1
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Goel D, Kumar S. Advancements in unravelling the fundamental function of the ATAD3 protein in multicellular organisms. Adv Biol Regul 2024; 93:101041. [PMID: 38909398 DOI: 10.1016/j.jbior.2024.101041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2024] [Revised: 06/05/2024] [Accepted: 06/18/2024] [Indexed: 06/25/2024]
Abstract
ATPase family AAA domain containing protein 3, commonly known as ATAD3 is a versatile mitochondrial protein that is involved in a large number of pathways. ATAD3 is a transmembrane protein that spans both the inner mitochondrial membrane and outer mitochondrial membrane. It, therefore, functions as a connecting link between the mitochondrial lumen and endoplasmic reticulum facilitating their cross-talk. ATAD3 contains an N-terminal domain which is amphipathic in nature and is inserted into the membranous space of the mitochondria, while the C-terminal domain is present towards the lumen of the mitochondria and contains the ATPase domain. ATAD3 is known to be involved in mitochondrial biogenesis, cholesterol transport, hormone synthesis, apoptosis and several other pathways. It has also been implicated to be involved in cancer and many neurological disorders making it an interesting target for extensive studies. This review aims to provide an updated comprehensive account of the role of ATAD3 in the mitochondria especially in lipid transport, mitochondrial-endoplasmic reticulum interactions, cancer and inhibition of mitophagy.
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Affiliation(s)
- Divya Goel
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Sudhir Kumar
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India.
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2
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Tábara LC, Burr SP, Frison M, Chowdhury SR, Paupe V, Nie Y, Johnson M, Villar-Azpillaga J, Viegas F, Segawa M, Anand H, Petkevicius K, Chinnery PF, Prudent J. MTFP1 controls mitochondrial fusion to regulate inner membrane quality control and maintain mtDNA levels. Cell 2024; 187:3619-3637.e27. [PMID: 38851188 DOI: 10.1016/j.cell.2024.05.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 03/19/2024] [Accepted: 05/09/2024] [Indexed: 06/10/2024]
Abstract
Mitochondrial dynamics play a critical role in cell fate decisions and in controlling mtDNA levels and distribution. However, the molecular mechanisms linking mitochondrial membrane remodeling and quality control to mtDNA copy number (CN) regulation remain elusive. Here, we demonstrate that the inner mitochondrial membrane (IMM) protein mitochondrial fission process 1 (MTFP1) negatively regulates IMM fusion. Moreover, manipulation of mitochondrial fusion through the regulation of MTFP1 levels results in mtDNA CN modulation. Mechanistically, we found that MTFP1 inhibits mitochondrial fusion to isolate and exclude damaged IMM subdomains from the rest of the network. Subsequently, peripheral fission ensures their segregation into small MTFP1-enriched mitochondria (SMEM) that are targeted for degradation in an autophagic-dependent manner. Remarkably, MTFP1-dependent IMM quality control is essential for basal nucleoid recycling and therefore to maintain adequate mtDNA levels within the cell.
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Affiliation(s)
- Luis Carlos Tábara
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK.
| | - Stephen P Burr
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK; Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge CB2 0QQ, UK
| | - Michele Frison
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK; Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge CB2 0QQ, UK
| | - Suvagata R Chowdhury
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | - Vincent Paupe
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | - Yu Nie
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK; Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge CB2 0QQ, UK
| | - Mark Johnson
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | - Jara Villar-Azpillaga
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | - Filipa Viegas
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | - Mayuko Segawa
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | - Hanish Anand
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | - Kasparas Petkevicius
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | - Patrick F Chinnery
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK; Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge CB2 0QQ, UK
| | - Julien Prudent
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK.
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3
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Li S, Xu R, Yao Y, Rousseau D. ATAD3 is a limiting factor in mitochondrial biogenesis and adipogenesis of white adipocyte-like 3T3-L1 cells. Cell Biol Int 2024. [PMID: 38923254 DOI: 10.1002/cbin.12206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 06/03/2024] [Accepted: 06/03/2024] [Indexed: 06/28/2024]
Abstract
ATAD3 is a vital ATPase of the inner mitochondrial membrane of pluri-cellular eukaryotes, with largely unknown functions but early required for organism development as necessary for mitochondrial biogenesis. ATAD3 knock-down in C. elegans inhibits at first the development of adipocyte-like intestinal tissue so we used mouse adipocyte model 3T3-L1 cells to analyze ATAD3 functions during adipogenesis and lipogenesis in a mammalian model. ATAD3 function was studied by stable and transient modulation of ATAD3 expression in adipogenesis- induced 3T3-L1 cells using Knock-Down and overexpression strategies, exploring different steps of adipocyte differentiation and lipogenesis. We show that (i) an increase in ATAD3 is preceding differentiation-induced mitochondrial biogenesis; (ii) downregulation of ATAD3 inhibits adipogenesis, lipogenesis, and impedes overexpression of many mitochondrial proteins; (iii) ATAD3 re-expression rescues the phenotype of ATAD3 KD, and (iv) differentiation and lipogenesis are accelerated by ATAD3 overexpression, but inhibited by expression of a dominant-negative mutant. We further show that the ATAD3 KD phenotype is not due to altered insulin signal but involves a limitation of mitochondrial biogenesis linked to Drp1. These results demonstrate that ATAD3 is limiting for in vitro mitochondrial biogenesis and adipogenesis/lipogenesis and therefore that ATAD3 mutation/over- or under-expression could be involved in adipogenic and lipogenic pathologies.
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Affiliation(s)
- Shuijie Li
- Department of Biology, University Grenoble Alpes, Grenoble, France
| | - Rui Xu
- Institute of Biochemistry and Cell Biology of Shanghai Institutes for Biological Sciences Chinese Academy of Sciences, Shanghai, China
| | - Yao Yao
- Institute of Biochemistry and Cell Biology of Shanghai Institutes for Biological Sciences Chinese Academy of Sciences, Shanghai, China
| | - Denis Rousseau
- Department of Biology, University Grenoble Alpes, Grenoble, France
- Laboratoire des Matériaux et du Génie Physique-Interfaces entre Matériaux et Matière Biologique -Institut National Polytechnique-Centre National de la Recherche Scientifique - Unité Mixte de Recherche, Grenoble, France
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4
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Gaudó P, de Tomás-Mateo E, Garrido-Pérez N, Santana A, Ruiz-Pesini E, Montoya J, Bayona-Bafaluy P. "ATAD3C regulates ATAD3A assembly and function in the mitochondrial membrane". Free Radic Biol Med 2024; 211:114-126. [PMID: 38092275 DOI: 10.1016/j.freeradbiomed.2023.12.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 11/28/2023] [Accepted: 12/07/2023] [Indexed: 12/21/2023]
Abstract
Mitochondrial ATAD3A is an ATPase Associated with diverse cellular Activities (AAA) domain containing enzyme, involved in the structural organization of the inner mitochondrial membrane and of increasing importance in childhood disease. In humans, two ATAD3A paralogs arose by gene duplication during evolution: ATAD3B and ATAD3C. Here we investigate the cellular activities of the ATAD3C paralog that has been considered a pseudogene. We detected unique ATAD3C peptides in HEK 293T cells, with expression similar to that in human tissues, and showed that it is an integral membrane protein that exposes its carboxy-terminus to the intermembrane space. Overexpression of ATAD3C, but not of ATAD3A, in fibroblasts caused a decrease in cell proliferation and oxygen consumption rate, and an increase of cellular ROS. This was due to the incorporation of ATAD3C monomers in ATAD3A complex in the mitochondrial membrane reducing its size. Consistent with a negative regulation of ATAD3A function in mitochondrial membrane organization, ATAD3C expression led to increased accumulation of respiratory chain dimeric CIII in the inner membrane, to the detriment to that assembled in respiratory supercomplexes. Our results demonstrate a negative dominant role of the ATAD3C paralog with implications for mitochondrial OXPHOS function and suggest that its expression regulates ATAD3A in the cell.
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Affiliation(s)
- Paula Gaudó
- Biochemistry and Molecular Biology Department. Universidad de Zaragoza, 50009- and 50013, Zaragoza, Spain
| | - Elena de Tomás-Mateo
- Biochemistry and Molecular Biology Department. Universidad de Zaragoza, 50009- and 50013, Zaragoza, Spain
| | - Nuria Garrido-Pérez
- Biochemistry and Molecular Biology Department. Universidad de Zaragoza, 50009- and 50013, Zaragoza, Spain; Institute for Health Research (IIS) de Aragón, 50009, Zaragoza, Spain; Rare Diseases Networking Biomedical Research Centre (CIBERER), 28029, Madrid, Spain; Institute for Biocomputation and Physics of Complex Systems, University of Zaragoza, 50018, Zaragoza, Spain
| | - Alfredo Santana
- Research Institute of Biomedical and Health Sciences (IUIBS), University of Las Palmas de Gran Canaria, 35001, Las Palmas de Gran Canaria, Spain; Clinical Genetics Unit, Complejo Hospitarlario Universitario Insular-Materno Infantil de Las Palamas de Gran Canaria, 35016, Las Palmas de Gran Canaria, Spain
| | - Eduardo Ruiz-Pesini
- Institute for Health Research (IIS) de Aragón, 50009, Zaragoza, Spain; Rare Diseases Networking Biomedical Research Centre (CIBERER), 28029, Madrid, Spain.
| | - Julio Montoya
- Biochemistry and Molecular Biology Department. Universidad de Zaragoza, 50009- and 50013, Zaragoza, Spain; Institute for Health Research (IIS) de Aragón, 50009, Zaragoza, Spain; Rare Diseases Networking Biomedical Research Centre (CIBERER), 28029, Madrid, Spain
| | - Pilar Bayona-Bafaluy
- Biochemistry and Molecular Biology Department. Universidad de Zaragoza, 50009- and 50013, Zaragoza, Spain; Institute for Health Research (IIS) de Aragón, 50009, Zaragoza, Spain; Rare Diseases Networking Biomedical Research Centre (CIBERER), 28029, Madrid, Spain; Institute for Biocomputation and Physics of Complex Systems, University of Zaragoza, 50018, Zaragoza, Spain.
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5
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Zhang C, Meng Y, Han J. Emerging roles of mitochondrial functions and epigenetic changes in the modulation of stem cell fate. Cell Mol Life Sci 2024; 81:26. [PMID: 38212548 PMCID: PMC11072137 DOI: 10.1007/s00018-023-05070-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 11/27/2023] [Accepted: 11/28/2023] [Indexed: 01/13/2024]
Abstract
Mitochondria serve as essential organelles that play a key role in regulating stem cell fate. Mitochondrial dysfunction and stem cell exhaustion are two of the nine distinct hallmarks of aging. Emerging research suggests that epigenetic modification of mitochondria-encoded genes and the regulation of epigenetics by mitochondrial metabolites have an impact on stem cell aging or differentiation. Here, we review how key mitochondrial metabolites and behaviors regulate stem cell fate through an epigenetic approach. Gaining insight into how mitochondria regulate stem cell fate will help us manufacture and preserve clinical-grade stem cells under strict quality control standards, contributing to the development of aging-associated organ dysfunction and disease.
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Affiliation(s)
- Chensong Zhang
- State Key Laboratory of Biotherapy and Cancer Center, Frontiers Science Center for Disease-Related Molecular Network, and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Yang Meng
- State Key Laboratory of Biotherapy and Cancer Center, Frontiers Science Center for Disease-Related Molecular Network, and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Junhong Han
- State Key Laboratory of Biotherapy and Cancer Center, Frontiers Science Center for Disease-Related Molecular Network, and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, 610041, China.
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6
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Nusir A, Sinclair P, Kabbani N. Mitochondrial Proteomes in Neural Cells: A Systematic Review. Biomolecules 2023; 13:1638. [PMID: 38002320 PMCID: PMC10669788 DOI: 10.3390/biom13111638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 11/07/2023] [Accepted: 11/09/2023] [Indexed: 11/26/2023] Open
Abstract
Mitochondria are ancient endosymbiotic double membrane organelles that support a wide range of eukaryotic cell functions through energy, metabolism, and cellular control. There are over 1000 known proteins that either reside within the mitochondria or are transiently associated with it. These mitochondrial proteins represent a functional subcellular protein network (mtProteome) that is encoded by mitochondrial and nuclear genomes and significantly varies between cell types and conditions. In neurons, the high metabolic demand and differential energy requirements at the synapses are met by specific modifications to the mtProteome, resulting in alterations in the expression and functional properties of the proteins involved in energy production and quality control, including fission and fusion. The composition of mtProteomes also impacts the localization of mitochondria in axons and dendrites with a growing number of neurodegenerative diseases associated with changes in mitochondrial proteins. This review summarizes the findings on the composition and properties of mtProteomes important for mitochondrial energy production, calcium and lipid signaling, and quality control in neural cells. We highlight strategies in mass spectrometry (MS) proteomic analysis of mtProteomes from cultured cells and tissue. The research into mtProteome composition and function provides opportunities in biomarker discovery and drug development for the treatment of metabolic and neurodegenerative disease.
