly structured RNA in vitro and associate with the mitoribosomal large subunit in HEK293T cells. Knockout of C6orf203 leads to a decrease in mitochondrial translation and consequent OXPHOS deficiency, without affecting mitochondrial RNA levels. Although mitoribosome stability is not affected in C6orf203-depleted cells, mitoribosome profiling analysis revealed a global disruption of the association of mt-mRNAs with the mitoribosome, suggesting that C6orf203 may be required for the proper maturation and functioning of the mitoribosome. We therefore propose C6orf203 to be a novel RNA-binding protein involved in mitochondrial translation, expanding the repertoire of factors engaged in this process.
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Affiliation(s)
- Shreekara Gopalakrishna
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Solnavägen 9, 171 77 Stockholm, Sweden.,Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Sarah F Pearce
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Solnavägen 9, 171 77 Stockholm, Sweden.,Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Adam M Dinan
- Department of Pathology, University of Cambridge, CB2 0QQ Cambridge, UK
| | - Florian A Schober
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, 171 77 Stockholm, Sweden.,Department of Molecular Medicine and Surgery, Karolinska Institutet, 171 76 Stockholm, Sweden
| | - Miriam Cipullo
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Solnavägen 9, 171 77 Stockholm, Sweden.,Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Henrik Spåhr
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Solnavägen 9, 171 77 Stockholm, Sweden.,Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Anas Khawaja
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Solnavägen 9, 171 77 Stockholm, Sweden.,Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Camilla Maffezzini
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Solnavägen 9, 171 77 Stockholm, Sweden.,Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Christoph Freyer
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Solnavägen 9, 171 77 Stockholm, Sweden.,Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Anna Wredenberg
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Solnavägen 9, 171 77 Stockholm, Sweden.,Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Ilian Atanassov
- Proteomics Core Facility, Max-Planck-Institute for Biology of Ageing, Joseph-Stelzmann-Str. 9b, 50931 Cologne, Germany
| | - Andrew E Firth
- Department of Pathology, University of Cambridge, CB2 0QQ Cambridge, UK
| | - Joanna Rorbach
- Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, Solnavägen 9, 171 77 Stockholm, Sweden.,Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, 171 77 Stockholm, Sweden
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24
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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: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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25
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Garone C, D’Souza AR, Dallabona C, Lodi T, Rebelo-Guiomar P, Rorbach J, Donati MA, Procopio E, Montomoli M, Guerrini R, Zeviani M, Calvo SE, Mootha VK, DiMauro S, Ferrero I, Minczuk M. Defective mitochondrial rRNA methyltransferase MRM2 causes MELAS-like clinical syndrome. Hum Mol Genet 2017; 26:4257-4266. [PMID: 28973171 PMCID: PMC5886288 DOI: 10.1093/hmg/ddx314] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 08/01/2017] [Accepted: 08/03/2017] [Indexed: 02/02/2023] Open
Abstract
Defects in nuclear-encoded proteins of the mitochondrial translation machinery cause early-onset and tissue-specific deficiency of one or more OXPHOS complexes. Here, we report a 7-year-old Italian boy with childhood-onset rapidly progressive encephalomyopathy and stroke-like episodes. Multiple OXPHOS defects and decreased mtDNA copy number (40%) were detected in muscle homogenate. Clinical features combined with low level of plasma citrulline were highly suggestive of mitochondrial encephalopathy, lactic acidosis and stroke-like episodes (MELAS) syndrome, however, the common m.3243 A > G mutation was excluded. Targeted exome sequencing of genes encoding the mitochondrial proteome identified a damaging mutation, c.567 G > A, affecting a highly conserved amino acid residue (p.Gly189Arg) of the MRM2 protein. MRM2 has never before been linked to a human disease and encodes an enzyme responsible for 2'-O-methyl modification at position U1369 in the human mitochondrial 16S rRNA. We generated a knockout yeast model for the orthologous gene that showed a defect in respiration and the reduction of the 2'-O-methyl modification at the equivalent position (U2791) in the yeast mitochondrial 21S rRNA. Complementation with the mrm2 allele carrying the equivalent yeast mutation failed to rescue the respiratory phenotype, which was instead completely rescued by expressing the wild-type allele. Our findings establish that defective MRM2 causes a MELAS-like phenotype, and suggests the genetic screening of the MRM2 gene in patients with a m.3243 A > G negative MELAS-like presentation.
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Affiliation(s)
- Caterina Garone
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
- Department of Neurology, Columbia University Medical Center, New York, NY 10032, USA
| | - Aaron R D’Souza
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | - Cristina Dallabona
- Department of Chemistry, Life Sciences and Environmental Sustainability - University of Parma, Parma 43121, Italy
| | - Tiziana Lodi
- Department of Chemistry, Life Sciences and Environmental Sustainability - University of Parma, Parma 43121, Italy
| | - Pedro Rebelo-Guiomar
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
- Graduate Program in Areas of Basic and Applied Biology (GABBA), University of Porto, 4099-002, Portugal
| | - Joanna Rorbach
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | | | - Elena Procopio
- Metabolic Unit, A. Meyer Children's Hospital, Florence 50139, Italy
| | - Martino Montomoli
- Pediatric Neurology Unit and Laboratories, “A. Meyer” Children's Hospital, University of Florence, 50139, Italy
| | - Renzo Guerrini
- Pediatric Neurology Unit and Laboratories, “A. Meyer” Children's Hospital, University of Florence, 50139, Italy
| | - Massimo Zeviani
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | - Sarah E Calvo
- Broad Institute of MIT & Harvard, Cambridge, MA 02142, USA
- Department of Molecular Biology and Howard Hughes Medical Institute, Massachusetts General Hospital, and Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Vamsi K Mootha
- Department of Molecular Biology and Howard Hughes Medical Institute, Massachusetts General Hospital, and Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Salvatore DiMauro
- Department of Neurology, Columbia University Medical Center, New York, NY 10032, USA
| | - Ileana Ferrero
- Department of Chemistry, Life Sciences and Environmental Sustainability - University of Parma, Parma 43121, Italy
| | - Michal Minczuk
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
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26
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Patel D, Rorbach J, Downes K, Szukszto MJ, Pekalski ML, Minczuk M. Macropinocytic entry of isolated mitochondria in epidermal growth factor-activated human osteosarcoma cells. Sci Rep 2017; 7:12886. [PMID: 29018288 PMCID: PMC5634993 DOI: 10.1038/s41598-017-13227-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 09/20/2017] [Indexed: 12/13/2022] Open
Abstract
Mammalian mitochondria can be transferred between cells both in culture and in vivo. There is evidence that isolated mitochondria enter cells by endocytosis, but the mechanism has not been fully characterised. We investigated the entry mechanism of isolated mitochondria into human osteosarcoma (HOS) cells. Initially we confirmed that respiratory-competent cells can be produced following incubation of HOS cells lacking mitochondrial DNA (mtDNA) with functional exogenous mitochondria and selection in a restrictive medium. Treatment of HOS cells with inhibitors of different endocytic pathways suggest that uptake of EGFP-labelled mitochondria occurs via an actin-dependent endocytic pathway which is consistent with macropinocytosis. We later utilised time-lapse microscopy to show that internalised mitochondria were found in large, motile cellular vesicles. Finally, we used confocal imaging to show that EGFP-labelled mitochondria colocalise with a macropinocytic cargo molecule during internalisation, HOS cells produce membrane ruffles interacting with external mitochondria during uptake and EGFP-labelled mitochondria are found within early macropinosomes inside cells. In conclusion our results are consistent with isolated mitochondria being internalised by macropinocytosis in HOS cells.
