1
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Zarges C, Riemer J. Oxidative protein folding in the intermembrane space of human mitochondria. FEBS Open Bio 2024; 14:1610-1626. [PMID: 38867508 PMCID: PMC11452306 DOI: 10.1002/2211-5463.13839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Revised: 05/03/2024] [Accepted: 05/23/2024] [Indexed: 06/14/2024] Open
Abstract
The mitochondrial intermembrane space hosts a machinery for oxidative protein folding, the mitochondrial disulfide relay. This machinery imports a large number of soluble proteins into the compartment, where they are retained through oxidative folding. Additionally, the disulfide relay enhances the stability of many proteins by forming disulfide bonds. In this review, we describe the mitochondrial disulfide relay in human cells, its components, and their coordinated collaboration in mechanistic detail. We also discuss the human pathologies associated with defects in this machinery and its protein substrates, providing a comprehensive overview of its biological importance and implications for health.
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Affiliation(s)
| | - Jan Riemer
- Institute for BiochemistryUniversity of CologneGermany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging‐Associated Diseases (CECAD)University of CologneGermany
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2
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Pines O, Horwitz M, Herrmann JM. Privileged proteins with a second residence: dual targeting and conditional re-routing of mitochondrial proteins. FEBS J 2024. [PMID: 38857249 DOI: 10.1111/febs.17191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 04/15/2024] [Accepted: 05/22/2024] [Indexed: 06/12/2024]
Abstract
Almost all mitochondrial proteins are encoded by nuclear genes and synthesized in the cytosol as precursor proteins. Signals in the amino acid sequence of these precursors ensure their targeting and translocation into mitochondria. However, in many cases, only a certain fraction of a specific protein is transported into mitochondria, while the rest either remains in the cytosol or undergoes reverse translocation to the cytosol, and can populate other cellular compartments. This phenomenon is called dual localization which can be instigated by different mechanisms. These include alternative start or stop codons, differential transcripts, and ambiguous or competing targeting sequences. In many cases, dual localization might serve as an economic strategy to reduce the number of required genes; for example, when the same groups of enzymes are required both in mitochondria and chloroplasts or both in mitochondria and the nucleus/cytoplasm. Such cases frequently employ ambiguous targeting sequences to distribute proteins between both organelles. However, alternative localizations can also be used for signaling, for example when non-imported precursors serve as mitophagy signals or when they represent transcription factors in the nucleus to induce the mitochondrial unfolded stress response. This review provides an overview regarding the mechanisms and the physiological consequences of dual targeting.
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Affiliation(s)
- Ophry Pines
- Microbiology and Genetics, Faculty of Medicine, Hebrew University of Jerusalem, Israel
| | - Margalit Horwitz
- Microbiology and Genetics, Faculty of Medicine, Hebrew University of Jerusalem, Israel
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3
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Krakowczyk M, Lenkiewicz AM, Sitarz T, Malinska D, Borrero M, Mussulini BHM, Linke V, Szczepankiewicz AA, Biazik JM, Wydrych A, Nieznanska H, Serwa RA, Chacinska A, Bragoszewski P. OMA1 protease eliminates arrested protein import intermediates upon mitochondrial depolarization. J Cell Biol 2024; 223:e202306051. [PMID: 38530280 PMCID: PMC10964989 DOI: 10.1083/jcb.202306051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 12/28/2023] [Accepted: 02/16/2024] [Indexed: 03/27/2024] Open
Abstract
Most mitochondrial proteins originate from the cytosol and require transport into the organelle. Such precursor proteins must be unfolded to pass through translocation channels in mitochondrial membranes. Misfolding of transported proteins can result in their arrest and translocation failure. Arrested proteins block further import, disturbing mitochondrial functions and cellular proteostasis. Cellular responses to translocation failure have been defined in yeast. We developed the cell line-based translocase clogging model to discover molecular mechanisms that resolve failed import events in humans. The mechanism we uncover differs significantly from these described in fungi, where ATPase-driven extraction of blocked protein is directly coupled with proteasomal processing. We found human cells to rely primarily on mitochondrial factors to clear translocation channel blockage. The mitochondrial membrane depolarization triggered proteolytic cleavage of the stalled protein, which involved mitochondrial protease OMA1. The cleavage allowed releasing the protein fragment that blocked the translocase. The released fragment was further cleared in the cytosol by VCP/p97 and the proteasome.
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Affiliation(s)
- Magda Krakowczyk
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Anna M. Lenkiewicz
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Tomasz Sitarz
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - Dominika Malinska
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Mayra Borrero
- IMol Polish Academy of Sciences, Warsaw, Poland
- ReMedy International Research Agenda Unit, IMol Polish Academy of Sciences, Warsaw, Poland
| | - Ben Hur Marins Mussulini
- IMol Polish Academy of Sciences, Warsaw, Poland
- ReMedy International Research Agenda Unit, IMol Polish Academy of Sciences, Warsaw, Poland
| | - Vanessa Linke
- IMol Polish Academy of Sciences, Warsaw, Poland
- ReMedy International Research Agenda Unit, IMol Polish Academy of Sciences, Warsaw, Poland
| | | | - Joanna M. Biazik
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
- University of New South Wales, Sydney, Australia
| | - Agata Wydrych
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Hanna Nieznanska
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Remigiusz A. Serwa
- IMol Polish Academy of Sciences, Warsaw, Poland
- ReMedy International Research Agenda Unit, IMol Polish Academy of Sciences, Warsaw, Poland
| | - Agnieszka Chacinska
- IMol Polish Academy of Sciences, Warsaw, Poland
- ReMedy International Research Agenda Unit, IMol Polish Academy of Sciences, Warsaw, Poland
| | - Piotr Bragoszewski
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
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4
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Yang EJN, Liao PC, Pon L. Mitochondrial protein and organelle quality control-Lessons from budding yeast. IUBMB Life 2024; 76:72-87. [PMID: 37731280 PMCID: PMC10842221 DOI: 10.1002/iub.2783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 08/11/2023] [Indexed: 09/22/2023]
Abstract
Mitochondria are essential for normal cellular function and have emerged as key aging determinants. Indeed, defects in mitochondrial function have been linked to cardiovascular, skeletal muscle and neurodegenerative diseases, premature aging, and age-linked diseases. Here, we describe mechanisms for mitochondrial protein and organelle quality control. These surveillance mechanisms mediate repair or degradation of damaged or mistargeted mitochondrial proteins, segregate mitochondria based on their functional state during asymmetric cell division, and modulate cellular fitness, the response to stress, and lifespan control in yeast and other eukaryotes.
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Affiliation(s)
- Emily Jie-Ning Yang
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY 10032
| | - Pin-Chao Liao
- Institute of Molecular Medicine & Department of Life Science, National Tsing Hua University, Hsinchu, Taiwan 30013
| | - Liza Pon
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY 10032
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5
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Poerschke S, Oeljeklaus S, Cruz-Zaragoza LD, Schenzielorz A, Dahal D, Hillen HS, Das H, Kremer LS, Valpadashi A, Breuer M, Sattmann J, Richter-Dennerlein R, Warscheid B, Dennerlein S, Rehling P. Identification of TMEM126A as OXA1L-interacting protein reveals cotranslational quality control in mitochondria. Mol Cell 2024; 84:345-358.e5. [PMID: 38199007 PMCID: PMC10805001 DOI: 10.1016/j.molcel.2023.12.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 10/17/2023] [Accepted: 12/08/2023] [Indexed: 01/12/2024]
Abstract
Cellular proteostasis requires transport of polypeptides across membranes. Although defective transport processes trigger cytosolic rescue and quality control mechanisms that clear translocases and membranes from unproductive cargo, proteins that are synthesized within mitochondria are not accessible to these mechanisms. Mitochondrial-encoded proteins are inserted cotranslationally into the inner membrane by the conserved insertase OXA1L. Here, we identify TMEM126A as a OXA1L-interacting protein. TMEM126A associates with mitochondrial ribosomes and translation products. Loss of TMEM126A leads to the destabilization of mitochondrial translation products, triggering an inner membrane quality control process, in which newly synthesized proteins are degraded by the mitochondrial iAAA protease. Our data reveal that TMEM126A cooperates with OXA1L in protein insertion into the membrane. Upon loss of TMEM126A, the cargo-blocked OXA1L insertase complexes undergo proteolytic clearance by the iAAA protease machinery together with its cargo.
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Affiliation(s)
- Sabine Poerschke
- Institute for Cellular Biochemistry, University of Goettingen, 37073 Goettingen, Germany
| | - Silke Oeljeklaus
- Faculty of Chemistry and Pharmacy, Biochemistry II, Theodor Boveri-Institute, University of Würzburg, 97074 Wuerzburg, Germany
| | | | - Alexander Schenzielorz
- Institute for Biology II, Faculty for Biology, Functional Proteomics, University of Freiburg, 79104 Freiburg, Germany
| | - Drishan Dahal
- Institute for Cellular Biochemistry, University of Goettingen, 37073 Goettingen, Germany
| | - Hauke Sven Hillen
- Institute for Cellular Biochemistry, University of Goettingen, 37073 Goettingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Goettingen, Goettingen, Germany; Research Group Structure and Function of Molecular Machines, Max Planck Institute for Multidisciplinary Sciences, 37077 Goettingen, Germany
| | - Hirak Das
- Faculty of Chemistry and Pharmacy, Biochemistry II, Theodor Boveri-Institute, University of Würzburg, 97074 Wuerzburg, Germany
| | - Laura Sophie Kremer
- Institute for Cellular Biochemistry, University of Goettingen, 37073 Goettingen, Germany
| | - Anusha Valpadashi
- Institute for Cellular Biochemistry, University of Goettingen, 37073 Goettingen, Germany
| | - Mirjam Breuer
- Institute for Cellular Biochemistry, University of Goettingen, 37073 Goettingen, Germany
| | - Johannes Sattmann
- Institute for Cellular Biochemistry, University of Goettingen, 37073 Goettingen, Germany
| | - Ricarda Richter-Dennerlein
- Institute for Cellular Biochemistry, University of Goettingen, 37073 Goettingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Goettingen, Goettingen, Germany; Goettingen Center for Molecular Biosciences, University of Goettingen, 37077 Goettingen, Germany
| | - Bettina Warscheid
- Faculty of Chemistry and Pharmacy, Biochemistry II, Theodor Boveri-Institute, University of Würzburg, 97074 Wuerzburg, Germany; Cluster of Excellence CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Sven Dennerlein
- Institute for Cellular Biochemistry, University of Goettingen, 37073 Goettingen, Germany.
| | - Peter Rehling
- Institute for Cellular Biochemistry, University of Goettingen, 37073 Goettingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Goettingen, Goettingen, Germany; Goettingen Center for Molecular Biosciences, University of Goettingen, 37077 Goettingen, Germany; Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Translational Neuroinflammation and Automated Microscopy, Goettingen, Germany; Max Planck Institute for Multidisciplinary Sciences, 37077 Goettingen, Germany.