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Affiliation(s)
- Aya Nusir
- Interdisciplinary Program in Neuroscience, School of Systems Biology, George Mason University, Fairfax, VA 22030, USA;
| | - Patricia Sinclair
- School of Systems Biology, George Mason University, Fairfax, VA 22030, USA;
| | - Nadine Kabbani
- Interdisciplinary Program in Neuroscience, School of Systems Biology, George Mason University, Fairfax, VA 22030, USA;
- School of Systems Biology, George Mason University, Fairfax, VA 22030, USA;
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7
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Potter A, Cabrera-Orefice A, Spelbrink JN. Let's make it clear: systematic exploration of mitochondrial DNA- and RNA-protein complexes by complexome profiling. Nucleic Acids Res 2023; 51:10619-10641. [PMID: 37615582 PMCID: PMC10602928 DOI: 10.1093/nar/gkad697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Revised: 07/18/2023] [Accepted: 08/11/2023] [Indexed: 08/25/2023] Open
Abstract
Complexome profiling (CP) is a powerful tool for systematic investigation of protein interactors that has been primarily applied to study the composition and dynamics of mitochondrial protein complexes. Here, we further optimized this method to extend its application to survey mitochondrial DNA- and RNA-interacting protein complexes. We established that high-resolution clear native gel electrophoresis (hrCNE) is a better alternative to preserve DNA- and RNA-protein interactions that are otherwise disrupted when samples are separated by the widely used blue native gel electrophoresis (BNE). In combination with enzymatic digestion of DNA, our CP approach improved the identification of a wide range of protein interactors of the mitochondrial gene expression system without compromising the detection of other multiprotein complexes. The utility of this approach was particularly demonstrated by analysing the complexome changes in human mitochondria with impaired gene expression after transient, chemically induced mitochondrial DNA depletion. Effects of RNase on mitochondrial protein complexes were also evaluated and discussed. Overall, our adaptations significantly improved the identification of mitochondrial DNA- and RNA-protein interactions by CP, thereby unlocking the comprehensive analysis of a near-complete mitochondrial complexome in a single experiment.
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Affiliation(s)
- Alisa Potter
- Department of Pediatrics, Amalia Children's Hospital, Radboud University Medical Center, Nijmegen, The Netherlands
- Radboud Center for Mitochondrial Medicine (RCMM), Radboud University Medical Center, Nijmegen, The Netherlands
| | - Alfredo Cabrera-Orefice
- Radboud Center for Mitochondrial Medicine (RCMM), Radboud University Medical Center, Nijmegen, The Netherlands
- Department of Medical BioSciences, Radboud University Medical Center, Nijmegen, The Netherlands
- Functional Proteomics, Institute for Cardiovascular Physiology, Goethe University, Frankfurt am Main, Germany
| | - Johannes N Spelbrink
- Department of Pediatrics, Amalia Children's Hospital, Radboud University Medical Center, Nijmegen, The Netherlands
- Radboud Center for Mitochondrial Medicine (RCMM), Radboud University Medical Center, Nijmegen, The Netherlands
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8
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Wu H, Zhang W, Xu F, Peng K, Liu X, Ding W, Ma Q, Cheng H, Wang X. C17orf80 binds the mitochondrial genome to promote its replication. J Cell Biol 2023; 222:e202302037. [PMID: 37676315 PMCID: PMC10484793 DOI: 10.1083/jcb.202302037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 06/26/2023] [Accepted: 07/17/2023] [Indexed: 09/08/2023] Open
Abstract
Serving as the power plant and signaling hub of a cell, mitochondria contain their own genome which encodes proteins essential for energy metabolism and forms DNA-protein assemblies called nucleoids. Mitochondrial DNA (mtDNA) exists in multiple copies within each cell ranging from hundreds to tens of thousands. Maintaining mtDNA homeostasis is vital for healthy cells, and its dysregulation causes multiple human diseases. However, the players involved in regulating mtDNA maintenance are largely unknown though the core components of its replication machinery have been characterized. Here, we identify C17orf80, a functionally uncharacterized protein, as a critical player in maintaining mtDNA homeostasis. C17orf80 primarily localizes to mitochondrial nucleoid foci and exhibits robust double-stranded DNA binding activity throughout the mitochondrial genome, thus constituting a bona fide new mitochondrial nucleoid protein. It controls mtDNA levels by promoting mtDNA replication and plays important roles in mitochondrial metabolism and cell proliferation. Our findings provide a potential target for therapeutics of human diseases associated with defective mtDNA control.
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Affiliation(s)
- Hao Wu
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
- Academy of Advanced Interdisciplinary Study, Peking University, Beijing, China
| | - Wenshuo Zhang
- Peking-Tsinghua Center for Life Sciences, College of Life Sciences, Peking University, Beijing, China
| | - Fengli Xu
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
| | - Kun Peng
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
| | - Xiaoyu Liu
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
| | - Wanqiu Ding
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
| | - Qi Ma
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
| | - Heping Cheng
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
- Research Unit of Mitochondria in Brain Diseases, Chinese Academy of Medical Sciences, PKU-Nanjing Institute of Translational Medicine, Nanjing, China
| | - Xianhua Wang
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China
- Research Unit of Mitochondria in Brain Diseases, Chinese Academy of Medical Sciences, PKU-Nanjing Institute of Translational Medicine, Nanjing, China
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9
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Potter A, Hangas A, Goffart S, Huynen MA, Cabrera-Orefice A, Spelbrink JN. Uncharacterized protein C17orf80 - a novel interactor of human mitochondrial nucleoids. J Cell Sci 2023; 136:jcs260822. [PMID: 37401363 PMCID: PMC10445727 DOI: 10.1242/jcs.260822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 06/26/2023] [Indexed: 07/05/2023] Open
Abstract
Molecular functions of many human proteins remain unstudied, despite the demonstrated association with diseases or pivotal molecular structures, such as mitochondrial DNA (mtDNA). This small genome is crucial for the proper functioning of mitochondria, the energy-converting organelles. In mammals, mtDNA is arranged into macromolecular complexes called nucleoids that serve as functional stations for its maintenance and expression. Here, we aimed to explore an uncharacterized protein C17orf80, which was previously detected close to the nucleoid components by proximity labelling mass spectrometry. To investigate the subcellular localization and function of C17orf80, we took advantage of immunofluorescence microscopy, interaction proteomics and several biochemical assays. We demonstrate that C17orf80 is a mitochondrial membrane-associated protein that interacts with nucleoids even when mtDNA replication is inhibited. In addition, we show that C17orf80 is not essential for mtDNA maintenance and mitochondrial gene expression in cultured human cells. These results provide a basis for uncovering the molecular function of C17orf80 and the nature of its association with nucleoids, possibly leading to new insights about mtDNA and its expression.
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Affiliation(s)
- Alisa Potter
- Department of Pediatrics, Amalia Children's Hospital, Radboud University Medical Center, Nijmegen, 6525 GA, The Netherlands
- Radboud Center for Mitochondrial Medicine (RCMM), Radboud University Medical Center, Nijmegen, 6525 GA, The Netherlands
| | - Anu Hangas
- Department of Environmental and Biological Sciences, University of Eastern Finland, Joensuu, 80101, Finland
| | - Steffi Goffart
- Department of Environmental and Biological Sciences, University of Eastern Finland, Joensuu, 80101, Finland
| | - Martijn A. Huynen
- Department of Medical BioSciences, Radboud University Medical Center, Nijmegen, 6525 GA, The Netherlands
| | - Alfredo Cabrera-Orefice
- Radboud Center for Mitochondrial Medicine (RCMM), Radboud University Medical Center, Nijmegen, 6525 GA, The Netherlands
- Department of Medical BioSciences, Radboud University Medical Center, Nijmegen, 6525 GA, The Netherlands
| | - Johannes N. Spelbrink
- Department of Pediatrics, Amalia Children's Hospital, Radboud University Medical Center, Nijmegen, 6525 GA, The Netherlands
- Radboud Center for Mitochondrial Medicine (RCMM), Radboud University Medical Center, Nijmegen, 6525 GA, The Netherlands
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10
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Wang J, Gao X, Du C, Tang D, Hou C, Zhu J. The Effect of Prohibitins on Mitochondrial Function during Octopus tankahkeei Spermiogenesis. Int J Mol Sci 2023; 24:10030. [PMID: 37373178 DOI: 10.3390/ijms241210030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 05/30/2023] [Accepted: 06/02/2023] [Indexed: 06/29/2023] Open
Abstract
Mitochondria are essential for spermiogenesis. Prohibitins (PHBs; prohibitin 1, PHB1 or PHB, and prohibitin 2, PHB2) are evolutionarily conserved and ubiquitously expressed mitochondrial proteins that act as scaffolds in the inner mitochondrial membrane. In this study, we analyzed the molecular structure and dynamic expression characteristics of Ot-PHBs, observed the colocalization of Ot-PHB1 with mitochondria and polyubiquitin, and studied the effect of phb1 knockdown on mitochondrial DNA (mtDNA) content, reactive oxygen species (ROS) levels, and apoptosis-related gene expression in spermatids. Our aim was to explore the effect of Ot-PHBs on mitochondrial function during the spermiogenesis of Octopus tankahkeei (O. tankahkeei), an economically important species in China. The predicted Ot-PHB1/PHB2 proteins contained an N-terminal transmembrane, a stomatin/prohibitin/flotillin/HflK/C (SPFH) domain (also known as the prohibitin domain), and a C-terminal coiled-coil domain. Ot-phb1/phb2 mRNA were widely expressed in the different tissues, with elevated expression in the testis. Further, Ot-PHB1 and Ot-PHB2 were highly colocalized, suggesting that they may function primarily as an Ot-PHB compiex in O. tankahkeei. Ot-PHB1 proteins were mainly expressed and localized in mitochondria during spermiogenesis, implying that their function may be localized to the mitochondria. In addition, Ot-PHB1 was colocalized with polyubiquitin during spermiogenesis, suggesting that it may be a polyubiquitin substrate that regulates mitochondrial ubiquitination during spermiogenesis to ensure mitochondrial quality. To further investigate the effect of Ot-PHBs on mitochondrial function, we knocked down Ot-phb1 and observed a decrease in mtDNA content, along with increases in ROS levels and the expressions of mitochondria-induced apoptosis-related genes bax, bcl2, and caspase-3 mRNA. These findings indicate that PHBs might influence mitochondrial function by maintaining mtDNA content and stabilizing ROS levels; in addition, PHBs might affect spermatocyte survival by regulating mitochondria-induced apoptosis during spermiogenesis in O. tankahkeei.
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Affiliation(s)
- Jingqian Wang
- Key Laboratory of Aquacultural Biotechnology, Ningbo University, Ministry of Education, Ningbo 315211, China
- Key Laboratory of Marine Biotechnology of Zhejiang Province, Ningbo University, Ningbo 315211, China
| | - Xinming Gao
- Key Laboratory of Aquacultural Biotechnology, Ningbo University, Ministry of Education, Ningbo 315211, China
- Key Laboratory of Marine Biotechnology of Zhejiang Province, Ningbo University, Ningbo 315211, China
| | - Chen Du
- Key Laboratory of Aquacultural Biotechnology, Ningbo University, Ministry of Education, Ningbo 315211, China
- Key Laboratory of Marine Biotechnology of Zhejiang Province, Ningbo University, Ningbo 315211, China
| | - Daojun Tang
- Key Laboratory of Aquacultural Biotechnology, Ningbo University, Ministry of Education, Ningbo 315211, China
- Key Laboratory of Marine Biotechnology of Zhejiang Province, Ningbo University, Ningbo 315211, China
| | - Congcong Hou
- Key Laboratory of Aquacultural Biotechnology, Ningbo University, Ministry of Education, Ningbo 315211, China
- Key Laboratory of Marine Biotechnology of Zhejiang Province, Ningbo University, Ningbo 315211, China
| | - Junquan Zhu
- Key Laboratory of Aquacultural Biotechnology, Ningbo University, Ministry of Education, Ningbo 315211, China
- Key Laboratory of Marine Biotechnology of Zhejiang Province, Ningbo University, Ningbo 315211, China
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11
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Kozhukhar N, Alexeyev MF. 35 Years of TFAM Research: Old Protein, New Puzzles. BIOLOGY 2023; 12:823. [PMID: 37372108 DOI: 10.3390/biology12060823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 05/29/2023] [Accepted: 06/03/2023] [Indexed: 06/29/2023]
Abstract
Transcription Factor A Mitochondrial (TFAM), through its contributions to mtDNA maintenance and expression, is essential for cellular bioenergetics and, therefore, for the very survival of cells. Thirty-five years of research on TFAM structure and function generated a considerable body of experimental evidence, some of which remains to be fully reconciled. Recent advancements allowed an unprecedented glimpse into the structure of TFAM complexed with promoter DNA and TFAM within the open promoter complexes. These novel insights, however, raise new questions about the function of this remarkable protein. In our review, we compile the available literature on TFAM structure and function and provide some critical analysis of the available data.