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Affiliation(s)
- Dipali Patel
- MRC Mitochondrial Biology Unit, University of Cambridge, Hills Road, Cambridge, CB2 0XY, UK.
| | - Joanna Rorbach
- MRC Mitochondrial Biology Unit, University of Cambridge, Hills Road, Cambridge, CB2 0XY, UK
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Solna, Sweden
| | - Kate Downes
- CIMR, University of Cambridge, Hills Road, Cambridge, CB2 0XY, UK
- Department of Haematology, University of Cambridge, NHS Blood and Transplant, Long Road, Cambridge, CB2 0PT, UK
| | - Maciej J Szukszto
- MRC Mitochondrial Biology Unit, University of Cambridge, Hills Road, Cambridge, CB2 0XY, UK
| | | | - Michal Minczuk
- MRC Mitochondrial Biology Unit, University of Cambridge, Hills Road, Cambridge, CB2 0XY, UK.
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27
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Abstract
High resolution cryoEM of mammalian mitoribosomes revealed the unexpected presence of mitochondrially encoded tRNA as a structural component of mitochondrial large ribosomal subunit (mt-LSU). Our previously published data identified that only mitochondrial (mt-) tRNAPhe and mt-tRNAVal can be incorporated into mammalian mt-LSU and within an organism there is no evidence of tissue specific variation. When mt-tRNAVal is limiting, human mitoribosomes can integrate mt-tRNAPhe instead to generate a translationally competent monosome. Here we discuss the possible reasons for and consequences of the observed plasticity of the structural mt-tRNA integration. We also indicate potential direction for further research that could help our understanding of the mechanistic and evolutionary aspects of this unprecedented system.
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Affiliation(s)
- Zofia Chrzanowska-Lightowlers
- a The Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience , Newcastle University , Newcastle upon Tyne , England , UK
| | - Joanna Rorbach
- b Department of Medical Biochemistry and Biophysics , Karolinska Institutet , Retzius väg 8, Stockholm , Sweden
| | - Michal Minczuk
- c MRC Mitochondrial Biology Unit , Wellcome Trust/MRC Building, Hills Road, Cambridge, England , UK
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28
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Pearce SF, Rorbach J, Haute LV, D’Souza AR, Rebelo-Guiomar P, Powell CA, Brierley I, Firth AE, Minczuk M. Maturation of selected human mitochondrial tRNAs requires deadenylation. eLife 2017; 6:e27596. [PMID: 28745585 PMCID: PMC5544427 DOI: 10.7554/elife.27596] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 07/21/2017] [Indexed: 02/02/2023] Open
Abstract
Human mitochondria contain a genome (mtDNA) that encodes essential subunits of the oxidative phosphorylation system. Expression of mtDNA entails multi-step maturation of precursor RNA. In other systems, the RNA life cycle involves surveillance mechanisms, however, the details of RNA quality control have not been extensively characterised in human mitochondria. Using a mitochondrial ribosome profiling and mitochondrial poly(A)-tail RNA sequencing (MPAT-Seq) assay, we identify the poly(A)-specific exoribonuclease PDE12 as a major factor for the quality control of mitochondrial non-coding RNAs. The lack of PDE12 results in a spurious polyadenylation of the 3' ends of the mitochondrial (mt-) rRNA and mt-tRNA. While the aberrant adenylation of 16S mt-rRNA did not affect the integrity of the mitoribosome, spurious poly(A) additions to mt-tRNA led to reduced levels of aminoacylated pool of certain mt-tRNAs and mitoribosome stalling at the corresponding codons. Therefore, our data uncover a new, deadenylation-dependent mtRNA maturation pathway in human mitochondria.
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Affiliation(s)
- Sarah F Pearce
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Joanna Rorbach
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Lindsey Van Haute
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Aaron R D’Souza
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Pedro Rebelo-Guiomar
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, United Kingdom
- Graduate Program in Areas of Basic and Applied Biology, University of Porto, Porto, Portugal
| | - Christopher A Powell
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Ian Brierley
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Andrew E Firth
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Michal Minczuk
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, United Kingdom
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29
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Gammage PA, Gaude E, Van Haute L, Rebelo-Guiomar P, Jackson CB, Rorbach J, Pekalski ML, Robinson AJ, Charpentier M, Concordet JP, Frezza C, Minczuk M. Near-complete elimination of mutant mtDNA by iterative or dynamic dose-controlled treatment with mtZFNs. Nucleic Acids Res 2016; 44:7804-16. [PMID: 27466392 PMCID: PMC5027515 DOI: 10.1093/nar/gkw676] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 07/20/2016] [Indexed: 01/08/2023] Open
Abstract
Mitochondrial diseases are frequently associated with mutations in mitochondrial DNA (mtDNA). In most cases, mutant and wild-type mtDNAs coexist, resulting in heteroplasmy. The selective elimination of mutant mtDNA, and consequent enrichment of wild-type mtDNA, can rescue pathological phenotypes in heteroplasmic cells. Use of the mitochondrially targeted zinc finger-nuclease (mtZFN) results in degradation of mutant mtDNA through site-specific DNA cleavage. Here, we describe a substantial enhancement of our previous mtZFN-based approaches to targeting mtDNA, allowing near-complete directional shifts of mtDNA heteroplasmy, either by iterative treatment or through finely controlled expression of mtZFN, which limits off-target catalysis and undesired mtDNA copy number depletion. To demonstrate the utility of this improved approach, we generated an isogenic distribution of heteroplasmic cells with variable mtDNA mutant level from the same parental source without clonal selection. Analysis of these populations demonstrated an altered metabolic signature in cells harbouring decreased levels of mutant m.8993T>G mtDNA, associated with neuropathy, ataxia, and retinitis pigmentosa (NARP). We conclude that mtZFN-based approaches offer means for mtDNA heteroplasmy manipulation in basic research, and may provide a strategy for therapeutic intervention in selected mitochondrial diseases.
