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Amore G, Romagnoli M, Carbonelli M, Cascavilla ML, De Negri AM, Carta A, Parisi V, Di Renzo A, Schiavi C, Lenzetti C, Zenesini C, Ormanbekova D, Palombo F, Fiorini C, Caporali L, Carelli V, Barboni P, La Morgia C. AFG3L2 and ACO2-Linked Dominant Optic Atrophy: Genotype-Phenotype Characterization Compared to OPA1 Patients. Am J Ophthalmol 2024; 262:114-124. [PMID: 38278202 DOI: 10.1016/j.ajo.2024.01.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Revised: 12/28/2023] [Accepted: 01/10/2024] [Indexed: 01/28/2024]
Abstract
PURPOSE Heterozygous mutations in the AFG3L2 gene (encoding a mitochondrial protease indirectly reflecting on OPA1 cleavage) and ACO2 gene (encoding the mitochondrial enzyme aconitase) are associated with isolated forms of Dominant Optic Atrophy (DOA). We aimed at describing their neuro-ophthalmological phenotype as compared with classic OPA1-related DOA. DESIGN Cross-sectional study. METHODS The following neuro-ophthalmological parameters were collected: logMAR visual acuity (VA), color vision, mean deviation and foveal threshold at visual fields, average and sectorial retinal nerve fiber layer (RNFL), and ganglion cell layer (GCL) thickness on optical coherence tomography. ACO2 and AFG3L2 patients were compared with an age- and sex-matched group of OPA1 patients with a 1:2 ratio. All eyes were analyzed using a clustered Wilcoxon rank sum test with the Rosner-Glynn-Lee method. RESULTS A total of 44 eyes from 23 ACO2 patients and 26 eyes from 13 AFG3L2 patients were compared with 143 eyes from 72 OPA1 patients. All cases presented with bilateral temporal-predominant optic atrophy with various degree of visual impairment. Comparison between AFG3L2 and OPA1 failed to reveal any significant difference. ACO2 patients compared to both AFG3L2 and OPA1 presented overall higher values of nasal RNFL thickness (P = .029, P = .023), average thickness (P = .012, P = .0007), and sectorial GCL thickness. These results were confirmed also comparing separately affected and subclinical patients. CONCLUSIONS Clinically, DOA remains a fairly homogeneous entity despite the growing genetic heterogeneity. ACO2 seems to be associated with an overall better preservation of retinal ganglion cells, probably depending on the different pathogenic mechanism involving mtDNA maintenance, as opposed to AFG3L2, which is involved in OPA1 processing and is virtually indistinguishable from classic OPA1-DOA.
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Affiliation(s)
- Giulia Amore
- From the Department of Biomedical and Neuromotor Sciences (G.A., M.C., V.C., C.L.M.), University of Bologna, Bologna, Italy; Ophthalmology Unit (G.A., C.S.), IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy.
| | - Martina Romagnoli
- IRCCS Istituto delle Scienze Neurologiche di Bologna (M.R., D.O., F.P., C.F.L.C.V.C.), Programma di Neurogenetica, Bologna, Italy
| | - Michele Carbonelli
- From the Department of Biomedical and Neuromotor Sciences (G.A., M.C., V.C., C.L.M.), University of Bologna, Bologna, Italy
| | - Maria Lucia Cascavilla
- Department of Ophthalmology (M.L.C., P.B.), University Vita-Salute, IRCCS Ospedale San Raffaele, Milan, Italy
| | | | - Arturo Carta
- Ophthalmology Unit (A.C.), University Hospital of Parma, University of Parma, Parma, Italy
| | | | | | - Costantino Schiavi
- Ophthalmology Unit (G.A., C.S.), IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Chiara Lenzetti
- Department of Surgery and Translational Medicine (C.L.), Eye Clinic, Careggi University Hospital, University of Florence, Florence, Italy
| | - Corrado Zenesini
- IRCCS Istituto delle Scienze Neurologiche di Bologna (C.Z.), Unità di Epidemiologia e Statistica, Bologna, Italy
| | - Danara Ormanbekova
- IRCCS Istituto delle Scienze Neurologiche di Bologna (M.R., D.O., F.P., C.F.L.C.V.C.), Programma di Neurogenetica, Bologna, Italy
| | - Flavia Palombo
- IRCCS Istituto delle Scienze Neurologiche di Bologna (M.R., D.O., F.P., C.F.L.C.V.C.), Programma di Neurogenetica, Bologna, Italy
| | - Claudio Fiorini
- IRCCS Istituto delle Scienze Neurologiche di Bologna (M.R., D.O., F.P., C.F.L.C.V.C.), Programma di Neurogenetica, Bologna, Italy
| | - Leonardo Caporali
- IRCCS Istituto delle Scienze Neurologiche di Bologna (M.R., D.O., F.P., C.F.L.C.V.C.), Programma di Neurogenetica, Bologna, Italy
| | - Valerio Carelli
- From the Department of Biomedical and Neuromotor Sciences (G.A., M.C., V.C., C.L.M.), University of Bologna, Bologna, Italy; IRCCS Istituto delle Scienze Neurologiche di Bologna (M.R., D.O., F.P., C.F.L.C.V.C.), Programma di Neurogenetica, Bologna, Italy
| | - Piero Barboni
- Department of Ophthalmology (M.L.C., P.B.), University Vita-Salute, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Chiara La Morgia
- From the Department of Biomedical and Neuromotor Sciences (G.A., M.C., V.C., C.L.M.), University of Bologna, Bologna, Italy; IRCCS Istituto delle Scienze Neurologiche di Bologna (C.L.M.), UOC Clinica Neurologica, Bologna, Italy
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Jung SJ, Sridhara S, Ott M. Early steps in the biogenesis of mitochondrially encoded oxidative phosphorylation subunits. IUBMB Life 2024; 76:125-139. [PMID: 37712772 DOI: 10.1002/iub.2784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 08/10/2023] [Indexed: 09/16/2023]
Abstract
The complexes mediating oxidative phosphorylation (OXPHOS) in the inner mitochondrial membrane consist of proteins encoded in the nuclear or the mitochondrial DNA. The mitochondrially encoded membrane proteins (mito-MPs) represent the catalytic core of these complexes and follow complicated pathways for biogenesis. Owing to their overall hydrophobicity, mito-MPs are co-translationally inserted into the inner membrane by the Oxa1 insertase. After insertion, OXPHOS biogenesis factors mediate the assembly of mito-MPs into complexes and participate in the regulation of mitochondrial translation, while protein quality control factors recognize and degrade faulty or excess proteins. This review summarizes the current understanding of these early steps occurring during the assembly of mito-MPs by concentrating on results obtained in the model organism baker's yeast.
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Affiliation(s)
- Sung-Jun Jung
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Sagar Sridhara
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Martin Ott
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
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Abeliovich H. Mitophagy in yeast: known unknowns and unknown unknowns. Biochem J 2023; 480:1639-1657. [PMID: 37850532 PMCID: PMC10586778 DOI: 10.1042/bcj20230279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 09/06/2023] [Accepted: 09/22/2023] [Indexed: 10/19/2023]
Abstract
Mitophagy, the autophagic breakdown of mitochondria, is observed in eukaryotic cells under various different physiological circumstances. These can be broadly categorized into two types: mitophagy related to quality control events and mitophagy induced during developmental transitions. Quality control mitophagy involves the lysosomal or vacuolar degradation of malfunctioning or superfluous mitochondria within lysosomes or vacuoles, and this is thought to serve as a vital maintenance function in respiring eukaryotic cells. It plays a crucial role in maintaining physiological balance, and its disruption has been associated with the progression of late-onset diseases. Developmentally induced mitophagy has been reported in the differentiation of metazoan tissues which undergo metabolic shifts upon developmental transitions, such as in the differentiation of red blood cells and muscle cells. Although the mechanistic studies of mitophagy in mammalian cells were initiated after the initial mechanistic findings in Saccharomyces cerevisiae, our current understanding of the physiological role of mitophagy in yeast remains more limited, despite the presence of better-defined assays and tools. In this review, I present my perspective on our present knowledge of mitophagy in yeast, focusing on physiological and mechanistic aspects. I aim to focus on areas where our understanding is still incomplete, such as the role of mitochondrial dynamics and the phenomenon of protein-level selectivity.
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Affiliation(s)
- Hagai Abeliovich
- Institute of Biochemistry, Food Science and Nutrition, Hebrew University of Jerusalem, 1 Hankin St, Rehovot 7610001, Israel
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4
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De Mario A, D'Angelo D, Zanotti G, Raffaello A, Mammucari C. The mitochondrial calcium uniporter complex–A play in five acts. Cell Calcium 2023; 112:102720. [PMID: 37001308 DOI: 10.1016/j.ceca.2023.102720] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 03/22/2023] [Accepted: 03/23/2023] [Indexed: 03/30/2023]
Abstract
Mitochondrial Ca2+ (mitCa2+) uptake controls both intraorganellar and cytosolic functions. Within the organelle, [Ca2+] increases regulate the activity of tricarboxylic acid (TCA) cycle enzymes, thus sustaining oxidative metabolism and ATP production. Reactive oxygen species (ROS) are also generated as side products of oxygen consumption. At the same time, mitochondria act as buffers of cytosolic Ca2+ (cytCa2+) increases, thus regulating Ca2+-dependent cellular processes. In pathological conditions, mitCa2+ overload triggers the opening of the mitochondrial permeability transition pore (mPTP) and the release of apoptotic cofactors. MitCa2+ uptake occurs in response of local [Ca2+] increases in sites of proximity between the endoplasmic reticulum (ER) and the mitochondria and is mediated by the mitochondrial Ca2+ uniporter (MCU), a highly selective channel of the inner mitochondrial membrane (IMM). Both channel and regulatory subunits form the MCU complex (MCUC). Cryogenic electron microscopy (Cryo-EM) and crystal structures revealed the correct assembly of MCUC and the function of critical residues for the regulation of Ca2+ conductance.
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Kumar A, Waingankar TP, D'Silva P. Functional crosstalk between the TIM22 complex and YME1 machinery maintains mitochondrial proteostasis and integrity. J Cell Sci 2023; 136:286750. [PMID: 36601773 DOI: 10.1242/jcs.260060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 12/13/2022] [Indexed: 01/06/2023] Open
Abstract
TIM22 pathway cargos are essential for sustaining mitochondrial homeostasis as an excess of these proteins leads to proteostatic stress and cell death. Yme1 is an inner membrane metalloprotease that regulates protein quality control with chaperone-like and proteolytic activities. Although the mitochondrial translocase and protease machinery are critical for organelle health, their functional association remains unexplored. The present study unravels a novel genetic connection between the TIM22 complex and YME1 machinery in Saccharomyces cerevisiae that is required for maintaining mitochondrial health. Our genetic analyses indicate that impairment in the TIM22 complex rescues the respiratory growth defects of cells without Yme1. Furthermore, Yme1 is essential for the stability of the TIM22 complex and regulates the proteostasis of TIM22 pathway substrates. Moreover, impairment in the TIM22 complex suppressed the mitochondrial structural and functional defects of Yme1-devoid cells. In summary, excessive levels of TIM22 pathway substrates could be one of the reasons for respiratory growth defects of cells lacking Yme1, and compromising the TIM22 complex can compensate for the imbalance in mitochondrial proteostasis caused by the loss of Yme1.
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Affiliation(s)
- Abhishek Kumar
- Department of Biochemistry, New Biological Sciences Building, Indian Institute of Science, C V Raman Avenue, Bangalore 560012, India
| | - Tejashree Pradip Waingankar
- Department of Biochemistry, New Biological Sciences Building, Indian Institute of Science, C V Raman Avenue, Bangalore 560012, India
| | - Patrick D'Silva
- Department of Biochemistry, New Biological Sciences Building, Indian Institute of Science, C V Raman Avenue, Bangalore 560012, India
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Liu C, Liu J, Wang T, Su Y, Li L, Lan M, Yu Y, Liu F, Xiong L, Wang K, Chen M, Li N, Xu Q, Hu Y, Jia Y, Meng Q. Immunoglobulin Superfamily Containing Leucine-Rich Repeat (Islr) Participates in IL-6-Mediated Crosstalk between Muscle and Brown Adipose Tissue to Regulate Energy Homeostasis. Int J Mol Sci 2022; 23:10008. [PMID: 36077405 DOI: 10.3390/ijms231710008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 08/20/2022] [Accepted: 08/27/2022] [Indexed: 12/01/2022] Open
Abstract
Brown adipose tissue (BAT) is functionally linked to skeletal muscle because both tissues originate from a common progenitor cell, but the precise mechanism controlling muscle-to-brown-fat communication is insufficiently understood. This report demonstrates that the immunoglobulin superfamily containing leucine-rich repeat (Islr), a marker of mesenchymal stromal/stem cells, is critical for the control of BAT mitochondrial function and whole-body energy homeostasis. The mice loss of Islr in BAT after cardiotoxin injury resulted in improved mitochondrial function, increased energy expenditure, and enhanced thermogenesis. Importantly, it was found that interleukin-6 (IL-6), as a myokine, participates in this process. Mechanistically, Islr interacts with NADH: Ubiquinone Oxidoreductase Core Subunit S2 (Ndufs2) to regulate IL-6 signaling; consequently, Islr functions as a brake that prevents IL-6 from promoting BAT activity. Together, these findings reveal a previously unrecognized mechanism for muscle-BAT cross talk driven by Islr, Ndufs2, and IL-6 to regulate energy homeostasis, which may be used as a potential therapeutic target in obesity.