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Affiliation(s)
- Natalya Kozhukhar
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, AL 36688, USA
| | - Mikhail F Alexeyev
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, AL 36688, USA
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12
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Grady CI, Walsh LM, Heiss JD. Mitoepigenetics and gliomas: epigenetic alterations to mitochondrial DNA and nuclear DNA alter mtDNA expression and contribute to glioma pathogenicity. Front Neurol 2023; 14:1154753. [PMID: 37332990 PMCID: PMC10270738 DOI: 10.3389/fneur.2023.1154753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 05/10/2023] [Indexed: 06/20/2023] Open
Abstract
Epigenetic mechanisms allow cells to fine-tune gene expression in response to environmental stimuli. For decades, it has been known that mitochondria have genetic material. Still, only recently have studies shown that epigenetic factors regulate mitochondrial DNA (mtDNA) gene expression. Mitochondria regulate cellular proliferation, apoptosis, and energy metabolism, all critical areas of dysfunction in gliomas. Methylation of mtDNA, alterations in mtDNA packaging via mitochondrial transcription factor A (TFAM), and regulation of mtDNA transcription via the micro-RNAs (mir 23-b) and long noncoding RNAs [RNA mitochondrial RNA processing (RMRP)] have all been identified as contributing to glioma pathogenicity. Developing new interventions interfering with these pathways may improve glioma therapy.
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Affiliation(s)
- Clare I. Grady
- Neurosurgery, MedStar Georgetown University Hospital, Washington, DC, United States
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health, Bethesda, MD, United States
| | - Lisa M. Walsh
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health, Bethesda, MD, United States
| | - John D. Heiss
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health, Bethesda, MD, United States
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13
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Identification of Proximity Interactors of Mammalian Nucleoid Proteins by BioID. Methods Mol Biol 2023; 2615:153-172. [PMID: 36807791 DOI: 10.1007/978-1-0716-2922-2_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Mitochondrial nucleoids are compact nucleoprotein complexes, in which mtDNA is located, replicated, and transcribed. Several proteomic approaches have been previously employed to identify nucleoid proteins; however, a consensus list of nucleoid-associated proteins has not been generated. Here we describe a proximity-biotinylation assay, BioID, which allows identification of proximity interactors of mitochondrial nucleoid proteins. It uses a promiscuous biotin ligase fused to a protein of interest which covalently attaches biotin to lysine residues of its proximal neighbors. Biotinylated proteins can be further enriched by a biotin-affinity purification and identified by mass-spectrometry. BioID can identify transient and weak interactions and can be used to identify changes in the interactions upon different cellular treatments, for different protein isoforms or for pathogenic variants.
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14
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D'Amato M, Morra F, Di Meo I, Tiranti V. Mitochondrial Transplantation in Mitochondrial Medicine: Current Challenges and Future Perspectives. Int J Mol Sci 2023; 24:1969. [PMID: 36768312 PMCID: PMC9916997 DOI: 10.3390/ijms24031969] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 01/16/2023] [Accepted: 01/17/2023] [Indexed: 01/20/2023] Open
Abstract
Mitochondrial diseases (MDs) are inherited genetic conditions characterized by pathogenic mutations in nuclear DNA (nDNA) or mitochondrial DNA (mtDNA). Current therapies are still far from being fully effective and from covering the broad spectrum of mutations in mtDNA. For example, unlike heteroplasmic conditions, MDs caused by homoplasmic mtDNA mutations do not yet benefit from advances in molecular approaches. An attractive method of providing dysfunctional cells and/or tissues with healthy mitochondria is mitochondrial transplantation. In this review, we discuss what is known about intercellular transfer of mitochondria and the methods used to transfer mitochondria both in vitro and in vivo, and we provide an outlook on future therapeutic applications. Overall, the transfer of healthy mitochondria containing wild-type mtDNA copies could induce a heteroplasmic shift even when homoplasmic mtDNA variants are present, with the aim of attenuating or preventing the progression of pathological clinical phenotypes. In summary, mitochondrial transplantation is a challenging but potentially ground-breaking option for the treatment of various mitochondrial pathologies, although several questions remain to be addressed before its application in mitochondrial medicine.
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Affiliation(s)
- Marco D'Amato
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20126 Milan, Italy
| | - Francesca Morra
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20126 Milan, Italy
| | - Ivano Di Meo
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20126 Milan, Italy
| | - Valeria Tiranti
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20126 Milan, Italy
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15
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Korchivaia E, Silaeva Y, Mazunin I, Volodyaev I. The mitochondrial challenge: Disorders and prevention strategies. Biosystems 2023; 223:104819. [PMID: 36450320 DOI: 10.1016/j.biosystems.2022.104819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Revised: 11/07/2022] [Accepted: 11/23/2022] [Indexed: 11/29/2022]
Abstract
This short review provides basic knowledge on mitochondrial inheritance, its disorders, and potential ways to overcome them in human reproductive medicine. The latter are currently mostly associated with the so-called mitochondrial replacement (nuclear transfer) procedures, performed at different stages and with slight technical differences. Being promising but obviously highly invasive, these procedures require detailed investigation of their delayed effects on embryogenesis, pregnancy and future health. A special attention is paid to the newest available data on these issues, as well as to their limitations and possible further research directions.
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Affiliation(s)
- Elena Korchivaia
- Department of Embryology, Biological Faculty, Lomonosov Moscow State University, Moscow, Russia.
| | - Yulia Silaeva
- Ministry of Science and Higher Education of the Russian Federation Institute of Gene Biology Russian Academy of Sciences, Moscow, Russia
| | - Ilya Mazunin
- Center for Molecular and Cellular Biology, Skolkovo Institute of Science and Technology (Skoltech), Skolkovo, Russia; Fomin Clinics, Russia; Medical Genomics LLC, Moscow, Russia
| | - Ilya Volodyaev
- Department of Embryology, Biological Faculty, Lomonosov Moscow State University, Moscow, Russia; European Medical Center, Moscow, Russia; ICARM (Interdisciplinary Clinical Association for Reproductive Medicine), Moscow, Russia
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16
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Whitehall JC, Smith ALM, Greaves LC. Mitochondrial DNA Mutations and Ageing. Subcell Biochem 2023; 102:77-98. [PMID: 36600130 DOI: 10.1007/978-3-031-21410-3_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Mitochondria are subcellular organelles present in most eukaryotic cells which play a significant role in numerous aspects of cell biology. These include carbohydrate and fatty acid metabolism to generate cellular energy through oxidative phosphorylation, apoptosis, cell signalling, haem biosynthesis and reactive oxygen species production. Mitochondrial dysfunction is a feature of many human ageing tissues, and since the discovery that mitochondrial DNA mutations were a major underlying cause of changes in oxidative phosphorylation capacity, it has been proposed that they have a role in human ageing. However, there is still much debate on whether mitochondrial DNA mutations play a causal role in ageing or are simply a consequence of the ageing process. This chapter describes the structure of mammalian mitochondria, and the unique features of mitochondrial genetics, and reviews the current evidence surrounding the role of mitochondrial DNA mutations in the ageing process. It then focusses on more recent discoveries regarding the role of mitochondrial dysfunction in stem cell ageing and age-related inflammation.
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Affiliation(s)
- Julia C Whitehall
- Wellcome Centre for Mitochondrial Research, Biosciences Institute, Newcastle University, Newcastle Upon Tyne, UK
| | - Anna L M Smith
- Wellcome Centre for Mitochondrial Research, Biosciences Institute, Newcastle University, Newcastle Upon Tyne, UK
| | - Laura C Greaves
- Wellcome Centre for Mitochondrial Research, Biosciences Institute, Newcastle University, Newcastle Upon Tyne, UK.
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17
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Peng GX, Mao XL, Cao Y, Yao SY, Li QR, Chen X, Wang ED, Zhou XL. RNA granule-clustered mitochondrial aminoacyl-tRNA synthetases form multiple complexes with the potential to fine-tune tRNA aminoacylation. Nucleic Acids Res 2022; 50:12951-12968. [PMID: 36503967 PMCID: PMC9825176 DOI: 10.1093/nar/gkac1141] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 10/23/2022] [Accepted: 11/15/2022] [Indexed: 12/14/2022] Open
Abstract
Mitochondrial RNA metabolism is suggested to occur in identified compartmentalized foci, i.e. mitochondrial RNA granules (MRGs). Mitochondrial aminoacyl-tRNA synthetases (mito aaRSs) catalyze tRNA charging and are key components in mitochondrial gene expression. Mutations of mito aaRSs are associated with various human disorders. However, the suborganelle distribution, interaction network and regulatory mechanism of mito aaRSs remain largely unknown. Here, we found that all mito aaRSs partly colocalize with MRG, and this colocalization is likely facilitated by tRNA-binding capacity. A fraction of human mitochondrial AlaRS (hmtAlaRS) and hmtSerRS formed a direct complex via interaction between catalytic domains in vivo. Aminoacylation activities of both hmtAlaRS and hmtSerRS were fine-tuned upon complex formation in vitro. We further established a full spectrum of interaction networks via immunoprecipitation and mass spectrometry for all mito aaRSs and discovered interactions between hmtSerRS and hmtAsnRS, between hmtSerRS and hmtTyrRS and between hmtThrRS and hmtArgRS. The activity of hmtTyrRS was also influenced by the presence of hmtSerRS. Notably, hmtSerRS utilized the same catalytic domain in mediating several interactions. Altogether, our results systematically analyzed the suborganelle localization and interaction network of mito aaRSs and discovered several mito aaRS-containing complexes, deepening our understanding of the functional and regulatory mechanisms of mito aaRSs.
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Affiliation(s)
| | | | - Yating Cao
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, China
| | - Shi-Ying Yao
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China
| | - Qing-Run Li
- CAS Key Laboratory of Systems Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China
| | - Xin Chen
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen 361102, China
| | - En-Duo Wang
- Correspondence may also be addressed to En-Duo Wang. Tel: +86 21 5492 1241; Fax: +86 21 5492 1011;
| | - Xiao-Long Zhou
- To whom correspondence should be addressed. Tel: +86 21 5492 1247; Fax: +86 21 5492 1011;
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18
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Vantaggiato L, Shaba E, Carleo A, Bezzini D, Pannuzzo G, Luddi A, Piomboni P, Bini L, Bianchi L. Neurodegenerative Disorder Risk in Krabbe Disease Carriers. Int J Mol Sci 2022; 23:13537. [PMID: 36362324 PMCID: PMC9654610 DOI: 10.3390/ijms232113537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 10/26/2022] [Accepted: 10/30/2022] [Indexed: 11/09/2022] Open
Abstract
Krabbe disease (KD) is a rare autosomal recessive disorder caused by mutations in the galactocerebrosidase gene (GALC). Defective GALC causes aberrant metabolism of galactolipids present almost exclusively in myelin, with consequent demyelinization and neurodegeneration of the central and peripheral nervous system (NS). KD shares some similar features with other neuropathies and heterozygous carriers of GALC mutations are emerging with an increased risk in developing NS disorders. In this work, we set out to identify possible variations in the proteomic profile of KD-carrier brain to identify altered pathways that may imbalance its homeostasis and that may be associated with neurological disorders. The differential analysis performed on whole brains from 33-day-old twitcher (galc -/-), heterozygous (galc +/-), and wild-type mice highlighted the dysregulation of several multifunctional factors in both heterozygous and twitcher mice. Notably, the KD-carrier mouse, despite its normal phenotype, presents the deregulation of vimentin, receptor of activated protein C kinase 1 (RACK1), myelin basic protein (MBP), 2',3'-cyclic-nucleotide 3'-phosphodiesterase (CNP), transitional endoplasmic reticulum ATPase (VCP), and N-myc downstream regulated gene 1 protein (NDRG1) as well as changes in the ubiquitinated-protein pattern. Our findings suggest the carrier may be affected by dysfunctions classically associated with neurodegeneration: (i) alteration of (mechano) signaling and intracellular trafficking, (ii) a generalized affection of proteostasis and lipid metabolism, with possible defects in myelin composition and turnover, and (iii) mitochondrion and energy supply dysfunctions.
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Affiliation(s)
- Lorenza Vantaggiato
- Functional Proteomics Laboratory, Department of Life Sciences, University of Siena, 53100 Siena, Italy
| | - Enxhi Shaba
- Functional Proteomics Laboratory, Department of Life Sciences, University of Siena, 53100 Siena, Italy
| | - Alfonso Carleo
- Department of Pulmonology, Hannover Medical School, Carl-Neuberg-Straße 1, 30625 Hannover, Germany
| | - Daiana Bezzini
- Department of Life Sciences, University of Siena, 53100 Siena, Italy
| | - Giovanna Pannuzzo
- Department of Biochemical and Biotechnological Sciences, Section of Physiology, University of Catania, 95121 Catania, Italy
| | - Alice Luddi
- Department of Molecular and Developmental Medicine, University of Siena, 53100 Siena, Italy
| | - Paola Piomboni
- Department of Molecular and Developmental Medicine, University of Siena, 53100 Siena, Italy
| | - Luca Bini
- Functional Proteomics Laboratory, Department of Life Sciences, University of Siena, 53100 Siena, Italy
| | - Laura Bianchi
- Functional Proteomics Laboratory, Department of Life Sciences, University of Siena, 53100 Siena, Italy
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19
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Sharma N, Thompson MK, Arrington JF, Terry DM, Chakravarthy S, Prevelige PE, Prakash A. Novel interaction interfaces mediate the interaction between the NEIL1 DNA glycosylase and mitochondrial transcription factor A. Front Cell Dev Biol 2022; 10:893806. [PMID: 35938152 PMCID: PMC9354671 DOI: 10.3389/fcell.2022.893806] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 07/01/2022] [Indexed: 02/01/2023] Open
Abstract
The maintenance of human mitochondrial DNA (mtDNA) is critical for proper cellular function as damage to mtDNA, if left unrepaired, can lead to a diverse array of pathologies. Of the pathways identified to participate in DNA repair within the mitochondria, base excision repair (BER) is the most extensively studied. Protein-protein interactions drive the step-by-step coordination required for the successful completion of this pathway and are important for crosstalk with other mitochondrial factors involved in genome maintenance. Human NEIL1 is one of seven DNA glycosylases that initiates BER in both the nuclear and mitochondrial compartments. In the current work, we scrutinized the interaction between NEIL1 and mitochondrial transcription factor A (TFAM), a protein that is essential for various aspects of mtDNA metabolism. We note, for the first time, that both the N- and C- terminal domains of NEIL1 interact with TFAM revealing a unique NEIL1 protein-binding interface. The interaction between the two proteins, as observed biochemically, appears to be transient and is most apparent at concentrations of low salt. The presence of DNA (or RNA) also positively influences the interaction between the two proteins, and molar mass estimates indicate that duplex DNA is required for complex formation at higher salt concentrations. Hydrogen deuterium exchange mass spectrometry data reveal that both proteins exchange less deuterium upon DNA binding, indicative of an interaction, and the addition of NEIL1 to the TFAM-DNA complex alters the interaction landscape. The transcriptional activity of TFAM appears to be independent of NEIL1 expression under normal cellular conditions, however, in the presence of DNA damage, we observe a significant reduction in the mRNA expression of TFAM-transcribed mitochondrial genes in the absence of NEIL1. Overall, our data indicate that the interaction between NEIL1 and TFAM can be modulated by local environment such as salt concentrations, protein availability, the presence of nucleic acids, as well as the presence of DNA damage.