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Affiliation(s)
| | | | | | - Pedro Rebelo-Guiomar
- MRC Mitochondrial Biology Unit, Cambridge, UK GABBA, University of Porto, Portugal
| | | | | | - Marcin L Pekalski
- JDRF/Wellcome Trust DIL, Cambridge Institute for Medical Research, University of Cambridge, UK
| | | | - Marine Charpentier
- INSERM U1154, CNRS UMR 7196, Muséum National d'Histoire Naturelle, Paris, France
| | - Jean-Paul Concordet
- INSERM U1154, CNRS UMR 7196, Muséum National d'Histoire Naturelle, Paris, France
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30
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Van Haute L, Dietmann S, Kremer L, Hussain S, Pearce SF, Powell CA, Rorbach J, Lantaff R, Blanco S, Sauer S, Kotzaeridou U, Hoffmann GF, Memari Y, Kolb-Kokocinski A, Durbin R, Mayr JA, Frye M, Prokisch H, Minczuk M. Deficient methylation and formylation of mt-tRNA(Met) wobble cytosine in a patient carrying mutations in NSUN3. Nat Commun 2016; 7:12039. [PMID: 27356879 PMCID: PMC4931328 DOI: 10.1038/ncomms12039] [Citation(s) in RCA: 155] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 05/24/2016] [Indexed: 12/22/2022] Open
Abstract
Epitranscriptome modifications are required for structure and function of RNA and defects in these pathways have been associated with human disease. Here we identify the RNA target for the previously uncharacterized 5-methylcytosine (m(5)C) methyltransferase NSun3 and link m(5)C RNA modifications with energy metabolism. Using whole-exome sequencing, we identified loss-of-function mutations in NSUN3 in a patient presenting with combined mitochondrial respiratory chain complex deficiency. Patient-derived fibroblasts exhibit severe defects in mitochondrial translation that can be rescued by exogenous expression of NSun3. We show that NSun3 is required for deposition of m(5)C at the anticodon loop in the mitochondrially encoded transfer RNA methionine (mt-tRNA(Met)). Further, we demonstrate that m(5)C deficiency in mt-tRNA(Met) results in the lack of 5-formylcytosine (f(5)C) at the same tRNA position. Our findings demonstrate that NSUN3 is necessary for efficient mitochondrial translation and reveal that f(5)C in human mitochondrial RNA is generated by oxidative processing of m(5)C.
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Affiliation(s)
| | - Sabine Dietmann
- Wellcome Trust—Medical Research Council Cambridge Stem Cell Institute, Genetics, University of Cambridge, Tennis Court Road, Cambridge CB2 1QR, UK
| | - Laura Kremer
- Helmholtz Zentrum München, Deutsches Forschungszentrum für Gesundheit und Umwelt (GmbH), Institute of Human Genetics, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany
- Technical University Munich, Institute of Human Genetics, Trogerstrasse 32, 81675 München, Germany
| | - Shobbir Hussain
- Department of Biology & Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - Sarah F. Pearce
- MRC Mitochondrial Biology Unit, Hills Road, Cambridge CB2 0XY, UK
| | | | - Joanna Rorbach
- MRC Mitochondrial Biology Unit, Hills Road, Cambridge CB2 0XY, UK
| | - Rebecca Lantaff
- Department of Physiology Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK
| | - Sandra Blanco
- Wellcome Trust—Medical Research Council Cambridge Stem Cell Institute, Genetics, University of Cambridge, Tennis Court Road, Cambridge CB2 1QR, UK
| | - Sascha Sauer
- Max-Planck-Institute for Molecular Genetics, Otto-Warburg Laboratory, 14195 Berlin, Germany
- University of Würzburg, CU Systems Medicine, 97080 Würzburg, Germany
- Max-Delbrück-Center for Molecular Medicine, Berlin Institute for Medical Systems Biology/Berlin Institute of Health, 13125 Berlin, Germany
| | - Urania Kotzaeridou
- Department of General Pediatrics, Division of Inherited Metabolic Diseases, University Children's Hospital, 69120 Heidelberg, Germany
| | - Georg F. Hoffmann
- Department of General Pediatrics, Division of Inherited Metabolic Diseases, University Children's Hospital, 69120 Heidelberg, Germany
| | - Yasin Memari
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton CB10 1SA, UK
| | - Anja Kolb-Kokocinski
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton CB10 1SA, UK
| | - Richard Durbin
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton CB10 1SA, UK
| | - Johannes A. Mayr
- Department of Paediatrics, Paracelsus Medical University, SALK Salzburg, Salzburg 5020, Austria
| | - Michaela Frye
- Wellcome Trust—Medical Research Council Cambridge Stem Cell Institute, Genetics, University of Cambridge, Tennis Court Road, Cambridge CB2 1QR, UK
| | - Holger Prokisch
- Helmholtz Zentrum München, Deutsches Forschungszentrum für Gesundheit und Umwelt (GmbH), Institute of Human Genetics, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany
- Technical University Munich, Institute of Human Genetics, Trogerstrasse 32, 81675 München, Germany
| | - Michal Minczuk
- MRC Mitochondrial Biology Unit, Hills Road, Cambridge CB2 0XY, UK
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31
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Affiliation(s)
- Joanna Rorbach
- MRC Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Payam A Gammage
- MRC Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Michal Minczuk
- MRC Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
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32
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Powell C, Kopajtich R, D’Souza AR, Rorbach J, Kremer L, Husain R, Dallabona C, Donnini C, Alston C, Griffin H, Pyle A, Chinnery P, Strom T, Meitinger T, Rodenburg R, Schottmann G, Schuelke M, Romain N, Haller R, Ferrero I, Haack T, Taylor R, Prokisch H, Minczuk M. TRMT5 Mutations Cause a Defect in Post-transcriptional Modification of Mitochondrial tRNA Associated with Multiple Respiratory-Chain Deficiencies. Am J Hum Genet 2015; 97:319-28. [PMID: 26189817 PMCID: PMC4573257 DOI: 10.1016/j.ajhg.2015.06.011] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 06/16/2015] [Indexed: 10/29/2022] Open
Abstract
Deficiencies in respiratory-chain complexes lead to a variety of clinical phenotypes resulting from inadequate energy production by the mitochondrial oxidative phosphorylation system. Defective expression of mtDNA-encoded genes, caused by mutations in either the mitochondrial or nuclear genome, represents a rapidly growing group of human disorders. By whole-exome sequencing, we identified two unrelated individuals carrying compound heterozygous variants in TRMT5 (tRNA methyltransferase 5). TRMT5 encodes a mitochondrial protein with strong homology to members of the class I-like methyltransferase superfamily. Both affected individuals presented with lactic acidosis and evidence of multiple mitochondrial respiratory-chain-complex deficiencies in skeletal muscle, although the clinical presentation of the two affected subjects was remarkably different; one presented in childhood with failure to thrive and hypertrophic cardiomyopathy, and the other was an adult with a life-long history of exercise intolerance. Mutations in TRMT5 were associated with the hypomodification of a guanosine residue at position 37 (G37) of mitochondrial tRNA; this hypomodification was particularly prominent in skeletal muscle. Deficiency of the G37 modification was also detected in human cells subjected to TRMT5 RNAi. The pathogenicity of the detected variants was further confirmed in a heterologous yeast model and by the rescue of the molecular phenotype after re-expression of wild-type TRMT5 cDNA in cells derived from the affected individuals. Our study highlights the importance of post-transcriptional modification of mitochondrial tRNAs for faithful mitochondrial function.
