1
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Chen J, Shao J, Wang Y, Wu K, Huang M. OPA1, a molecular regulator of dilated cardiomyopathy. J Cell Mol Med 2023; 27:3017-3025. [PMID: 37603376 PMCID: PMC10568666 DOI: 10.1111/jcmm.17918] [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: 06/01/2023] [Revised: 08/08/2023] [Accepted: 08/11/2023] [Indexed: 08/22/2023] Open
Abstract
Dilated cardiomyopathy (DCM) is a disease with no specific treatment, poor prognosis and high mortality. During DCM development, there is apoptosis, mitochondrial dynamics imbalance and changes in cristae structure. Optic atrophy 1 (OPA1) appears at high frequency in these three aspects. DCM LMNA (LaminA/C) gene mutation can activate TP53, and the study of P53 shows that P53 affects OPA1 through Bak/Bax and OMA1 (a metalloprotease). OPA1 can be considered the missing link between DCMp53 and DCM apoptosis, mitochondrial dynamics imbalance and changes in cristae structure. OPA1 regulates apoptosis by regulating the release of cytochrome c from the mitochondrial matrix through CJs (crisp linkages, located in the inner mitochondrial membrane) and unbalances mitochondrial fusion and fission by affecting mitochondrial inner membrane (IM) fusion. OPA1 is also associated with the formation and maintenance of mitochondrial cristae. OPA1 is not the root cause of DCM, but it is an essential mediator in P53 mediating the occurrence and development of DCM, so OPA1 also becomes a molecular regulator of DCM. This review discusses the implication of OPA1 for DCM from three aspects: apoptosis, mitochondrial dynamics and ridge structure.
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Affiliation(s)
- Jiaqi Chen
- The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical UniversityWenzhouChina
| | - Jianan Shao
- The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical UniversityWenzhouChina
| | - Yaoyao Wang
- Fuwai HospitalChinese Academy of Medical Sciences & Peking Union Medical College/National Center for Cardiovascular DiseasesBeijingChina
| | - Kangxiang Wu
- The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical UniversityWenzhouChina
| | - Mingyuan Huang
- The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical UniversityWenzhouChina
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2
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von der Malsburg A, Sapp GM, Zuccaro KE, von Appen A, Moss FR, Kalia R, Bennett JA, Abriata LA, Dal Peraro M, van der Laan M, Frost A, Aydin H. Structural mechanism of mitochondrial membrane remodelling by human OPA1. Nature 2023; 620:1101-1108. [PMID: 37612504 PMCID: PMC10875962 DOI: 10.1038/s41586-023-06441-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 07/14/2023] [Indexed: 08/25/2023]
Abstract
Distinct morphologies of the mitochondrial network support divergent metabolic and regulatory processes that determine cell function and fate1-3. The mechanochemical GTPase optic atrophy 1 (OPA1) influences the architecture of cristae and catalyses the fusion of the mitochondrial inner membrane4,5. Despite its fundamental importance, the molecular mechanisms by which OPA1 modulates mitochondrial morphology are unclear. Here, using a combination of cellular and structural analyses, we illuminate the molecular mechanisms that are key to OPA1-dependent membrane remodelling and fusion. Human OPA1 embeds itself into cardiolipin-containing membranes through a lipid-binding paddle domain. A conserved loop within the paddle domain inserts deeply into the bilayer, further stabilizing the interactions with cardiolipin-enriched membranes. OPA1 dimerization through the paddle domain promotes the helical assembly of a flexible OPA1 lattice on the membrane, which drives mitochondrial fusion in cells. Moreover, the membrane-bending OPA1 oligomer undergoes conformational changes that pull the membrane-inserting loop out of the outer leaflet and contribute to the mechanics of membrane remodelling. Our findings provide a structural framework for understanding how human OPA1 shapes mitochondrial morphology and show us how human disease mutations compromise OPA1 functions.
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Affiliation(s)
- Alexander von der Malsburg
- Medical Biochemistry & Molecular Biology, Center for Molecular Signaling, PZMS, Saarland University Medical School, Homburg, Germany
| | - Gracie M Sapp
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
| | - Kelly E Zuccaro
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
| | - Alexander von Appen
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Frank R Moss
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA
- Altos Labs, Bay Area Institute of Science, San Francisco, CA, USA
| | - Raghav Kalia
- Department of Physiology, University of California, San Francisco, San Francisco, CA, USA
| | - Jeremy A Bennett
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
| | - Luciano A Abriata
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Protein Production and Structure Core Facility, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Matteo Dal Peraro
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Martin van der Laan
- Medical Biochemistry & Molecular Biology, Center for Molecular Signaling, PZMS, Saarland University Medical School, Homburg, Germany
| | - Adam Frost
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA.
- Altos Labs, Bay Area Institute of Science, San Francisco, CA, USA.
- Chan Zuckerberg Biohub, San Francisco, CA, USA.
- Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, CA, USA.
| | - Halil Aydin
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA.