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Affiliation(s)
- Nidhi Sharma
- Department of Biochemistry and Molecular Biology, Mitchell Cancer Institute, University of South Alabama, Mobile, AL, United States
| | - Marlo K. Thompson
- Department of Biochemistry and Molecular Biology, Mitchell Cancer Institute, University of South Alabama, Mobile, AL, United States
| | - Jennifer F. Arrington
- Department of Biochemistry and Molecular Biology, Mitchell Cancer Institute, University of South Alabama, Mobile, AL, United States
| | - Dava M. Terry
- Department of Biochemistry and Molecular Biology, Mitchell Cancer Institute, University of South Alabama, Mobile, AL, United States
| | - Srinivas Chakravarthy
- Advanced Photon Source, Illinois Institute of Technology, Chicago, IL, United States
| | - Peter E. Prevelige
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Aishwarya Prakash
- Department of Biochemistry and Molecular Biology, Mitchell Cancer Institute, University of South Alabama, Mobile, AL, United States
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20
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Roy A, Kandettu A, Ray S, Chakrabarty S. Mitochondrial DNA replication and repair defects: Clinical phenotypes and therapeutic interventions. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2022; 1863:148554. [PMID: 35341749 DOI: 10.1016/j.bbabio.2022.148554] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 03/06/2022] [Accepted: 03/16/2022] [Indexed: 12/15/2022]
Abstract
Mitochondria is a unique cellular organelle involved in multiple cellular processes and is critical for maintaining cellular homeostasis. This semi-autonomous organelle contains its circular genome - mtDNA (mitochondrial DNA), that undergoes continuous cycles of replication and repair to maintain the mitochondrial genome integrity. The majority of the mitochondrial genes, including mitochondrial replisome and repair genes, are nuclear-encoded. Although the repair machinery of mitochondria is quite efficient, the mitochondrial genome is highly susceptible to oxidative damage and other types of exogenous and endogenous agent-induced DNA damage, due to the absence of protective histones and their proximity to the main ROS production sites. Mutations in replication and repair genes of mitochondria can result in mtDNA depletion and deletions subsequently leading to mitochondrial genome instability. The combined action of mutations and deletions can result in compromised mitochondrial genome maintenance and lead to various mitochondrial disorders. Here, we review the mechanism of mitochondrial DNA replication and repair process, key proteins involved, and their altered function in mitochondrial disorders. The focus of this review will be on the key genes of mitochondrial DNA replication and repair machinery and the clinical phenotypes associated with mutations in these genes.
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Affiliation(s)
- Abhipsa Roy
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Amoolya Kandettu
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Swagat Ray
- Department of Life Sciences, School of Life and Environmental Sciences, University of Lincoln, Lincoln LN6 7TS, United Kingdom
| | - Sanjiban Chakrabarty
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India.
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21
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Coordination of mitochondrial and nuclear gene expression regulation in health, evolution and disease. CURRENT OPINION IN PHYSIOLOGY 2022. [DOI: 10.1016/j.cophys.2022.100554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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22
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The fate of damaged mitochondrial DNA in the cell. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2022; 1869:119233. [PMID: 35131372 DOI: 10.1016/j.bbamcr.2022.119233] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 01/25/2022] [Accepted: 01/31/2022] [Indexed: 12/12/2022]
Abstract
Mitochondrion is a double membrane organelle that is responsible for cellular respiration and production of most of the ATP in eukaryotic cells. Mitochondrial DNA (mtDNA) is the genetic material carried by mitochondria, which encodes some essential subunits of respiratory complexes independent of nuclear DNA. Normally, mtDNA binds to certain proteins to form a nucleoid that is stable in mitochondria. Nevertheless, a variety of physiological or pathological stresses can cause mtDNA damage, and the accumulation of damaged mtDNA in mitochondria leads to mitochondrial dysfunction, which triggers the occurrence of mitochondrial diseases in vivo. In response to mtDNA damage, cell initiates multiple pathways including mtDNA repair, degradation, clearance and release, to recover mtDNA, and maintain mitochondrial quality and cell homeostasis. In this review, we provide our current understanding of the fate of damaged mtDNA, focus on the pathways and mechanisms of removing damaged mtDNA in the cell.
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23
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Chihanga T, Vicente-Muñoz S, Ruiz-Torres S, Pal B, Sertorio M, Andreassen PR, Khoury R, Mehta P, Davies SM, Lane AN, Romick-Rosendale LE, Wells SI. Head and Neck Cancer Susceptibility and Metabolism in Fanconi Anemia. Cancers (Basel) 2022; 14:cancers14082040. [PMID: 35454946 PMCID: PMC9025423 DOI: 10.3390/cancers14082040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 04/05/2022] [Accepted: 04/11/2022] [Indexed: 02/06/2023] Open
Abstract
Fanconi anemia (FA) is a rare inherited, generally autosomal recessive syndrome, but it displays X-linked or dominant negative inheritance for certain genes. FA is characterized by a deficiency in DNA damage repair that results in bone marrow failure, and in an increased risk for various epithelial tumors, most commonly squamous cell carcinomas of the head and neck (HNSCC) and of the esophagus, anogenital tract and skin. Individuals with FA exhibit increased human papilloma virus (HPV) prevalence. Furthermore, a subset of anogenital squamous cell carcinomas (SCCs) in FA harbor HPV sequences and FA-deficient laboratory models reveal molecular crosstalk between HPV and FA proteins. However, a definitive role for HPV in HNSCC development in the FA patient population is unproven. Cellular metabolism plays an integral role in tissue homeostasis, and metabolic deregulation is a known hallmark of cancer progression that supports uncontrolled proliferation, tumor development and metastatic dissemination. The metabolic consequences of FA deficiency in keratinocytes and associated impact on the development of SCC in the FA population is poorly understood. Herein, we review the current literature on the metabolic consequences of FA deficiency and potential effects of resulting metabolic reprogramming on FA cancer phenotypes.
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Affiliation(s)
- Tafadzwa Chihanga
- Division of Oncology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA; (T.C.); (S.R.-T.); (B.P.)
| | - Sara Vicente-Muñoz
- Department of Pathology and Laboratory Medicine, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA; (S.V.-M.); (L.E.R.-R.)
| | - Sonya Ruiz-Torres
- Division of Oncology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA; (T.C.); (S.R.-T.); (B.P.)
| | - Bidisha Pal
- Division of Oncology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA; (T.C.); (S.R.-T.); (B.P.)
| | - Mathieu Sertorio
- Department of Radiation Oncology, College of Medicine, University of Cincinnati, Cincinnati, OH 45229, USA;
| | - Paul R. Andreassen
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA;
| | - Ruby Khoury
- Division of Bone Marrow Transplantation and Immune Deficiency, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA; (R.K.); (P.M.); (S.M.D.)
| | - Parinda Mehta
- Division of Bone Marrow Transplantation and Immune Deficiency, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA; (R.K.); (P.M.); (S.M.D.)
| | - Stella M. Davies
- Division of Bone Marrow Transplantation and Immune Deficiency, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA; (R.K.); (P.M.); (S.M.D.)
| | - Andrew N. Lane
- Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, KY 40536, USA;
| | - Lindsey E. Romick-Rosendale
- Department of Pathology and Laboratory Medicine, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA; (S.V.-M.); (L.E.R.-R.)
| | - Susanne I. Wells
- Division of Oncology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA; (T.C.); (S.R.-T.); (B.P.)
- Correspondence: ; Tel.: +1-513-636-5986
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24
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Hernández-Cruz EY, Amador-Martínez I, Aranda-Rivera AK, Cruz-Gregorio A, Pedraza Chaverri J. Renal damage induced by cadmium and its possible therapy by mitochondrial transplantation. Chem Biol Interact 2022; 361:109961. [DOI: 10.1016/j.cbi.2022.109961] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 04/05/2022] [Accepted: 04/22/2022] [Indexed: 12/14/2022]
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25
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Kim M, Schulz V, Brings L, Schoeller T, Kühn K, Vierling E. mTERF18 and ATAD3 are required for mitochondrial nucleoid structure and their disruption confers heat tolerance in Arabidopsis thaliana. THE NEW PHYTOLOGIST 2021; 232:2026-2042. [PMID: 34482561 DOI: 10.1111/nph.17717] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 08/23/2021] [Indexed: 05/27/2023]
Abstract
Mitochondria play critical roles in generating ATP through oxidative phosphorylation (OXPHOS) and produce both damaging and signaling reactive oxygen species (ROS). They have reduced genomes that encode essential subunits of the OXPHOS machinery. Mitochondrial Transcription tERmination Factor-related (mTERF) proteins are involved in organelle gene expression, interacting with organellar DNA or RNA. We previously found that mutations in Arabidopsis thaliana mTERF18/SHOT1 enable plants to better tolerate heat and oxidative stresses, presumably due to low ROS production and reduced oxidative damage. Here we discover that shot1 mutants have greatly reduced OXPHOS complexes I and IV and reveal that suppressor of hot1-4 1 (SHOT1) binds DNA and localizes to mitochondrial nucleoids, which are disrupted in shot1. Furthermore, three homologues of animal ATPase family AAA domain-containing protein 3 (ATAD3), which is involved in mitochondrial nucleoid organization, were identified as SHOT1-interacting proteins. Importantly, disrupting ATAD3 function disrupts nucleoids, reduces accumulation of complex I, and enhances heat tolerance, as is seen in shot1 mutants. Our data link nucleoid organization to OXPHOS biogenesis and suggest that the common defects in shot1 mutants and ATAD3-disrupted plants lead to critical changes in mitochondrial metabolism and signaling that result in plant heat tolerance.
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Affiliation(s)
- Minsoo Kim
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA, 01003, USA
| | - Vincent Schulz
- Department of Life Sciences, Institute of Biology, Humboldt-Universität zu Berlin, 10099, Berlin, Germany
| | - Lea Brings
- Department of Life Sciences, Institute of Biology, Humboldt-Universität zu Berlin, 10099, Berlin, Germany
| | - Theresa Schoeller
- Department of Plant Physiology, Institute of Biology, Martin-Luther-Universität Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Kristina Kühn
- Department of Life Sciences, Institute of Biology, Humboldt-Universität zu Berlin, 10099, Berlin, Germany
- Department of Plant Physiology, Institute of Biology, Martin-Luther-Universität Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Elizabeth Vierling
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA, 01003, USA
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Brüser C, Keller-Findeisen J, Jakobs S. The TFAM-to-mtDNA ratio defines inner-cellular nucleoid populations with distinct activity levels. Cell Rep 2021; 37:110000. [PMID: 34818548 DOI: 10.1016/j.celrep.2021.110000] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 09/20/2021] [Accepted: 10/22/2021] [Indexed: 11/30/2022] Open
Abstract
In human cells, generally a single mitochondrial DNA (mtDNA) is compacted into a nucleoprotein complex denoted the nucleoid. Each cell contains hundreds of nucleoids, which tend to cluster into small groups. It is unknown whether all nucleoids are equally involved in mtDNA replication and transcription or whether distinct nucleoid subpopulations exist. Here, we use multi-color STED super-resolution microscopy to determine the activity of individual nucleoids in primary human cells. We demonstrate that only a minority of all nucleoids are active. Active nucleoids are physically larger and tend to be involved in both replication and transcription. Inactivity correlates with a high ratio of the mitochondrial transcription factor A (TFAM) to the mtDNA of the individual nucleoid, suggesting that TFAM-induced nucleoid compaction regulates nucleoid replication and transcription activity in vivo. We propose that the stable population of highly compacted inactive nucleoids represents a storage pool of mtDNAs with a lower mutational load.