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33
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Rorbach J, Boesch P, Gammage PA, Nicholls TJJ, Pearce SF, Patel D, Hauser A, Perocchi F, Minczuk M. MRM2 and MRM3 are involved in biogenesis of the large subunit of the mitochondrial ribosome. Mol Biol Cell 2014; 25:2542-55. [PMID: 25009282 PMCID: PMC4148245 DOI: 10.1091/mbc.e14-01-0014] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] 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. Ribosome production in all organisms studied thus far entails a complex, multistep pathway involving a number of auxiliary factors. This includes several RNA processing and modification steps required for correct rRNA maturation. Little is known about the maturation of human mitochondrial 16S rRNA and its role in biogenesis of the mitoribosome. Here we investigate two methyltransferases, MRM2 (also known as RRMJ2, encoded by FTSJ2) and MRM3 (also known as RMTL1, encoded by RNMTL1), that are responsible for modification of nucleotides of the 16S rRNA A-loop, an essential component of the peptidyl transferase center. Our studies show that inactivation of MRM2 or MRM3 in human cells by RNA interference results in respiratory incompetence as a consequence of diminished mitochondrial translation. Ineffective translation in MRM2- and MRM3-depleted cells results from aberrant assembly of the large subunit of the mitochondrial ribosome (mt-LSU). Our findings show that MRM2 and MRM3 are human mitochondrial methyltransferases involved in the modification of 16S rRNA and are important factors for the biogenesis and function of the large subunit of the mitochondrial ribosome.
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Affiliation(s)
- Joanna Rorbach
- MRC Mitochondrial Biology Unit, Cambridge CB2 0XY, United Kingdom
| | - Pierre Boesch
- MRC Mitochondrial Biology Unit, Cambridge CB2 0XY, United Kingdom
| | - Payam A Gammage
- MRC Mitochondrial Biology Unit, Cambridge CB2 0XY, United Kingdom
| | | | - Sarah F Pearce
- MRC Mitochondrial Biology Unit, Cambridge CB2 0XY, United Kingdom
| | - Dipali Patel
- MRC Mitochondrial Biology Unit, Cambridge CB2 0XY, United Kingdom
| | - Andreas Hauser
- Gene Center Munich, Ludwig-Maximilians University, 81377 Munich, Germany
| | - Fabiana Perocchi
- Gene Center Munich, Ludwig-Maximilians University, 81377 Munich, Germany Institute of Human Genetics, Helmholtz Zentrum Munich, 85764 Munich, Germany
| | - Michal Minczuk
- MRC Mitochondrial Biology Unit, Cambridge CB2 0XY, United Kingdom
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34
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Dalla Rosa I, Durigon R, Pearce SF, Rorbach J, Hirst EMA, Vidoni S, Reyes A, Brea-Calvo G, Minczuk M, Woellhaf MW, Herrmann JM, Huynen MA, Holt IJ, Spinazzola A. MPV17L2 is required for ribosome assembly in mitochondria. Nucleic Acids Res 2014; 42:8500-15. [PMID: 24948607 PMCID: PMC4117752 DOI: 10.1093/nar/gku513] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
MPV17 is a mitochondrial protein of unknown function, and mutations in MPV17 are associated with mitochondrial deoxyribonucleic acid (DNA) maintenance disorders. Here we investigated its most similar relative, MPV17L2, which is also annotated as a mitochondrial protein. Mitochondrial fractionation analyses demonstrate MPV17L2 is an integral inner membrane protein, like MPV17. However, unlike MPV17, MPV17L2 is dependent on mitochondrial DNA, as it is absent from ρ(0) cells, and co-sediments on sucrose gradients with the large subunit of the mitochondrial ribosome and the monosome. Gene silencing of MPV17L2 results in marked decreases in the monosome and both subunits of the mitochondrial ribosome, leading to impaired protein synthesis in the mitochondria. Depletion of MPV17L2 also induces mitochondrial DNA aggregation. The DNA and ribosome phenotypes are linked, as in the absence of MPV17L2 proteins of the small subunit of the mitochondrial ribosome are trapped in the enlarged nucleoids, in contrast to a component of the large subunit. These findings suggest MPV17L2 contributes to the biogenesis of the mitochondrial ribosome, uniting the two subunits to create the translationally competent monosome, and provide evidence that assembly of the small subunit of the mitochondrial ribosome occurs at the nucleoid.