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Sharma N, Osman C. Yme2, a putative RNA recognition motif and AAA+ domain containing protein, genetically interacts with the mitochondrial protein export machinery. Biol Chem 2022; 403:807-817. [PMID: 35100666 PMCID: PMC9284673 DOI: 10.1515/hsz-2021-0398] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 01/19/2022] [Indexed: 02/04/2023]
Abstract
The mitochondrial respiratory chain is composed of nuclear as well as mitochondrial-encoded subunits. A variety of factors mediate co-translational integration of mtDNA-encoded proteins into the inner membrane. In Saccharomyces cerevisiae, Mdm38 and Mba1 are ribosome acceptors that recruit the mitochondrial ribosome to the inner membrane, where the insertase Oxa1, facilitates membrane integration of client proteins. The protein Yme2 has previously been shown to be localized in the inner mitochondrial membrane and has been implicated in mitochondrial protein biogenesis, but its mode of action remains unclear. Here, we show that multiple copies of Yme2 assemble into a high molecular weight complex. Using a combination of bioinformatics and mutational analyses, we find that Yme2 possesses an RNA recognition motif (RRM), which faces the mitochondrial matrix and a AAA+ domain that is located in the intermembrane space. We further show that YME2 genetically interacts with MDM38, MBA1 and OXA1, which links the function of Yme2 to the mitochondrial protein biogenesis machinery.
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Affiliation(s)
- Nupur Sharma
- Faculty of Biology, Ludwig Maximilian University Munich, D-82152Planegg-Martinsried, Germany
- Graduate School of Life Sciences, Ludwig Maximilian University Munich, D-82152Planegg-Martinsried, Germany
| | - Christof Osman
- Faculty of Biology, Ludwig Maximilian University Munich, D-82152Planegg-Martinsried, Germany
- Graduate School of Life Sciences, Ludwig Maximilian University Munich, D-82152Planegg-Martinsried, Germany
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Abstract
Mitochondria are vital organelles with distinct morphological features and functional properties. The dynamic network of mitochondria undergoes structural and functional adaptations in response to cell-type-specific metabolic demands. Even within the same cell, mitochondria can display wide diversity and separate into functionally distinct subpopulations. Mitochondrial heterogeneity supports unique subcellular functions and is crucial to polarized cells, such as neurons. The spatiotemporal metabolic burden within the complex shape of a neuron requires precisely localized mitochondria. By travelling great lengths throughout neurons and experiencing bouts of immobility, mitochondria meet distant local fuel demands. Understanding mitochondrial heterogeneity and homeostasis mechanisms in neurons provides a framework to probe their significance to many other cell types. Here, we put forth an outline of the multifaceted role of mitochondria in regulating neuronal physiology and cellular functions more broadly.
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Affiliation(s)
- Gulcin Pekkurnaz
- Neurobiology Department, School of Biological Sciences, University of California San Diego, La Jolla, CA, USA.
| | - Xinnan Wang
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA.
- Wu Tsai Neurosciences Institute, Stanford University School of Medicine, Stanford, CA, USA.
- Maternal & Child Health Research Institute, Stanford University School of Medicine, Stanford, CA, USA.
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Yi L, Liu B, Nixon PJ, Yu J, Chen F. Recent Advances in Understanding the Structural and Functional Evolution of FtsH Proteases. Front Plant Sci 2022; 13:837528. [PMID: 35463435 PMCID: PMC9020784 DOI: 10.3389/fpls.2022.837528] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 02/24/2022] [Indexed: 05/18/2023]
Abstract
The FtsH family of proteases are membrane-anchored, ATP-dependent, zinc metalloproteases. They are universally present in prokaryotes and the mitochondria and chloroplasts of eukaryotic cells. Most bacteria bear a single ftsH gene that produces hexameric homocomplexes with diverse house-keeping roles. However, in mitochondria, chloroplasts and cyanobacteria, multiple FtsH homologs form homo- and heterocomplexes with specialized functions in maintaining photosynthesis and respiration. The diversification of FtsH homologs combined with selective pairing of FtsH isomers is a versatile strategy to enable functional adaptation. In this article we summarize recent progress in understanding the evolution, structure and function of FtsH proteases with a focus on the role of FtsH in photosynthesis and respiration.
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Affiliation(s)
- Lanbo Yi
- Institute for Food and Bioresource Engineering, College of Engineering, Peking University, Beijing, China
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, China
- Institute for Innovative Development of Food Industry, Shenzhen University, Shenzhen, China
| | - Bin Liu
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, China
- Institute for Innovative Development of Food Industry, Shenzhen University, Shenzhen, China
| | - Peter J. Nixon
- Sir Ernst Chain Building-Wolfson Laboratories, Department of Life Sciences, Imperial College London, London, United Kingdom
- *Correspondence: Peter J. Nixon, ; orcid.org/0000-0003-1952-6937
| | - Jianfeng Yu
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, China
- Sir Ernst Chain Building-Wolfson Laboratories, Department of Life Sciences, Imperial College London, London, United Kingdom
- Jianfeng Yu, ; orcid.org/0000-0001-7174-3803
| | - Feng Chen
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, China
- Institute for Innovative Development of Food Industry, Shenzhen University, Shenzhen, China
- Feng Chen, ; orcid.org/0000-0002-9054-943X
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Abstract
Mitochondria contain two membranes, the outer and inner membrane. The outer membrane fulfills crucial functions for the communication of mitochondria with the cellular environment like exchange of lipids via organelle contact sites, the transport of metabolites and the formation of a signaling platform in apoptosis and innate immunity. The translocase of the outer membrane (TOM complex) forms the entry gate for the vast majority of precursor proteins that are produced on cytosolic ribosomes. Surveillance of the functionality of outer membrane proteins is critical for mitochondrial functions and biogenesis. Quality control mechanisms remove defective and mistargeted proteins from the outer membrane as well as precursor proteins that clog the TOM complex. Selective degradation of single proteins is also an important mode to regulate mitochondrial dynamics and initiation of mitophagy pathways. Whereas inner mitochondrial compartments are equipped with specific proteases, the ubiquitin-proteasome system is a central player in protein surveillance on the mitochondrial surface. In this review, we summarize our current knowledge about the molecular mechanisms that govern quality control of proteins at the outer mitochondrial membrane.
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Affiliation(s)
- Fabian den Brave
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Bonn, Bonn, Germany
| | - Arushi Gupta
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Bonn, Bonn, Germany
| | - Thomas Becker
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Bonn, Bonn, Germany
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Luo S, Kim C. Current Understanding of Temperature Stress-Responsive Chloroplast FtsH Metalloproteases. Int J Mol Sci 2021; 22:ijms222212106. [PMID: 34829988 PMCID: PMC8622299 DOI: 10.3390/ijms222212106] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 11/07/2021] [Accepted: 11/08/2021] [Indexed: 12/22/2022] Open
Abstract
Low and high temperatures are life-threatening stress factors, diminishing plant productivity. One of the earliest responses of plants to stress is a rapid burst of reactive oxygen species (ROS) in chloroplasts. Widespread efforts over the past decade shed new light on the chloroplast as an environmental sensor, translating the environmental fluctuation into varying physiological responses by utilizing distinct retrograde (chloroplast-to-nucleus) signals. Recent studies have unveiled that chloroplasts mediate a similar unfolded/misfolded/damaged protein response (cpUPR) as observed in the endoplasmic reticulum and mitochondria. Although observing cpUPR is not surprising since the chloroplast is a prime organelle producing harmful ROS, the intertwined relationship among ROS, protein damage, and chloroplast protein quality controls (cpPQCs) with retrograde signaling has recently been reported. This finding also gives rise to critical attention on chloroplast proteins involved in cpPQCs, ROS detoxifiers, transcription/translation, import of precursor proteins, and assembly/maturation, the deficiency of which compromises chloroplast protein homeostasis (proteostasis). Any perturbation in the protein may require readjustment of proteostasis by transmitting retrograde signal(s) to the nucleus, whose genome encodes most of the chloroplast proteins involved in proteostasis. This review focuses on recent findings on cpUPR and chloroplast-targeted FILAMENTOUS TEMPERATURE-SENSITIVE H proteases involved in cpPQC and retrograde signaling and their impacts on plant responses to temperature stress.
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Affiliation(s)
- Shengji Luo
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China;
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Chanhong Kim
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China;
- Correspondence:
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Pacheco R, Quezada SA, Kalergis AM, Becker MI, Ferreira J, De Ioannes AE. Allergens of the urushiol family promote mitochondrial dysfunction by inhibiting the electron transport at the level of cytochromes b and chemically modify cytochrome c 1. Biol Res 2021; 54:35. [PMID: 34711292 PMCID: PMC8554850 DOI: 10.1186/s40659-021-00357-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 10/06/2021] [Indexed: 11/10/2022] Open
Abstract
Background Urushiols are pro-electrophilic haptens that cause severe contact dermatitis mediated by CD8+ effector T-cells and downregulated by CD4+ T-cells. However, the molecular mechanism by which urushiols stimulate innate immunity in the initial stages of this allergic reaction is poorly understood. Here we explore the sub-cellular mechanisms by which urushiols initiate the allergic response. Results Electron microscopy observations of mouse ears exposed to litreol (3-n-pentadecyl-10-enyl-catechol]) showed keratinocytes containing swollen mitochondria with round electron-dense inclusion bodies in the matrix. Biochemical analyses of sub-mitochondrial fractions revealed an inhibitory effect of urushiols on electron flow through the mitochondrial respiratory chain, which requires both the aliphatic and catecholic moieties of these allergens. Moreover, urushiols extracted from poison ivy/oak (mixtures of 3-n-pentadecyl-8,11,13 enyl/3-n-heptadecyl-8,11 enyl catechol) exerted a higher inhibitory effect on mitochondrial respiration than did pentadecyl catechol or litreol, indicating that the higher number of unsaturations in the aliphatic chain, stronger the allergenicity of urushiols. Furthermore, the analysis of radioactive proteins isolated from mitochondria incubated with 3H-litreol, indicated that this urushiol was bound to cytochrome c1. According to the proximity of cytochromes c1 and b, functional evidence indicated the site of electron flow inhibition was within complex III, in between cytochromes bL (cyt b566) and bH (cyt b562). Conclusion Our data provide functional and molecular evidence indicating that the interruption of the mitochondrial electron transport chain constitutes an important mechanism by which urushiols initiates the allergic response. Thus, mitochondria may constitute a source of cellular targets for generating neoantigens involved in the T-cell mediated allergy induced by urushiols. Supplementary Information The online version contains supplementary material available at 10.1186/s40659-021-00357-z.
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Affiliation(s)
- Rodrigo Pacheco
- Laboratorio de Neuroinmunología, Fundación Ciencia & Vida, Santiago, Chile. .,Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile.
| | - Sergio A Quezada
- Cancer Immunology Unit, University College London (UCL) Cancer Institute, London, England, UK
| | - Alexis M Kalergis
- Instituto Milenio de Inmunología e Inmunoterapia, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Departamento de Endocrinología, Facultad de Medicina, Pontificia Universidad Católica, Santiago, Chile
| | - María Inés Becker
- Fundación Ciencia y Tecnología para el Desarrollo (FUCITED), Santiago, Chile.,Department of Research and Development, Biosonda Corporation, Santiago, Chile.,Faculty of Physical and Mathematical Sciences, Department of Chemical Engineering, Biotechnology and Materials, Universidad de Chile, Santiago, Chile
| | - Jorge Ferreira
- Faculty of Medicine, Institute of Biomedical Sciences, Molecular and Clinical Pharmacology Program, Universidad de Chile, Santiago, Chile
| | - Alfredo E De Ioannes
- Department of Research and Development, Biosonda Corporation, Santiago, Chile.,Faculty of Physical and Mathematical Sciences, Department of Chemical Engineering, Biotechnology and Materials, Universidad de Chile, Santiago, Chile.,Faculty of Medicine, Institute of Biomedical Sciences, Molecular and Clinical Pharmacology Program, Universidad de Chile, Santiago, Chile
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Yousefi R, Jevdokimenko K, Kluever V, Pacheu-Grau D, Fornasiero EF. Influence of Subcellular Localization and Functional State on Protein Turnover. Cells 2021; 10:cells10071747. [PMID: 34359917 PMCID: PMC8306977 DOI: 10.3390/cells10071747] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 07/02/2021] [Accepted: 07/07/2021] [Indexed: 12/14/2022] Open
Abstract
Protein homeostasis is an equilibrium of paramount importance that maintains cellular performance by preserving an efficient proteome. This equilibrium avoids the accumulation of potentially toxic proteins, which could lead to cellular stress and death. While the regulators of proteostasis are the machineries controlling protein production, folding and degradation, several other factors can influence this process. Here, we have considered two factors influencing protein turnover: the subcellular localization of a protein and its functional state. For this purpose, we used an imaging approach based on the pulse-labeling of 17 representative SNAP-tag constructs for measuring protein lifetimes. With this approach, we obtained precise measurements of protein turnover rates in several subcellular compartments. We also tested a selection of mutants modulating the function of three extensively studied proteins, the Ca2+ sensor calmodulin, the small GTPase Rab5a and the brain creatine kinase (CKB). Finally, we followed up on the increased lifetime observed for the constitutively active Rab5a (Q79L), and we found that its stabilization correlates with enlarged endosomes and increased interaction with membranes. Overall, our data reveal that both changes in protein localization and functional state are key modulators of protein turnover, and protein lifetime fluctuations can be considered to infer changes in cellular behavior.