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6
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Mukhtar M, Thakkur K, Chacinska A, Bragoszewski P. Mechanisms of stress management in mitochondrial protein import. Biochem Soc Trans 2023; 51:2117-2126. [PMID: 37987513 DOI: 10.1042/bst20230377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 11/10/2023] [Accepted: 11/14/2023] [Indexed: 11/22/2023]
Abstract
Mitochondria are vital to the functions of eukaryotic cells. Most mitochondrial proteins are transported into the organelle following their synthesis by cytoplasmic ribosomes. However, precise protein targeting is complex because the two diverse lipid membranes encase mitochondria. Efficient protein translocation across membranes and accurate sorting to specific sub-compartments require the cooperation of multiple factors. Any failure in mitochondrial protein import can disrupt organelle fitness. Proteins intended for mitochondria make up a significant portion of all proteins produced in the cytosol. Therefore, import defects causing their mislocalization can significantly stress cellular protein homeostasis. Recognition of this phenomenon has increased interest in molecular mechanisms that respond to import-related stress and restore proteostasis, which is the focus of this review. Significantly, disruptions in protein homeostasis link strongly to the pathology of several degenerative disorders highly relevant in ageing societies. A comprehensive understanding of protein import quality control will allow harnessing this machinery in therapeutic approaches.
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Affiliation(s)
- Maryam Mukhtar
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Krutika Thakkur
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | | | - Piotr Bragoszewski
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
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7
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Uoselis L, Nguyen TN, Lazarou M. Mitochondrial degradation: Mitophagy and beyond. Mol Cell 2023; 83:3404-3420. [PMID: 37708893 DOI: 10.1016/j.molcel.2023.08.021] [Citation(s) in RCA: 38] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 08/10/2023] [Accepted: 08/17/2023] [Indexed: 09/16/2023]
Abstract
Mitochondria are central hubs of cellular metabolism that also play key roles in signaling and disease. It is therefore fundamentally important that mitochondrial quality and activity are tightly regulated. Mitochondrial degradation pathways contribute to quality control of mitochondrial networks and can also regulate the metabolic profile of mitochondria to ensure cellular homeostasis. Here, we cover the many and varied ways in which cells degrade or remove their unwanted mitochondria, ranging from mitophagy to mitochondrial extrusion. The molecular signals driving these varied pathways are discussed, including the cellular and physiological contexts under which the different degradation pathways are engaged.
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Affiliation(s)
- Louise Uoselis
- Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia; Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne, VIC, Australia; Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia; Aligning Science Across Parkinson's Collaborative Research Network, Chevy Chase, MD 20185, USA
| | - Thanh Ngoc Nguyen
- Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia; Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne, VIC, Australia; Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia; Aligning Science Across Parkinson's Collaborative Research Network, Chevy Chase, MD 20185, USA.
| | - Michael Lazarou
- Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia; Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne, VIC, Australia; Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia; Aligning Science Across Parkinson's Collaborative Research Network, Chevy Chase, MD 20185, USA.
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8
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Rödl S, Herrmann JM. The role of the proteasome in mitochondrial protein quality control. IUBMB Life 2023; 75:868-879. [PMID: 37178401 DOI: 10.1002/iub.2734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 04/15/2023] [Indexed: 05/15/2023]
Abstract
The abundance of each cellular protein is dynamically adjusted to the prevailing metabolic and stress conditions by modulation of their synthesis and degradation rates. The proteasome represents the major machinery for the degradation of proteins in eukaryotic cells. How the ubiquitin-proteasome system (UPS) controls protein levels and removes superfluous and damaged proteins from the cytosol and the nucleus is well characterized. However, recent studies showed that the proteasome also plays a crucial role in mitochondrial protein quality control. This mitochondria-associated degradation (MAD) thereby acts on two layers: first, the proteasome removes mature, functionally compromised or mis-localized proteins from the mitochondrial surface; and second, the proteasome cleanses the mitochondrial import pore of import intermediates of nascent proteins that are stalled during translocation. In this review, we provide an overview about the components and their specific functions that facilitate proteasomal degradation of mitochondrial proteins in the yeast Saccharomyces cerevisiae. Thereby we explain how the proteasome, in conjunction with a set of intramitochondrial proteases, maintains mitochondrial protein homeostasis and dynamically adapts the levels of mitochondrial proteins to specific conditions.
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Affiliation(s)
- Saskia Rödl
- Cell Biology, University of Kaiserslautern, Kaiserslautern, Germany
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9
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Sheryazdanova A, Amoedo ND, Dufour S, Impens F, Rossignol R, Sablina A. The deubiquitinase OTUB1 governs lung cancer cell fitness by modulating proteostasis of OXPHOS proteins. Biochim Biophys Acta Mol Basis Dis 2023:166767. [PMID: 37245529 DOI: 10.1016/j.bbadis.2023.166767] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 05/04/2023] [Accepted: 05/23/2023] [Indexed: 05/30/2023]
Abstract
Aerobic glycolysis is a hallmark of cancer development, but this dogma has been challenged by reports showing a key role of oxidative phosphorylation (OXPHOS) in cancer cell survival. It has been proposed that increased levels of intramitochondrial proteins in cancer cells are associated with high OXPHOS activity and increased sensitivity to OXPHOS inhibitors. However, the molecular mechanisms leading to the high expression of OXPHOS proteins in cancer cells remain unknown. Multiple proteomics studies have detected the ubiquitination of intramitochondrial proteins, suggesting the contribution of the ubiquitin system to the proteostatic regulation of OXPHOS proteins. Here, we identified the ubiquitin hydrolase OTUB1 as a regulator of the mitochondrial metabolic machinery essential for lung cancer cell survival. Mitochondria-localized OTUB1 modulates respiration by inhibiting K48-linked ubiquitination and turnover of OXPHOS proteins. An increase in OTUB1 expression is commonly observed in one-third of non-small-cell lung carcinomas and is associated with high OXPHOS signatures. Moreover, OTUB1 expression highly correlates with the sensitivity of lung cancer cells to mitochondrial inhibitors.
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Affiliation(s)
- Aidana Sheryazdanova
- VIB-KU Leuven Center for Cancer Biology, VIB, Leuven, Belgium; Department of Oncology, KULeuven, Leuven, Belgium
| | - Nivea Dias Amoedo
- INSERM U1211 Rare Diseases, Genetics and Metabolism, University of Bordeaux, Bordeaux, France
| | - Sara Dufour
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium; VIB Center for Medical Biotechnology, Ghent, Belgium; VIB Proteomics Core, Ghent, Belgium
| | - Francis Impens
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium; VIB Center for Medical Biotechnology, Ghent, Belgium; VIB Proteomics Core, Ghent, Belgium
| | - Rodrigue Rossignol
- INSERM U1211 Rare Diseases, Genetics and Metabolism, University of Bordeaux, Bordeaux, France
| | - Anna Sablina
- VIB-KU Leuven Center for Cancer Biology, VIB, Leuven, Belgium; Department of Oncology, KULeuven, Leuven, Belgium.
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10
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Khalimonchuk O, Becker DF. Molecular Determinants of Mitochondrial Shape and Function and Their Role in Glaucoma. Antioxid Redox Signal 2023; 38:896-919. [PMID: 36301938 PMCID: PMC10171965 DOI: 10.1089/ars.2022.0124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 10/07/2022] [Accepted: 10/22/2022] [Indexed: 01/12/2023]
Abstract
Significance: Cells depend on well-functioning mitochondria for essential processes such as energy production, redox signaling, coordination of metabolic pathways, and cofactor biosynthesis. Mitochondrial dysfunction, metabolic decline, and protein stress have been implicated in the etiology of multiple late-onset diseases, including various ataxias, diabetes, sarcopenia, neuromuscular disorders, and neurodegenerative diseases such as parkinsonism, amyotrophic lateral sclerosis, and glaucoma. Recent Advances: New evidence supports that increased energy metabolism protects neuron function during aging. Key energy metabolic enzymes, however, are susceptible to oxidative damage making it imperative that the mitochondrial proteome is protected. More than 40 different enzymes have been identified as important factors for guarding mitochondrial health and maintaining a dynamic pool of mitochondria. Critical Issues: Understanding shared mechanisms of age-related disorders of neurodegenerative diseases such as glaucoma, Alzheimer's disease, and Parkinson's disease is important for developing new therapies. Functional mitochondrial shape and dynamics rely on complex interactions between mitochondrial proteases and membrane proteins. Identifying the sequence of molecular events that lead to mitochondrial dysfunction and metabolic stress is a major challenge. Future Directions: A critical need exists for new strategies that reduce mitochondrial protein stress and promote mitochondrial dynamics in age-related neurological disorders. Discovering how mitochondria-associated degradation is related to proteostatic mechanisms in mitochondrial compartments may reveal new opportunities for therapeutic interventions. Also, little is known about how protein and membrane contacts in the inner and outer mitochondrial membrane are regulated, even though they are pivotal for mitochondrial architecture. Future work will need to delineate the molecular details of these processes.
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Affiliation(s)
- Oleh Khalimonchuk
- Department of Biochemistry, University of Nebraska–Lincoln, Lincoln, Nebraska, USA
- Department of Biochemistry and Nebraska Redox Biology Center, University of Nebraska–Lincoln, Lincoln, Nebraska, USA
- Fred & Pamela Buffett Cancer Center, Omaha, Nebraska, USA
| | - Donald F. Becker
- Department of Biochemistry, University of Nebraska–Lincoln, Lincoln, Nebraska, USA
- Department of Biochemistry and Nebraska Redox Biology Center, University of Nebraska–Lincoln, Lincoln, Nebraska, USA
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11
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Busch JD, Fielden LF, Pfanner N, Wiedemann N. Mitochondrial protein transport: Versatility of translocases and mechanisms. Mol Cell 2023; 83:890-910. [PMID: 36931257 DOI: 10.1016/j.molcel.2023.02.020] [Citation(s) in RCA: 31] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 02/14/2023] [Accepted: 02/16/2023] [Indexed: 03/17/2023]
Abstract
Biogenesis of mitochondria requires the import of approximately 1,000 different precursor proteins into and across the mitochondrial membranes. Mitochondria exhibit a wide variety of mechanisms and machineries for the translocation and sorting of precursor proteins. Five major import pathways that transport proteins to their functional intramitochondrial destination have been elucidated; these pathways range from the classical amino-terminal presequence-directed pathway to pathways using internal or even carboxy-terminal targeting signals in the precursors. Recent studies have provided important insights into the structural organization of membrane-embedded preprotein translocases of mitochondria. A comparison of the different translocases reveals the existence of at least three fundamentally different mechanisms: two-pore-translocase, β-barrel switching, and transport cavities open to the lipid bilayer. In addition, translocases are physically engaged in dynamic interactions with respiratory chain complexes, metabolite transporters, quality control factors, and machineries controlling membrane morphology. Thus, mitochondrial preprotein translocases are integrated into multi-functional networks of mitochondrial and cellular machineries.
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Affiliation(s)
- Jakob D Busch
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Laura F Fielden
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Nikolaus Pfanner
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany.
| | - Nils Wiedemann
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany.