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Affiliation(s)
- Ilaria Dalla Rosa
- MRC National Institute for Medical Research, Mill Hill, London NW7 1AA, UK
| | - Romina Durigon
- MRC National Institute for Medical Research, Mill Hill, London NW7 1AA, UK
| | - Sarah F Pearce
- MRC Mitochondrial Biology Unit, Wellcome Trust-MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Joanna Rorbach
- MRC Mitochondrial Biology Unit, Wellcome Trust-MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | | | - Sara Vidoni
- MRC Mitochondrial Biology Unit, Wellcome Trust-MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Aurelio Reyes
- MRC Mitochondrial Biology Unit, Wellcome Trust-MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Gloria Brea-Calvo
- MRC Mitochondrial Biology Unit, Wellcome Trust-MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Michal Minczuk
- MRC Mitochondrial Biology Unit, Wellcome Trust-MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Michael W Woellhaf
- Cell Biology, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | | | - Martijn A Huynen
- Centre for Molecular and Biomolecular Informatics, Radboud University Medical Centre, Geert Grooteplein Zuid 26-28, 6525 GA Nijmegen, Netherlands
| | - Ian J Holt
- MRC National Institute for Medical Research, Mill Hill, London NW7 1AA, UK
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35
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Johnson MA, Vidoni S, Durigon R, Pearce SF, Rorbach J, He J, Brea-Calvo G, Minczuk M, Reyes A, Holt IJ, Spinazzola A. Amino acid starvation has opposite effects on mitochondrial and cytosolic protein synthesis. PLoS One 2014; 9:e93597. [PMID: 24718614 PMCID: PMC3981720 DOI: 10.1371/journal.pone.0093597] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 03/07/2014] [Indexed: 01/07/2023] Open
Abstract
Amino acids are essential for cell growth and proliferation for they can serve as precursors of protein synthesis, be remodelled for nucleotide and fat biosynthesis, or be burnt as fuel. Mitochondria are energy producing organelles that additionally play a central role in amino acid homeostasis. One might expect mitochondrial metabolism to be geared towards the production and preservation of amino acids when cells are deprived of an exogenous supply. On the contrary, we find that human cells respond to amino acid starvation by upregulating the amino acid-consuming processes of respiration, protein synthesis, and amino acid catabolism in the mitochondria. The increased utilization of these nutrients in the organelle is not driven primarily by energy demand, as it occurs when glucose is plentiful. Instead it is proposed that the changes in the mitochondrial metabolism complement the repression of cytosolic protein synthesis to restrict cell growth and proliferation when amino acids are limiting. Therefore, stimulating mitochondrial function might offer a means of inhibiting nutrient-demanding anabolism that drives cellular proliferation.
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Affiliation(s)
- Mark A. Johnson
- MRC-Mitochondrial Biology Unit, Wellcome Trust-MRC Building, Cambridge, United Kingdom
| | - Sara Vidoni
- MRC-Mitochondrial Biology Unit, Wellcome Trust-MRC Building, Cambridge, United Kingdom
| | - Romina Durigon
- NIMR-National Institute for Medical Research, Mill Hill, London, United Kingdom
| | - Sarah F. Pearce
- MRC-Mitochondrial Biology Unit, Wellcome Trust-MRC Building, Cambridge, United Kingdom
| | - Joanna Rorbach
- MRC-Mitochondrial Biology Unit, Wellcome Trust-MRC Building, Cambridge, United Kingdom
| | - Jiuya He
- MRC-Mitochondrial Biology Unit, Wellcome Trust-MRC Building, Cambridge, United Kingdom
| | - Gloria Brea-Calvo
- MRC-Mitochondrial Biology Unit, Wellcome Trust-MRC Building, Cambridge, United Kingdom
| | - Michal Minczuk
- MRC-Mitochondrial Biology Unit, Wellcome Trust-MRC Building, Cambridge, United Kingdom
| | - Aurelio Reyes
- MRC-Mitochondrial Biology Unit, Wellcome Trust-MRC Building, Cambridge, United Kingdom
| | - Ian J. Holt
- NIMR-National Institute for Medical Research, Mill Hill, London, United Kingdom
| | - Antonella Spinazzola
- NIMR-National Institute for Medical Research, Mill Hill, London, United Kingdom
- * E-mail:
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36
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Gammage PA, Rorbach J, Vincent AI, Rebar EJ, Minczuk M. Mitochondrially targeted ZFNs for selective degradation of pathogenic mitochondrial genomes bearing large-scale deletions or point mutations. EMBO Mol Med 2014; 6:458-66. [PMID: 24567072 PMCID: PMC3992073 DOI: 10.1002/emmm.201303672] [Citation(s) in RCA: 192] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
We designed and engineered mitochondrially targeted obligate heterodimeric zinc finger nucleases (mtZFNs) for site-specific elimination of pathogenic human mitochondrial DNA (mtDNA). We used mtZFNs to target and cleave mtDNA harbouring the m.8993T>G point mutation associated with neuropathy, ataxia, retinitis pigmentosa (NARP) and the “common deletion” (CD), a 4977-bp repeat-flanked deletion associated with adult-onset chronic progressive external ophthalmoplegia and, less frequently, Kearns-Sayre and Pearson's marrow pancreas syndromes. Expression of mtZFNs led to a reduction in mutant mtDNA haplotype load, and subsequent repopulation of wild-type mtDNA restored mitochondrial respiratory function in a CD cybrid cell model. This study constitutes proof-of-principle that, through heteroplasmy manipulation, delivery of site-specific nuclease activity to mitochondria can alleviate a severe biochemical phenotype in primary mitochondrial disease arising from deleted mtDNA species.
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Affiliation(s)
- Payam A Gammage
- Medical Research Council, Mitochondrial Biology Unit, Cambridge, UK
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37
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Abstract
Polyadenylation is a posttranscriptional modification present throughout all the kingdoms of life with important roles in regulation of RNA stability, translation, and quality control. Functions of polyadenylation in prokaryotic and organellar RNA metabolism are still not fully characterized, and poly(A) tails appear to play contrasting roles in different systems. Here we present a general overview of the polyadenylation process and the factors involved in its regulation, with an emphasis on the diverse functions of 3' end modification in the control of gene expression in different biological systems.