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Affiliation(s)
- Roya Yousefi
- Department of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073 Göttingen, Germany; (R.Y.); (K.J.); (V.K.)
- Department of Cellular Biochemistry, University Medical Center Göttingen, 37073 Göttingen, Germany;
| | - Kristina Jevdokimenko
- Department of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073 Göttingen, Germany; (R.Y.); (K.J.); (V.K.)
| | - Verena Kluever
- Department of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073 Göttingen, Germany; (R.Y.); (K.J.); (V.K.)
| | - David Pacheu-Grau
- Department of Cellular Biochemistry, University Medical Center Göttingen, 37073 Göttingen, Germany;
| | - Eugenio F. Fornasiero
- Department of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073 Göttingen, Germany; (R.Y.); (K.J.); (V.K.)
- Correspondence:
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14
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Wang Y, Li X, Zhao F. MCU-Dependent mROS Generation Regulates Cell Metabolism and Cell Death Modulated by the AMPK/PGC-1α/SIRT3 Signaling Pathway. Front Med (Lausanne) 2021; 8:674986. [PMID: 34307407 PMCID: PMC8299052 DOI: 10.3389/fmed.2021.674986] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 06/14/2021] [Indexed: 11/13/2022] Open
Abstract
The mitochondrial calcium uniporter is an intensively investigated calcium channel, and its molecular components, structural features, and encoded genes have long been explored. Further studies have shown that the mitochondrial calcium unidirectional transporter (MCU) is a macromolecular complex related to intracellular and extracellular calcium regulation. Based on the current understanding, the MCU is crucial for maintaining cytosolic Ca2+ (cCa2+) homeostasis by modulating mitochondrial Ca2+ (mCa2+) uptake. The elevation of MCU-induced calcium levels is confirmed to be the main cause of mitochondrial reactive oxygen species (mROS) generation, which leads to disordered cellular metabolic patterns and cell death. In particular, in an I/R injury model, cancer cells, and adipocytes, MCU expression is maintained at high levels. As is well accepted, the AMPK/PGC-1α/SIRT3 pathway is believed to have an affinity for mROS formation and energy consumption. Therefore, we identified a link between MCU-related mROS formation and the AMPK/PGC-1α/SIRT3 signaling pathway in controlling cell metabolism and cell death, which may provide a new possibility of targeting the MCU to reverse relevant diseases.
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Affiliation(s)
- Yuxin Wang
- Department of Orthopaedic Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiang Li
- Department of Orthopaedic Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Fengchao Zhao
- Department of Orthopaedic Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
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15
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Cormio A, Sanguedolce F, Pesce V, Musicco C. Mitochondrial Caseinolytic Protease P: A Possible Novel Prognostic Marker and Therapeutic Target in Cancer. Int J Mol Sci 2021; 22:6228. [PMID: 34207660 DOI: 10.3390/ijms22126228] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 06/06/2021] [Accepted: 06/07/2021] [Indexed: 12/25/2022] Open
Abstract
Caseinolytic protease P (ClpP) is a mitochondrial serine protease. In mammalian cells, the heterodimerization of ClpP and its AAA+ ClpX chaperone results in a complex called ClpXP, which has a relevant role in protein homeostasis and in maintaining mitochondrial functionality through the degradation of mitochondrial misfolded or damaged proteins. Recent studies demonstrate that ClpP is upregulated in primary and metastatic human tumors, supports tumor cell proliferation, and its overexpression desensitizes cells to cisplatin. Interestingly, small modulators of ClpP activity, both activators and inhibitors, are able to impair oxidative phosphorylation in cancer cells and to induce apoptosis. This review provides an overview of the role of ClpP in regulating mitochondrial functionality, in supporting tumor cell proliferation and cisplatin resistance; finally, we discuss whether this protease could represent a new prognostic marker and therapeutic target for the treatment of cancer.
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16
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Ivanova A, Ghifari AS, Berkowitz O, Whelan J, Murcha MW. The mitochondrial AAA protease FTSH3 regulates Complex I abundance by promoting its disassembly. Plant Physiol 2021; 186:599-610. [PMID: 33616659 PMCID: PMC8154063 DOI: 10.1093/plphys/kiab074] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 01/28/2021] [Indexed: 06/02/2023]
Abstract
ATP is generated in mitochondria by oxidative phosphorylation. Complex I (NADH:ubiquinone oxidoreductase or NADH dehydrogenase) is the first multisubunit protein complex of this pathway, oxidizing NADH and transferring electrons to the ubiquinone pool. Typically, Complex I mutants display a slow growth rate compared to wild-type plants. Here, using a forward genetic screen approach for restored growth of a Complex I mutant, we have identified the mitochondrial ATP-dependent metalloprotease, Filamentous Temperature Sensitive H 3 (FTSH3), as a factor that is required for the disassembly of Complex I. An ethyl methanesulfonate-induced mutation in FTSH3, named as rmb1 (restoration of mitochondrial biogenesis 1), restored Complex I abundance and plant growth. Complementation could be achieved with FTSH3 lacking proteolytic activity, suggesting the unfoldase function of FTSH3 has a role in Complex I disassembly. The introduction of the rmb1 to an additional, independent, and extensively characterized Complex I mutant, ndufs4, resulted in similar increases to Complex I abundance and a partial restoration of growth. These results show that disassembly or degradation of Complex I plays a role in determining its steady-state abundance and thus turnover may vary under different conditions.
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Affiliation(s)
- Aneta Ivanova
- School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Perth 6009, Australia
- The ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, 35 Stirling Highway, Crawley, Perth 6009, Australia
| | - Abi S Ghifari
- School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Perth 6009, Australia
- The ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, 35 Stirling Highway, Crawley, Perth 6009, Australia
| | - Oliver Berkowitz
- Department of Animal, Plant and Soil Science, School of Life Science, The ARC Centre of Excellence in Plant Energy Biology, La Trobe University, Bundoora 3086, Vic, Australia
| | - James Whelan
- Department of Animal, Plant and Soil Science, School of Life Science, The ARC Centre of Excellence in Plant Energy Biology, La Trobe University, Bundoora 3086, Vic, Australia
| | - Monika W Murcha
- School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Perth 6009, Australia
- The ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, 35 Stirling Highway, Crawley, Perth 6009, Australia
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17
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Pareek G, Pallanck LJ. Inactivation of the mitochondrial protease Afg3l2 results in severely diminished respiratory chain activity and widespread defects in mitochondrial gene expression. PLoS Genet 2020; 16:e1009118. [PMID: 33075064 PMCID: PMC7595625 DOI: 10.1371/journal.pgen.1009118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 10/29/2020] [Accepted: 09/15/2020] [Indexed: 11/18/2022] Open
Abstract
The m-AAA proteases play a critical role in the proteostasis of inner mitochondrial membrane proteins, and mutations in the genes encoding these proteases cause severe incurable neurological diseases. To further explore the biological role of the m-AAA proteases and the pathological consequences of their deficiency, we used a genetic approach in the fruit fly Drosophila melanogaster to inactivate the ATPase family gene 3-like 2 (AFG3L2) gene, which encodes a critical component of the m-AAA proteases. We found that null alleles of Drosophila AFG3L2 die early in development, but partial inactivation of AFG3L2 using RNAi allowed survival to the late pupal and adult stages of development. Flies with partial inactivation of AFG3L2 exhibited behavioral defects, neurodegeneration, accumulation of unfolded mitochondrial proteins, and diminished respiratory chain (RC) activity. Further work revealed that the reduced RC activity was primarily a consequence of severely diminished mitochondrial transcription and translation. These defects were accompanied by activation of the mitochondrial unfolded protein response (mito-UPR) and autophagy. Overexpression of mito-UPR components partially rescued the AFG3L2-deficient phenotypes, indicating that protein aggregation partly accounts for the defects of AFG3L2-deficient animals. Our work suggests that strategies designed to activate mitochondrial stress pathways and mitochondrial gene expression could be therapeutic in the diseases caused by mutations in AFG3L2.
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Affiliation(s)
- Gautam Pareek
- Department of Genome Sciences, University of Washington, Seattle, United States of America
| | - Leo J. Pallanck
- Department of Genome Sciences, University of Washington, Seattle, United States of America
- * E-mail:
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18
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Wali G, Kumar KR, Liyanage E, Davis RL, Mackay-Sim A, Sue CM. Mitochondrial Function in Hereditary Spastic Paraplegia: Deficits in SPG7 but Not SPAST Patient-Derived Stem Cells. Front Neurosci 2020; 14:820. [PMID: 32973427 PMCID: PMC7469654 DOI: 10.3389/fnins.2020.00820] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 07/14/2020] [Indexed: 12/22/2022] Open
Abstract
Mutations in SPG7 and SPAST are common causes of hereditary spastic paraplegia (HSP). While some SPG7 mutations cause paraplegin deficiency, other SPG7 mutations cause increased paraplegin expression. Mitochondrial function has been studied in models that are paraplegin-deficient (human, mouse, and Drosophila models with large exonic deletions, null mutations, or knockout models) but not in models of mutations that express paraplegin. Here, we evaluated mitochondrial function in olfactory neurosphere-derived cells, derived from patients with a variety of SPG7 mutations that express paraplegin and compared them to cells derived from healthy controls and HSP patients with SPAST mutations, as a disease control. We quantified paraplegin expression and an extensive range of mitochondrial morphology measures (fragmentation, interconnectivity, and mass), mitochondrial function measures (membrane potential, oxidative phosphorylation, and oxidative stress), and cell proliferation. Compared to control cells, SPG7 patient cells had increased paraplegin expression, fragmented mitochondria with low interconnectivity, reduced mitochondrial mass, decreased mitochondrial membrane potential, reduced oxidative phosphorylation, reduced ATP content, increased mitochondrial oxidative stress, and reduced cellular proliferation. Mitochondrial dysfunction was specific to SPG7 patient cells and not present in SPAST patient cells, which displayed mitochondrial functions similar to control cells. The mitochondrial dysfunction observed here in SPG7 patient cells that express paraplegin was similar to the dysfunction reported in cell models without paraplegin expression. The p.A510V mutation was common to all patients and was the likely species associated with increased expression, albeit seemingly non-functional. The lack of a mitochondrial phenotype in SPAST patient cells indicates genotype-specific mechanisms of disease in these HSP patients.
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Affiliation(s)
- Gautam Wali
- Department of Neurogenetics, Royal North Shore Hospital, Kolling Institute of Medical Research, The University of Sydney, Sydney, NSW, Australia.,Faculty of Medicine and Health, Sydney Medical School, The University of Sydney, Sydney, NSW, Australia
| | - Kishore Raj Kumar
- Department of Neurogenetics, Royal North Shore Hospital, Kolling Institute of Medical Research, The University of Sydney, Sydney, NSW, Australia.,Faculty of Medicine and Health, Sydney Medical School, The University of Sydney, Sydney, NSW, Australia.,Molecular Medicine Laboratory, Department of Neurology, Concord Hospital, Sydney, NSW, Australia.,Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Sydney, NSW, Australia.,Department of Neurology, Royal North Shore Hospital, Northern Sydney Local Health District, Sydney, NSW, Australia
| | - Erandhi Liyanage
- Department of Neurogenetics, Royal North Shore Hospital, Kolling Institute of Medical Research, The University of Sydney, Sydney, NSW, Australia
| | - Ryan L Davis
- Department of Neurogenetics, Royal North Shore Hospital, Kolling Institute of Medical Research, The University of Sydney, Sydney, NSW, Australia.,Faculty of Medicine and Health, Sydney Medical School, The University of Sydney, Sydney, NSW, Australia.,Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Sydney, NSW, Australia
| | - Alan Mackay-Sim
- Faculty of Medicine and Health, Sydney Medical School, The University of Sydney, Sydney, NSW, Australia.,Griffith Institute for Drug Discovery, Griffith University, Brisbane, QLD, Australia
| | - Carolyn M Sue
- Department of Neurogenetics, Royal North Shore Hospital, Kolling Institute of Medical Research, The University of Sydney, Sydney, NSW, Australia.,Faculty of Medicine and Health, Sydney Medical School, The University of Sydney, Sydney, NSW, Australia.,Department of Neurology, Royal North Shore Hospital, Northern Sydney Local Health District, Sydney, NSW, Australia
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19
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Frazier AE, Compton AG, Kishita Y, Hock DH, Welch AE, Amarasekera SSC, Rius R, Formosa LE, Imai-Okazaki A, Francis D, Wang M, Lake NJ, Tregoning S, Jabbari JS, Lucattini A, Nitta KR, Ohtake A, Murayama K, Amor DJ, McGillivray G, Wong FY, van der Knaap MS, Jeroen Vermeulen R, Wiltshire EJ, Fletcher JM, Lewis B, Baynam G, Ellaway C, Balasubramaniam S, Bhattacharya K, Freckmann ML, Arbuckle S, Rodriguez M, Taft RJ, Sadedin S, Cowley MJ, Minoche AE, Calvo SE, Mootha VK, Ryan MT, Okazaki Y, Stroud DA, Simons C, Christodoulou J, Thorburn DR. Fatal perinatal mitochondrial cardiac failure caused by recurrent de novo duplications in the ATAD3 locus. Med (N Y) 2020; 2:49-73. [PMID: 33575671 DOI: 10.1016/j.medj.2020.06.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Background In about half of all patients with a suspected monogenic disease, genomic investigations fail to identify the diagnosis. A contributing factor is the difficulty with repetitive regions of the genome, such as those generated by segmental duplications. The ATAD3 locus is one such region, in which recessive deletions and dominant duplications have recently been reported to cause lethal perinatal mitochondrial diseases characterized by pontocerebellar hypoplasia or cardiomyopathy, respectively. Methods Whole exome, whole genome and long-read DNA sequencing techniques combined with studies of RNA and quantitative proteomics were used to investigate 17 subjects from 16 unrelated families with suspected mitochondrial disease. Findings We report six different de novo duplications in the ATAD3 gene locus causing a distinctive presentation including lethal perinatal cardiomyopathy, persistent hyperlactacidemia, and frequently corneal clouding or cataracts and encephalopathy. The recurrent 68 Kb ATAD3 duplications are identifiable from genome and exome sequencing but usually missed by microarrays. The ATAD3 duplications result in the formation of identical chimeric ATAD3A/ATAD3C proteins, altered ATAD3 complexes and a striking reduction in mitochondrial oxidative phosphorylation complex I and its activity in heart tissue. Conclusions ATAD3 duplications appear to act in a dominant-negative manner and the de novo inheritance infers a low recurrence risk for families, unlike most pediatric mitochondrial diseases. More than 350 genes underlie mitochondrial diseases. In our experience the ATAD3 locus is now one of the five most common causes of nuclear-encoded pediatric mitochondrial disease but the repetitive nature of the locus means ATAD3 diagnoses may be frequently missed by current genomic strategies. Funding Australian NHMRC, US Department of Defense, Japanese AMED and JSPS agencies, Australian Genomics Health Alliance and Australian Mito Foundation.