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12
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Lionaki E, Gkikas I, Tavernarakis N. Mitochondrial protein import machinery conveys stress signals to the cytosol and beyond. Bioessays 2023; 45:e2200160. [PMID: 36709422 DOI: 10.1002/bies.202200160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 12/14/2022] [Accepted: 01/02/2023] [Indexed: 01/30/2023]
Abstract
Mitochondria hold diverse and pivotal roles in fundamental processes that govern cell survival, differentiation, and death, in addition to organismal growth, maintenance, and aging. The mitochondrial protein import system is a major contributor to mitochondrial biogenesis and lies at the crossroads between mitochondrial and cellular homeostasis. Recent findings highlight the mitochondrial protein import system as a signaling hub, receiving inputs from other cellular compartments and adjusting its function accordingly. Impairment of protein import, in a physiological, or disease context, elicits adaptive responses inside and outside mitochondria. In this review, we discuss recent developments, relevant to the mechanisms of mitochondrial protein import regulation, with a particular focus on quality control, proteostatic and metabolic cellular responses, triggered upon impairment of mitochondrial protein import.
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Affiliation(s)
- Eirini Lionaki
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology - Hellas, Heraklion, Crete, Greece
| | - Ilias Gkikas
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology - Hellas, Heraklion, Crete, Greece
- Department of Biology, School of Sciences and Engineering, University of Crete, Heraklion, Crete, Greece
| | - Nektarios Tavernarakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology - Hellas, Heraklion, Crete, Greece
- Department of Basic Sciences, Faculty of Medicine, University of Crete, Heraklion, Crete, Greece
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13
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Jacobs LJHC, Riemer J. Maintenance of small molecule redox homeostasis in mitochondria. FEBS Lett 2023; 597:205-223. [PMID: 36030088 DOI: 10.1002/1873-3468.14485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 08/18/2022] [Accepted: 08/21/2022] [Indexed: 01/26/2023]
Abstract
Compartmentalisation of eukaryotic cells enables fundamental otherwise often incompatible cellular processes. Establishment and maintenance of distinct compartments in the cell relies not only on proteins, lipids and metabolites but also on small redox molecules. In particular, small redox molecules such as glutathione, NAD(P)H and hydrogen peroxide (H2 O2 ) cooperate with protein partners in dedicated machineries to establish specific subcellular redox compartments with conditions that enable oxidative protein folding and redox signalling. Dysregulated redox homeostasis has been directly linked with a number of diseases including cancer, neurological disorders, cardiovascular diseases, obesity, metabolic diseases and ageing. In this review, we will summarise mechanisms regulating establishment and maintenance of redox homeostasis in the mitochondrial subcompartments of mammalian cells.
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Affiliation(s)
- Lianne J H C Jacobs
- Institute for Biochemistry and Center of Excellence for Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Germany
| | - Jan Riemer
- Institute for Biochemistry and Center of Excellence for Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Germany
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14
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Li L, Chen M, Liu W, Tai P, Liu X, Liu JX. Zebrafish cox17 modulates primitive erythropoiesis via regulation of mitochondrial metabolism to facilitate hypoxia tolerance. FASEB J 2022; 36:e22596. [PMID: 36208295 DOI: 10.1096/fj.202200829r] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Revised: 08/31/2022] [Accepted: 09/26/2022] [Indexed: 11/11/2022]
Abstract
Cox17 is required in the assembly of mitochondrial intermembrane space (IMS) and Cu metallization of cytochrome C oxidase (CcO) in mitochondria as well as Cu homeostasis in cells. Cox deficiency is associated with hematopoietic diseases such as tubulopathy and leukodystrophy, but whether and how cox17 functions in hematopoiesis are still unknown. Here, we report the effects of zebrafish cox17 deficiency on primitive erythropoiesis, mitochondrial metabolism, and hypoxia tolerance. Cox17-/- larvae were sensitive to hypoxia stress, with reduced primitive erythropoiesis. Meanwhile, cox17-/- mutants showed a significant reduction in the expression of pivotal transcriptional regulators in erythropoiesis, such as scl, lmo2, and gata1a at 14 h post fertilization (hpf), with expression remaining downregulated for scl but upregulated for lmo2 and gata1a at 24 hpf. Mechanistically, cox17-/- mutants showed impaired mitochondrial metabolism, coupled with a significant decrease in the mitochondrial membrane potential, ATP and SAM content, and the ratio of SAM and SAH. Additionally, disrupting mitochondrial metabolism in wild type (WT) larvae treated with carbonyl cyanide 3-chlorophenylhydrazone (CCCP) could mimic the primitive erythropoiesis defects observed in cox17-/- mutants. Moreover, cox17-/- mutants exhibited significantly downregulated WNT signaling and upregulated ER stress, with a significant reduction of beta-Catenin in gata1a+ cells and of binding enrichment in both scl and lmo2 promoters of the WNT transcriptional factor TCF4. This is the first report on the novel linkage of cox17 deficiency with defective primitive erythropoiesis and reduced hypoxia tolerance. This study has shed light on the potential mechanism by which Cox deficiency, especially cox17 deficiency, induces Cu homeostasis imbalance, leading to hematopoietic diseases.
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Affiliation(s)
- LingYa Li
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, China
| | - MingYue Chen
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, China
| | - WenYe Liu
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, China
| | - PengZhi Tai
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, China
| | - Xingguo Liu
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Science, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Science; Guangzhou Medical University, Guangzhou, China
| | - Jing-Xia Liu
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, China
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15
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Mitochondrial proteotoxicity: implications and ubiquitin-dependent quality control mechanisms. Cell Mol Life Sci 2022; 79:574. [DOI: 10.1007/s00018-022-04604-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 06/04/2022] [Accepted: 10/17/2022] [Indexed: 11/27/2022]
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16
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Ford HC, Allen WJ, Pereira GC, Liu X, Dillingham MS, Collinson I. Towards a molecular mechanism underlying mitochondrial protein import through the TOM and TIM23 complexes. eLife 2022; 11:75426. [PMID: 35674314 PMCID: PMC9255969 DOI: 10.7554/elife.75426] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 06/07/2022] [Indexed: 12/27/2022] Open
Abstract
Nearly all mitochondrial proteins need to be targeted for import from the cytosol. For the majority, the first port of call is the translocase of the outer membrane (TOM complex), followed by a procession of alternative molecular machines, conducting transport to their final destination. The pre-sequence translocase of the inner membrane (TIM23-complex) imports proteins with cleavable pre-sequences. Progress in understanding these transport mechanisms has been hampered by the poor sensitivity and time resolution of import assays. However, with the development of an assay based on split NanoLuc luciferase, we can now explore this process in greater detail. Here, we apply this new methodology to understand how ∆ψ and ATP hydrolysis, the two main driving forces for import into the matrix, contribute to the transport of pre-sequence-containing precursors (PCPs) with varying properties. Notably, we found that two major rate-limiting steps define PCP import time: passage of PCP across the outer membrane and initiation of inner membrane transport by the pre-sequence - the rates of which are influenced by PCP size and net charge. The apparent distinction between transport through the two membranes (passage through TOM is substantially complete before PCP-TIM engagement) is in contrast with the current view that import occurs through TOM and TIM in a single continuous step. Our results also indicate that PCPs spend very little time in the TIM23 channel - presumably rapid success or failure of import is critical for maintenance of mitochondrial fitness.
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Affiliation(s)
- Holly C Ford
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | - William J Allen
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | - Gonçalo C Pereira
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | - Xia Liu
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | | | - Ian Collinson
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
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17
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A proteostasis network safeguards the chloroplast proteome. Essays Biochem 2022; 66:219-228. [PMID: 35670042 PMCID: PMC9400067 DOI: 10.1042/ebc20210058] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 05/17/2022] [Accepted: 05/25/2022] [Indexed: 12/12/2022]
Abstract
Several protein homeostasis (proteostasis) pathways safeguard the integrity of thousands of proteins that localize in plant chloroplasts, the indispensable organelles that perform photosynthesis, produce metabolites, and sense environmental stimuli. In this review, we discuss the latest efforts directed to define the molecular process by which proteins are imported and sorted into the chloroplast. Moreover, we describe the recently elucidated protein folding and degradation pathways that modulate the levels and activities of chloroplast proteins. We also discuss the links between the accumulation of misfolded proteins and the activation of signalling pathways that cope with folding stress within the organelle. Finally, we propose new research directions that would help to elucidate novel molecular mechanisms to maintain chloroplast proteostasis.
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18
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Eldeeb MA, Thomas RA, Ragheb MA, Fallahi A, Fon EA. Mitochondrial quality control in health and in Parkinson's disease. Physiol Rev 2022; 102:1721-1755. [PMID: 35466694 DOI: 10.1152/physrev.00041.2021] [Citation(s) in RCA: 86] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
As a central hub for cellular metabolism and intracellular signalling, the mitochondrion is a pivotal organelle, dysfunction of which has been linked to several human diseases including neurodegenerative disorders, and in particular Parkinson's disease. An inherent challenge that mitochondria face is the continuous exposure to diverse stresses which increase their likelihood of dysregulation. In response, eukaryotic cells have evolved sophisticated quality control mechanisms to monitor, identify, repair and/or eliminate abnormal or misfolded proteins within the mitochondrion and/or the dysfunctional mitochondrion itself. Chaperones identify unstable or otherwise abnormal conformations in mitochondrial proteins and can promote their refolding to recover their correct conformation and stability. However, if repair is not possible, the abnormal protein is selectively degraded to prevent potentially damaging interactions with other proteins or its oligomerization into toxic multimeric complexes. The autophagic-lysosomal system and the ubiquitin-proteasome system mediate the selective and targeted degradation of such abnormal or misfolded protein species. Mitophagy (a specific kind of autophagy) mediates the selective elimination of dysfunctional mitochondria, in order to prevent the deleterious effects the dysfunctional organelles within the cell. Despite our increasing understanding of the molecular responses toward dysfunctional mitochondria, many key aspects remain relatively poorly understood. Herein, we review the emerging mechanisms of mitochondrial quality control including quality control strategies coupled to mitochondrial import mechanisms. In addition, we review the molecular mechanisms regulating mitophagy with an emphasis on the regulation of PINK1/PARKIN-mediated mitophagy in cellular physiology and in the context of Parkinson's disease cell biology.