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Affiliation(s)
- Christian Brüser
- Department of NanoBiophotonics, Research Group Mitochondrial Structure and Dynamics, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany; Clinic of Neurology, High Resolution Microscopy of the Cell, University Medical Center Göttingen, 37075 Göttingen, Germany
| | - Jan Keller-Findeisen
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Stefan Jakobs
- Department of NanoBiophotonics, Research Group Mitochondrial Structure and Dynamics, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany; Clinic of Neurology, High Resolution Microscopy of the Cell, University Medical Center Göttingen, 37075 Göttingen, Germany; Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Translational Neuroinflammation and Automated Microscopy, 37075 Göttingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany.
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27
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Phase separation drives the self-assembly of mitochondrial nucleoids for transcriptional modulation. Nat Struct Mol Biol 2021; 28:900-908. [PMID: 34711968 DOI: 10.1038/s41594-021-00671-w] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 09/14/2021] [Indexed: 11/08/2022]
Abstract
Mitochondria, the only semiautonomous organelles in mammalian cells, possess a circular, double-stranded genome termed mitochondrial DNA (mtDNA). While nuclear genomic DNA compaction, chromatin compartmentalization and transcription are known to be regulated by phase separation, how the mitochondrial nucleoid, a highly compacted spherical suborganelle, is assembled and functions is unknown. Here we assembled mitochondrial nucleoids in vitro and show that mitochondrial transcription factor A (TFAM) undergoes phase separation with mtDNA to drive nucleoid self-assembly. Moreover, nucleoid droplet formation promotes recruitment of the transcription machinery via a special, co-phase separation that concentrates transcription initiation, elongation and termination factors, and retains substrates to facilitate mtDNA transcription. We propose a model of mitochondrial nucleoid self-assembly driven by phase separation, and a pattern of co-phase separation involved in mitochondrial transcriptional regulation, which orchestrates the roles of TFAM in both mitochondrial nucleoid organization and transcription.
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28
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Allkanjari K, Baldock RA. Beyond base excision repair: an evolving picture of mitochondrial DNA repair. Biosci Rep 2021; 41:BSR20211320. [PMID: 34608928 PMCID: PMC8527207 DOI: 10.1042/bsr20211320] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 09/29/2021] [Accepted: 10/04/2021] [Indexed: 12/11/2022] Open
Abstract
Mitochondria are highly specialised organelles required for key cellular processes including ATP production through cellular respiration and controlling cell death via apoptosis. Unlike other organelles, mitochondria contain their own DNA genome which encodes both protein and RNA required for cellular respiration. Each cell may contain hundreds to thousands of copies of the mitochondrial genome, which is essential for normal cellular function - deviation of mitochondrial DNA (mtDNA) copy number is associated with cellular ageing and disease. Furthermore, mtDNA lesions can arise from both endogenous or exogenous sources and must either be tolerated or corrected to preserve mitochondrial function. Importantly, replication of damaged mtDNA can lead to stalling and introduction of mutations or genetic loss, mitochondria have adapted mechanisms to repair damaged DNA. These mechanisms rely on nuclear-encoded DNA repair proteins that are translocated into the mitochondria. Despite the presence of many known nuclear DNA repair proteins being found in the mitochondrial proteome, it remains to be established which DNA repair mechanisms are functional in mammalian mitochondria. Here, we summarise the existing and emerging research, alongside examining proteomic evidence, demonstrating that mtDNA damage can be repaired using Base Excision Repair (BER), Homologous Recombination (HR) and Microhomology-mediated End Joining (MMEJ). Critically, these repair mechanisms do not operate in isolation and evidence for interplay between pathways and repair associated with replication is discussed. Importantly, characterising non-canonical functions of key proteins and understanding the bespoke pathways used to tolerate, repair or bypass DNA damage will be fundamental in fully understanding the causes of mitochondrial genome mutations and mitochondrial dysfunction.
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Affiliation(s)
- Kathrin Allkanjari
- Formerly: Solent University Southampton, East Park Terrace, Southampton, SO14 0YN, UK
| | - Robert A. Baldock
- School of Natural and Social Sciences, University of Gloucestershire, Francis Close Hall, Swindon Road, Cheltenham GL50 4AZ, UK
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29
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The Role of Mitochondria in Oocyte Maturation. Cells 2021; 10:cells10092484. [PMID: 34572133 PMCID: PMC8469615 DOI: 10.3390/cells10092484] [Citation(s) in RCA: 112] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 09/09/2021] [Accepted: 09/16/2021] [Indexed: 12/13/2022] Open
Abstract
With the nucleus as an exception, mitochondria are the only animal cell organelles containing their own genetic information, called mitochondrial DNA (mtDNA). During oocyte maturation, the mtDNA copy number dramatically increases and the distribution of mitochondria changes significantly. As oocyte maturation requires a large amount of ATP for continuous transcription and translation, the availability of the right number of functional mitochondria is crucial. There is a correlation between the quality of oocytes and both the amount of mtDNA and the amount of ATP. Suboptimal conditions of in vitro maturation (IVM) might lead to changes in the mitochondrial morphology as well as alternations in the expression of genes encoding proteins associated with mitochondrial function. Dysfunctional mitochondria have a lower ability to counteract reactive oxygen species (ROS) production which leads to oxidative stress. The mitochondrial function might be improved with the application of antioxidants and significant expectations are laid on the development of new IVM systems supplemented with mitochondria-targeted reagents. Different types of antioxidants have been tested already on animal models and human rescue IVM oocytes, showing promising results. This review focuses on the recent observations on oocytes’ intracellular mitochondrial distribution and on mitochondrial genomes during their maturation, both in vivo and in vitro. Recent mitochondrial supplementation studies, aiming to improve oocyte developmental potential, are summarized.
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Kaur P, Pan H, Longley MJ, Copeland WC, Wang H. Using Atomic Force Microscopy to Study the Real Time Dynamics of DNA Unwinding by Mitochondrial Twinkle Helicase. Bio Protoc 2021; 11:e4139. [PMID: 34604445 DOI: 10.21769/bioprotoc.4139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 05/23/2021] [Accepted: 06/29/2021] [Indexed: 12/06/2022] Open
Abstract
Understanding the structure and dynamics of DNA-protein interactions during DNA replication is crucial for elucidating the origins of disorders arising from its dysfunction. In this study, we employed Atomic Force Microscopy as a single-molecule imaging tool to examine the mitochondrial DNA helicase Twinkle and its interactions with DNA. We used imaging in air and time-lapse imaging in liquids to observe the DNA binding and unwinding activities of Twinkle hexamers at the single-molecule level. These procedures helped us visualize Twinkle loading onto and unloading from the DNA in the open-ring conformation. Using traditional methods, it has been shown that Twinkle is capable of unwinding dsDNA up to 20-55 bps. We found that the addition of mitochondrial single-stranded DNA binding protein (mtSSB) facilitates a 5-fold increase in the DNA unwinding rate for the Twinkle helicase. The protocols developed in this study provide new platforms to examine DNA replication and to explore the mechanism driving DNA deletion and human diseases. Graphic abstract: Mitochondrial Twinkle Helicase Dynamics.
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Affiliation(s)
- Parminder Kaur
- Physics Department, North Carolina State University, Raleigh, North Carolina, USA.,Center for Human Health and the Environment, North Carolina State University, Raleigh, North Carolina, USA
| | - Hai Pan
- Physics Department, North Carolina State University, Raleigh, North Carolina, USA
| | - Matthew J Longley
- Genome Integrity and Structural Biology Laboratory, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - William C Copeland
- Genome Integrity and Structural Biology Laboratory, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - Hong Wang
- Physics Department, North Carolina State University, Raleigh, North Carolina, USA.,Center for Human Health and the Environment, North Carolina State University, Raleigh, North Carolina, USA.,Toxicology Program, North Carolina State University, Raleigh, North Carolina, USA
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31
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Xavier VJ, Martinou JC. RNA Granules in the Mitochondria and Their Organization under Mitochondrial Stresses. Int J Mol Sci 2021; 22:9502. [PMID: 34502411 PMCID: PMC8431320 DOI: 10.3390/ijms22179502] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 08/25/2021] [Accepted: 08/27/2021] [Indexed: 12/25/2022] Open
Abstract
The human mitochondrial genome (mtDNA) regulates its transcription products in specialised and distinct ways as compared to nuclear transcription. Thanks to its mtDNA mitochondria possess their own set of tRNAs, rRNAs and mRNAs that encode a subset of the protein subunits of the electron transport chain complexes. The RNA regulation within mitochondria is organised within specialised, membraneless, compartments of RNA-protein complexes, called the Mitochondrial RNA Granules (MRGs). MRGs were first identified to contain nascent mRNA, complexed with many proteins involved in RNA processing and maturation and ribosome assembly. Most recently, double-stranded RNA (dsRNA) species, a hybrid of the two complementary mRNA strands, were found to form granules in the matrix of mitochondria. These RNA granules are therefore components of the mitochondrial post-transcriptional pathway and as such play an essential role in mitochondrial gene expression. Mitochondrial dysfunctions in the form of, for example, RNA processing or RNA quality control defects, or inhibition of mitochondrial fission, can cause the loss or the aberrant accumulation of these RNA granules. These findings underline the important link between mitochondrial maintenance and the efficient expression of its genome.
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Affiliation(s)
| | - Jean-Claude Martinou
- Department of Cell Biology, Faculty of Sciences, University of Geneva, 1205 Geneva, Switzerland;
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Menger KE, Rodríguez-Luis A, Chapman J, Nicholls TJ. Controlling the topology of mammalian mitochondrial DNA. Open Biol 2021; 11:210168. [PMID: 34547213 PMCID: PMC8455175 DOI: 10.1098/rsob.210168] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The genome of mitochondria, called mtDNA, is a small circular DNA molecule present at thousands of copies per human cell. MtDNA is packaged into nucleoprotein complexes called nucleoids, and the density of mtDNA packaging affects mitochondrial gene expression. Genetic processes such as transcription, DNA replication and DNA packaging alter DNA topology, and these topological problems are solved by a family of enzymes called topoisomerases. Within mitochondria, topoisomerases are involved firstly in the regulation of mtDNA supercoiling and secondly in disentangling interlinked mtDNA molecules following mtDNA replication. The loss of mitochondrial topoisomerase activity leads to defects in mitochondrial function, and variants in the dual-localized type IA topoisomerase TOP3A have also been reported to cause human mitochondrial disease. We review the current knowledge on processes that alter mtDNA topology, how mtDNA topology is modulated by the action of topoisomerases, and the consequences of altered mtDNA topology for mitochondrial function and human health.
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Affiliation(s)
- Katja E. Menger
- Wellcome Centre for Mitochondrial Research, Biosciences Institute, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Alejandro Rodríguez-Luis
- Wellcome Centre for Mitochondrial Research, Biosciences Institute, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - James Chapman
- Wellcome Centre for Mitochondrial Research, Biosciences Institute, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Thomas J. Nicholls
- Wellcome Centre for Mitochondrial Research, Biosciences Institute, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
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33
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Machado de Amorim A, Chakrabarti S. Assembly of multicomponent machines in RNA metabolism: A common theme in mRNA decay pathways. WILEY INTERDISCIPLINARY REVIEWS-RNA 2021; 13:e1684. [PMID: 34351053 DOI: 10.1002/wrna.1684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 07/07/2021] [Accepted: 07/08/2021] [Indexed: 11/05/2022]
Abstract
Multicomponent protein-RNA complexes comprising a ribonuclease and partner RNA helicase facilitate the turnover of mRNA in all domains of life. While these higher-order complexes provide an effective means of physically and functionally coupling the processes of RNA remodeling and decay, most ribonucleases and RNA helicases do not exhibit sequence specificity in RNA binding. This raises the question as to how these assemblies select substrates for processing and how the activities are orchestrated at the precise moment to ensure efficient decay. The answers to these apparent puzzles lie in the auxiliary components of the assemblies that might relay decay-triggering signals. Given their function within the assemblies, these components may be viewed as "sensors." The functions and mechanisms of action of the sensor components in various degradation complexes in bacteria and eukaryotes are highlighted here to discuss their roles in RNA decay processes. This article is categorized under: RNA Turnover and Surveillance > Regulation of RNA Stability RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms RNA Interactions with Proteins and Other Molecules > Protein-RNA Recognition.
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Affiliation(s)
| | - Sutapa Chakrabarti
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany
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34
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Mitochondrial HSP70 Chaperone System-The Influence of Post-Translational Modifications and Involvement in Human Diseases. Int J Mol Sci 2021; 22:ijms22158077. [PMID: 34360841 PMCID: PMC8347752 DOI: 10.3390/ijms22158077] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 07/23/2021] [Accepted: 07/26/2021] [Indexed: 01/25/2023] Open
Abstract
Since their discovery, heat shock proteins (HSPs) have been identified in all domains of life, which demonstrates their importance and conserved functional role in maintaining protein homeostasis. Mitochondria possess several members of the major HSP sub-families that perform essential tasks for keeping the organelle in a fully functional and healthy state. In humans, the mitochondrial HSP70 chaperone system comprises a central molecular chaperone, mtHSP70 or mortalin (HSPA9), which is actively involved in stabilizing and importing nuclear gene products and in refolding mitochondrial precursor proteins, and three co-chaperones (HSP70-escort protein 1-HEP1, tumorous imaginal disc protein 1-TID-1, and Gro-P like protein E-GRPE), which regulate and accelerate its protein folding functions. In this review, we summarize the roles of mitochondrial molecular chaperones with particular focus on the human mtHsp70 and its co-chaperones, whose deregulated expression, mutations, and post-translational modifications are often considered to be the main cause of neurological disorders, genetic diseases, and malignant growth.