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Affiliation(s)
- Ann E Frazier
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia.,These authors contributed equally: A.E. Frazier, A.G. Compton
| | - Alison G Compton
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia.,These authors contributed equally: A.E. Frazier, A.G. Compton
| | - Yoshihito Kishita
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Juntendo University, Graduate School of Medicine, Tokyo, 113-8421, Japan
| | - Daniella H Hock
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, VIC 3052, Australia
| | - AnneMarie E Welch
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia
| | - Sumudu S C Amarasekera
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia
| | - Rocio Rius
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia
| | - Luke E Formosa
- Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC 3800, Australia
| | - Atsuko Imai-Okazaki
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Juntendo University, Graduate School of Medicine, Tokyo, 113-8421, Japan.,Division of Genomic Medicine Research, Medical Genomics Center, National Center for Global Health and Medicine, Tokyo 162-8655, Japan
| | - David Francis
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia
| | - Min Wang
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia
| | - Nicole J Lake
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia.,Department of Genetics, Yale School of Medicine, New Haven, CT 06510, USA
| | - Simone Tregoning
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia.,Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia
| | - Jafar S Jabbari
- Australian Genome Research Facility Ltd, Victorian Comprehensive Cancer Centre, Melbourne VIC 3052, Australia
| | - Alexis Lucattini
- Australian Genome Research Facility Ltd, Victorian Comprehensive Cancer Centre, Melbourne VIC 3052, Australia
| | - Kazuhiro R Nitta
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Juntendo University, Graduate School of Medicine, Tokyo, 113-8421, Japan
| | - Akira Ohtake
- Department of Pediatrics & Clinical Genomics, Saitama Medical University Hospital, Saitama, 350-0495, Japan
| | - Kei Murayama
- Department of Metabolism, Chiba Children's Hospital, Chiba, 266-0007, Japan
| | - David J Amor
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia
| | - George McGillivray
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia
| | - Flora Y Wong
- Ritchie Centre, Hudson Institute of Medical Research; Department of Paediatrics, Monash University; and Monash Newborn, Monash Children's Hospital, Melbourne, VIC 3168, Australia
| | - Marjo S van der Knaap
- Child Neurology, Emma Children's Hospital, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, 1081 HV Amsterdam, The Netherlands.,Functional Genomics, Center for Neurogenomics and Cognitive Research, Vrije Universiteit and Amsterdam Neuroscience, 1081 HV Amsterdam, The Netherlands
| | - R Jeroen Vermeulen
- Department of Neurology, Maastricht University Medical Center, 6229 HX, Maastricht, The Netherlands
| | - Esko J Wiltshire
- Department of Paediatrics and Child Health, University of Otago Wellington and Capital and Coast District Health Board, Wellington 6021, New Zealand
| | - Janice M Fletcher
- Department of Genetics and Molecular Pathology, SA Pathology, Adelaide, SA 5000, Australia
| | - Barry Lewis
- Department of Clinical Biochemistry, PathWest Laboratory Medicine Western Australia, Nedlands, WA 6009, Australia
| | - Gareth Baynam
- Western Australian Register of Developmental Anomalies and Genetic Services of Western Australia and King Edward Memorial Hospital for Women Perth, Subiaco, WA 6008, Australia.,Telethon Kids Institute and School of Paediatrics and Child Health, The University of Western Australia, Perth, WA 6009, Australia
| | - Carolyn Ellaway
- Genetic Metabolic Disorders Service, Sydney Children's Hospital Network, The Children's Hospital at Westmead, Sydney, NSW 2145, Australia.,Disciplines of Genomic Medicine and Child and Adolescent Health, Sydney Medical School, University of Sydney, NSW 2145, Australia
| | - Shanti Balasubramaniam
- Genetic Metabolic Disorders Service, Sydney Children's Hospital Network, The Children's Hospital at Westmead, Sydney, NSW 2145, Australia
| | - Kaustuv Bhattacharya
- Genetic Metabolic Disorders Service, Sydney Children's Hospital Network, The Children's Hospital at Westmead, Sydney, NSW 2145, Australia.,Disciplines of Genomic Medicine and Child and Adolescent Health, Sydney Medical School, University of Sydney, NSW 2145, Australia
| | | | - Susan Arbuckle
- Department of Histopathology, The Children's Hospital at Westmead, Sydney Children's Hospital Network, Sydney, NSW 2145, Australia
| | - Michael Rodriguez
- Discipline of Pathology, School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | | | - Simon Sadedin
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia.,Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia
| | - Mark J Cowley
- Children's Cancer Institute, Kensington, NSW 2750, Australia; St Vincent's Clinical School, UNSW Sydney, Darlinghurst, NSW 2010, Australia.,Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Darlinghurst, NSW 2010, Australia
| | - André E Minoche
- Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Darlinghurst, NSW 2010, Australia
| | - Sarah E Calvo
- Broad Institute, Cambridge, MA 02142, USA; Howard Hughes Medical Institute and Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Harvard Medical School, Boston, MA 02446, USA
| | - Vamsi K Mootha
- Broad Institute, Cambridge, MA 02142, USA; Howard Hughes Medical Institute and Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Harvard Medical School, Boston, MA 02446, USA
| | - Michael T Ryan
- Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC 3800, Australia
| | - Yasushi Okazaki
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Juntendo University, Graduate School of Medicine, Tokyo, 113-8421, Japan
| | - David A Stroud
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, VIC 3052, Australia
| | - Cas Simons
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia.,Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072 Australia
| | - John Christodoulou
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia.,Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia.,Disciplines of Genomic Medicine and Child and Adolescent Health, Sydney Medical School, University of Sydney, NSW 2145, Australia
| | - David R Thorburn
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia.,Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia.,Lead contact
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20
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Venditti P, Di Meo S. The Role of Reactive Oxygen Species in the Life Cycle of the Mitochondrion. Int J Mol Sci 2020; 21:E2173. [PMID: 32245255 DOI: 10.3390/ijms21062173] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 03/12/2020] [Accepted: 03/19/2020] [Indexed: 02/07/2023] Open
Abstract
Currently, it is known that, in living systems, free radicals and other reactive oxygen and nitrogen species play a double role, because they can cause oxidative damage and tissue dysfunction and serve as molecular signals activating stress responses that are beneficial to the organism. It is also known that mitochondria, because of their capacity to produce free radicals, play a major role in tissue oxidative damage and dysfunction and provide protection against excessive tissue dysfunction through several mechanisms, including the stimulation of permeability transition pore opening. This process leads to mitoptosis and mitophagy, two sequential processes that are a universal route of elimination of dysfunctional mitochondria and is essential to protect cells from the harm due to mitochondrial disordered metabolism. To date, there is significant evidence not only that the above processes are induced by enhanced reactive oxygen species (ROS) production, but also that such production is involved in the other phases of the mitochondrial life cycle. Accumulating evidence also suggests that these effects are mediated through the regulation of the expression and the activity of proteins that are engaged in processes such as genesis, fission, fusion, and removal of mitochondria. This review provides an account of the developments of the knowledge on the dynamics of the mitochondrial population, examining the mechanisms governing their genesis, life, and death, and elucidating the role played by free radicals in such processes.
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21
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Abstract
Mitochondria are essential for the viability of eukaryotic cells as they perform crucial functions in bioenergetics, metabolism and signalling and have been associated with numerous diseases. Recent functional and proteomic studies have revealed the remarkable complexity of mitochondrial protein organization. Protein machineries with diverse functions such as protein translocation, respiration, metabolite transport, protein quality control and the control of membrane architecture interact with each other in dynamic networks. In this Review, we discuss the emerging role of the mitochondrial protein import machinery as a key organizer of these mitochondrial protein networks. The preprotein translocases that reside on the mitochondrial membranes not only function during organelle biogenesis to deliver newly synthesized proteins to their final mitochondrial destination but also cooperate with numerous other mitochondrial protein complexes that perform a wide range of functions. Moreover, these protein networks form membrane contact sites, for example, with the endoplasmic reticulum, that are key for integration of mitochondria with cellular function, and defects in protein import can lead to diseases.
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Affiliation(s)
- Nikolaus Pfanner
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany. .,CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
| | - Bettina Warscheid
- CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany.,Institute of Biology II, Biochemistry - Functional Proteomics, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Nils Wiedemann
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany. .,CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
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22
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Abstract
Mitochondria are essential metabolic hubs that dynamically adapt to physiological demands. More than 40 proteases residing in different compartments of mitochondria, termed mitoproteases, preserve mitochondrial proteostasis and are emerging as central regulators of mitochondrial plasticity. These multifaceted enzymes limit the accumulation of short-lived, regulatory proteins within mitochondria, modulate the activity of mitochondrial proteins by protein processing, and mediate the degradation of damaged proteins. Various signaling cascades coordinate the activity of mitoproteases to preserve mitochondrial homeostasis and ensure cell survival. Loss of mitoproteases severely impairs the functional integrity of mitochondria, is associated with aging, and causes pleiotropic diseases. Understanding the dual function of mitoproteases as regulatory and quality control enzymes will help unravel the role of mitochondrial plasticity in aging and disease.
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Affiliation(s)
- Soni Deshwal
- Max Planck Institute for Biology of Ageing, 50931 Cologne, Germany;
| | - Kai Uwe Fiedler
- Max Planck Institute for Biology of Ageing, 50931 Cologne, Germany;
| | - Thomas Langer
- Max Planck Institute for Biology of Ageing, 50931 Cologne, Germany; .,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany
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23
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Zheng J, Li L, Jiang H. Molecular pathways of mitochondrial outer membrane protein degradation. Biochem Soc Trans 2019; 47:1437-47. [DOI: 10.1042/bst20190275] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 09/12/2019] [Accepted: 09/17/2019] [Indexed: 01/23/2023]
Abstract
Abstract
Mitochondrial outer membrane (MOM) encloses inner compartments of mitochondria and integrates cytoplasmic signals to regulate essential mitochondrial processes, such as protein import, dynamics, metabolism, cell death, etc. A substantial understanding of MOM associated proteostatic stresses and quality control pathways has been obtained in recent years. Six MOM associated protein degradation (MAD) pathways center on three AAA ATPases: Cdc48 in the cytoplasm, Msp1 integral to MOM, and Yme1 integral to the inner membrane. These pathways survey MOM proteome from the cytoplasmic and the inter-membrane space (IMS) sides. They detect and degrade MOM proteins with misfolded cytoplasmic and IMS domains, remove mistargeted tail-anchored proteins, and clear mitochondrial precursor proteins clogged in the TOM import complex. These MOM associated protein quality control pathways collaboratively maintain mitochondrial proteostasis and cell viability.
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24
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Hannah-Shmouni F, MacNeil L, Brady L, Nilsson MI, Tarnopolsky M. Expanding the Clinical Spectrum of LONP1-Related Mitochondrial Cytopathy. Front Neurol 2019; 10:981. [PMID: 31636596 PMCID: PMC6787162 DOI: 10.3389/fneur.2019.00981] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 08/28/2019] [Indexed: 12/12/2022] Open
Abstract
Pathogenic variants in the LONP1 gene have been associated with CODAS syndrome (Cerebral, Ocular, Dental, Auricular, and Skeletal Anomalies Syndrome). A recent report identified the first newborn case with LONP1-related mitochondrial cytopathy due to a compound heterozygous pathogenic variant in LONP1 without features of CODAS. The proband had manifested with severe congenital lactic acidosis and profound multiple respiratory chain complex activity deficiencies associated with the quantitative loss of mtDNA copy number in muscle. A subsequent report identified two siblings with regression during infancy, profound hypotonia and muscle weakness, severe intellectual disability, progressive cerebellar atrophy, where muscle biopsy showed an electron dense mitochondrial inclusions without ragged-red fibers and normal electron transport chain enzyme activities. Here, we report an additional case of autosomal recessive mitochondrial cytopathy due to a homozygous missense variant in LONP1 that was identified on whole exome sequencing (c.810G > A; p.D463N). The proband, a 20-year-old male born to consanguineous parents, presented with global developmental delay, emotional outbursts, speech and swallowing difficulties, hypotonia, and ataxia since childhood. Muscle biopsy showed massive granular bodies, increased oxidative stress, and autophagic block and reduced mitochondrial state 3 respiration. We have identified another case of LONP1-related mitochondrial cytopathy further confirming a neurological phenotype without CODAS features.