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Affiliation(s)
- Mohamed A Eldeeb
- McGill Parkinson Program, Neurodegenerative Diseases Group, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Rhalena A Thomas
- McGill Parkinson Program, Neurodegenerative Diseases Group, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Mohamed A Ragheb
- Chemistry Department (Biochemistry Division), Faculty of Science, Cairo University, Giza, Egypt
| | - Armaan Fallahi
- McGill Parkinson Program, Neurodegenerative Diseases Group, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Edward A Fon
- McGill Parkinson Program, Neurodegenerative Diseases Group, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
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19
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Fessler E, Krumwiede L, Jae LT. DELE1 tracks perturbed protein import and processing in human mitochondria. Nat Commun 2022; 13:1853. [PMID: 35388015 PMCID: PMC8986780 DOI: 10.1038/s41467-022-29479-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Accepted: 03/11/2022] [Indexed: 12/15/2022] Open
Abstract
Protein homeostatic control of mitochondria is key to age-related diseases and organismal decline. However, it is unknown how the diverse types of stress experienced by mitochondria can be integrated and appropriately responded to in human cells. Here we identify perturbations in the ancient conserved processes of mitochondrial protein import and processing as sources of DELE1 activation: DELE1 is continuously sorted across both mitochondrial membranes into the matrix and detects different types of perturbations along the way. DELE1 molecules in transit can become licensed for mitochondrial release and stress signaling through proteolytic removal of N-terminal sorting signals. Import defects that occur at the mitochondrial surface allow DELE1 precursors to bind and activate downstream factor HRI without the need for cleavage. Genome-wide genetics reveal that DELE1 additionally responds to compromised presequence processing by the matrix proteases PITRM1 and MPP, which are mutated in neurodegenerative diseases. These mechanisms rationalize DELE1-dependent mitochondrial stress integration in the human system and may inform future therapies of neuropathies.
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Affiliation(s)
- Evelyn Fessler
- Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377, Munich, Germany.
| | - Luisa Krumwiede
- Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377, Munich, Germany
| | - Lucas T Jae
- Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377, Munich, Germany.
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20
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Cytosolic Quality Control of Mitochondrial Protein Precursors-The Early Stages of the Organelle Biogenesis. Int J Mol Sci 2021; 23:ijms23010007. [PMID: 35008433 PMCID: PMC8745001 DOI: 10.3390/ijms23010007] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/15/2021] [Accepted: 12/16/2021] [Indexed: 12/12/2022] Open
Abstract
With few exceptions, proteins that constitute the proteome of mitochondria originate outside of this organelle in precursor forms. Such protein precursors follow dedicated transportation paths to reach specific parts of mitochondria, where they complete their maturation and perform their functions. Mitochondrial precursor targeting and import pathways are essential to maintain proper mitochondrial function and cell survival, thus are tightly controlled at each stage. Mechanisms that sustain protein homeostasis of the cytosol play a vital role in the quality control of proteins targeted to the organelle. Starting from their synthesis, precursors are constantly chaperoned and guided to reduce the risk of premature folding, erroneous interactions, or protein damage. The ubiquitin-proteasome system provides proteolytic control that is not restricted to defective proteins but also regulates the supply of precursors to the organelle. Recent discoveries provide evidence that stress caused by the mislocalization of mitochondrial proteins may contribute to disease development. Precursors are not only subject to regulation but also modulate cytosolic machinery. Here we provide an overview of the cellular pathways that are involved in precursor maintenance and guidance at the early cytosolic stages of mitochondrial biogenesis. Moreover, we follow the circumstances in which mitochondrial protein import deregulation disturbs the cellular balance, carefully looking for rescue paths that can restore proteostasis.
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21
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Mitochondrial Quality Control in the Maintenance of Cardiovascular Homeostasis: The Roles and Interregulation of UPS, Mitochondrial Dynamics and Mitophagy. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:3960773. [PMID: 34804365 PMCID: PMC8601824 DOI: 10.1155/2021/3960773] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 09/20/2021] [Accepted: 10/24/2021] [Indexed: 12/20/2022]
Abstract
Maintenance of normal function of mitochondria is vital to the fate and health of cardiomyocytes. Mitochondrial quality control (MQC) mechanisms are essential in governing mitochondrial integrity and function. The ubiquitin-proteasome system (UPS), mitochondrial dynamics, and mitophagy are three major components of MQC. With the progress of research, our understanding of MQC mechanisms continues to deepen. Gradually, we realize that the three MQC mechanisms are not independent of each other. To the contrary, there are crosstalk among the mechanisms, which can make them interact with each other and cooperate well, forming a triangle interplay. Briefly, the UPS system can regulate the level of mitochondrial dynamic proteins and mitophagy receptors. In the process of Parkin-dependent mitophagy, the UPS is also widely activated, performing critical roles. Mitochondrial dynamics have a profound influence on mitophagy. In this review, we provide new processes of the three major MQC mechanisms in the background of cardiomyocytes and delve into the relationship between them.
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22
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Geldon S, Fernández-Vizarra E, Tokatlidis K. Redox-Mediated Regulation of Mitochondrial Biogenesis, Dynamics, and Respiratory Chain Assembly in Yeast and Human Cells. Front Cell Dev Biol 2021; 9:720656. [PMID: 34557489 PMCID: PMC8452992 DOI: 10.3389/fcell.2021.720656] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 08/04/2021] [Indexed: 12/24/2022] Open
Abstract
Mitochondria are double-membrane organelles that contain their own genome, the mitochondrial DNA (mtDNA), and reminiscent of its endosymbiotic origin. Mitochondria are responsible for cellular respiration via the function of the electron oxidative phosphorylation system (OXPHOS), located in the mitochondrial inner membrane and composed of the four electron transport chain (ETC) enzymes (complexes I-IV), and the ATP synthase (complex V). Even though the mtDNA encodes essential OXPHOS components, the large majority of the structural subunits and additional biogenetical factors (more than seventy proteins) are encoded in the nucleus and translated in the cytoplasm. To incorporate these proteins and the rest of the mitochondrial proteome, mitochondria have evolved varied, and sophisticated import machineries that specifically target proteins to the different compartments defined by the two membranes. The intermembrane space (IMS) contains a high number of cysteine-rich proteins, which are mostly imported via the MIA40 oxidative folding system, dependent on the reduction, and oxidation of key Cys residues. Several of these proteins are structural components or assembly factors necessary for the correct maturation and function of the ETC complexes. Interestingly, many of these proteins are involved in the metalation of the active redox centers of complex IV, the terminal oxidase of the mitochondrial ETC. Due to their function in oxygen reduction, mitochondria are the main generators of reactive oxygen species (ROS), on both sides of the inner membrane, i.e., in the matrix and the IMS. ROS generation is important due to their role as signaling molecules, but an excessive production is detrimental due to unwanted oxidation reactions that impact on the function of different types of biomolecules contained in mitochondria. Therefore, the maintenance of the redox balance in the IMS is essential for mitochondrial function. In this review, we will discuss the role that redox regulation plays in the maintenance of IMS homeostasis as well as how mitochondrial ROS generation may be a key regulatory factor for ETC biogenesis, especially for complex IV.
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Affiliation(s)
| | - Erika Fernández-Vizarra
- Institute of Molecular Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Kostas Tokatlidis
- Institute of Molecular Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
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23
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Quality control of protein import into mitochondria. Biochem J 2021; 478:3125-3143. [PMID: 34436539 DOI: 10.1042/bcj20190584] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 07/29/2021] [Accepted: 08/03/2021] [Indexed: 12/19/2022]
Abstract
Mitochondria import about 1000 proteins that are produced as precursors on cytosolic ribosomes. Defects in mitochondrial protein import result in the accumulation of non-imported precursor proteins and proteotoxic stress. The cell is equipped with different quality control mechanisms to monitor protein transport into mitochondria. First, molecular chaperones guide unfolded proteins to mitochondria and deliver non-imported proteins to proteasomal degradation. Second, quality control factors remove translocation stalled precursor proteins from protein translocases. Third, protein translocases monitor protein sorting to mitochondrial subcompartments. Fourth, AAA proteases of the mitochondrial subcompartments remove mislocalized or unassembled proteins. Finally, impaired efficiency of protein transport is an important sensor for mitochondrial dysfunction and causes the induction of cellular stress responses, which could eventually result in the removal of the defective mitochondria by mitophagy. In this review, we summarize our current understanding of quality control mechanisms that govern mitochondrial protein transport.
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24
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Dederer V, Lemberg MK. Transmembrane dislocases: a second chance for protein targeting. Trends Cell Biol 2021; 31:898-911. [PMID: 34147299 DOI: 10.1016/j.tcb.2021.05.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 05/11/2021] [Accepted: 05/14/2021] [Indexed: 12/31/2022]
Abstract
Precise distribution of proteins is essential to sustain the viability of cells. A complex network of protein synthesis and targeting factors cooperate with protein quality control systems to ensure protein homeostasis. Defective proteins are inevitably degraded by the ubiquitin-proteasome system and lysosomes. However, due to overlapping targeting information and limited targeting fidelity, certain proteins become mislocalized. In this review, we present the idea that transmembrane dislocases recognize and remove mislocalized membrane proteins from cellular organelles. This enables other targeting attempts and prevents degradation of mislocalized but otherwise functional proteins. These transmembrane dislocases can be found in the outer mitochondrial membrane (OMM) and endoplasmic reticulum (ER). We highlight common principles regarding client recognition and outline open questions in our understanding of transmembrane dislocases.
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Affiliation(s)
- Verena Dederer
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany; Current address: Institute for Pharmaceutical Biology and Buchmann Institute for Molecular Life Science, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Marius K Lemberg
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany; Center for Biochemistry, Medical Faculty, University of Cologne, 50931 Cologne, Germany.
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25
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Finger Y, Riemer J. Protein import by the mitochondrial disulfide relay in higher eukaryotes. Biol Chem 2021; 401:749-763. [PMID: 32142475 DOI: 10.1515/hsz-2020-0108] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 02/24/2020] [Indexed: 12/19/2022]
Abstract
The proteome of the mitochondrial intermembrane space (IMS) contains more than 100 proteins, all of which are synthesized on cytosolic ribosomes and consequently need to be imported by dedicated machineries. The mitochondrial disulfide relay is the major import machinery for soluble proteins in the IMS. Its major component, the oxidoreductase MIA40, interacts with incoming substrates, retains them in the IMS, and oxidatively folds them. After this reaction, MIA40 is reoxidized by the sulfhydryl oxidase augmenter of liver regeneration, which couples disulfide formation by this machinery to the activity of the respiratory chain. In this review, we will discuss the import of IMS proteins with a focus on recent findings showing the diversity of disulfide relay substrates, describing the cytosolic control of this import system and highlighting the physiological relevance of the disulfide relay machinery in higher eukaryotes.
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Affiliation(s)
- Yannik Finger
- Institute for Biochemistry, Redox Biochemistry, University of Cologne, Zülpicher Str. 47a/R. 3.49, D-50674 Cologne, Germany
| | - Jan Riemer
- Department of Chemistry, Institute for Biochemistry, Redox Biochemistry, University of Cologne, and Cologne Excellence Cluster on Cellular Stress Response in Aging-Associated Diseases, Zülpicher Str. 47a/R. 3.49, D-50674 Cologne, Germany
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26
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Edwards R, Gerlich S, Tokatlidis K. The biogenesis of mitochondrial intermembrane space proteins. Biol Chem 2021; 401:737-747. [PMID: 32061164 DOI: 10.1515/hsz-2020-0114] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 02/13/2020] [Indexed: 01/09/2023]
Abstract
The mitochondrial intermembrane space (IMS) houses a large spectrum of proteins with distinct and critical functions. Protein import into this mitochondrial sub-compartment is underpinned by an intriguing variety of pathways, many of which are still poorly understood. The constricted volume of the IMS and the topological segregation by the inner membrane cristae into a bulk area surrounded by the boundary inner membrane and the lumen within the cristae is an important factor that adds to the complexity of the protein import, folding and assembly processes. We discuss the main import pathways into the IMS, but also how IMS proteins are degraded or even retro-translocated to the cytosol in an integrated network of interactions that is necessary to maintain a healthy balance of IMS proteins under physiological and cellular stress conditions. We conclude this review by highlighting new and exciting perspectives in this area with a view to develop a better understanding of yet unknown, likely unconventional import pathways, how presequence-less proteins can be targeted and the basis for dual localisation in the IMS and the cytosol. Such knowledge is critical to understanding the dynamic changes of the IMS proteome in response to stress, and particularly important for maintaining optimal mitochondrial fitness.