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35
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He L, Xiong K, Wang L, Guan R, Chen Y, Ji L, Chao H. Iridium(iii) complexes as mitochondrial topoisomerase inhibitors against cisplatin-resistant cancer cells. Chem Commun (Camb) 2021; 57:8308-8311. [PMID: 34319315 DOI: 10.1039/d1cc02178h] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Herein, we developed the first metal-based mitochondrial topoisomerase inhibitors to achieve an effective therapeutic outcome for the therapy of cisplatin-resistant tumour cells.
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Affiliation(s)
- Liting He
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry, Sun Yat-Sen University, Guangzhou, 510275, P. R. China.
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36
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Lenaers G, Neutzner A, Le Dantec Y, Jüschke C, Xiao T, Decembrini S, Swirski S, Kieninger S, Agca C, Kim US, Reynier P, Yu-Wai-Man P, Neidhardt J, Wissinger B. Dominant optic atrophy: Culprit mitochondria in the optic nerve. Prog Retin Eye Res 2021; 83:100935. [PMID: 33340656 DOI: 10.1016/j.preteyeres.2020.100935] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 12/05/2020] [Accepted: 12/09/2020] [Indexed: 12/14/2022]
Abstract
Dominant optic atrophy (DOA) is an inherited mitochondrial disease leading to specific degeneration of retinal ganglion cells (RGCs), thus compromising transmission of visual information from the retina to the brain. Usually, DOA starts during childhood and evolves to poor vision or legal blindness, affecting the central vision, whilst sparing the peripheral visual field. In 20% of cases, DOA presents as syndromic disorder, with secondary symptoms affecting neuronal and muscular functions. Twenty years ago, we demonstrated that heterozygous mutations in OPA1 are the most frequent molecular cause of DOA. Since then, variants in additional genes, whose functions in many instances converge with those of OPA1, have been identified by next generation sequencing. OPA1 encodes a dynamin-related GTPase imported into mitochondria and located to the inner membrane and intermembrane space. The many OPA1 isoforms, resulting from alternative splicing of three exons, form complex homopolymers that structure mitochondrial cristae, and contribute to fusion of the outer membrane, thus shaping the whole mitochondrial network. Moreover, OPA1 is required for oxidative phosphorylation, maintenance of mitochondrial genome, calcium homeostasis and regulation of apoptosis, thus making OPA1 the Swiss army-knife of mitochondria. Understanding DOA pathophysiology requires the understanding of RGC peculiarities with respect to OPA1 functions. Besides the tremendous energy requirements of RGCs to relay visual information from the eye to the brain, these neurons present unique features related to their differential environments in the retina, and to the anatomical transition occurring at the lamina cribrosa, which parallel major adaptations of mitochondrial physiology and shape, in the pre- and post-laminar segments of the optic nerve. Three DOA mouse models, with different Opa1 mutations, have been generated to study intrinsic mechanisms responsible for RGC degeneration, and these have further revealed secondary symptoms related to mitochondrial dysfunctions, mirroring the more severe syndromic phenotypes seen in a subgroup of patients. Metabolomics analyses of cells, mouse organs and patient plasma mutated for OPA1 revealed new unexpected pathophysiological mechanisms related to mitochondrial dysfunction, and biomarkers correlated quantitatively to the severity of the disease. Here, we review and synthesize these data, and propose different approaches for embracing possible therapies to fulfil the unmet clinical needs of this disease, and provide hope to affected DOA patients.
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Affiliation(s)
- Guy Lenaers
- MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, Angers University and Hospital, Angers, France.
| | - Albert Neutzner
- Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland; Department of Ophthalmology University Hospital Basel, University of Basel, Basel, Switzerland.
| | - Yannick Le Dantec
- MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, Angers University and Hospital, Angers, France
| | - Christoph Jüschke
- Human Genetics, Faculty VI - School of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany
| | - Ting Xiao
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Center for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Sarah Decembrini
- Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland; Department of Ophthalmology University Hospital Basel, University of Basel, Basel, Switzerland
| | - Sebastian Swirski
- Human Genetics, Faculty VI - School of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany
| | - Sinja Kieninger
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Center for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Cavit Agca
- Molecular Biology, Genetics and Bioengineering Program, Sabanci University, Istanbul, Turkey; Nanotechnology Research and Application Center (SUNUM), Sabanci University, Istanbul, Turkey
| | - Ungsoo S Kim
- Kim's Eye Hospital, Seoul, South Korea; Cambridge Centre for Brain Repair and MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK; Cambridge Eye Unit, Addenbrooke's Hospital, Cambridge University Hospitals, Cambridge, UK; Moorfields Eye Hospital, London, UK
| | - Pascal Reynier
- MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, Angers University and Hospital, Angers, France; Department of Biochemistry, University Hospital of Angers, Angers, France
| | - Patrick Yu-Wai-Man
- Cambridge Centre for Brain Repair and MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK; Cambridge Eye Unit, Addenbrooke's Hospital, Cambridge University Hospitals, Cambridge, UK; Moorfields Eye Hospital, London, UK; UCL Institute of Ophthalmology, University College London, London, UK
| | - John Neidhardt
- Human Genetics, Faculty VI - School of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany; Research Center Neurosensory Science, University Oldenburg, Oldenburg, Germany.
| | - Bernd Wissinger
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Center for Ophthalmology, University of Tübingen, Tübingen, Germany.
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Wang LJ, Hsu T, Lin HL, Fu CY. Modulation of mitochondrial nucleoid structure during aging and by mtDNA content in Drosophila. Biol Open 2021; 10:269285. [PMID: 34180963 PMCID: PMC8380045 DOI: 10.1242/bio.058553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 04/07/2021] [Indexed: 12/02/2022] Open
Abstract
Mitochondrial DNA (mtDNA) encodes gene products that are essential for oxidative phosphorylation. They organize as higher order nucleoid structures (mtNucleoids) that were shown to be critical for the maintenance of mtDNA stability and integrity. While mtNucleoid structures are associated with cellular health, how they change in situ under physiological maturation and aging requires further investigation. In this study, we investigated the mtNucleoid assembly at an ultrastructural level in situ using the TFAM-Apex2 Drosophila model. We found that smaller and more compact TFAM-nucleoids are populated in the mitochondria of indirect flight muscle of aged flies. Furthermore, mtDNA transcription and replication were cross-regulated in the mtTFB2-knockdown flies as in the mtRNAPol-knockdown flies that resulted in reductions in mtDNA copy numbers and nucleoid-associated TFAM. Overall, our study reveals that the modulation of TFAM-nucleoid structure under physiological aging, which is critically regulated by mtDNA content. Summary: The TFAM-nucleoid structure is critically regulated by mtDNA content and changes during aging. Mitochondrial transcription factor B2 plays a role in mtDNA replication.
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Affiliation(s)
- Li-Jie Wang
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 115, Taiwan
| | - Tian Hsu
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 115, Taiwan
| | - Hsiang-Ling Lin
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 115, Taiwan
| | - Chi-Yu Fu
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 115, Taiwan
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38
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High-resolution imaging reveals compartmentalization of mitochondrial protein synthesis in cultured human cells. Proc Natl Acad Sci U S A 2021; 118:2008778118. [PMID: 33526660 PMCID: PMC8017971 DOI: 10.1073/pnas.2008778118] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
In mitochondria from various species, the OXPHOS complexes reside mainly in the invaginated cristae membranes, as opposed to the inner boundary membrane (IBM) that parallels the mitochondrial outer membrane. However, the IBM contains dynamic contact sites enriched for translocases that import proteins from the cytosol. As the majority of OXPHOS components are imported and need to be integrated in assembly with the mtDNA-encoded components, where does intramitochondrial translation occur? Here we report: 1) a method for visualizing protein synthesis in human mitochondria at super resolution; 2) that synthesis is enriched at cristae membranes, in preference to the IBM; and 3) that sites of translation are spatially separated from RNA granules where RNA processing, maturation, and mitoribosomal assembly occur. Human mitochondria contain their own genome, mitochondrial DNA, that is expressed in the mitochondrial matrix. This genome encodes 13 vital polypeptides that are components of the multisubunit complexes that couple oxidative phosphorylation (OXPHOS). The inner mitochondrial membrane that houses these complexes comprises the inner boundary membrane that runs parallel to the outer membrane, infoldings that form the cristae membranes, and the cristae junctions that separate the two. It is in these cristae membranes that the OXPHOS complexes have been shown to reside in various species. The majority of the OXPHOS subunits are nuclear-encoded and must therefore be imported from the cytosol through the outer membrane at contact sites with the inner boundary membrane. As the mitochondrially encoded components are also integral members of these complexes, where does protein synthesis occur? As transcription, mRNA processing, maturation, and at least part of the mitoribosome assembly process occur at the nucleoid and the spatially juxtaposed mitochondrial RNA granules, is protein synthesis also performed at the RNA granules close to these entities, or does it occur distal to these sites? We have adapted a click chemistry-based method coupled with stimulated emission depletion nanoscopy to address these questions. We report that, in human cells in culture, within the limits of our methodology, the majority of mitochondrial protein synthesis is detected at the cristae membranes and is spatially separated from the sites of RNA processing and maturation.
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Gao X, Du C, Zheng X, Hou C, Wang Y, Xu S, Yang Y, Zhu J, Jin S. Characterisation, expression and possible functions of prohibitin during spermatogenesis in the silver pomfret Pampus argenteus. Reprod Fertil Dev 2021; 32:1084-1098. [PMID: 32741428 DOI: 10.1071/rd19381] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 12/13/2019] [Indexed: 01/14/2023] Open
Abstract
Mitochondria play an important role in spermatogenesis, and some mitochondrial proteins are specifically related to this process. In this study we investigated the cytological characteristics of spermatogenic cells, including mitochondrial dynamics, during spermatogenesis in Pampus argenteus. In addition, we characterised the mitochondria-related protein prohibitin (PHB), which has been reported to play roles in mitochondrial dynamics and animal fertility. The full-length cDNA of the P. argenteus phb gene (Pa-phb) is 1687bp, including a 102-bp 5'-untranslated region (UTR), a 772-bp 3'-UTR and an 813-bp open reading frame encoding 271 amino acids. The predicted P. argenteus PHB protein (Pa-PHB) contains three functional domains (a transmembrane domain, an SPFH domain (the conserved region of stomatins, prohibitins, flotillins and HflK/C) and a coiled-coil domain) and exhibits high similarity with its homologue in other animals. The Pa-phb gene was widely expressed in all tissues examined, especially the liver and heart. We primarily focused on Pa-phb expression during spermatogenesis after observing the cytological features of male germ cells, and found that Pa-phb transcripts were detected throughout the course of development of male germ cells. Notably, we observed colocalised signals of Pa-PHB and mitochondria, which were distributed in the cytoplasm around the nucleus in spermatogonia, spermatocytes and early spermatids, tended to move to one side of the cell in middle spermatids and, finally, were colocalised in the sperm midpiece. These observations indicate that Pa-PHB is primarily localised in mitochondria during spermatogenesis, indicating that it has a role in mitochondria. Based on the results of this and previous studies regarding the essential roles of PHB in mitochondria and spermatogenesis in animals, we propose a functional model for PHB during spermatogenesis, including possible roles in the proliferation of spermatogonia and in the regulation of mitochondrial morphology and function in spermatogenic cells.
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Affiliation(s)
- Xinming Gao
- Key Laboratory of Applied Marine Biotechnology by the Ministry of Education, School of Marine Sciences, Ningbo University, Ningbo, Zhejiang 315211, PR China
| | - Chen Du
- Key Laboratory of Applied Marine Biotechnology by the Ministry of Education, School of Marine Sciences, Ningbo University, Ningbo, Zhejiang 315211, PR China
| | - Xuebin Zheng
- Key Laboratory of Applied Marine Biotechnology by the Ministry of Education, School of Marine Sciences, Ningbo University, Ningbo, Zhejiang 315211, PR China
| | - Congcong Hou
- Key Laboratory of Applied Marine Biotechnology by the Ministry of Education, School of Marine Sciences, Ningbo University, Ningbo, Zhejiang 315211, PR China
| | - Yajun Wang
- Key Laboratory of Applied Marine Biotechnology by the Ministry of Education, School of Marine Sciences, Ningbo University, Ningbo, Zhejiang 315211, PR China
| | - Shanliang Xu
- Key Laboratory of Applied Marine Biotechnology by the Ministry of Education, School of Marine Sciences, Ningbo University, Ningbo, Zhejiang 315211, PR China
| | - Yang Yang
- Key Laboratory of Applied Marine Biotechnology by the Ministry of Education, School of Marine Sciences, Ningbo University, Ningbo, Zhejiang 315211, PR China
| | - Junquan Zhu
- Key Laboratory of Applied Marine Biotechnology by the Ministry of Education, School of Marine Sciences, Ningbo University, Ningbo, Zhejiang 315211, PR China; and Corresponding author.
| | - Shan Jin
- Key Laboratory of Applied Marine Biotechnology by the Ministry of Education, School of Marine Sciences, Ningbo University, Ningbo, Zhejiang 315211, PR China
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Abstract
Mitochondria are organelles with vital functions in almost all eukaryotic cells. Often described as the cellular 'powerhouses' due to their essential role in aerobic oxidative phosphorylation, mitochondria perform many other essential functions beyond energy production. As signaling organelles, mitochondria communicate with the nucleus and other organelles to help maintain cellular homeostasis, allow cellular adaptation to diverse stresses, and help steer cell fate decisions during development. Mitochondria have taken center stage in the research of normal and pathological processes, including normal tissue homeostasis and metabolism, neurodegeneration, immunity and infectious diseases. The central role that mitochondria assume within cells is evidenced by the broad impact of mitochondrial diseases, caused by defects in either mitochondrial or nuclear genes encoding for mitochondrial proteins, on different organ systems. In this Review, we will provide the reader with a foundation of the mitochondrial 'hardware', the mitochondrion itself, with its specific dynamics, quality control mechanisms and cross-organelle communication, including its roles as a driver of an innate immune response, all with a focus on development, disease and aging. We will further discuss how mitochondrial DNA is inherited, how its mutation affects cell and organismal fitness, and current therapeutic approaches for mitochondrial diseases in both model organisms and humans.