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Affiliation(s)
- Fady Hannah-Shmouni
- Clinical Biochemical Genetics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada.,Section on Endocrinology and Genetics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Lauren MacNeil
- Division of Pediatric Laboratory Medicine, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Lauren Brady
- Department of Pediatrics, McMaster University, Hamilton, ON, Canada
| | - Mats I Nilsson
- Department of Pediatrics, McMaster University, Hamilton, ON, Canada
| | - Mark Tarnopolsky
- Department of Pediatrics, McMaster University, Hamilton, ON, Canada
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25
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Coyne LP, Chen XJ. Consequences of inner mitochondrial membrane protein misfolding. Mitochondrion 2019; 49:46-55. [PMID: 31195097 DOI: 10.1016/j.mito.2019.06.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 05/07/2019] [Accepted: 06/06/2019] [Indexed: 02/04/2023]
Abstract
Proteins embedded in the inner mitochondrial membrane (IMM) perform essential cellular functions. Maintaining the folding state of these proteins is therefore of the utmost importance, and this is ensured by IMM chaperones and proteases that refold and degrade unassembled and misfolded proteins. However, the physiological consequences specific to IMM protein misfolding remain obscure because deletion of these chaperones/proteases (the typical experimental strategy) often affects many mitochondrial processes other than protein folding and turnover. Thus, novel experimental systems are needed to evaluate the direct effects of misfolded protein on the membrane. Such a system has been developed in recent years. Studies suggest that numerous pathogenic mutations in isoform 1 of adenine nucleotide translocase (Ant1) cause its misfolding on the IMM. In this review, we first discuss potential mechanisms by which dominant Ant1 mutations may cause disease, highlighting IMM protein misfolding, per se, as a likely pathological factor. Then we discuss the intramitochondrial effects of Ant1 misfolding such as IMM proteostatic stress, respiratory chain dysfunction, and mtDNA instability. Finally, we summarize the mounting evidence that IMM proteostatic stress can perturb mitochondrial protein import to cause the toxic accumulation of mitochondrial proteins in the cytosol: a cell stress mechanism termed mitochondrial Precursor Overaccumulation Stress (mPOS).
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Affiliation(s)
- Liam P Coyne
- Departments of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY, USA
| | - Xin Jie Chen
- Departments of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY, USA; Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, NY, USA.
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26
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Granatiero V, Manfredi G. Mitochondrial Transport and Turnover in the Pathogenesis of Amyotrophic Lateral Sclerosis. Biology (Basel) 2019; 8:E36. [PMID: 31083575 DOI: 10.3390/biology8020036] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Revised: 01/20/2019] [Accepted: 02/03/2019] [Indexed: 02/06/2023]
Abstract
Neurons are high-energy consuming cells, heavily dependent on mitochondria for ATP generation and calcium buffering. These mitochondrial functions are particularly critical at specific cellular sites, where ionic currents impose a large energetic burden, such as at synapses. The highly polarized nature of neurons, with extremely large axoplasm relative to the cell body, requires mitochondria to be efficiently transported along microtubules to reach distant sites. Furthermore, neurons are post-mitotic cells that need to maintain pools of healthy mitochondria throughout their lifespan. Hence, mitochondrial transport and turnover are essential processes for neuronal survival and function. In neurodegenerative diseases, the maintenance of a healthy mitochondrial network is often compromised. Numerous lines of evidence indicate that mitochondrial impairment contributes to neuronal demise in a variety of neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), where degeneration of motor neurons causes a fatal muscle paralysis. Dysfunctional mitochondria accumulate in motor neurons affected by genetic or sporadic forms of ALS, strongly suggesting that the inability to maintain a healthy pool of mitochondria plays a pathophysiological role in the disease. This article critically reviews current hypotheses on mitochondrial involvement in the pathogenesis of ALS, focusing on the alterations of mitochondrial axonal transport and turnover in motor neurons.
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27
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Chen X, Glytsou C, Zhou H, Narang S, Reyna DE, Lopez A, Sakellaropoulos T, Gong Y, Kloetgen A, Yap YS, Wang E, Gavathiotis E, Tsirigos A, Tibes R, Aifantis I. Targeting Mitochondrial Structure Sensitizes Acute Myeloid Leukemia to Venetoclax Treatment. Cancer Discov 2019; 9:890-909. [PMID: 31048321 DOI: 10.1158/2159-8290.cd-19-0117] [Citation(s) in RCA: 158] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Revised: 04/15/2019] [Accepted: 04/30/2019] [Indexed: 02/06/2023]
Abstract
The BCL2 family plays important roles in acute myeloid leukemia (AML). Venetoclax, a selective BCL2 inhibitor, has received FDA approval for the treatment of AML. However, drug resistance ensues after prolonged treatment, highlighting the need for a greater understanding of the underlying mechanisms. Using a genome-wide CRISPR/Cas9 screen in human AML, we identified genes whose inactivation sensitizes AML blasts to venetoclax. Genes involved in mitochondrial organization and function were significantly depleted throughout our screen, including the mitochondrial chaperonin CLPB. We demonstrated that CLPB is upregulated in human AML, it is further induced upon acquisition of venetoclax resistance, and its ablation sensitizes AML to venetoclax. Mechanistically, CLPB maintains the mitochondrial cristae structure via its interaction with the cristae-shaping protein OPA1, whereas its loss promotes apoptosis by inducing cristae remodeling and mitochondrial stress responses. Overall, our data suggest that targeting mitochondrial architecture may provide a promising approach to circumvent venetoclax resistance. SIGNIFICANCE: A genome-wide CRISPR/Cas9 screen reveals genes involved in mitochondrial biological processes participate in the acquisition of venetoclax resistance. Loss of the mitochondrial protein CLPB leads to structural and functional defects of mitochondria, hence sensitizing AML cells to apoptosis. Targeting CLPB synergizes with venetoclax and the venetoclax/azacitidine combination in AML in a p53-independent manner.See related commentary by Savona and Rathmell, p. 831.This article is highlighted in the In This Issue feature, p. 813.
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Affiliation(s)
- Xufeng Chen
- Department of Pathology, NYU Langone Health and NYU School of Medicine, New York, New York.,Laura and Isaac Perlmutter Cancer Center, NYU Langone Health and NYU School of Medicine, New York, New York
| | - Christina Glytsou
- Department of Pathology, NYU Langone Health and NYU School of Medicine, New York, New York.,Laura and Isaac Perlmutter Cancer Center, NYU Langone Health and NYU School of Medicine, New York, New York
| | - Hua Zhou
- Applied Bioinformatics Laboratories, NYU School of Medicine, New York, New York
| | - Sonali Narang
- Laura and Isaac Perlmutter Cancer Center, NYU Langone Health and NYU School of Medicine, New York, New York
| | - Denis E Reyna
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York.,Department of Medicine, Albert Einstein College of Medicine, Bronx, New York.,Albert Einstein Cancer Center, Albert Einstein College of Medicine, Bronx, New York
| | - Andrea Lopez
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York.,Department of Medicine, Albert Einstein College of Medicine, Bronx, New York.,Albert Einstein Cancer Center, Albert Einstein College of Medicine, Bronx, New York
| | - Theodore Sakellaropoulos
- Department of Pathology, NYU Langone Health and NYU School of Medicine, New York, New York.,Laura and Isaac Perlmutter Cancer Center, NYU Langone Health and NYU School of Medicine, New York, New York
| | - Yixiao Gong
- Department of Pathology, NYU Langone Health and NYU School of Medicine, New York, New York.,Laura and Isaac Perlmutter Cancer Center, NYU Langone Health and NYU School of Medicine, New York, New York.,Marie-Josée and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Andreas Kloetgen
- Department of Pathology, NYU Langone Health and NYU School of Medicine, New York, New York.,Laura and Isaac Perlmutter Cancer Center, NYU Langone Health and NYU School of Medicine, New York, New York
| | - Yoon Sing Yap
- Department of Pathology, NYU Langone Health and NYU School of Medicine, New York, New York.,Laura and Isaac Perlmutter Cancer Center, NYU Langone Health and NYU School of Medicine, New York, New York
| | - Eric Wang
- Department of Pathology, NYU Langone Health and NYU School of Medicine, New York, New York.,Laura and Isaac Perlmutter Cancer Center, NYU Langone Health and NYU School of Medicine, New York, New York
| | - Evripidis Gavathiotis
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York.,Department of Medicine, Albert Einstein College of Medicine, Bronx, New York.,Albert Einstein Cancer Center, Albert Einstein College of Medicine, Bronx, New York
| | - Aristotelis Tsirigos
- Department of Pathology, NYU Langone Health and NYU School of Medicine, New York, New York.,Laura and Isaac Perlmutter Cancer Center, NYU Langone Health and NYU School of Medicine, New York, New York.,Applied Bioinformatics Laboratories, NYU School of Medicine, New York, New York
| | - Raoul Tibes
- Laura and Isaac Perlmutter Cancer Center, NYU Langone Health and NYU School of Medicine, New York, New York.
| | - Iannis Aifantis
- Department of Pathology, NYU Langone Health and NYU School of Medicine, New York, New York. .,Laura and Isaac Perlmutter Cancer Center, NYU Langone Health and NYU School of Medicine, New York, New York
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28
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Li L, Zheng J, Wu X, Jiang H. Mitochondrial AAA-ATPase Msp1 detects mislocalized tail-anchored proteins through a dual-recognition mechanism. EMBO Rep 2019; 20:embr.201846989. [PMID: 30858337 DOI: 10.15252/embr.201846989] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 01/28/2019] [Accepted: 02/11/2019] [Indexed: 01/09/2023] Open
Abstract
The conserved AAA-ATPase Msp1 is embedded in the outer mitochondrial membrane and removes mislocalized tail-anchored (TA) proteins upon dysfunction of the guided entry of tail-anchored (GET) pathway. It remains unclear how Msp1 recognizes its substrates. Here, we extensively characterize Msp1 and its substrates, including the mitochondrially targeted Pex15Δ30, and full-length Pex15, which mislocalizes to mitochondria upon dysfunction of Pex19 but not the GET pathway. Moreover, we identify two new substrates, Frt1 and Ysy6. Our results suggest that mislocalized TA proteins expose hydrophobic surfaces in the cytoplasm and are recognized by Msp1 through conserved hydrophobic residues. Introducing a hydrophobic patch into mitochondrial TA proteins transforms them into Msp1 substrates. In addition, Pex15Δ30 and Frt1 contain basic inter-membrane space (IMS) residues critical for their mitochondrial mistargeting. Remarkably, Msp1 recognizes this feature through the acidic D12 residue in its IMS domain. This dual-recognition mechanism involving interactions at the cytoplasmic and IMS domains of Msp1 and substrates greatly facilitates substrate recognition and is required by Msp1 to safeguard mitochondrial functions.
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Affiliation(s)
- Lanlan Li
- College of Life Sciences, Beijing Normal University, Beijing, China.,National Institute of Biological Sciences, Beijing, China.,Beijing Key Laboratory of Cell Biology for Animal Aging, Beijing, China
| | - Jing Zheng
- National Institute of Biological Sciences, Beijing, China.,Beijing Key Laboratory of Cell Biology for Animal Aging, Beijing, China.,School of Life Sciences, Peking University, Beijing, China
| | - Xi Wu
- National Institute of Biological Sciences, Beijing, China
| | - Hui Jiang
- National Institute of Biological Sciences, Beijing, China .,Beijing Key Laboratory of Cell Biology for Animal Aging, Beijing, China.,Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China
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29
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Vanhauwaert R, Bharat V, Wang X. Surveillance and transportation of mitochondria in neurons. Curr Opin Neurobiol 2019; 57:87-93. [PMID: 30784981 DOI: 10.1016/j.conb.2019.01.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 01/14/2019] [Indexed: 10/27/2022]
Abstract
Neurons need to allocate and sustain mitochondria to provide adequate energy and sufficient Ca2+-buffering capacity in each sub specialization of their extensive arborizations. Damaged mitochondria, which are highly deleterious to the neuron, must be rapidly repaired or eliminated, even when they are left at terminals extremely far away from the soma. The unique shape of neurons complicates the tasks of both transporting and clearing mitochondria. Errors in the underlying molecular regulations cause detrimental neurodegeneration. Here, we review the molecular machinery and regulatory mechanisms employed to transport, distribute, and clear mitochondria in neurons, and how these fundamental regulations are compromised in neurological disorders.
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Affiliation(s)
- Roeland Vanhauwaert
- Department of Neurosurgery, Stanford University School of Medicine, Palo Alto, CA 94304, United States
| | - Vinita Bharat
- Department of Neurosurgery, Stanford University School of Medicine, Palo Alto, CA 94304, United States
| | - Xinnan Wang
- Department of Neurosurgery, Stanford University School of Medicine, Palo Alto, CA 94304, United States.