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Affiliation(s)
- Joanna Rorbach
- Mitochondrial Genetics Group, MRC Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY, UK,
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38
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Kornblum C, Nicholls T, Haack T, Schoeler S, Peeva V, Danhauser K, Hallmann K, Zsurka G, Rorbach J, Iuso A, Wieland T, Sciacco M, Ronchi D, Comi G, Moggio M, Quinzii C, DiMauro S, Calvo S, Mootha V, Klopstock T, Strom T, Meitinger T, Minczuk M, Kunz W, Prokisch H. O.24 Loss of function of MGME1, a novel player in mitochondrial DNA replication, causes a distinct autosomal recessive mitochondrial disorder. Neuromuscul Disord 2013. [DOI: 10.1016/j.nmd.2013.06.734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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39
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Haack T, Kopajtich R, Freisinger P, Wieland T, Rorbach J, Nicholls T, Baruffini E, Walther A, Danhauser K, Zimmermann F, Husain R, Schum J, Mundy H, Ferrero I, Strom T, Meitinger T, Taylor R, Minczuk M, Mayr J, Prokisch H. ELAC2 mutations cause a mitochondrial RNA processing defect associated with hypertrophic cardiomyopathy. Am J Hum Genet 2013; 93:211-23. [PMID: 23849775 PMCID: PMC3738821 DOI: 10.1016/j.ajhg.2013.06.006] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Revised: 05/22/2013] [Accepted: 06/05/2013] [Indexed: 11/16/2022] Open
Abstract
The human mitochondrial genome encodes RNA components of its own translational machinery to produce the 13 mitochondrial-encoded subunits of the respiratory chain. Nuclear-encoded gene products are essential for all processes within the organelle, including RNA processing. Transcription of the mitochondrial genome generates large polycistronic transcripts punctuated by the 22 mitochondrial (mt) tRNAs that are conventionally cleaved by the RNase P-complex and the RNase Z activity of ELAC2 at 5' and 3' ends, respectively. We report the identification of mutations in ELAC2 in five individuals with infantile hypertrophic cardiomyopathy and complex I deficiency. We observed accumulated mtRNA precursors in affected individuals muscle and fibroblasts. Although mature mt-tRNA, mt-mRNA, and mt-rRNA levels were not decreased in fibroblasts, the processing defect was associated with impaired mitochondrial translation. Complementation experiments in mutant cell lines restored RNA processing and a yeast model provided additional evidence for the disease-causal role of defective ELAC2, thereby linking mtRNA processing to human disease.
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MESH Headings
- Amino Acid Sequence
- Cardiomyopathy, Hypertrophic/genetics
- Cardiomyopathy, Hypertrophic/metabolism
- Cardiomyopathy, Hypertrophic/pathology
- Cell Nucleus/genetics
- Cell Nucleus/metabolism
- Electron Transport/genetics
- Endoribonucleases/genetics
- Endoribonucleases/metabolism
- Female
- Fibroblasts/metabolism
- Fibroblasts/pathology
- Genetic Complementation Test
- Humans
- Infant
- Male
- Mitochondria/genetics
- Mitochondria/metabolism
- Molecular Sequence Data
- Muscles/metabolism
- Muscles/pathology
- Mutation
- Neoplasm Proteins/genetics
- Neoplasm Proteins/metabolism
- Pedigree
- RNA Processing, Post-Transcriptional
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Mitochondrial
- RNA, Ribosomal/genetics
- RNA, Ribosomal/metabolism
- RNA, Transfer/genetics
- RNA, Transfer/metabolism
- Saccharomyces cerevisiae/genetics
- Saccharomyces cerevisiae/metabolism
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Affiliation(s)
- Tobias B. Haack
- Institute of Human Genetics, Technische Universität München, 81675 Munich, Germany
- Institute of Human Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764 Neuherberg, Germany
| | - Robert Kopajtich
- Institute of Human Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764 Neuherberg, Germany
| | - Peter Freisinger
- Department of Pediatrics, Klinikum Reutlingen, 72764 Reutlingen, Germany
| | - Thomas Wieland
- Institute of Human Genetics, Technische Universität München, 81675 Munich, Germany
- Institute of Human Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764 Neuherberg, Germany
| | - Joanna Rorbach
- MRC Mitochondrial Biology Unit, Hills Road, Cambridge CB2 0XY, UK
| | | | - Enrico Baruffini
- Department of Life Sciences, University of Parma, 43124 Parma, Italy
| | - Anett Walther
- Institute of Human Genetics, Technische Universität München, 81675 Munich, Germany
- Institute of Human Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764 Neuherberg, Germany
| | - Katharina Danhauser
- Institute of Human Genetics, Technische Universität München, 81675 Munich, Germany
| | - Franz A. Zimmermann
- Department of Pediatrics, Paracelsus Medical University Salzburg, 5020 Salzburg, Austria
| | - Ralf A. Husain
- Department of Neuropediatrics, Jena University Hospital, 07740 Jena, Germany
| | - Jessica Schum
- Institute of Human Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764 Neuherberg, Germany
| | - Helen Mundy
- Centre for Inherited Metabolic Disease, Evelina Children’s Hospital, Guys and St Thomas’ NHS Foundation Trust, London SE1 7EH, UK
| | - Ileana Ferrero
- Department of Life Sciences, University of Parma, 43124 Parma, Italy
| | - Tim M. Strom
- Institute of Human Genetics, Technische Universität München, 81675 Munich, Germany
- Institute of Human Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764 Neuherberg, Germany
| | - Thomas Meitinger
- Institute of Human Genetics, Technische Universität München, 81675 Munich, Germany
- Institute of Human Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764 Neuherberg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Munich, 81675 Munich, Germany
- Munich Heart Alliance, 80802 Munich, Germany
| | - Robert W. Taylor
- Wellcome Trust Centre for Mitochondrial Research, Institute for Ageing and Health, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Michal Minczuk
- MRC Mitochondrial Biology Unit, Hills Road, Cambridge CB2 0XY, UK
| | - Johannes A. Mayr
- Department of Pediatrics, Paracelsus Medical University Salzburg, 5020 Salzburg, Austria
| | - Holger Prokisch
- Institute of Human Genetics, Technische Universität München, 81675 Munich, Germany
- Institute of Human Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764 Neuherberg, Germany
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40
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Nicholls TJ, Rorbach J, Minczuk M. Mitochondria: mitochondrial RNA metabolism and human disease. Int J Biochem Cell Biol 2013; 45:845-9. [PMID: 23333854 DOI: 10.1016/j.biocel.2013.01.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Accepted: 01/08/2013] [Indexed: 10/27/2022]
Abstract
Post-transcriptional control of RNA stability, processing, modification, and degradation is key to the regulation of gene expression in all living cells. In mitochondria, these post-transcriptional processes are also vital for proper expression of the thirteen proteins encoded by the mitochondrial genome, as well as mitochondrial tRNAs and rRNAs. Our knowledge on mitochondrial RNA (mt-RNA) metabolic pathways, however, is far from complete. All the proteins involved in mt-RNA metabolism are encoded by the nucleus, and must be imported into the organelle. Mutations in these nuclear genes can lead to perturbations in mitochondrial RNA processing, modification, stability and decay and thus are a cause of human mitochondrial disease. This review summarises the current knowledge on mt-RNA metabolism and its links with human mitochondrial pathologies.