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Affiliation(s)
- Marlies P. Rossmann
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 01238, USA
- Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Howard Hughes Medical Institute, Boston, MA 02115, USA
| | - Sonia M. Dubois
- Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Suneet Agarwal
- Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Leonard I. Zon
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 01238, USA
- Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Howard Hughes Medical Institute, Boston, MA 02115, USA
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41
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Aretz I, Jakubke C, Osman C. Power to the daughters - mitochondrial and mtDNA transmission during cell division. Biol Chem 2021; 401:533-546. [PMID: 31812944 DOI: 10.1515/hsz-2019-0337] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 11/08/2019] [Indexed: 11/15/2022]
Abstract
Mitochondria supply virtually all eukaryotic cells with energy through ATP production by oxidative phosphoryplation (OXPHOS). Accordingly, maintenance of mitochondrial function is fundamentally important to sustain cellular health and various diseases have been linked to mitochondrial dysfunction. Biogenesis of OXPHOS complexes crucially depends on mitochondrial DNA (mtDNA) that encodes essential subunits of the respiratory chain and is distributed in multiple copies throughout the mitochondrial network. During cell division, mitochondria, including mtDNA, need to be accurately apportioned to daughter cells. This process requires an intimate and coordinated interplay between the cell cycle, mitochondrial dynamics and the replication and distribution of mtDNA. Recent years have seen exciting advances in the elucidation of the mechanisms that facilitate these processes and essential key players have been identified. Moreover, segregation of qualitatively distinct mitochondria during asymmetric cell division is emerging as an important quality control step, which secures the maintenance of a healthy cell population.
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Affiliation(s)
- Ina Aretz
- Department of Biology II, Ludwig-Maximilians-University Munich, Großhaderner Str. 2, 82152Planegg-Martinsried, Germany
| | - Christopher Jakubke
- Department of Biology II, Ludwig-Maximilians-University Munich, Großhaderner Str. 2, 82152Planegg-Martinsried, Germany
| | - Christof Osman
- Department of Biology II, Ludwig-Maximilians-University Munich, Großhaderner Str. 2, 82152Planegg-Martinsried, Germany
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42
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Garg P, Martin-Trujillo A, Rodriguez OL, Gies SJ, Hadelia E, Jadhav B, Jain M, Paten B, Sharp AJ. Pervasive cis effects of variation in copy number of large tandem repeats on local DNA methylation and gene expression. Am J Hum Genet 2021; 108:809-824. [PMID: 33794196 DOI: 10.1016/j.ajhg.2021.03.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 03/11/2021] [Indexed: 12/27/2022] Open
Abstract
Variable number tandem repeats (VNTRs) are composed of large tandemly repeated motifs, many of which are highly polymorphic in copy number. However, because of their large size and repetitive nature, they remain poorly studied. To investigate the regulatory potential of VNTRs, we used read-depth data from Illumina whole-genome sequencing to perform association analysis between copy number of ∼70,000 VNTRs (motif size ≥ 10 bp) with both gene expression (404 samples in 48 tissues) and DNA methylation (235 samples in peripheral blood), identifying thousands of VNTRs that are associated with local gene expression (eVNTRs) and DNA methylation levels (mVNTRs). Using an independent cohort, we validated 73%-80% of signals observed in the two discovery cohorts, while allelic analysis of VNTR length and CpG methylation in 30 Oxford Nanopore genomes gave additional support for mVNTR loci, thus providing robust evidence to support that these represent genuine associations. Further, conditional analysis indicated that many eVNTRs and mVNTRs act as QTLs independently of other local variation. We also observed strong enrichments of eVNTRs and mVNTRs for regulatory features such as enhancers and promoters. Using the Human Genome Diversity Panel, we define sets of VNTRs that show highly divergent copy numbers among human populations and show that these are enriched for regulatory effects and preferentially associate with genes that have been linked with human phenotypes through GWASs. Our study provides strong evidence supporting functional variation at thousands of VNTRs and defines candidate sets of VNTRs, copy number variation of which potentially plays a role in numerous human phenotypes.
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43
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Ghazal N, Peoples JN, Mohiuddin TA, Kwong JQ. Mitochondrial functional resilience after TFAM ablation in the adult heart. Am J Physiol Cell Physiol 2021; 320:C929-C942. [PMID: 33760663 DOI: 10.1152/ajpcell.00508.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The nuclear genome-encoded mitochondrial DNA (mtDNA) transcription factor A (TFAM) is indispensable for mitochondrial energy production in the developing and postnatal heart; a similar role for TFAM is inferred in adult heart. Here, we provide evidence that challenges this long-standing paradigm. Unexpectedly, conditional Tfam ablation in vivo in adult mouse cardiomyocytes resulted in a prolonged period of functional resilience characterized by preserved mtDNA content, mitochondrial function, and cardiac function, despite mitochondrial structural alterations and decreased transcript abundance. Remarkably, TFAM protein levels did not directly dictate mtDNA content in the adult heart, and mitochondrial translation was preserved with acute TFAM inactivation, suggesting maintenance of respiratory chain assembly/function. Long-term Tfam inactivation, however, downregulated the core mtDNA transcription and replication machinery, leading to mitochondrial dysfunction and cardiomyopathy. Collectively, in contrast to the developing heart, these data reveal a striking resilience of the differentiated adult heart to acute insults to mtDNA regulation.
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Affiliation(s)
- Nasab Ghazal
- Division of Pediatric Cardiology, Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, Georgia
| | - Jessica N Peoples
- Division of Pediatric Cardiology, Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, Georgia
| | | | - Jennifer Q Kwong
- Division of Pediatric Cardiology, Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, Georgia
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44
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Feric M, Demarest TG, Tian J, Croteau DL, Bohr VA, Misteli T. Self-assembly of multi-component mitochondrial nucleoids via phase separation. EMBO J 2021; 40:e107165. [PMID: 33619770 DOI: 10.15252/embj.2020107165] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 01/08/2021] [Accepted: 01/19/2021] [Indexed: 11/09/2022] Open
Abstract
Mitochondria contain an autonomous and spatially segregated genome. The organizational unit of their genome is the nucleoid, which consists of mitochondrial DNA (mtDNA) and associated architectural proteins. Here, we show that phase separation is the primary physical mechanism for assembly and size control of the mitochondrial nucleoid (mt-nucleoid). The major mtDNA-binding protein TFAM spontaneously phase separates in vitro via weak, multivalent interactions into droplets with slow internal dynamics. TFAM and mtDNA form heterogenous, viscoelastic structures in vitro, which recapitulate the dynamics and behavior of mt-nucleoids in vivo. Mt-nucleoids coalesce into larger droplets in response to various forms of cellular stress, as evidenced by the enlarged and transcriptionally active nucleoids in mitochondria from patients with the premature aging disorder Hutchinson-Gilford Progeria Syndrome (HGPS). Our results point to phase separation as an evolutionarily conserved mechanism of genome organization.
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Affiliation(s)
- Marina Feric
- National Cancer Institute, NIH, Bethesda, MD, USA.,National Institute of General Medical Sciences, NIH, Bethesda, MD, USA
| | | | - Jane Tian
- National Institute on Aging, NIH, Baltimore, MD, USA
| | | | | | - Tom Misteli
- National Cancer Institute, NIH, Bethesda, MD, USA
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45
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Oláhová M, Peter B, Szilagyi Z, Diaz-Maldonado H, Singh M, Sommerville EW, Blakely EL, Collier JJ, Hoberg E, Stránecký V, Hartmannová H, Bleyer AJ, McBride KL, Bowden SA, Korandová Z, Pecinová A, Ropers HH, Kahrizi K, Najmabadi H, Tarnopolsky MA, Brady LI, Weaver KN, Prada CE, Õunap K, Wojcik MH, Pajusalu S, Syeda SB, Pais L, Estrella EA, Bruels CC, Kunkel LM, Kang PB, Bonnen PE, Mráček T, Kmoch S, Gorman GS, Falkenberg M, Gustafsson CM, Taylor RW. POLRMT mutations impair mitochondrial transcription causing neurological disease. Nat Commun 2021; 12:1135. [PMID: 33602924 PMCID: PMC7893070 DOI: 10.1038/s41467-021-21279-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 12/18/2020] [Indexed: 02/06/2023] Open
Abstract
While >300 disease-causing variants have been identified in the mitochondrial DNA (mtDNA) polymerase γ, no mitochondrial phenotypes have been associated with POLRMT, the RNA polymerase responsible for transcription of the mitochondrial genome. Here, we characterise the clinical and molecular nature of POLRMT variants in eight individuals from seven unrelated families. Patients present with global developmental delay, hypotonia, short stature, and speech/intellectual disability in childhood; one subject displayed an indolent progressive external ophthalmoplegia phenotype. Massive parallel sequencing of all subjects identifies recessive and dominant variants in the POLRMT gene. Patient fibroblasts have a defect in mitochondrial mRNA synthesis, but no mtDNA deletions or copy number abnormalities. The in vitro characterisation of the recombinant POLRMT mutants reveals variable, but deleterious effects on mitochondrial transcription. Together, our in vivo and in vitro functional studies of POLRMT variants establish defective mitochondrial transcription as an important disease mechanism.
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Affiliation(s)
- Monika Oláhová
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Bradley Peter
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden
| | - Zsolt Szilagyi
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden
| | - Hector Diaz-Maldonado
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden
| | - Meenakshi Singh
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden
| | - Ewen W Sommerville
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Emma L Blakely
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Jack J Collier
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Emily Hoberg
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden
| | - Viktor Stránecký
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University, Prague, 120 00, Czech Republic
| | - Hana Hartmannová
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University, Prague, 120 00, Czech Republic
| | - Anthony J Bleyer
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University, Prague, 120 00, Czech Republic
- Section on Nephrology, Wake Forest School of Medicine, Winston-Salem, USA
| | - Kim L McBride
- Center for Cardiovascular and Pulmonary Research, Department of Pediatrics, Nationwide Children's Hospital, The Ohio State University College of Medicine, Columbus, USA
| | - Sasigarn A Bowden
- Division of Endocrinology, Nationwide Children's Hospital, The Ohio State University College of Medicine, Columbus, USA
| | - Zuzana Korandová
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University, Prague, 120 00, Czech Republic
- Department of Bioenergetics, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Alena Pecinová
- Department of Bioenergetics, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Hans-Hilger Ropers
- Department of Human Molecular Genetics, Max Planck Institute for Molecular Genetics, Berlin, Germany
- Institute of Human Genetics, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Kimia Kahrizi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Hossein Najmabadi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Mark A Tarnopolsky
- Department of Pediatric and Medicines, Division of Neuromuscular and Neurometabolic Diseases, McMaster University Children's Hospital, Hamilton, Canada
| | - Lauren I Brady
- Department of Pediatric and Medicines, Division of Neuromuscular and Neurometabolic Diseases, McMaster University Children's Hospital, Hamilton, Canada
| | - K Nicole Weaver
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Carlos E Prada
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
- Department of Pediatrics, Cardiovascular Foundation of Colombia, Floridablanca, Colombia
| | - Katrin Õunap
- Department of Clinical Genetics, United Laboratories, Tartu University Hospital, Tartu, Estonia
- Department of Clinical Genetics, Institute of Clinical Medicine, University of Tartu, Tartu, Estonia
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Monica H Wojcik
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Divisions of Newborn Medicine and Genetics and Genomics, Department of Pediatrics, Boston Children's Hospital, Boston, MA, USA
| | - Sander Pajusalu
- Department of Clinical Genetics, United Laboratories, Tartu University Hospital, Tartu, Estonia
- Department of Clinical Genetics, Institute of Clinical Medicine, University of Tartu, Tartu, Estonia
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
| | - Safoora B Syeda
- Division of Pediatric Neurology, Department of Pediatrics, University of Florida College of Medicine, Gainesville, FL, USA
| | - Lynn Pais
- Center for Mendelian Genomics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Elicia A Estrella
- Division of Genetics & Genomics, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - Christine C Bruels
- Division of Pediatric Neurology, Department of Pediatrics, University of Florida College of Medicine, Gainesville, FL, USA
| | - Louis M Kunkel
- Division of Genetics & Genomics, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - Peter B Kang
- Division of Pediatric Neurology, Department of Pediatrics, University of Florida College of Medicine, Gainesville, FL, USA
- Department of Molecular Genetics & Microbiology, and Department of Neurology, University of Florida College of Medicine, Gainesville, FL, USA
- Genetics Institute and Myology Institute, University of Florida, Gainesville, FL, USA
| | - Penelope E Bonnen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Tomáš Mráček
- Department of Bioenergetics, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Stanislav Kmoch
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University, Prague, 120 00, Czech Republic
| | - Gráinne S Gorman
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Maria Falkenberg
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden
| | - Claes M Gustafsson
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden.
| | - Robert W Taylor
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.