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Affiliation(s)
- Ruairidh Edwards
- Institute of Molecular Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, University Avenue, Glasgow, G12 8QQ Scotland, UK
| | - Sarah Gerlich
- Institute of Molecular Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, University Avenue, Glasgow, G12 8QQ Scotland, UK.,Department for Chemistry, Institute for Biochemistry, University of Cologne, 50674 Cologne, Germany
| | - Kostas Tokatlidis
- Institute of Molecular Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, University Avenue, Glasgow, G12 8QQ Scotland, UK
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27
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Kong KYE, Fischer B, Meurer M, Kats I, Li Z, Rühle F, Barry JD, Kirrmaier D, Chevyreva V, San Luis BJ, Costanzo M, Huber W, Andrews BJ, Boone C, Knop M, Khmelinskii A. Timer-based proteomic profiling of the ubiquitin-proteasome system reveals a substrate receptor of the GID ubiquitin ligase. Mol Cell 2021; 81:2460-2476.e11. [PMID: 33974913 PMCID: PMC8189435 DOI: 10.1016/j.molcel.2021.04.018] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 03/15/2021] [Accepted: 04/19/2021] [Indexed: 01/01/2023]
Abstract
Selective protein degradation by the ubiquitin-proteasome system (UPS) is involved in all cellular processes. However, the substrates and specificity of most UPS components are not well understood. Here we systematically characterized the UPS in Saccharomyces cerevisiae. Using fluorescent timers, we determined how loss of individual UPS components affects yeast proteome turnover, detecting phenotypes for 76% of E2, E3, and deubiquitinating enzymes. We exploit this dataset to gain insights into N-degron pathways, which target proteins carrying N-terminal degradation signals. We implicate Ubr1, an E3 of the Arg/N-degron pathway, in targeting mitochondrial proteins processed by the mitochondrial inner membrane protease. Moreover, we identify Ylr149c/Gid11 as a substrate receptor of the glucose-induced degradation-deficient (GID) complex, an E3 of the Pro/N-degron pathway. Our results suggest that Gid11 recognizes proteins with N-terminal threonines, expanding the specificity of the GID complex. This resource of potential substrates and relationships between UPS components enables exploring functions of selective protein degradation.
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Affiliation(s)
| | - Bernd Fischer
- Computational Genome Biology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Matthias Meurer
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Ilia Kats
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Zhaoyan Li
- Institute of Molecular Biology (IMB), Mainz, Germany
| | - Frank Rühle
- Institute of Molecular Biology (IMB), Mainz, Germany
| | - Joseph D Barry
- Genome Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Daniel Kirrmaier
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany; Cell Morphogenesis and Signal Transduction, German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Veronika Chevyreva
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Bryan-Joseph San Luis
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Michael Costanzo
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Wolfgang Huber
- Genome Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Brenda J Andrews
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Charles Boone
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Michael Knop
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany; Cell Morphogenesis and Signal Transduction, German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, Heidelberg, Germany.
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28
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Mitochondrial Glucocorticoid Receptors and Their Actions. Int J Mol Sci 2021; 22:ijms22116054. [PMID: 34205227 PMCID: PMC8200016 DOI: 10.3390/ijms22116054] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 05/27/2021] [Accepted: 05/29/2021] [Indexed: 12/18/2022] Open
Abstract
Mitochondria are membrane organelles present in almost all eukaryotic cells. In addition to their well-known role in energy production, mitochondria regulate central cellular processes, including calcium homeostasis, Reactive Oxygen Species (ROS) generation, cell death, thermogenesis, and biosynthesis of lipids, nucleic acids, and steroid hormones. Glucocorticoids (GCs) regulate the mitochondrially encoded oxidative phosphorylation gene expression and mitochondrial energy metabolism. The identification of Glucocorticoid Response Elements (GREs) in mitochondrial sequences and the detection of Glucocorticoid Receptor (GR) in mitochondria of different cell types gave support to hypothesis that mitochondrial GR directly regulates mitochondrial gene expression. Numerous studies have revealed changes in mitochondrial gene expression alongside with GR import/export in mitochondria, confirming the direct effects of GCs on mitochondrial genome. Further evidence has made clear that mitochondrial GR is involved in mitochondrial function and apoptosis-mediated processes, through interacting or altering the distribution of Bcl2 family members. Even though its exact translocation mechanisms remain unknown, data have shown that GR chaperones (Hsp70/90, Bag-1, FKBP51), the anti-apoptotic protein Bcl-2, the HDAC6- mediated deacetylation and the outer mitochondrial translocation complexes (Tom complexes) co-ordinate GR mitochondrial trafficking. A role of mitochondrial GR in stress and depression as well as in lung and hepatic inflammation has also been demonstrated.
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Liao PC, Wolken DMA, Serrano E, Srivastava P, Pon LA. Mitochondria-Associated Degradation Pathway (MAD) Function beyond the Outer Membrane. Cell Rep 2021; 32:107902. [PMID: 32668258 PMCID: PMC7391283 DOI: 10.1016/j.celrep.2020.107902] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 01/07/2020] [Accepted: 06/23/2020] [Indexed: 12/01/2022] Open
Abstract
The mitochondria-associated degradation pathway (MAD) mediates ubiquitination and degradation of mitochondrial outer membrane (MOM) proteins by the proteasome. We find that the MAD, but not other quality-control pathways including macroautophagy, mitophagy, or mitochondrial chaperones and proteases, is critical for yeast cellular fitness under conditions of paraquat (PQ)-induced oxidative stress in mitochondria. Specifically, inhibition of the MAD increases PQ-induced defects in growth and mitochondrial quality and decreases chronological lifespan. We use mass spectrometry analysis to identify possible MAD substrates as mitochondrial proteins that exhibit increased ubiquitination in response to PQ treatment and inhibition of the MAD. We identify candidate substrates in the mitochondrial matrix and inner membrane and confirm that two matrix proteins are MAD substrates. Our studies reveal a broader function for the MAD in mitochondrial protein surveillance beyond the MOM and a major role for the MAD in cellular and mitochondrial fitness in response to chronic, low-level oxidative stress in mitochondria.
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Affiliation(s)
- Pin-Chao Liao
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | | | - Edith Serrano
- Department of Chemistry, Barnard College, Columbia University, New York, NY 10027, USA
| | - Pallavi Srivastava
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB T6G1H9, Canada
| | - Liza A Pon
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA.
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Ng MYW, Wai T, Simonsen A. Quality control of the mitochondrion. Dev Cell 2021; 56:881-905. [PMID: 33662258 DOI: 10.1016/j.devcel.2021.02.009] [Citation(s) in RCA: 175] [Impact Index Per Article: 58.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 01/06/2021] [Accepted: 02/08/2021] [Indexed: 12/22/2022]
Abstract
Mitochondria are essential organelles that execute and coordinate various metabolic processes in the cell. Mitochondrial dysfunction severely affects cell fitness and contributes to disease. Proper organellar function depends on the biogenesis and maintenance of mitochondria and its >1,000 proteins. As a result, the cell has evolved mechanisms to coordinate protein and organellar quality control, such as the turnover of proteins via mitochondria-associated degradation, the ubiquitin-proteasome system, and mitoproteases, as well as the elimination of mitochondria through mitophagy. Specific quality control mechanisms are engaged depending upon the nature and severity of mitochondrial dysfunction, which can also feed back to elicit transcriptional or proteomic remodeling by the cell. Here, we will discuss the current understanding of how these different quality control mechanisms are integrated and overlap to maintain protein and organellar quality and how they may be relevant for cellular and organismal health.
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Affiliation(s)
- Matthew Yoke Wui Ng
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0372 Oslo, Norway; Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, University of Oslo, 0316 Oslo, Norway
| | - Timothy Wai
- Institut Pasteur CNRS UMR 3691, 25-28 Rue du Docteur Roux, Paris, France.
| | - Anne Simonsen
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0372 Oslo, Norway; Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, University of Oslo, 0316 Oslo, Norway.
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Edwards R, Eaglesfield R, Tokatlidis K. The mitochondrial intermembrane space: the most constricted mitochondrial sub-compartment with the largest variety of protein import pathways. Open Biol 2021; 11:210002. [PMID: 33715390 PMCID: PMC8061763 DOI: 10.1098/rsob.210002] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The mitochondrial intermembrane space (IMS) is the most constricted sub-mitochondrial compartment, housing only about 5% of the mitochondrial proteome, and yet is endowed with the largest variability of protein import mechanisms. In this review, we summarize our current knowledge of the major IMS import pathway based on the oxidative protein folding pathway and discuss the stunning variability of other IMS protein import pathways. As IMS-localized proteins only have to cross the outer mitochondrial membrane, they do not require energy sources like ATP hydrolysis in the mitochondrial matrix or the inner membrane electrochemical potential which are critical for import into the matrix or insertion into the inner membrane. We also explore several atypical IMS import pathways that are still not very well understood and are guided by poorly defined or completely unknown targeting peptides. Importantly, many of the IMS proteins are linked to several human diseases, and it is therefore crucial to understand how they reach their normal site of function in the IMS. In the final part of this review, we discuss current understanding of how such IMS protein underpin a large spectrum of human disorders.
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Affiliation(s)
- Ruairidh Edwards
- Institute of Molecular Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, University Avenue, Glasgow G12 8QQ, UK
| | - Ross Eaglesfield
- Institute of Molecular Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, University Avenue, Glasgow G12 8QQ, UK
| | - Kostas Tokatlidis
- Institute of Molecular Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, University Avenue, Glasgow G12 8QQ, UK
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32
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Krämer L, Groh C, Herrmann JM. The proteasome: friend and foe of mitochondrial biogenesis. FEBS Lett 2020; 595:1223-1238. [PMID: 33249599 DOI: 10.1002/1873-3468.14010] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 10/26/2020] [Accepted: 11/01/2020] [Indexed: 01/06/2023]
Abstract
Most mitochondrial proteins are synthesized in the cytosol and subsequently translocated as unfolded polypeptides into mitochondria. Cytosolic chaperones maintain precursor proteins in an import-competent state. This post-translational import reaction is under surveillance of the cytosolic ubiquitin-proteasome system, which carries out several distinguishable activities. On the one hand, the proteasome degrades nonproductive protein precursors from the cytosol and nucleus, import intermediates that are stuck in mitochondrial translocases, and misfolded or damaged proteins from the outer membrane and the intermembrane space. These surveillance activities of the proteasome are essential for mitochondrial functionality, as well as cellular fitness and survival. On the other hand, the proteasome competes with mitochondria for nonimported cytosolic precursor proteins, which can compromise mitochondrial biogenesis. In order to balance the positive and negative effects of the cytosolic protein quality control system on mitochondria, mitochondrial import efficiency directly regulates the capacity of the proteasome via transcription factor Rpn4 in yeast and nuclear respiratory factor (Nrf) 1 and 2 in animal cells. In this review, we provide a thorough overview of how the proteasome regulates mitochondrial biogenesis.