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30
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Peter B, Waddington CL, Oláhová M, Sommerville EW, Hopton S, Pyle A, Champion M, Ohlson M, Siibak T, Chrzanowska-Lightowlers ZMA, Taylor RW, Falkenberg M, Lightowlers RN. Defective mitochondrial protease LonP1 can cause classical mitochondrial disease. Hum Mol Genet 2019. [PMID: 29518248 PMCID: PMC5932559 DOI: 10.1093/hmg/ddy080] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
LonP1 is a mitochondrial matrix protease whose selective substrate specificity is essential for maintaining mitochondrial homeostasis. Recessively inherited, pathogenic defects in LonP1 have been previously reported to underlie cerebral, ocular, dental, auricular and skeletal anomalies (CODAS) syndrome, a complex multisystemic and developmental disorder. Intriguingly, although classical mitochondrial disease presentations are well-known to exhibit marked clinical heterogeneity, the skeletal and dental features associated with CODAS syndrome are pathognomonic. We have applied whole exome sequencing to a patient with congenital lactic acidosis, muscle weakness, profound deficiencies in mitochondrial oxidative phosphorylation associated with loss of mtDNA copy number and MRI abnormalities consistent with Leigh syndrome, identifying biallelic variants in the LONP1 (NM_004793.3) gene; c.1693T > C predicting p.(Tyr565His) and c.2197G > A predicting p.(Glu733Lys); no evidence of the classical skeletal or dental defects observed in CODAS syndrome patients were noted in our patient. In vitro experiments confirmed the p.(Tyr565His) LonP1 mutant alone could not bind or degrade a substrate, consistent with the predicted function of Tyr565, whilst a second missense [p.(Glu733Lys)] variant had minimal effect. Mixtures of p.(Tyr565His) mutant and wild-type LonP1 retained partial protease activity but this was severely depleted when the p.(Tyr565His) mutant was mixed with the p.(Glu733Lys) mutant, data consistent with the compound heterozygosity detected in our patient. In summary, we conclude that pathogenic LONP1 variants can lead to a classical mitochondrial disease presentations associated with severe biochemical defects in oxidative phosphorylation in clinically relevant tissues.
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Affiliation(s)
- Bradley Peter
- Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Christie L Waddington
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Monika Oláhová
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Ewen W Sommerville
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Newcastle upon Tyne, UK.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Sila Hopton
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Angela Pyle
- Wellcome Centre for Mitochondrial Research, Institute of Genetics, The Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Michael Champion
- Department of Inherited Metabolic Disease, Guy's and St Thomas' NHS Foundation Trusts, Evelina London Children's Hospital, London, UK
| | - Monica Ohlson
- Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Triinu Siibak
- Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | | | - Robert W Taylor
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Maria Falkenberg
- Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Robert N Lightowlers
- Wellcome Centre for Mitochondrial Research, Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne, UK
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31
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Ghosh S, Iadarola DM, Ball WB, Gohil VM. Mitochondrial dysfunctions in barth syndrome. IUBMB Life 2019; 71:791-801. [PMID: 30746873 DOI: 10.1002/iub.2018] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 01/14/2019] [Accepted: 01/15/2019] [Indexed: 12/18/2022]
Abstract
Barth syndrome (BTHS) is a rare multisystemic genetic disorder caused by mutations in the TAZ gene. TAZ encodes a mitochondrial enzyme that remodels the acyl chain composition of newly synthesized cardiolipin, a phospholipid unique to mitochondrial membranes. The clinical abnormalities observed in BTHS patients are caused by perturbations in various mitochondrial functions that rely on remodeled cardiolipin. However, the contribution of different cardiolipin-dependent mitochondrial functions to the pathology of BTHS is not fully understood. In this review, we will discuss recent findings from different genetic models of BTHS, including the yeast model of cardiolipin deficiency that has uncovered the specific in vivo roles of cardiolipin in mitochondrial respiratory chain biogenesis, bioenergetics, intermediary metabolism, mitochondrial dynamics, and quality control. We will also describe findings from higher eukaryotic models of BTHS that highlight a link between cardiolipin-dependent mitochondrial function and its impact on tissue and organ function. © 2019 IUBMB Life, 9999(9999):1-11, 2019.
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Affiliation(s)
- Sagnika Ghosh
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA
| | - Donna M Iadarola
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA
| | - Writoban Basu Ball
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA
| | - Vishal M Gohil
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA
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32
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Cadete VJJ, Vasam G, Menzies KJ, Burelle Y. Mitochondrial quality control in the cardiac system: An integrative view. Biochim Biophys Acta Mol Basis Dis 2018; 1865:782-796. [PMID: 30472159 DOI: 10.1016/j.bbadis.2018.11.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 10/29/2018] [Accepted: 11/15/2018] [Indexed: 01/26/2023]
Abstract
Recent studies have led to the discovery of multiple mitochondrial quality control (mQC) processes that operate at various scales, ranging from the degradation of proteins by mitochondrial proteases to the degradation of selected cargos or entire organelles in lysosomes. While the mechanisms governing these mQC processes are progressively being delineated, their role and importance remain unclear. Converging evidence however point to a complex system whereby multiple and partly overlapping processes are recruited to orchestrate a cell type specific mQC response that is adapted to the physiological state and level of stress encountered. Knowledge gained from basic model systems of mQC therefore need to be integrated within organ-specific (patho)physiological frameworks. Building on this notion, this article focuses on mQC in the heart, where developmental metabolic reprogramming, sustained contraction, and multiple pathophysiological conditions pose broadly different constraints. We provide an overview of current knowledge of mQC processes, and discuss their implication in cardiac mQC under normal and diseased conditions.
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Affiliation(s)
- Virgilio J J Cadete
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada; Sinclair Centre for Regenerative Medicine, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Goutham Vasam
- Interdisciplinary School of Health Sciences, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Keir J Menzies
- Interdisciplinary School of Health Sciences, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada; Department of Biochemistry, Microbiology and Immunology, University of Ottawa Brain and Mind Research Institute and Centre for Neuromuscular Disease, University of Ottawa, Ottawa, ON, Canada
| | - Yan Burelle
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada; Interdisciplinary School of Health Sciences, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada.
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33
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Mancini C, Hoxha E, Iommarini L, Brussino A, Richter U, Montarolo F, Cagnoli C, Parolisi R, Gondor Morosini DI, Nicolò V, Maltecca F, Muratori L, Ronchi G, Geuna S, Arnaboldi F, Donetti E, Giorgio E, Cavalieri S, Di Gregorio E, Pozzi E, Ferrero M, Riberi E, Casari G, Altruda F, Turco E, Gasparre G, Battersby BJ, Porcelli AM, Ferrero E, Brusco A, Tempia F. Mice harbouring a SCA28 patient mutation in AFG3L2 develop late-onset ataxia associated with enhanced mitochondrial proteotoxicity. Neurobiol Dis 2018; 124:14-28. [PMID: 30389403 DOI: 10.1016/j.nbd.2018.10.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 10/05/2018] [Accepted: 10/28/2018] [Indexed: 12/20/2022] Open
Abstract
Spinocerebellar ataxia 28 is an autosomal dominant neurodegenerative disorder caused by missense mutations affecting the proteolytic domain of AFG3L2, a major component of the mitochondrial m-AAA protease. However, little is known of the underlying pathogenetic mechanisms or how to treat patients with SCA28. Currently available Afg3l2 mutant mice harbour deletions that lead to severe, early-onset neurological phenotypes that do not faithfully reproduce the late-onset and slowly progressing SCA28 phenotype. Here we describe production and detailed analysis of a new knock-in murine model harbouring an Afg3l2 allele carrying the p.Met665Arg patient-derived mutation. Heterozygous mutant mice developed normally but adult mice showed signs of cerebellar ataxia detectable by beam test. Although cerebellar pathology was negative, electrophysiological analysis showed a trend towards increased spontaneous firing in Purkinje cells from heterozygous mutants with respect to wild-type controls. As homozygous mutants died perinatally with evidence of cardiac atrophy, for each genotype we generated mouse embryonic fibroblasts (MEFs) to investigate mitochondrial function. MEFs from mutant mice showed altered mitochondrial bioenergetics, with decreased basal oxygen consumption rate, ATP synthesis and mitochondrial membrane potential. Mitochondrial network formation and morphology was altered, with greatly reduced expression of fusogenic Opa1 isoforms. Mitochondrial alterations were also detected in cerebella of 18-month-old heterozygous mutants and may be a hallmark of disease. Pharmacological inhibition of de novo mitochondrial protein translation with chloramphenicol caused reversal of mitochondrial morphology in homozygous mutant MEFs, supporting the relevance of mitochondrial proteotoxicity for SCA28 pathogenesis and therapy development.
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Affiliation(s)
- Cecilia Mancini
- Department of Medical Sciences, University of Torino, Torino, Italy
| | - Eriola Hoxha
- Department of Neuroscience, University of Torino, Torino, Italy; Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Italy
| | - Luisa Iommarini
- Department of Pharmacy and Biotechnologies (FABIT), University of Bologna, Bologna, Italy
| | | | - Uwe Richter
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Francesca Montarolo
- Department of Neuroscience, University of Torino, Torino, Italy; Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Italy
| | - Claudia Cagnoli
- Department of Medical Sciences, University of Torino, Torino, Italy
| | - Roberta Parolisi
- Department of Neuroscience, University of Torino, Torino, Italy; Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Italy
| | - Diana Iulia Gondor Morosini
- Department of Neuroscience, University of Torino, Torino, Italy; Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Italy
| | - Valentina Nicolò
- Department of Neuroscience, University of Torino, Torino, Italy; Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Italy
| | - Francesca Maltecca
- Università Vita-Salute San Raffaele, Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy
| | - Luisa Muratori
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Italy; Department of Clinical and Biological Sciences, University of Torino, Torino, Italy
| | - Giulia Ronchi
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Italy; Department of Clinical and Biological Sciences, University of Torino, Torino, Italy
| | - Stefano Geuna
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Italy; Department of Clinical and Biological Sciences, University of Torino, Torino, Italy
| | - Francesca Arnaboldi
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milan, Italy
| | - Elena Donetti
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milan, Italy
| | - Elisa Giorgio
- Department of Medical Sciences, University of Torino, Torino, Italy
| | - Simona Cavalieri
- Department of Medical Sciences, University of Torino, Torino, Italy
| | - Eleonora Di Gregorio
- Medical Genetics Unit, Città della Salute e della Scienza University Hospital, Torino, Italy
| | - Elisa Pozzi
- Department of Medical Sciences, University of Torino, Torino, Italy
| | - Marta Ferrero
- Department of Medical Sciences, University of Torino, Torino, Italy
| | - Evelise Riberi
- Department of Public Health and Pediatrics, University of Torino, Torino, Italy
| | - Giorgio Casari
- Università Vita-Salute San Raffaele, Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy
| | - Fiorella Altruda
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Emilia Turco
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Giuseppe Gasparre
- Department Medical and Surgical Sciences, Medical Genetics, University of Bologna, Bologna, Italy
| | | | - Anna Maria Porcelli
- Department of Pharmacy and Biotechnologies (FABIT), University of Bologna, Bologna, Italy
| | - Enza Ferrero
- Department of Medical Sciences, University of Torino, Torino, Italy
| | - Alfredo Brusco
- Department of Medical Sciences, University of Torino, Torino, Italy; Medical Genetics Unit, Città della Salute e della Scienza University Hospital, Torino, Italy.
| | - Filippo Tempia
- Department of Neuroscience, University of Torino, Torino, Italy; Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Italy
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Vargas Möller-Hergt B, Carlström A, Suhm T, Ott M. Insertion Defects of Mitochondrially Encoded Proteins Burden the Mitochondrial Quality Control System. Cells 2018; 7:cells7100172. [PMID: 30336542 PMCID: PMC6211022 DOI: 10.3390/cells7100172] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 10/07/2018] [Accepted: 10/16/2018] [Indexed: 12/31/2022] Open
Abstract
The mitochondrial proteome contains proteins from two different genetic systems. Proteins are either synthesized in the cytosol and imported into the different compartments of the organelle or directly produced in the mitochondrial matrix. To ensure proteostasis, proteins are monitored by the mitochondrial quality control system, which will degrade non-native polypeptides. Defective mitochondrial membrane proteins are degraded by membrane-bound AAA-proteases. These proteases are regulated by factors promoting protein turnover or preventing their degradation. Here we determined genetic interactions between the mitoribosome receptors Mrx15 and Mba1 with the quality control system. We show that simultaneous absence of Mrx15 and the regulators of the i-AAA protease Mgr1 and Mgr3 provokes respiratory deficiency. Surprisingly, mutants lacking Mrx15 were more tolerant against proteotoxic stress. Furthermore, yeast cells became hypersensitive against proteotoxic stress upon deletion of MBA1. Contrary to Mrx15, Mba1 cooperates with the regulators of the m-AAA and i-AAA proteases. Taken together, these results suggest that membrane protein insertion and mitochondrial AAA-proteases are functionally coupled, possibly reflecting an early quality control step during mitochondrial protein synthesis.
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Affiliation(s)
| | - Andreas Carlström
- Department of Biochemistry and Biophysics, Stockholm University, SE-10691 Stockholm, Sweden.
| | - Tamara Suhm
- Department of Biochemistry and Biophysics, Stockholm University, SE-10691 Stockholm, Sweden.
| | - Martin Ott
- Department of Biochemistry and Biophysics, Stockholm University, SE-10691 Stockholm, Sweden.