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Affiliation(s)
- Thomas J Nicholls
- MRC Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
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41
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Kazak L, Reyes A, Duncan AL, Rorbach J, Wood SR, Brea-Calvo G, Gammage PA, Robinson AJ, Minczuk M, Holt IJ. Alternative translation initiation augments the human mitochondrial proteome. Nucleic Acids Res 2012; 41:2354-69. [PMID: 23275553 PMCID: PMC3575844 DOI: 10.1093/nar/gks1347] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Alternative translation initiation (ATI) is a mechanism of producing multiple proteins from a single transcript, which in some cases regulates trafficking of proteins to different cellular compartments, including mitochondria. Application of a genome-wide computational screen predicts a cryptic mitochondrial targeting signal for 126 proteins in mouse and man that is revealed when an AUG codon located downstream from the canonical initiator methionine codon is used as a translation start site, which we term downstream ATI (dATI). Experimental evidence in support of dATI is provided by immunoblotting of endogenous truncated proteins enriched in mitochondrial cell fractions or of co-localization with mitochondria using immunocytochemistry. More detailed cellular localization studies establish mitochondrial targeting of a member of the cytosolic poly(A) binding protein family, PABPC5, and of the RNA/DNA helicase PIF1α. The mitochondrial isoform of PABPC5 co-immunoprecipitates with the mitochondrial poly(A) polymerase, and is markedly reduced in abundance when mitochondrial DNA and RNA are depleted, suggesting it plays a role in RNA metabolism in the organelle. Like PABPC5 and PIF1α, most of the candidates identified by the screen are not currently annotated as mitochondrial proteins, and so dATI expands the human mitochondrial proteome.
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Affiliation(s)
- Lawrence Kazak
- MRC-Mitochondrial Biology Unit, Wellcome Trust-MRC Building, Cambridge CB2 0XY, UK
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42
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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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43
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Abstract
Polyadenylation of mRNA in human mitochondria is crucial for gene expression and perturbation of poly(A) tail length has been linked to a human neurodegenerative disease. Here we show that 2′-phosphodiesterase (2′-PDE), (hereafter PDE12), is a mitochondrial protein that specifically removes poly(A) extensions from mitochondrial mRNAs both in vitro and in mitochondria of cultured cells. In eukaryotes, poly(A) tails generally stabilize mature mRNAs, whereas in bacteria they increase mRNA turnover. In human mitochondria, the effects of increased PDE12 expression were transcript dependent. An excess of PDE12 led to an increase in the level of three mt-mRNAs (ND1, ND2 and CytB) and two (CO1 and CO2) were less abundant than in mitochondria of control cells and there was no appreciable effect on the steady-state level of the remainder of the mitochondrial transcripts. The alterations in poly(A) tail length accompanying elevated PDE12 expression were associated with severe inhibition of mitochondrial protein synthesis, and consequently respiratory incompetence. Therefore, we propose that mRNA poly(A) tails are important in regulating protein synthesis in human mitochondria, as it is the case for nuclear-encoded eukaryotic mRNA.
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Affiliation(s)
- Joanna Rorbach
- MRC Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Cambridge CB2 0XY, UK
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44
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Ziabreva I, Campbell G, Rist J, Zambonin J, Rorbach J, Wydro MM, Lassmann H, Franklin RJM, Mahad D. Injury and differentiation following inhibition of mitochondrial respiratory chain complex IV in rat oligodendrocytes. Glia 2011; 58:1827-37. [PMID: 20665559 PMCID: PMC3580049 DOI: 10.1002/glia.21052] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Oligodendrocyte lineage cells are susceptible to a variety of insults including hypoxia, excitotoxicity, and reactive oxygen species. Demyelination is a well-recognized feature of several CNS disorders including multiple sclerosis, white matter strokes, progressive multifocal leukoencephalopathy, and disorders due to mitochondrial DNA mutations. Although mitochondria have been implicated in the demise of oligodendrocyte lineage cells, the consequences of mitochondrial respiratory chain defects have not been examined. We determine the in vitro impact of established inhibitors of mitochondrial respiratory chain complex IV or cytochrome c oxidase on oligodendrocyte progenitor cells (OPCs) and mature oligodendrocytes as well as on differentiation capacity of OPCs from P0 rat. Injury to mature oligodendrocytes following complex IV inhibition was significantly greater than to OPCs, judged by cell detachment and mitochondrial membrane potential (MMP) changes, although viability of cells that remained attached was not compromised. Active mitochondria were abundant in processes of differentiated oligodendrocytes and MMP was significantly greater in differentiated oligodendrocytes than OPCs. MMP dissipated following complex IV inhibition in oligodendrocytes. Furthermore, complex IV inhibition impaired process formation within oligodendrocyte lineage cells. Injury to and impaired process formation of oligodendrocytes following complex IV inhibition has potentially important implications for the pathogenesis and repair of CNS myelin disorders. © 2010 Wiley-Liss, Inc.
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Affiliation(s)
- Iryna Ziabreva
- The Mitochondrial Research Group, Newcastle University, Framlington Place, Newcastle upon Tyne, United Kingdom
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45
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Richter R, Rorbach J, Pajak A, Smith PM, Wessels HJ, Huynen MA, Smeitink JA, Lightowlers RN, Chrzanowska-Lightowlers ZM. A functional peptidyl-tRNA hydrolase, ICT1, has been recruited into the human mitochondrial ribosome. EMBO J 2010; 29:1116-25. [PMID: 20186120 PMCID: PMC2845271 DOI: 10.1038/emboj.2010.14] [Citation(s) in RCA: 136] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Accepted: 01/25/2010] [Indexed: 11/18/2022] Open
Abstract
Bioinformatic analysis classifies the human protein encoded by immature colon carcinoma transcript-1 (ICT1) as one of a family of four putative mitochondrial translation release factors. However, this has not been supported by any experimental evidence. As only a single member of this family, mtRF1a, is required to terminate the synthesis of all 13 mitochondrially encoded polypeptides, the true physiological function of ICT1 was unclear. Here, we report that ICT1 is an essential mitochondrial protein, but unlike the other family members that are matrix-soluble, ICT1 has become an integral component of the human mitoribosome. Release-factor assays show that although ICT1 has retained its ribosome-dependent PTH activity, this is codon-independent; consistent with its loss of both domains that promote codon recognition in class-I release factors. Mutation of the GGQ domain common to ribosome-dependent PTHs causes a loss of activity in vitro and, crucially, a loss of cell viability, in vivo. We suggest that ICT1 may be essential for hydrolysis of prematurely terminated peptidyl-tRNA moieties in stalled mitoribosomes.