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Affiliation(s)
- Lena Krämer
- Cell Biology, University of Kaiserslautern, Germany
| | - Carina Groh
- Cell Biology, University of Kaiserslautern, Germany
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Alsayyah C, Ozturk O, Cavellini L, Belgareh-Touzé N, Cohen MM. The regulation of mitochondrial homeostasis by the ubiquitin proteasome system. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148302. [PMID: 32861697 DOI: 10.1016/j.bbabio.2020.148302] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 08/05/2020] [Accepted: 08/24/2020] [Indexed: 02/07/2023]
Abstract
From mitochondrial quality control pathways to the regulation of specific functions, the Ubiquitin Proteasome System (UPS) could be compared to a Swiss knife without which mitochondria could not maintain its integrity in the cell. Here, we review the mechanisms that the UPS employs to regulate mitochondrial function and efficiency. For this purpose, we depict how Ubiquitin and the Proteasome participate in diverse quality control pathways that safeguard entry into the mitochondrial compartment. A focus is then achieved on the UPS-mediated control of the yeast mitofusin Fzo1 which provides insights into the complex regulation of this particular protein in mitochondrial fusion. We ultimately dissect the mechanisms by which the UPS controls the degradation of mitochondria by autophagy in both mammalian and yeast systems. This organization should offer a useful overview of this abundant but fascinating literature on the crosstalks between mitochondria and the UPS.
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Affiliation(s)
- Cynthia Alsayyah
- Sorbonne Université, CNRS, UMR8226, Institut de Biologie Physico-Chimique, Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, F-75005 Paris, France
| | - Oznur Ozturk
- Sorbonne Université, CNRS, UMR8226, Institut de Biologie Physico-Chimique, Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, F-75005 Paris, France
| | - Laetitia Cavellini
- Sorbonne Université, CNRS, UMR8226, Institut de Biologie Physico-Chimique, Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, F-75005 Paris, France
| | - Naïma Belgareh-Touzé
- Sorbonne Université, CNRS, UMR8226, Institut de Biologie Physico-Chimique, Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, F-75005 Paris, France
| | - Mickael M Cohen
- Sorbonne Université, CNRS, UMR8226, Institut de Biologie Physico-Chimique, Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, F-75005 Paris, France.
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Quantitative proteomics revealed energy metabolism pathway alterations in human epithelial ovarian carcinoma and their regulation by the antiparasite drug ivermectin: data interpretation in the context of 3P medicine. EPMA J 2020; 11:661-694. [PMID: 33240452 DOI: 10.1007/s13167-020-00224-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Accepted: 09/23/2020] [Indexed: 12/15/2022]
Abstract
Objective Energy metabolism abnormality is the hallmark in epithelial ovarian carcinoma (EOC). This study aimed to investigate energy metabolism pathway alterations and their regulation by the antiparasite drug ivermectin in EOC for the discovery of energy metabolism pathway-based molecular biomarker pattern and therapeutic targets in the context of predictive, preventive, and personalized medicine (PPPM) in EOC. Methods iTRAQ-based quantitative proteomics was used to identify mitochondrial differentially expressed proteins (mtDEPs) between human EOC and control mitochondrial samples isolated from 8 EOC and 11 control ovary tissues from gynecologic surgery of Chinese patients, respectively. Stable isotope labeling with amino acids in cell culture (SILAC)-based quantitative proteomics was used to analyze the protein expressions of energy metabolic pathways in EOC cells treated with and without ivermectin. Cell proliferation, cell cycle, apoptosis, and important molecules in energy metabolism pathway were examined before and after ivermectin treatment of different EOC cells. Results In total, 1198 mtDEPs were identified, and various mtDEPs were related to energy metabolism changes in EOC, with an interesting result that EOC tissues had enhanced abilities in oxidative phosphorylation (OXPHOS), Kreb's cycle, and aerobic glycolysis, for ATP generation, with experiment-confirmed upregulations of UQCRH in OXPHOS; IDH2, CS, and OGDHL in Kreb's cycle; and PKM2 in glycolysis pathways. Importantly, PDHB that links glycolysis with Kreb's cycle was upregulated in EOC. SILAC-based quantitative proteomics found that the protein expression levels of energy metabolic pathways were regulated by ivermectin in EOC cells. Furthermore, ivermectin demonstrated its strong abilities to inhibit proliferation and cell cycle and promote apoptosis in EOC cells, through molecular networks to target PFKP in glycolysis; IDH2 and IDH3B in Kreb's cycle; ND2, ND5, CYTB, and UQCRH in OXPHOS; and MCT1 and MCT4 in lactate shuttle to inhibit EOC growth. Conclusions Our findings revealed that the Warburg and reverse Warburg effects coexisted in human ovarian cancer tissues, provided the first multiomics-based molecular alteration spectrum of ovarian cancer energy metabolism pathways (aerobic glycolysis, Kreb's cycle, oxidative phosphorylation, and lactate shuttle), and demonstrated that the antiparasite drug ivermectin effectively regulated these changed molecules in energy metabolism pathways and had strong capability to inhibit cell proliferation and cell cycle progression and promote cell apoptosis in ovarian cancer cells. The observed molecular changes in energy metabolism pathways bring benefits for an in-depth understanding of the molecular mechanisms of energy metabolism heterogeneity and the discovery of effective biomarkers for individualized patient stratification and predictive/prognostic assessment and therapeutic targets/drugs for personalized therapy of ovarian cancer patients.
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35
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Sulkshane P, Ram J, Glickman MH. Ubiquitination of Intramitochondrial Proteins: Implications for Metabolic Adaptability. Biomolecules 2020; 10:biom10111559. [PMID: 33207558 PMCID: PMC7697252 DOI: 10.3390/biom10111559] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 11/11/2020] [Accepted: 11/12/2020] [Indexed: 02/07/2023] Open
Abstract
Mitochondria are constantly subjected to stressful conditions due to their unique physiology and organization. The resulting damage leads to mitochondrial dysfunction, which underlies many pathophysiological conditions. Hence, constant surveillance is required to closely monitor mitochondrial health for sound maintenance of cellular metabolism and thus, for viability. In addition to internal mitochondrial chaperones and proteases, mitochondrial health is also governed by host cell protein quality control systems. The ubiquitin-proteasome system (UPS) and autophagy constitute the main pathways for removal of damaged or superfluous proteins in the cytosol, nucleus, and from certain organelles such as the Endoplasmic Reticulum (ER) and mitochondria. Although stress-induced ubiquitin-dependent degradation of mitochondrial outer membrane proteins has been widely studied, mechanisms of intramitochondrial protein ubiquitination has remained largely elusive due to the predominantly cytosolic nature of UPS components, separated from internal mitochondrial proteins by a double membrane. However, recent research has illuminated examples of intramitochondrial protein ubiquitination pathways and highlighted their importance under basal and stressful conditions. Owing to the dependence of mitochondria on the error-prone process of protein import from the cytosol, it is imperative that the cell eliminate any accumulated proteins in the event of mitochondrial protein import deficiency. Apparently, a significant portion of this activity involves ubiquitination in one way or another. In the present review article, following a brief introduction to mitochondrial protein quality control mechanisms, we discuss our recent understanding of intramitochondrial protein ubiquitination, its importance for basal function of mitochondria, metabolic implications, and possible therapeutic applications.
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Affiliation(s)
- Prasad Sulkshane
- Correspondence: (P.S.); (M.H.G.); Tel.: +972-58779-2319 (P.S.); +972-4-829-4552 (M.H.G.)
| | | | - Michael H Glickman
- Correspondence: (P.S.); (M.H.G.); Tel.: +972-58779-2319 (P.S.); +972-4-829-4552 (M.H.G.)
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36
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Killackey SA, Philpott DJ, Girardin SE. Mitophagy pathways in health and disease. J Cell Biol 2020; 219:e202004029. [PMID: 32926082 PMCID: PMC7594502 DOI: 10.1083/jcb.202004029] [Citation(s) in RCA: 124] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 08/12/2020] [Accepted: 08/13/2020] [Indexed: 02/07/2023] Open
Abstract
Mitophagy is an evolutionarily conserved process involving the autophagic targeting and clearance of mitochondria destined for removal. Recent insights into the complex nature of the overlapping pathways regulating mitophagy illustrate mitophagy's essential role in maintaining the health of the mitochondrial network. In this review, we highlight recent studies that have changed the way mitophagy is understood, from initiation through lysosomal degradation. We outline the numerous mitophagic receptors and triggers, with a focus on basal and physiologically relevant cues, offering insight into why they lead to mitochondrial removal. We also explore how mitophagy maintains mitochondrial homeostasis at the organ and system levels and how a loss of mitophagy may play a role in a diverse group of diseases, including cardiovascular, metabolic, and neurodegenerative diseases. With disrupted mitophagy affecting such a wide array of physiological processes, a deeper understanding of how to modulate mitophagy could provide avenues for numerous therapies.
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Affiliation(s)
- Samuel A. Killackey
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Dana J. Philpott
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Stephen E. Girardin
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
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37
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Zöller E, Laborenz J, Krämer L, Boos F, Räschle M, Alexander RT, Herrmann JM. The intermembrane space protein Mix23 is a novel stress-induced mitochondrial import factor. J Biol Chem 2020; 295:14686-14697. [PMID: 32826315 PMCID: PMC7586232 DOI: 10.1074/jbc.ra120.014247] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 08/19/2020] [Indexed: 12/20/2022] Open
Abstract
The biogenesis of mitochondria requires the import of hundreds of precursor proteins. These proteins are transported post-translationally with the help of chaperones, meaning that the overproduction of mitochondrial proteins or the limited availability of chaperones can lead to the accumulation of cytosolic precursor proteins. This imposes a severe challenge to cytosolic proteostasis and triggers a specific transcription program called the mitoprotein-induced stress response, which activates the proteasome system. This coincides with the repression of mitochondrial proteins, including many proteins of the intermembrane space. In contrast, herein we report that the so-far-uncharacterized intermembrane space protein Mix23 is considerably up-regulated when mitochondrial import is perturbed. Mix23 is evolutionarily conserved and a homolog of the human protein CCDC58. We found that, like the subunits of the proteasome, Mix23 is under control of the transcription factor Rpn4. It is imported into mitochondria by the mitochondrial disulfide relay. Mix23 is critical for the efficient import of proteins into the mitochondrial matrix, particularly if the function of the translocase of the inner membrane 23 is compromised such as in temperature-sensitive mutants of Tim17. Our observations identify Mix23 as a novel regulator or stabilizer of the mitochondrial protein import machinery that is specifically up-regulated upon mitoprotein-induced stress conditions.