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Opalińska M, Jańska H. AAA Proteases: Guardians of Mitochondrial Function and Homeostasis. Cells 2018; 7:E163. [PMID: 30314276 DOI: 10.3390/cells7100163] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 10/04/2018] [Accepted: 10/09/2018] [Indexed: 12/30/2022] Open
Abstract
Mitochondria are dynamic, semi-autonomous organelles that execute numerous life-sustaining tasks in eukaryotic cells. Functioning of mitochondria depends on the adequate action of versatile proteinaceous machineries. Fine-tuning of mitochondrial activity in response to cellular needs involves continuous remodeling of organellar proteome. This process not only includes modulation of various biogenetic pathways, but also the removal of superfluous proteins by adenosine triphosphate (ATP)-driven proteolytic machineries. Accordingly, all mitochondrial sub-compartments are under persistent surveillance of ATP-dependent proteases. Particularly important are highly conserved two inner mitochondrial membrane-bound metalloproteases known as m-AAA and i-AAA (ATPases associated with diverse cellular activities), whose mis-functioning may lead to impaired organellar function and consequently to development of severe diseases. Herein, we discuss the current knowledge of yeast, mammalian, and plant AAA proteases and their implications in mitochondrial function and homeostasis maintenance.
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Ruer M, Krainer G, Gröger P, Schlierf M. ATPase and Protease Domain Movements in the Bacterial AAA+ Protease FtsH Are Driven by Thermal Fluctuations. J Mol Biol 2018; 430:4592-602. [PMID: 30044948 DOI: 10.1016/j.jmb.2018.07.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 07/10/2018] [Accepted: 07/17/2018] [Indexed: 01/27/2023]
Abstract
AAA+ proteases are essential players in cellular pathways of protein degradation. Elucidating their conformational behavior is key for understanding their reaction mechanism and, importantly, for elaborating our understanding of mutation-induced protease deficiencies. Here, we study the structural dynamics of the Thermotoga maritima AAA+ hexameric ring metalloprotease FtsH (TmFtsH). Using a single-molecule Förster resonance energy transfer approach to monitor ATPase and protease inter-domain conformational changes in real time, we show that TmFtsH-even in the absence of nucleotide-is a highly dynamic protease undergoing sequential transitions between five states on the second timescale. Addition of ATP does not influence the number of states or change the timescale of domain motions but affects the state occupancy distribution leading to an inter-domain compaction. These findings suggest that thermal energy, but not chemical energy, provides the major driving force for conformational switching, while ATP, through a state reequilibration, introduces directionality into this process. The TmFtsH A359V mutation, a homolog of the human pathogenic A510V mutation of paraplegin (SPG7) causing hereditary spastic paraplegia, does not affect the dynamic behavior of the protease but impairs the ATP-coupled domain compaction and, thus, may account for protease malfunctioning and pathogenesis in hereditary spastic paraplegia.
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37
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Franco-Iborra S, Vila M, Perier C. Mitochondrial Quality Control in Neurodegenerative Diseases: Focus on Parkinson's Disease and Huntington's Disease. Front Neurosci 2018; 12:342. [PMID: 29875626 PMCID: PMC5974257 DOI: 10.3389/fnins.2018.00342] [Citation(s) in RCA: 127] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 05/02/2018] [Indexed: 12/15/2022] Open
Abstract
In recent years, several important advances have been made in our understanding of the pathways that lead to cell dysfunction and death in Parkinson's disease (PD) and Huntington's disease (HD). Despite distinct clinical and pathological features, these two neurodegenerative diseases share critical processes, such as the presence of misfolded and/or aggregated proteins, oxidative stress, and mitochondrial anomalies. Even though the mitochondria are commonly regarded as the "powerhouses" of the cell, they are involved in a multitude of cellular events such as heme metabolism, calcium homeostasis, and apoptosis. Disruption of mitochondrial homeostasis and subsequent mitochondrial dysfunction play a key role in the pathophysiology of neurodegenerative diseases, further highlighting the importance of these organelles, especially in neurons. The maintenance of mitochondrial integrity through different surveillance mechanisms is thus critical for neuron survival. Mitochondria display a wide range of quality control mechanisms, from the molecular to the organellar level. Interestingly, many of these lines of defense have been found to be altered in neurodegenerative diseases such as PD and HD. Current knowledge and further elucidation of the novel pathways that protect the cell through mitochondrial quality control may offer unique opportunities for disease therapy in situations where ongoing mitochondrial damage occurs. In this review, we discuss the involvement of mitochondrial dysfunction in neurodegeneration with a special focus on the recent findings regarding mitochondrial quality control pathways, beyond the classical effects of increased production of reactive oxygen species (ROS) and bioenergetic alterations. We also discuss how disturbances in these processes underlie the pathophysiology of neurodegenerative disorders such as PD and HD.
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Affiliation(s)
- Sandra Franco-Iborra
- Vall d'Hebron Research Institute (VHIR)-Center for Networked Biomedical Research in Neurodegenerative Diseases (CIBERNED), Barcelona, Spain
| | - Miquel Vila
- Vall d'Hebron Research Institute (VHIR)-Center for Networked Biomedical Research in Neurodegenerative Diseases (CIBERNED), Barcelona, Spain
- Catalan Institution for Research and Advanced Studies, Barcelona, Spain
- Department of Biochemistry and Molecular Biology, Autonomous University of Barcelona, Barcelona, Spain
| | - Celine Perier
- Vall d'Hebron Research Institute (VHIR)-Center for Networked Biomedical Research in Neurodegenerative Diseases (CIBERNED), Barcelona, Spain
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38
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Rubalcava-Gracia D, Vázquez-Acevedo M, Funes S, Pérez-Martínez X, González-Halphen D. Mitochondrial versus nuclear gene expression and membrane protein assembly: the case of subunit 2 of yeast cytochrome c oxidase. Mol Biol Cell 2018; 29:820-833. [PMID: 29437907 PMCID: PMC5905295 DOI: 10.1091/mbc.e17-09-0560] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 01/12/2018] [Accepted: 02/01/2018] [Indexed: 12/24/2022] Open
Abstract
Deletion of the yeast mitochondrial gene COX2, encoding subunit 2 (mtCox2) of cytochrome c oxidase (CcO), results in a respiratory-incompetent Δcox2 strain. For a cytosol-synthesized Cox2 to restore respiratory growth, it must carry the W56R mutation (cCox2W56R). Nevertheless, only a fraction of cCox2W56R is matured in mitochondria, allowing ∼60% steady-state accumulation of CcO. This can be attributed either to the point mutation or to an inefficient biogenesis of cCox2W56R. We generated a strain expressing the mutant protein mtCox2W56R inside mitochondria which should follow the canonical biogenesis of mitochondria-encoded Cox2. This strain exhibited growth rates, CcO steady-state levels, and CcO activity similar to those of the wild type; therefore, the efficiency of Cox2 biogenesis is the limiting step for successful allotopic expression. Upon coexpression of cCox2W56R and mtCox2, each protein assembled into CcO independently from its genetic origin, resulting in a mixed population of CcO with most complexes containing the mtCox2 version. Notably, the presence of the mtCox2 enhances cCox2W56R incorporation. We provide proof of principle that an allotopically expressed Cox2 may complement a phenotype due to a mutant mitochondrial COX2 gene. These results are relevant to developing a rational design of genes for allotopic expression intended to treat human mitochondrial diseases.
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Affiliation(s)
- Diana Rubalcava-Gracia
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510 Ciudad México, D. F., Mexico
| | - Miriam Vázquez-Acevedo
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510 Ciudad México, D. F., Mexico
| | - Soledad Funes
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510 Ciudad México, D. F., Mexico
| | - Xochitl Pérez-Martínez
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510 Ciudad México, D. F., Mexico
| | - Diego González-Halphen
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510 Ciudad México, D. F., Mexico
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Puchades C, Rampello AJ, Shin M, Giuliano CJ, Wiseman RL, Glynn SE, Lander GC. Structure of the mitochondrial inner membrane AAA+ protease YME1 gives insight into substrate processing. Science 2018; 358:358/6363/eaao0464. [PMID: 29097521 DOI: 10.1126/science.aao0464] [Citation(s) in RCA: 149] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 09/25/2017] [Indexed: 12/20/2022]
Abstract
We present an atomic model of a substrate-bound inner mitochondrial membrane AAA+ quality control protease in yeast, YME1. Our ~3.4-angstrom cryo-electron microscopy structure reveals how the adenosine triphosphatases (ATPases) form a closed spiral staircase encircling an unfolded substrate, directing it toward the flat, symmetric protease ring. Three coexisting nucleotide states allosterically induce distinct positioning of tyrosines in the central channel, resulting in substrate engagement and translocation to the negatively charged proteolytic chamber. This tight coordination by a network of conserved residues defines a sequential, around-the-ring adenosine triphosphate hydrolysis cycle that results in stepwise substrate translocation. A hingelike linker accommodates the large-scale nucleotide-driven motions of the ATPase spiral relative to the planar proteolytic base. The translocation mechanism is likely conserved for other AAA+ ATPases.
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Affiliation(s)
- Cristina Puchades
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute HZ 175, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.,Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Anthony J Rampello
- Department of Biochemistry and Cell Biology, Stony Brook University, 450 Life Sciences Building, Stony Brook, NY 11794, USA
| | - Mia Shin
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute HZ 175, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.,Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Christopher J Giuliano
- Department of Biochemistry and Cell Biology, Stony Brook University, 450 Life Sciences Building, Stony Brook, NY 11794, USA
| | - R Luke Wiseman
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Steven E Glynn
- Department of Biochemistry and Cell Biology, Stony Brook University, 450 Life Sciences Building, Stony Brook, NY 11794, USA.
| | - Gabriel C Lander
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute HZ 175, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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40
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Abstract
The function of mitochondria depends on ubiquitously expressed and evolutionary conserved m-AAA proteases in the inner membrane. These ATP-dependent peptidases form hexameric complexes built up of homologous subunits. AFG3L2 subunits assemble either into homo-oligomeric isoenzymes or with SPG7 (paraplegin) subunits into hetero-oligomeric proteolytic complexes. Mutations in AFG3L2 are associated with dominant spinocerebellar ataxia (SCA28) characterized by the loss of Purkinje cells, whereas mutations in SPG7 cause a recessive form of hereditary spastic paraplegia (HSP7) with motor neurons of the cortico-spinal tract being predominantly affected. Pleiotropic functions have been assigned to m-AAA proteases, which act as quality control and regulatory enzymes in mitochondria. Loss of m-AAA proteases affects mitochondrial protein synthesis and respiration and leads to mitochondrial fragmentation and deficiencies in the axonal transport of mitochondria. Moreover m-AAA proteases regulate the assembly of the mitochondrial calcium uniporter (MCU) complex. Impaired degradation of the MCU subunit EMRE in AFG3L2-deficient mitochondria results in the formation of deregulated MCU complexes, increased mitochondrial calcium uptake and increased vulnerability of neurons for calcium-induced cell death. A reduction of calcium influx into the cytosol of Purkinje cells rescues ataxia in an AFG3L2-deficient mouse model. In this review, we discuss the relationship between the m-AAA protease and mitochondrial calcium homeostasis and its relevance for neurodegeneration and describe a novel mouse model lacking MCU specifically in Purkinje cells. Our results pledge for a novel view on m-AAA proteases that integrates their pleiotropic functions in mitochondria to explain the pathogenesis of associated neurodegenerative disorders.
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Affiliation(s)
- Maria Patron
- Max Planck Institute for Biology of Aging, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Response in Aging-Associated Disease (CECAD), and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Hans-Georg Sprenger
- Max Planck Institute for Biology of Aging, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Response in Aging-Associated Disease (CECAD), and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Thomas Langer
- Max Planck Institute for Biology of Aging, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Response in Aging-Associated Disease (CECAD), and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
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41
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Kawamata H, Manfredi G. Proteinopathies and OXPHOS dysfunction in neurodegenerative diseases. J Cell Biol 2017; 216:3917-3929. [PMID: 29167179 PMCID: PMC5716291 DOI: 10.1083/jcb.201709172] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 11/08/2017] [Accepted: 11/10/2017] [Indexed: 12/12/2022] Open
Abstract
Mitochondria participate in essential processes in the nervous system such as energy and intermediate metabolism, calcium homeostasis, and apoptosis. Major neurodegenerative diseases are characterized pathologically by accumulation of misfolded proteins as a result of gene mutations or abnormal protein homeostasis. Misfolded proteins associate with mitochondria, forming oligomeric and fibrillary aggregates. As mitochondrial dysfunction, particularly of the oxidative phosphorylation system (OXPHOS), occurs in neurodegeneration, it is postulated that such defects are caused by the accumulation of misfolded proteins. However, this hypothesis and the pathological role of proteinopathies in mitochondria remain elusive. In this study, we critically review the proposed mechanisms whereby exemplary misfolded proteins associate with mitochondria and their consequences on OXPHOS.
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Affiliation(s)
- Hibiki Kawamata
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY
| | - Giovanni Manfredi
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY
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42
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Wu X, Li L, Jiang H. Mitochondrial inner-membrane protease Yme1 degrades outer-membrane proteins Tom22 and Om45. J Cell Biol 2017; 217:139-149. [PMID: 29138251 PMCID: PMC5748973 DOI: 10.1083/jcb.201702125] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 09/03/2017] [Accepted: 10/18/2017] [Indexed: 01/26/2023] Open
Abstract
The turnover of mitochondrial outer-membrane proteins is known to be mediated by the cytoplasmic ubiquitin–proteasome pathway. Wu et al. report the unexpected finding that two outer-membrane proteins Tom22 and Om45 are inwardly translocated into mitochondria and degraded by the inner-membrane protease Yme1. Mitochondria are double-membraned organelles playing essential metabolic and signaling functions. The mitochondrial proteome is under surveillance by two proteolysis systems: the ubiquitin–proteasome system degrades mitochondrial outer-membrane (MOM) proteins, and the AAA proteases maintain the proteostasis of intramitochondrial compartments. We previously identified a Doa1–Cdc48-Ufd1-Npl4 complex that retrogradely translocates ubiquitinated MOM proteins to the cytoplasm for degradation. In this study, we report the unexpected identification of MOM proteins whose degradation requires the Yme1-Mgr1-Mgr3i-AAA protease complex in mitochondrial inner membrane. Through immunoprecipitation and in vivo site-specific photo–cross-linking experiments, we show that both Yme1 adapters Mgr1 and Mgr3 recognize the intermembrane space (IMS) domains of the MOM substrates and facilitate their recruitment to Yme1 for proteolysis. We also provide evidence that the cytoplasmic domain of substrate can be dislocated into IMS by the ATPase activity of Yme1. Our findings indicate a proteolysis pathway monitoring MOM proteins from the IMS side and suggest that the MOM proteome is surveilled by mitochondrial and cytoplasmic quality control machineries in parallel.