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46
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Kotrasová V, Keresztesová B, Ondrovičová G, Bauer JA, Havalová H, Pevala V, Kutejová E, Kunová N. Mitochondrial Kinases and the Role of Mitochondrial Protein Phosphorylation in Health and Disease. Life (Basel) 2021; 11:life11020082. [PMID: 33498615 PMCID: PMC7912454 DOI: 10.3390/life11020082] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/19/2021] [Accepted: 01/20/2021] [Indexed: 02/07/2023] Open
Abstract
The major role of mitochondria is to provide cells with energy, but no less important are their roles in responding to various stress factors and the metabolic changes and pathological processes that might occur inside and outside the cells. The post-translational modification of proteins is a fast and efficient way for cells to adapt to ever changing conditions. Phosphorylation is a post-translational modification that signals these changes and propagates these signals throughout the whole cell, but it also changes the structure, function and interaction of individual proteins. In this review, we summarize the influence of kinases, the proteins responsible for phosphorylation, on mitochondrial biogenesis under various cellular conditions. We focus on their role in keeping mitochondria fully functional in healthy cells and also on the changes in mitochondrial structure and function that occur in pathological processes arising from the phosphorylation of mitochondrial proteins.
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Affiliation(s)
- Veronika Kotrasová
- Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská Cesta 21, 845 51 Bratislava, Slovakia; (V.K.); (B.K.); (G.O.); (J.A.B.); (H.H.); (V.P.)
| | - Barbora Keresztesová
- Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská Cesta 21, 845 51 Bratislava, Slovakia; (V.K.); (B.K.); (G.O.); (J.A.B.); (H.H.); (V.P.)
- First Faculty of Medicine, Institute of Biology and Medical Genetics, Charles University, 128 00 Prague, Czech Republic
| | - Gabriela Ondrovičová
- Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská Cesta 21, 845 51 Bratislava, Slovakia; (V.K.); (B.K.); (G.O.); (J.A.B.); (H.H.); (V.P.)
| | - Jacob A. Bauer
- Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská Cesta 21, 845 51 Bratislava, Slovakia; (V.K.); (B.K.); (G.O.); (J.A.B.); (H.H.); (V.P.)
| | - Henrieta Havalová
- Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská Cesta 21, 845 51 Bratislava, Slovakia; (V.K.); (B.K.); (G.O.); (J.A.B.); (H.H.); (V.P.)
| | - Vladimír Pevala
- Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská Cesta 21, 845 51 Bratislava, Slovakia; (V.K.); (B.K.); (G.O.); (J.A.B.); (H.H.); (V.P.)
| | - Eva Kutejová
- Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská Cesta 21, 845 51 Bratislava, Slovakia; (V.K.); (B.K.); (G.O.); (J.A.B.); (H.H.); (V.P.)
- Correspondence: (E.K.); (N.K.)
| | - Nina Kunová
- Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská Cesta 21, 845 51 Bratislava, Slovakia; (V.K.); (B.K.); (G.O.); (J.A.B.); (H.H.); (V.P.)
- First Faculty of Medicine, Institute of Biology and Medical Genetics, Charles University, 128 00 Prague, Czech Republic
- Correspondence: (E.K.); (N.K.)
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47
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Chao T, Shih HT, Hsu SC, Chen PJ, Fan YS, Jeng YM, Shen ZQ, Tsai TF, Chang ZF. Autophagy restricts mitochondrial DNA damage-induced release of ENDOG (endonuclease G) to regulate genome stability. Autophagy 2021; 17:3444-3460. [PMID: 33465003 DOI: 10.1080/15548627.2021.1874209] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Genotoxic insult causes nuclear and mitochondrial DNA damages with macroautophagy/autophagy induction. The role of mitochondrial DNA (mtDNA) damage in the requirement of autophagy for nuclear DNA (nDNA) stability is unclear. Using site-specific DNA damage approaches, we show that specific nDNA damage alone does not require autophagy for repair unless in the presence of mtDNA damage. We provide evidence that after IR exposure-induced mtDNA and nDNA damages, autophagy suppression causes non-apoptotic mitochondrial permeability, by which mitochondrial ENDOG (endonuclease G) is released and translocated to nuclei to sustain nDNA damage in a TET (tet methylcytosine dioxygenase)-dependent manner. Furthermore, blocking lysosome function is sufficient to increase the amount of mtDNA leakage to the cytosol, accompanied by ENDOG-free mitochondrial puncta formation with concurrent ENDOG nuclear accumulation. We proposed that autophagy eliminates the mitochondria specified by mtDNA damage-driven mitochondrial permeability to prevent ENDOG-mediated genome instability. Finally, we showed that HBx, a hepatitis B viral protein capable of suppressing autophagy, also causes mitochondrial permeability-dependent ENDOG mis-localization in nuclei and is linked to hepatitis B virus (HBV)-mediated hepatocellular carcinoma development.Abbreviations: 3-MA: 3-methyladenine; 5-hmC: 5-hydroxymethylcytosine; ACTB: actin beta; ATG5: autophagy related 5; ATM: ATM serine/threonine kinase; DFFB/CAD: DNA fragmentation factor subunit beta; cmtDNA: cytosolic mitochondrial DNA; ConA: concanamycin A; CQ: chloroquine; CsA: cyclosporin A; Dox: doxycycline; DSB: double-strand break; ENDOG: endonuclease G; GFP: green fluorescent protein; Gy: gray; H2AX: H2A.X variant histone; HBV: hepatitis B virus; HBx: hepatitis B virus X protein; HCC: hepatocellular carcinoma; I-PpoI: intron-encoded endonuclease; IR: ionizing radiation; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MOMP: mitochondrial outer membrane permeability; mPTP: mitochondrial permeability transition pore; mtDNA: mitochondrial DNA; nDNA: nuclear DNA; 4-OHT: 4-hydroxytamoxifen; rDNA: ribosomal DNA; ROS: reactive oxygen species; SQSTM1/p62: sequestosome 1; TET: tet methylcytosine dioxygenase; TFAM: transcription factor A, mitochondrial; TOMM20: translocase of outer mitochondrial membrane 20; VDAC: voltage dependent anion channel.
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Affiliation(s)
- Tung Chao
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.,Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Hsueh-Tzu Shih
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.,Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Shih-Chin Hsu
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.,Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Pei-Jer Chen
- Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.,Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan.,Hepatitis Research Center, National Taiwan University Hospital, Taipei, Taiwan
| | - Yu-Shan Fan
- Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yung-Ming Jeng
- Department of Pathology, National Taiwan University, Hospital, Taipei, Taiwan
| | - Zhao-Qing Shen
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan
| | - Ting-Fen Tsai
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan
| | - Zee-Fen Chang
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.,Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
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Young CKJ, Wheeler JH, Rahman MM, Young MJ. The antiretroviral 2',3'-dideoxycytidine causes mitochondrial dysfunction in proliferating and differentiated HepaRG human cell cultures. J Biol Chem 2021; 296:100206. [PMID: 33334881 PMCID: PMC7948951 DOI: 10.1074/jbc.ra120.014885] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 12/15/2020] [Accepted: 12/17/2020] [Indexed: 02/06/2023] Open
Abstract
Nucleoside reverse transcriptase inhibitors (NRTIs) were the first drugs used to treat human immunodeficiency virus infection, and their use can cause mitochondrial toxicity, including mitochondrial DNA (mtDNA) depletion in several cases. The first-generation NRTIs, including 2',3'-dideoxycytidine (ddC), were originally and are still pursued as anticancer agents. NRTI-sensitive DNA polymerases localizing to mitochondria allow for the opportunity to poison proliferating cancer cell mtDNA replication as certain cancers rely heavily on mitochondrial functions. However, mtDNA replication is independent of the cell cycle creating a significant concern that toxicants such as ddC impair mtDNA maintenance in both proliferating and nonproliferating cells. To examine this possibility, we tested the utility of the HepaRG cell line to study ddC-induced toxicity in isogenic proliferating (undifferentiated) and nonproliferating (differentiated) cells. Following ddC exposures, we measured cell viability, mtDNA copy number, and mitochondrial bioenergetics utilizing trypan blue, Southern blotting, and extracellular flux analysis, respectively. After 13 days of 1 μM ddC exposure, proliferating and differentiated HepaRG harbored mtDNA levels of 0.9% and 17.9% compared with control cells, respectively. Cells exposed to 12 μM ddC contained even less mtDNA. By day 13, differentiated cell viability was maintained but declined for proliferating cells. Proliferating HepaRG bioenergetic parameters were severely impaired by day 8, with 1 and 12 μM ddC, whereas differentiated cells displayed defects of spare and maximal respiratory capacities (day 8) and proton-leak linked respiration (day 14) with 12 μM ddC. These results indicate HepaRG is a useful model to study proliferating and differentiated cell mitochondrial toxicant exposures.
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Affiliation(s)
- Carolyn K J Young
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois, USA
| | - Joel H Wheeler
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois, USA
| | - Md Mostafijur Rahman
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois, USA
| | - Matthew J Young
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois, USA.
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Basu U, Bostwick AM, Das K, Dittenhafer-Reed KE, Patel SS. Structure, mechanism, and regulation of mitochondrial DNA transcription initiation. J Biol Chem 2020; 295:18406-18425. [PMID: 33127643 PMCID: PMC7939475 DOI: 10.1074/jbc.rev120.011202] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 10/29/2020] [Indexed: 12/14/2022] Open
Abstract
Mitochondria are specialized compartments that produce requisite ATP to fuel cellular functions and serve as centers of metabolite processing, cellular signaling, and apoptosis. To accomplish these roles, mitochondria rely on the genetic information in their small genome (mitochondrial DNA) and the nucleus. A growing appreciation for mitochondria's role in a myriad of human diseases, including inherited genetic disorders, degenerative diseases, inflammation, and cancer, has fueled the study of biochemical mechanisms that control mitochondrial function. The mitochondrial transcriptional machinery is different from nuclear machinery. The in vitro re-constituted transcriptional complexes of Saccharomyces cerevisiae (yeast) and humans, aided with high-resolution structures and biochemical characterizations, have provided a deeper understanding of the mechanism and regulation of mitochondrial DNA transcription. In this review, we will discuss recent advances in the structure and mechanism of mitochondrial transcription initiation. We will follow up with recent discoveries and formative findings regarding the regulatory events that control mitochondrial DNA transcription, focusing on those involved in cross-talk between the mitochondria and nucleus.
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Affiliation(s)
- Urmimala Basu
- Department of Biochemistry and Molecular Biology, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey, USA; Graduate School of Biomedical Sciences, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
| | | | - Kalyan Das
- Department of Microbiology, Immunology, and Transplantation, Rega Institute for Medical Research, KU Leuven, Leuven, Belgium
| | | | - Smita S Patel
- Department of Biochemistry and Molecular Biology, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey, USA.
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Mitochondrial Dysfunction in Parkinson's Disease: Focus on Mitochondrial DNA. Biomedicines 2020; 8:biomedicines8120591. [PMID: 33321831 PMCID: PMC7763033 DOI: 10.3390/biomedicines8120591] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 12/05/2020] [Accepted: 12/08/2020] [Indexed: 12/14/2022] Open
Abstract
Mitochondria, the energy stations of the cell, are the only extranuclear organelles, containing their own (mitochondrial) DNA (mtDNA) and the protein synthesizing machinery. The location of mtDNA in close proximity to the oxidative phosphorylation system of the inner mitochondrial membrane, the main source of reactive oxygen species (ROS), is an important factor responsible for its much higher mutation rate than nuclear DNA. Being more vulnerable to damage than nuclear DNA, mtDNA accumulates mutations, crucial for the development of mitochondrial dysfunction playing a key role in the pathogenesis of various diseases. Good evidence exists that some mtDNA mutations are associated with increased risk of Parkinson’s disease (PD), the movement disorder resulted from the degenerative loss of dopaminergic neurons of substantia nigra. Although their direct impact on mitochondrial function/dysfunction needs further investigation, results of various studies performed using cells isolated from PD patients or their mitochondria (cybrids) suggest their functional importance. Studies involving mtDNA mutator mice also demonstrated the importance of mtDNA deletions, which could also originate from abnormalities induced by mutations in nuclear encoded proteins needed for mtDNA replication (e.g., polymerase γ). However, proteomic studies revealed only a few mitochondrial proteins encoded by mtDNA which were downregulated in various PD models. This suggests nuclear suppression of the mitochondrial defects, which obviously involve cross-talk between nuclear and mitochondrial genomes for maintenance of mitochondrial functioning.
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