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Affiliation(s)
- Eva Zöller
- Department of Cell Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Janina Laborenz
- Department of Cell Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Lena Krämer
- Department of Cell Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Felix Boos
- Department of Cell Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Markus Räschle
- Department of Molecular Genetics, University of Kaiserslautern, Kaiserslautern, Germany
| | - R Todd Alexander
- Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
| | - Johannes M Herrmann
- Department of Cell Biology, University of Kaiserslautern, Kaiserslautern, Germany.
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Abstract
Mitochondria contain about 1,000-1,500 proteins that fulfil multiple functions. Mitochondrial proteins originate from two genomes: mitochondrial and nuclear. Hence, proper mitochondrial function requires synchronization of gene expression in the nucleus and in mitochondria and necessitates efficient import of mitochondrial proteins into the organelle from the cytosol. Furthermore, the mitochondrial proteome displays high plasticity to allow the adaptation of mitochondrial function to cellular requirements. Maintenance of this complex and adaptable mitochondrial proteome is challenging, but is of crucial importance to cell function. Defects in mitochondrial proteostasis lead to proteotoxic insults and eventually cell death. Different quality control systems monitor the mitochondrial proteome. The cytosolic ubiquitin-proteasome system controls protein transport across the mitochondrial outer membrane and removes damaged or mislocalized proteins. Concomitantly, a number of mitochondrial chaperones and proteases govern protein folding and degrade damaged proteins inside mitochondria. The quality control factors also regulate processing and turnover of native proteins to control protein import, mitochondrial metabolism, signalling cascades, mitochondrial dynamics and lipid biogenesis, further ensuring proper function of mitochondria. Thus, mitochondrial protein quality control mechanisms are of pivotal importance to integrate mitochondria into the cellular environment.
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The ubiquitin-proteasome system and its crosstalk with mitochondria as therapeutic targets in medicine. Pharmacol Res 2020; 163:105248. [PMID: 33065283 DOI: 10.1016/j.phrs.2020.105248] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 10/06/2020] [Accepted: 10/07/2020] [Indexed: 12/12/2022]
Abstract
The ubiquitin-proteasome system constitutes a major pathway for protein degradation in the cell. Therefore the crosstalk of this pathway with mitochondria is a major topic with direct relevance to many mitochondrial diseases. Proteasome dysfunction triggers not only protein toxicity, but also mitochondrial dysfunction. The involvement of proteasomes in the regulation of protein transport into mitochondria contributes to an increase in mitochondrial function defects. On the other hand, mitochondrial impairment stimulates reactive oxygen species production, which increases protein damage, and protein misfolding and aggregation leading to proteasome overload. Concurrently, mitochondrial dysfunction compromises cellular ATP production leading to reduced protein ubiquitination and proteasome activity. In this review we discuss the complex relationship and interdependence of the ubiquitin-proteasome system and mitochondria. Furthermore, we describe pharmacological inhibition of proteasome activity as a novel strategy to treat a group of mitochondrial diseases.
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Tolomeo M, Nisco A, Leone P, Barile M. Development of Novel Experimental Models to Study Flavoproteome Alterations in Human Neuromuscular Diseases: The Effect of Rf Therapy. Int J Mol Sci 2020; 21:ijms21155310. [PMID: 32722651 PMCID: PMC7432027 DOI: 10.3390/ijms21155310] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 07/20/2020] [Accepted: 07/21/2020] [Indexed: 02/07/2023] Open
Abstract
Inborn errors of Riboflavin (Rf) transport and metabolism have been recently related to severe human neuromuscular disorders, as resulting in profound alteration of human flavoproteome and, therefore, of cellular bioenergetics. This explains why the interest in studying the “flavin world”, a topic which has not been intensively investigated before, has increased much over the last few years. This also prompts basic questions concerning how Rf transporters and FAD (flavin adenine dinucleotide) -forming enzymes work in humans, and how they can create a coordinated network ensuring the maintenance of intracellular flavoproteome. The concept of a coordinated cellular “flavin network”, introduced long ago studying humans suffering for Multiple Acyl-CoA Dehydrogenase Deficiency (MADD), has been, later on, addressed in model organisms and more recently in cell models. In the frame of the underlying relevance of a correct supply of Rf in humans and of a better understanding of the molecular rationale of Rf therapy in patients, this review wants to deal with theories and existing experimental models in the aim to potentiate possible therapeutic interventions in Rf-related neuromuscular diseases.
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Alsina D, Lytovchenko O, Schab A, Atanassov I, Schober FA, Jiang M, Koolmeister C, Wedell A, Taylor RW, Wredenberg A, Larsson NG. FBXL4 deficiency increases mitochondrial removal by autophagy. EMBO Mol Med 2020; 12:e11659. [PMID: 32525278 PMCID: PMC7338799 DOI: 10.15252/emmm.201911659] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 05/11/2020] [Accepted: 05/14/2020] [Indexed: 01/29/2023] Open
Abstract
Pathogenic variants in FBXL4 cause a severe encephalopathic syndrome associated with mtDNA depletion and deficient oxidative phosphorylation. To gain further insight into the enigmatic pathophysiology caused by FBXL4 deficiency, we generated homozygous Fbxl4 knockout mice and found that they display a predominant perinatal lethality. Surprisingly, the few surviving animals are apparently normal until the age of 8–12 months when they gradually develop signs of mitochondrial dysfunction and weight loss. One‐year‐old Fbxl4 knockouts show a global reduction in a variety of mitochondrial proteins and mtDNA depletion, whereas lysosomal proteins are upregulated. Fibroblasts from patients with FBXL4 deficiency and human FBXL4 knockout cells also have reduced steady‐state levels of mitochondrial proteins that can be attributed to increased mitochondrial turnover. Inhibition of lysosomal function in these cells reverses the mitochondrial phenotype, whereas proteasomal inhibition has no effect. Taken together, the results we present here show that FBXL4 prevents mitochondrial removal via autophagy and that loss of FBXL4 leads to decreased mitochondrial content and mitochondrial disease.
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Affiliation(s)
- David Alsina
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Oleksandr Lytovchenko
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Aleksandra Schab
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Ilian Atanassov
- Proteomics Core Facility, Max Planck Institute for Biology of Ageing, Cologne, Germnay
| | - Florian A Schober
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden.,Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Min Jiang
- Key Laboratory of Growth Regulation and Translation Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China
| | - Camilla Koolmeister
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Anna Wedell
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.,Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden
| | - Robert W Taylor
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Anna Wredenberg
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden.,Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden
| | - Nils-Göran Larsson
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden.,Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden
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Quiles JM, Gustafsson ÅB. Mitochondrial Quality Control and Cellular Proteostasis: Two Sides of the Same Coin. Front Physiol 2020; 11:515. [PMID: 32528313 PMCID: PMC7263099 DOI: 10.3389/fphys.2020.00515] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 04/27/2020] [Indexed: 12/12/2022] Open
Abstract
Mitochondrial dysfunction is a hallmark of cardiac pathophysiology. Defects in mitochondrial performance disrupt contractile function, overwhelm myocytes with reactive oxygen species (ROS), and transform these cellular powerhouses into pro-death organelles. Thus, quality control (QC) pathways aimed at identifying and removing damaged mitochondrial proteins, components, or entire mitochondria are crucial processes in post-mitotic cells such as cardiac myocytes. Almost all of the mitochondrial proteins are encoded by the nuclear genome and the trafficking of these nuclear-encoded proteins necessitates significant cross-talk with the cytosolic protein QC machinery to ensure that only functional proteins are delivered to the mitochondria. Within the organelle, mitochondria contain their own protein QC system consisting of chaperones and proteases. This system represents another level of QC to promote mitochondrial protein folding and prevent aggregation. If this system is overwhelmed, a conserved transcriptional response known as the mitochondrial unfolded protein response is activated to increase the expression of proteins involved in restoring mitochondrial proteostasis. If the mitochondrion is beyond repair, the entire organelle must be removed before it becomes cytotoxic and causes cellular damage. Recent evidence has also uncovered mitochondria as participants in cytosolic protein QC where misfolded cytosolic proteins can be imported and degraded inside mitochondria. However, this process also places increased pressure on mitochondrial QC pathways to ensure that the imported proteins do not cause mitochondrial dysfunction. This review is focused on discussing the pathways involved in regulating mitochondrial QC and their relationship to cellular proteostasis and mitochondrial health in the heart.
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Affiliation(s)
- Justin M Quiles
- Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States
| | - Åsa B Gustafsson
- Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States
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43
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Singh RP, Jeyaraju DV, Voisin V, Hurren R, Xu C, Hawley JR, Barghout SH, Khan DH, Gronda M, Wang X, Jitkova Y, Sharon D, Liyanagae S, MacLean N, Seneviratene AK, Mirali S, Borenstein A, Thomas GE, Soriano J, Orouji E, Minden MD, Arruda A, Chan SM, Bader GD, Lupien M, Schimmer AD. Disrupting Mitochondrial Copper Distribution Inhibits Leukemic Stem Cell Self-Renewal. Cell Stem Cell 2020; 26:926-937.e10. [PMID: 32416059 DOI: 10.1016/j.stem.2020.04.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 02/27/2020] [Accepted: 04/15/2020] [Indexed: 12/14/2022]
Abstract
Leukemic stem cells (LSCs) rely on oxidative metabolism and are differentially sensitive to targeting mitochondrial pathways, which spares normal hematopoietic cells. A subset of mitochondrial proteins is folded in the intermembrane space via the mitochondrial intermembrane assembly (MIA) pathway. We found increased mRNA expression of MIA pathway substrates in acute myeloid leukemia (AML) stem cells. Therefore, we evaluated the effects of inhibiting this pathway in AML. Genetic and chemical inhibition of ALR reduces AML growth and viability, disrupts LSC self-renewal, and induces their differentiation. ALR inhibition preferentially decreases its substrate COX17, a mitochondrial copper chaperone, and knockdown of COX17 phenocopies ALR loss. Inhibiting ALR and COX17 increases mitochondrial copper levels which in turn inhibit S-adenosylhomocysteine hydrolase (SAHH) and lower levels of S-adenosylmethionine (SAM), DNA methylation, and chromatin accessibility to lower LSC viability. These results provide insight into mechanisms through which mitochondrial copper controls epigenetic status and viability of LSCs.
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Affiliation(s)
- Rashim Pal Singh
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Danny V Jeyaraju
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | | | - Rose Hurren
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Changjiang Xu
- The Donnelly Centre, University of Toronto, Toronto, ON, Canada
| | - James R Hawley
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Samir H Barghout
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Dilshad H Khan
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Marcela Gronda
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Xiaoming Wang
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Yulia Jitkova
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - David Sharon
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Sanduni Liyanagae
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Neil MacLean
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | | | - Sara Mirali
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Adina Borenstein
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Geethu E Thomas
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Joelle Soriano
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Elias Orouji
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Mark D Minden
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Andrea Arruda
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Steven M Chan
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Gary D Bader
- The Donnelly Centre, University of Toronto, Toronto, ON, Canada
| | - Mathieu Lupien
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Aaron D Schimmer
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada.