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Affiliation(s)
- Ricarda Richter
- Mitochondrial Research Group, Institute for Ageing and Health, Medical School, Newcastle University, Newcastle upon Tyne, UK
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46
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Rorbach J, Richter R, Wessels HJ, Wydro M, Pekalski M, Farhoud M, Kühl I, Gaisne M, Bonnefoy N, Smeitink JA, Lightowlers RN, Chrzanowska-Lightowlers ZMA. The human mitochondrial ribosome recycling factor is essential for cell viability. Nucleic Acids Res 2008; 36:5787-99. [PMID: 18782833 PMCID: PMC2566884 DOI: 10.1093/nar/gkn576] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The molecular mechanism of human mitochondrial translation has yet to be fully described. We are particularly interested in understanding the process of translational termination and ribosome recycling in the mitochondrion. Several candidates have been implicated, for which subcellular localization and characterization have not been reported. Here, we show that the putative mitochondrial recycling factor, mtRRF, is indeed a mitochondrial protein. Expression of human mtRRF in fission yeast devoid of endogenous mitochondrial recycling factor suppresses the respiratory phenotype. Further, human mtRRF is able to associate with Escherichia coli ribosomes in vitro and can associate with mitoribosomes in vivo. Depletion of mtRRF in human cell lines is lethal, initially causing profound mitochondrial dysmorphism, aggregation of mitoribosomes, elevated mitochondrial superoxide production and eventual loss of OXPHOS complexes. Finally, mtRRF was shown to co-immunoprecipitate a large number of mitoribosomal proteins attached to other mitochondrial proteins, including putative members of the mitochondrial nucleoid.
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Affiliation(s)
- Joanna Rorbach
- Mitochondrial Research Group, Institute of Cellular Medicine, Medical School, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
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47
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Rorbach J, Yusoff AA, Tuppen H, Abg-Kamaludin DP, Chrzanowska-Lightowlers ZMA, Taylor RW, Turnbull DM, McFarland R, Lightowlers RN. Overexpression of human mitochondrial valyl tRNA synthetase can partially restore levels of cognate mt-tRNAVal carrying the pathogenic C25U mutation. Nucleic Acids Res 2008; 36:3065-74. [PMID: 18400783 PMCID: PMC2396425 DOI: 10.1093/nar/gkn147] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Phenotypic diversity associated with pathogenic mutations of the human mitochondrial genome (mtDNA) has often been explained by unequal segregation of the mutated and wild-type genomes (heteroplasmy). However, this simple hypothesis cannot explain the tissue specificity of disorders caused by homoplasmic mtDNA mutations. We have previously associated a homoplasmic point mutation (1624C>T) in MTTV with a profound metabolic disorder that resulted in the neonatal deaths of numerous siblings. Affected tissues harboured a marked biochemical defect in components of the mitochondrial respiratory chain, presumably due to the extremely low (<1%) steady-state levels of mt-tRNAVal. In primary myoblasts and transmitochondrial cybrids established from the proband (index case) and offspring, the marked respiratory deficiency was lost and steady-state levels of the mutated mt-tRNAVal were greater than in the biopsy material, but were still an order of magnitude lower than in control myoblasts. We present evidence that the generalized decrease in steady-state mt-tRNAVal observed in the homoplasmic 1624C>T-cell lines is caused by a rapid degradation of the deacylated form of the abnormal mt-tRNAVal. By both establishing the identity of the human mitochondrial valyl-tRNA synthetase then inducing its overexpression in transmitochondrial cell lines, we have been able to partially restore steady-state levels of the mutated mt-tRNAVal, consistent with an increased stability of the charged mt-tRNA. These data indicate that variations in the levels of VARS2L between tissue types and patients could underlie the difference in clinical presentation between individuals homoplasmic for the 1624C>T mutation.
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Affiliation(s)
- Joanna Rorbach
- Mitochondrial Research Group, Institute of Neuroscience, Medical School, University of Newcastle upon Tyne, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
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48
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Soleimanpour-Lichaei HR, Kühl I, Gaisne M, Passos JF, Wydro M, Rorbach J, Temperley R, Bonnefoy N, Tate W, Lightowlers R, Chrzanowska-Lightowlers Z. mtRF1a is a human mitochondrial translation release factor decoding the major termination codons UAA and UAG. Mol Cell 2007; 27:745-57. [PMID: 17803939 PMCID: PMC1976341 DOI: 10.1016/j.molcel.2007.06.031] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2007] [Revised: 05/30/2007] [Accepted: 06/21/2007] [Indexed: 11/28/2022]
Abstract
Human mitochondria contain their own genome, encoding 13 polypeptides that are synthesized within the organelle. The molecular processes that govern and facilitate this mitochondrial translation remain unclear. Many key factors have yet to be characterized—for example, those required for translation termination. All other systems have two classes of release factors that either promote codon-specific hydrolysis of peptidyl-tRNA (class I) or lack specificity but stimulate the dissociation of class I factors from the ribosome (class II). One human mitochondrial protein has been previously identified in silico as a putative member of the class I release factors. Although we could not confirm the function of this factor, we report the identification of a different mitochondrial protein, mtRF1a, that is capable in vitro and in vivo of terminating translation at UAA/UAG codons. Further, mtRF1a depletion in HeLa cells led to compromised growth in galactose and increased production of reactive oxygen species.
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Affiliation(s)
| | - Inge Kühl
- Centre de Génétique Moléculaire, CNRS Batiment 26, Avenue de la Terrasse, 91198 Gif sur Yvette Cedex, France
| | - Mauricette Gaisne
- Centre de Génétique Moléculaire, CNRS Batiment 26, Avenue de la Terrasse, 91198 Gif sur Yvette Cedex, France
| | - Joao F. Passos
- Centre for Integrated Systems Biology of Ageing and Nutrition, Newcastle University, Newcastle upon Tyne NE4 6BE, UK
| | - Mateusz Wydro
- Mitochondrial Research Group, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Joanna Rorbach
- Mitochondrial Research Group, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Richard Temperley
- Mitochondrial Research Group, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Nathalie Bonnefoy
- Centre de Génétique Moléculaire, CNRS Batiment 26, Avenue de la Terrasse, 91198 Gif sur Yvette Cedex, France
| | - Warren Tate
- Department of Biochemistry, University of Otago, P.O. Box 56, 710 Cumberland Street, Dunedin 9016, New Zealand
| | - Robert Lightowlers
- Mitochondrial Research Group, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Zofia Chrzanowska-Lightowlers
- Mitochondrial Research Group, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
- Corresponding author
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