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Affiliation(s)
- Xi Wu
- School of Life Sciences, Peking University, Beijing, China .,National Institute of Biological Sciences, Beijing, China
| | - Lanlan Li
- College of Life Sciences, Beijing Normal University, Beijing, China
| | - Hui Jiang
- National Institute of Biological Sciences, Beijing, China
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43
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Abstract
Abstract
The ‘oxygen paradox’ arises from the fact that oxygen, the molecule that aerobic life depends on, threatens its very existence. An oxygen-rich environment provided life on Earth with more efficient bioenergetics and, with it, the challenge of having to deal with a host of oxygen-derived reactive species capable of damaging proteins and other crucial cellular components. In this minireview, we explore recent insights into the metabolism of proteins that have been reversibly or irreversibly damaged by oxygen-derived species. We discuss recent data on the important roles played by the proteasomal and lysosomal systems in the proteolytic degradation of oxidatively damaged proteins and the effects of oxidative damage on the function of the proteolytic pathways themselves. Mitochondria are central to oxygen utilisation in the cell, and their ability to handle oxygen-derived radicals is an important and still emerging area of research. Current knowledge of the proteolytic machinery in the mitochondria, including the ATP-dependent AAA+ proteases and mitochondrial-derived vesicles, is also highlighted in the review. Significant progress is still being made in regard to understanding the mechanisms underlying the detection and degradation of oxidised proteins and how proteolytic pathways interact with each other. Finally, we highlight a few unanswered questions such as the possibility of oxidised amino acids released from oxidised proteins by proteolysis being re-utilised in protein synthesis thus establishing a vicious cycle of oxidation in cells.
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44
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Lee S, Lee H, Yoo S, Kim H. Molecular insights into the m-AAA protease-mediated dislocation of transmembrane helices in the mitochondrial inner membrane. J Biol Chem 2017; 292:20058-20066. [PMID: 29030426 DOI: 10.1074/jbc.m117.796763] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 09/29/2017] [Indexed: 11/06/2022] Open
Abstract
Protein complexes involved in respiration, ATP synthesis, and protein import reside in the mitochondrial inner membrane; thus, proper regulation of these proteins is essential for cell viability. The m-AAA protease, a conserved hetero-hexameric AAA (ATPase associated with diverse cellular activities) protease, composed of the Yta10 and Yta12 proteins, regulates mitochondrial proteostasis by mediating protein maturation and degradation. It also recognizes and mediates the dislocation of membrane-embedded substrates, including foreign transmembrane (TM) segments, but the molecular mechanism involved in these processes remains elusive. This study investigated the role of the TM domains in the m-AAA protease by systematic replacement of one TM domain at a time in yeast. Our data indicated that replacement of the Yta10 TM2 domain abolishes membrane dislocation for only a subset of substrates, whereas replacement of the Yta12 TM2 domain impairs membrane dislocation for all tested substrates, suggesting different roles of the TM domains in each m-AAA protease subunit. Furthermore, m-AAA protease-mediated membrane dislocation was impaired in the presence of a large downstream hydrophilic moiety in a membrane substrate. This finding suggested that the m-AAA protease cannot dislocate large hydrophilic domains across the membrane, indicating that the membrane dislocation probably occurs in a lipid environment. In summary, this study highlights previously underappreciated biological roles of TM domains of the m-AAA proteases in mediating the recognition and dislocation of membrane-embedded substrates.
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Affiliation(s)
- Seoeun Lee
- School of Biological Sciences, Seoul National University, Seoul 08826, South Korea
| | - Hunsang Lee
- School of Biological Sciences, Seoul National University, Seoul 08826, South Korea; Donnelly Centre, Toronto, Ontario M5S 3E1, Canada
| | - Suji Yoo
- School of Biological Sciences, Seoul National University, Seoul 08826, South Korea
| | - Hyun Kim
- School of Biological Sciences, Seoul National University, Seoul 08826, South Korea.
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45
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Schwerter DP, Grimm I, Platta HW, Erdmann R. ATP-driven processes of peroxisomal matrix protein import. Biol Chem 2017; 398:607-624. [PMID: 27977397 DOI: 10.1515/hsz-2016-0293] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 12/11/2016] [Indexed: 12/13/2022]
Abstract
In peroxisomal matrix protein import two processes directly depend on the binding and hydrolysis of ATP, both taking place at the late steps of the peroxisomal import cycle. First, ATP hydrolysis is required to initiate a ubiquitin-transfer cascade to modify the import (co-)receptors. These receptors display a dual localization in the cytosol and at the peroxisomal membrane, whereas only the membrane bound fraction receives the ubiquitin modification. The second ATP-dependent process of the import cycle is carried out by the two AAA+-proteins Pex1p and Pex6p. These ATPases form a heterohexameric complex, which is recruited to the peroxisomal import machinery by the membrane anchor protein Pex15p. The Pex1p/Pex6p complex recognizes the ubiquitinated import receptors, pulls them out of the membrane and releases them into the cytosol. There the deubiquitinated receptors are provided for further rounds of import. ATP binding and hydrolysis are required for Pex1p/Pex6p complex formation and receptor export. In this review, we summarize the current knowledge on the peroxisomal import cascade. In particular, we will focus on the ATP-dependent processes, which are so far best understood in the model organism Saccharomyces cerevisiae.
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Affiliation(s)
- Daniel P Schwerter
- Abteilung für Systembiochemie, Institut für Biochemie und Pathobiochemie, Medizinische Fakultät der Ruhr-Universität Bochum, Universitätsstr. 150, D-44780 Bochum
| | - Immanuel Grimm
- Abteilung für Systembiochemie, Institut für Biochemie und Pathobiochemie, Medizinische Fakultät der Ruhr-Universität Bochum, Universitätsstr. 150, D-44780 Bochum
| | - Harald W Platta
- Biochemie Intrazellulärer Transportprozesse, Medizinische Fakultät der Ruhr-Universität Bochum, D-44780 Bochum
| | - Ralf Erdmann
- Abteilung für Systembiochemie, Institut für Biochemie und Pathobiochemie, Medizinische Fakultät der Ruhr-Universität Bochum, Universitätsstr. 150, D-44780 Bochum
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46
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Voos W, Jaworek W, Wilkening A, Bruderek M. Protein quality control at the mitochondrion. Essays Biochem 2016; 60:213-25. [PMID: 27744337 DOI: 10.1042/EBC20160009] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 05/31/2016] [Indexed: 12/17/2022]
Abstract
Mitochondria are essential constituents of a eukaryotic cell by supplying ATP and contributing to many mayor metabolic processes. As endosymbiotic organelles, they represent a cellular subcompartment exhibiting many autonomous functions, most importantly containing a complete endogenous machinery responsible for protein expression, folding and degradation. This article summarizes the biochemical processes and the enzymatic components that are responsible for maintaining mitochondrial protein homoeostasis. As mitochondria lack a large part of the required genetic information, most proteins are synthesized in the cytosol and imported into the organelle. After reaching their destination, polypeptides must fold and assemble into active proteins. Under pathological conditions, mitochondrial proteins become misfolded or damaged and need to be repaired with the help of molecular chaperones or eventually removed by specific proteases. Failure of these protein quality control mechanisms results in loss of mitochondrial function and structural integrity. Recently, novel mechanisms have been identified that support mitochondrial quality on the organellar level. A mitochondrial unfolded protein response allows the adaptation of chaperone and protease activities. Terminally damaged mitochondria may be removed by a variation of autophagy, termed mitophagy. An understanding of the role of protein quality control in mitochondria is highly relevant for many human pathologies, in particular neurodegenerative diseases.
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Abstract
Mitochondria perform numerous functions necessary for the survival of eukaryotic cells. These activities are coordinated by a diverse complement of proteins encoded in both the nuclear and mitochondrial genomes that must be properly organized and maintained. Misregulation of mitochondrial proteostasis impairs organellar function and can result in the development of severe human diseases. ATP-driven AAA+ proteins play crucial roles in preserving mitochondrial activity by removing and remodeling protein molecules in accordance with the needs of the cell. Two mitochondrial AAA proteases, i-AAA and m-AAA, are anchored to either face of the mitochondrial inner membrane, where they engage and process an array of substrates to impact protein biogenesis, quality control, and the regulation of key metabolic pathways. The functionality of these proteases is extended through multiple substrate-dependent modes of action, including complete degradation, partial processing, or dislocation from the membrane without proteolysis. This review discusses recent advances made toward elucidating the mechanisms of substrate recognition, handling, and degradation that allow these versatile proteases to control diverse activities in this multifunctional organelle.
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Affiliation(s)
- Steven E Glynn
- Department of Biochemistry and Cell Biology, Stony Brook UniversityStony Brook, NY, United States
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48
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Abstract
Members of the ATPases Associated with various cellular Activities (AAA+) superfamily participate in essential and diverse cellular pathways in all kingdoms of life by harnessing the energy of ATP binding and hydrolysis to drive their biological functions. Although most AAA+ proteins share a ring-shaped architecture, AAA+ proteins have evolved distinct structural elements that are fine-tuned to their specific functions. A central question in the field is how ATP binding and hydrolysis are coupled to substrate translocation through the central channel of ring-forming AAA+ proteins. In this mini-review, we will discuss structural elements present in AAA+ proteins involved in protein quality control, drawing similarities to their known role in substrate interaction by AAA+ proteins involved in DNA translocation. Elements to be discussed include the pore loop-1, the Inter-Subunit Signaling (ISS) motif, and the Pre-Sensor I insert (PS-I) motif. Lastly, we will summarize our current understanding on the inter-relationship of those structural elements and propose a model how ATP binding and hydrolysis might be coupled to polypeptide translocation in protein quality control machines.
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Affiliation(s)
- Chiung-Wen Chang
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of MedicineHouston, TX, USA
| | - Sukyeong Lee
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of MedicineHouston, TX, USA
| | - Francis T F Tsai
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of MedicineHouston, TX, USA.,Departments of Molecular and Cellular Biology, and Molecular Virology and Microbiology, Baylor College of MedicineHouston, TX, USA
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Tsai CW, Wu Y, Pao PC, Phillips CB, Williams C, Miller C, Ranaghan M, Tsai MF. Proteolytic control of the mitochondrial calcium uniporter complex. Proc Natl Acad Sci U S A 2017; 114:4388-93. [PMID: 28396416 DOI: 10.1073/pnas.1702938114] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The mitochondrial calcium uniporter is a Ca2+-activated Ca2+ channel complex mediating mitochondrial Ca2+ uptake, a process crucial for Ca2+ signaling, bioenergetics, and cell death. The uniporter is composed of the pore-forming MCU protein, the gatekeeping MICU1 and MICU2 subunits, and EMRE, a single-pass membrane protein that links MCU and MICU1 together. As a bridging subunit required for channel function, EMRE could paradoxically inhibit uniporter complex formation if expressed in excess. Here, we show that mitochondrial mAAA proteases AFG3L2 and SPG7 rapidly degrade unassembled EMRE using the energy of ATP hydrolysis. Once EMRE is incorporated into the complex, its turnover is inhibited >15-fold. Protease-resistant EMRE mutants produce uniporter subcomplexes that induce constitutive Ca2+ leakage into mitochondria, a condition linked to debilitating neuromuscular disorders in humans. The results highlight the dynamic nature of uniporter subunit assembly, which must be tightly regulated to ensure proper mitochondrial responses to intracellular Ca2+ signals.
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Bischof J, Salzmann M, Streubel MK, Hasek J, Geltinger F, Duschl J, Bresgen N, Briza P, Haskova D, Lejskova R, Sopjani M, Richter K, Rinnerthaler M. Clearing the outer mitochondrial membrane from harmful proteins via lipid droplets. Cell Death Discov 2017; 3:17016. [PMID: 28386457 DOI: 10.1038/cddiscovery.2017.16] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 01/27/2017] [Accepted: 02/10/2017] [Indexed: 01/25/2023] Open
Abstract
In recent years it turned out that there is not only extensive communication between the nucleus and mitochondria but also between mitochondria and lipid droplets (LDs) as well. We were able to demonstrate that a number of proteins shuttle between LDs and mitochondria and it depends on the metabolic state of the cell on which organelle these proteins are predominantly localized. Responsible for the localization of the particular proteins is a protein domain consisting of two α-helices, which we termed V-domain according to the predicted structure. So far we have detected this domain in the following proteins: mammalian BAX, BCL-XL, TCTP and yeast Mmi1p and Erg6p. According to our experiments there are two functions of this domain: (1) shuttling of proteins to mitochondria in times of stress and apoptosis; (2) clearing the outer mitochondrial membrane from pro- as well as anti-apoptotic proteins by moving them to LDs after the stress ceases. In this way the LDs are used by the cell to modulate stress response.
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