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44
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Stehlik T, Kremp M, Kahnt J, Bölker M, Freitag J. Peroxisomal targeting of a protein phosphatase type 2C via mitochondrial transit. Nat Commun 2020; 11:2355. [PMID: 32398688 PMCID: PMC7217942 DOI: 10.1038/s41467-020-16146-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 04/16/2020] [Indexed: 11/16/2022] Open
Abstract
Correct intracellular distribution of proteins is critical for the function of eukaryotic cells. Certain proteins are targeted to more than one cellular compartment, e.g. to mitochondria and peroxisomes. The protein phosphatase Ptc5 from Saccharomyces cerevisiae contains an N-terminal mitochondrial presequence followed by a transmembrane domain, and has been detected in the mitochondrial intermembrane space. Here we show mitochondrial transit of Ptc5 to peroxisomes. Translocation of Ptc5 to peroxisomes depended both on the C-terminal peroxisomal targeting signal (PTS1) and N-terminal cleavage by the mitochondrial inner membrane peptidase complex. Indirect targeting of Ptc5 to peroxisomes prevented deleterious effects of its phosphatase activity in the cytosol. Sorting of Ptc5 involves simultaneous interaction with import machineries of both organelles. We identify additional mitochondrial proteins with PTS1, which localize in both organelles and can increase their physical association. Thus, a tug-of-war-like mechanism can influence the interaction and communication of two cellular compartments.
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Affiliation(s)
- Thorsten Stehlik
- Department of Biology, Philipps University Marburg, Marburg, Germany
| | - Marco Kremp
- Department of Biology, Philipps University Marburg, Marburg, Germany
| | - Jörg Kahnt
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Michael Bölker
- Department of Biology, Philipps University Marburg, Marburg, Germany.
- LOEWE Center for Synthetic Microbiology, Marburg, Germany.
| | - Johannes Freitag
- Department of Biology, Philipps University Marburg, Marburg, Germany.
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45
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Krupinska K, Blanco NE, Oetke S, Zottini M. Genome communication in plants mediated by organelle-n-ucleus-located proteins. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190397. [PMID: 32362260 PMCID: PMC7209962 DOI: 10.1098/rstb.2019.0397] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
An increasing number of eukaryotic proteins have been shown to have a dual localization in the DNA-containing organelles, mitochondria and plastids, and/or the nucleus. Regulation of dual targeting and relocation of proteins from organelles to the nucleus offer the most direct means for communication between organelles as well as organelles and nucleus. Most of the mitochondrial proteins of animals have functions in DNA repair and gene expression by modelling of nucleoid architecture and/or chromatin. In plants, such proteins can affect replication and early development. Most plastid proteins with a confirmed or predicted second location in the nucleus are associated with the prokaryotic core RNA polymerase and are required for chloroplast development and light responses. Few plastid–nucleus-located proteins are involved in pathogen defence and cell cycle control. For three proteins, it has been clearly shown that they are first targeted to the organelle and then relocated to the nucleus, i.e. the nucleoid-associated proteins HEMERA and Whirly1 and the stroma-located defence protein NRIP1. Relocation to the nucleus can be experimentally demonstrated by plastid transformation leading to the synthesis of proteins with a tag that enables their detection in the nucleus or by fusions with fluoroproteins in different experimental set-ups. This article is part of the theme issue ‘Retrograde signalling from endosymbiotic organelles’.
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Affiliation(s)
- Karin Krupinska
- Institute of Botany, Christian-Albrechts-University of Kiel, Olshausenstraße 40, 24098 Kiel, Germany
| | - Nicolás E Blanco
- Centre of Photosynthetic and Biochemical Studies, Faculty of Biochemical Science and Pharmacy, National University of Rosario (CEFOBI/UNR-CONICET), Rosario, Argentina
| | - Svenja Oetke
- Institute of Botany, Christian-Albrechts-University of Kiel, Olshausenstraße 40, 24098 Kiel, Germany
| | - Michela Zottini
- Department of Biology, University of Padova, Via U. Bassi 58B, 35131 Padova, Italy
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46
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Habich M, Riemer J. Stop wasting protein-Proteasome inhibition to target diseases linked to mitochondrial import. EMBO Mol Med 2020; 11:emmm.201910441. [PMID: 30944106 PMCID: PMC6505575 DOI: 10.15252/emmm.201910441] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Mitochondrial dysfunction is linked to various human diseases. Symptoms can occur early in life or manifest progressively during life and include poor muscle coordination or weakness, neurological or developmental problems, or immunodeficiency (Lightowlers et al, 2015). Most mitochondrial diseases are caused by mutations in genes encoding mitochondrial proteins. Mutations can affect protein functions in many ways; they can not only impair enzymatic activities, but also lower protein stability, hamper assembly into multimeric protein complexes, or abrogate protein transport into mitochondria. Understanding the impact of mutations on protein function is crucial to understand pathophysiological mechanisms of mitochondrial diseases and to develop therapeutic approaches.
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Affiliation(s)
- Markus Habich
- Department of Chemistry, Institute for Biochemistry, University of Cologne, Cologne, Germany
| | - Jan Riemer
- Department of Chemistry, Institute for Biochemistry, University of Cologne, Cologne, Germany
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47
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Ravanelli S, den Brave F, Hoppe T. Mitochondrial Quality Control Governed by Ubiquitin. Front Cell Dev Biol 2020; 8:270. [PMID: 32391359 PMCID: PMC7193050 DOI: 10.3389/fcell.2020.00270] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 03/30/2020] [Indexed: 12/15/2022] Open
Abstract
Mitochondria are essential organelles important for energy production, proliferation, and cell death. Biogenesis, homeostasis, and degradation of this organelle are tightly controlled to match cellular needs and counteract chronic stress conditions. Despite providing their own DNA, the vast majority of mitochondrial proteins are encoded in the nucleus, synthesized by cytosolic ribosomes, and subsequently imported into different mitochondrial compartments. The integrity of the mitochondrial proteome is permanently challenged by defects in folding, transport, and turnover of mitochondrial proteins. Therefore, damaged proteins are constantly sequestered from the outer mitochondrial membrane and targeted for proteasomal degradation in the cytosol via mitochondrial-associated degradation (MAD). Recent studies identified specialized quality control mechanisms important to decrease mislocalized proteins, which affect the mitochondrial import machinery. Interestingly, central factors of these ubiquitin-dependent pathways are shared with the ER-associated degradation (ERAD) machinery, indicating close collaboration between both tubular organelles. Here, we summarize recently described cellular stress response mechanisms, which are triggered by defects in mitochondrial protein import and quality control. Moreover, we discuss how ubiquitin-dependent degradation is integrated with cytosolic stress responses, particularly focused on the crosstalk between MAD and ERAD.
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Affiliation(s)
- Sonia Ravanelli
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany
| | - Fabian den Brave
- Department of Molecular Cell Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Thorsten Hoppe
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
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48
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Habich M, Salscheider SL, Murschall LM, Hoehne MN, Fischer M, Schorn F, Petrungaro C, Ali M, Erdogan AJ, Abou-Eid S, Kashkar H, Dengjel J, Riemer J. Vectorial Import via a Metastable Disulfide-Linked Complex Allows for a Quality Control Step and Import by the Mitochondrial Disulfide Relay. Cell Rep 2020; 26:759-774.e5. [PMID: 30650365 DOI: 10.1016/j.celrep.2018.12.092] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 11/15/2018] [Accepted: 12/20/2018] [Indexed: 01/31/2023] Open
Abstract
Disulfide formation in the mitochondrial intermembrane space (IMS) is an essential process. It is catalyzed by the disulfide relay machinery, which couples substrate import and oxidation. The machinery relies on the oxidoreductase and chaperone CHCHD4-Mia40. Here, we report on the driving force for IMS import and on a redox quality control mechanism. We demonstrate that unfolded reduced proteins, upon translocation into the IMS, initiate formation of a metastable disulfide-linked complex with CHCHD4. If this interaction does not result in productive oxidation, then substrates are released to the cytosol and degraded by the proteasome. Based on these data, we propose a redox quality control step at the level of the disulfide-linked intermediate that relies on the vectorial nature of IMS import. Our findings also provide the mechanistic framework to explain failures in import of numerous human disease mutants in CHCHD4 substrates.
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Affiliation(s)
- Markus Habich
- Institute for Biochemistry, Department of Chemistry, University of Cologne, Zuelpicher Str. 47a/R. 3.49, 50674 Cologne, Germany
| | - Silja Lucia Salscheider
- Institute for Biochemistry, Department of Chemistry, University of Cologne, Zuelpicher Str. 47a/R. 3.49, 50674 Cologne, Germany
| | - Lena Maria Murschall
- Institute for Biochemistry, Department of Chemistry, University of Cologne, Zuelpicher Str. 47a/R. 3.49, 50674 Cologne, Germany
| | - Michaela Nicole Hoehne
- Institute for Biochemistry, Department of Chemistry, University of Cologne, Zuelpicher Str. 47a/R. 3.49, 50674 Cologne, Germany
| | - Manuel Fischer
- Institute for Biochemistry, Department of Chemistry, University of Cologne, Zuelpicher Str. 47a/R. 3.49, 50674 Cologne, Germany
| | - Fabian Schorn
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center for Molecular Medicine Cologne (CMMC) and Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, CECAD Research Center, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany
| | - Carmelina Petrungaro
- Institute for Biochemistry, Department of Chemistry, University of Cologne, Zuelpicher Str. 47a/R. 3.49, 50674 Cologne, Germany
| | - Muna Ali
- Institute for Biochemistry, Department of Chemistry, University of Cologne, Zuelpicher Str. 47a/R. 3.49, 50674 Cologne, Germany
| | - Alican J Erdogan
- Institute for Biochemistry, Department of Chemistry, University of Cologne, Zuelpicher Str. 47a/R. 3.49, 50674 Cologne, Germany
| | - Shadi Abou-Eid
- Department of Biology, University of Fribourg, Chemin du Musée 10, 1700 Fribourg, Switzerland
| | - Hamid Kashkar
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center for Molecular Medicine Cologne (CMMC) and Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, CECAD Research Center, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany
| | - Joern Dengjel
- Department of Biology, University of Fribourg, Chemin du Musée 10, 1700 Fribourg, Switzerland
| | - Jan Riemer
- Institute for Biochemistry, Department of Chemistry, University of Cologne, Zuelpicher Str. 47a/R. 3.49, 50674 Cologne, Germany.
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49
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Pfanner N, Warscheid B, Wiedemann N. Mitochondrial proteins: from biogenesis to functional networks. Nat Rev Mol Cell Biol 2020; 20:267-284. [PMID: 30626975 DOI: 10.1038/s41580-018-0092-0] [Citation(s) in RCA: 541] [Impact Index Per Article: 135.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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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50
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Phu L, Rose CM, Tea JS, Wall CE, Verschueren E, Cheung TK, Kirkpatrick DS, Bingol B. Dynamic Regulation of Mitochondrial Import by the Ubiquitin System. Mol Cell 2020; 77:1107-1123.e10. [DOI: 10.1016/j.molcel.2020.02.012] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 12/30/2019] [Accepted: 02/12/2020] [Indexed: 01/05/2023]
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