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3
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Nyenhuis SB, Wu X, Strub MP, Yim YI, Stanton AE, Baena V, Syed ZA, Canagarajah B, Hammer JA, Hinshaw JE. OPA1 helical structures give perspective to mitochondrial dysfunction. Nature 2023; 620:1109-1116. [PMID: 37612506 DOI: 10.1038/s41586-023-06462-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 07/19/2023] [Indexed: 08/25/2023]
Abstract
Dominant optic atrophy is one of the leading causes of childhood blindness. Around 60-80% of cases1 are caused by mutations of the gene that encodes optic atrophy protein 1 (OPA1), a protein that has a key role in inner mitochondrial membrane fusion and remodelling of cristae and is crucial for the dynamic organization and regulation of mitochondria2. Mutations in OPA1 result in the dysregulation of the GTPase-mediated fusion process of the mitochondrial inner and outer membranes3. Here we used cryo-electron microscopy methods to solve helical structures of OPA1 assembled on lipid membrane tubes, in the presence and absence of nucleotide. These helical assemblies organize into densely packed protein rungs with minimal inter-rung connectivity, and exhibit nucleotide-dependent dimerization of the GTPase domains-a hallmark of the dynamin superfamily of proteins4. OPA1 also contains several unique secondary structures in the paddle domain that strengthen its membrane association, including membrane-inserting helices. The structural features identified in this study shed light on the effects of pathogenic point mutations on protein folding, inter-protein assembly and membrane interactions. Furthermore, mutations that disrupt the assembly interfaces and membrane binding of OPA1 cause mitochondrial fragmentation in cell-based assays, providing evidence of the biological relevance of these interactions.
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Affiliation(s)
- Sarah B Nyenhuis
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD, USA
| | - Xufeng Wu
- Light Microscopy Facility, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD, USA
| | - Marie-Paule Strub
- Protein Expression Facility, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD, USA
| | - Yang-In Yim
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD, USA
| | - Abigail E Stanton
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD, USA
- Molecular Biology Department, Princeton University, Princeton, NJ, USA
| | - Valentina Baena
- Electron Microscopy Core, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD, USA
| | - Zulfeqhar A Syed
- Electron Microscopy Core, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD, USA
| | - Bertram Canagarajah
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD, USA
| | - John A Hammer
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD, USA
| | - Jenny E Hinshaw
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD, USA.
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4
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Ozeir M, Cohen MM. From dynamin related proteins structures and oligomers to membrane fusion mediated by mitofusins. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2022; 1863:148913. [PMID: 36057374 DOI: 10.1016/j.bbabio.2022.148913] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Revised: 07/17/2022] [Accepted: 08/26/2022] [Indexed: 06/15/2023]
Abstract
Mitochondria assemble in a highly dynamic network where interconnected tubules evolve in length and size through regulated cycles of fission and fusion of mitochondrial membranes thereby adapting to cellular needs. Mitochondrial fusion and fission processes are mediated by specific sets of mechano-chemical large GTPases that belong to the Dynamin-Related Proteins (DRPs) super family. DRPs bind to cognate membranes and auto-oligomerize to drive lipid bilayers remodeling in a nucleotide dependent manner. Although structural characterization and mechanisms of DRPs that mediate membrane fission are well established, the capacity of DRPs to mediate membrane fusion is only emerging. In this review, we discuss the distinct structures and mechanisms of DRPs that trigger the anchoring and fusion of biological membranes with a specific focus on mitofusins that are dedicated to the fusion of mitochondrial outer membranes. In particular, we will highlight oligomeric assemblies of distinct DRPs and confront their mode of action against existing models of mitofusins assemblies with emphasis on recent biochemical, structural and computational reports. As we will see, the literature brings valuable insights into the presumed macro-assemblies mitofusins may form during anchoring and fusion of mitochondrial outer membranes.
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Affiliation(s)
- Mohammad Ozeir
- 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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5
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Green A, Hossain T, Eckmann DM. Mitochondrial dynamics involves molecular and mechanical events in motility, fusion and fission. Front Cell Dev Biol 2022; 10:1010232. [PMID: 36340034 PMCID: PMC9626967 DOI: 10.3389/fcell.2022.1010232] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 10/06/2022] [Indexed: 11/13/2022] Open
Abstract
Mitochondria are cell organelles that play pivotal roles in maintaining cell survival, cellular metabolic homeostasis, and cell death. Mitochondria are highly dynamic entities which undergo fusion and fission, and have been shown to be very motile in vivo in neurons and in vitro in multiple cell lines. Fusion and fission are essential for maintaining mitochondrial homeostasis through control of morphology, content exchange, inheritance of mitochondria, maintenance of mitochondrial DNA, and removal of damaged mitochondria by autophagy. Mitochondrial motility occurs through mechanical and molecular mechanisms which translocate mitochondria to sites of high energy demand. Motility also plays an important role in intracellular signaling. Here, we review key features that mediate mitochondrial dynamics and explore methods to advance the study of mitochondrial motility as well as mitochondrial dynamics-related diseases and mitochondrial-targeted therapeutics.
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Affiliation(s)
- Adam Green
- Department of Anesthesiology, The Ohio State University, Columbus, OH, United States
| | - Tanvir Hossain
- Department of Anesthesiology, The Ohio State University, Columbus, OH, United States
| | - David M. Eckmann
- Department of Anesthesiology, The Ohio State University, Columbus, OH, United States
- Center for Medical and Engineering Innovation, The Ohio State University, Columbus, OH, United States
- *Correspondence: David M. Eckmann,
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6
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Yang Z, Wang L, Yang C, Pu S, Guo Z, Wu Q, Zhou Z, Zhao H. Mitochondrial Membrane Remodeling. Front Bioeng Biotechnol 2022; 9:786806. [PMID: 35059386 PMCID: PMC8763711 DOI: 10.3389/fbioe.2021.786806] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/22/2021] [Indexed: 02/05/2023] Open
Abstract
Mitochondria are key regulators of many important cellular processes and their dysfunction has been implicated in a large number of human disorders. Importantly, mitochondrial function is tightly linked to their ultrastructure, which possesses an intricate membrane architecture defining specific submitochondrial compartments. In particular, the mitochondrial inner membrane is highly folded into membrane invaginations that are essential for oxidative phosphorylation. Furthermore, mitochondrial membranes are highly dynamic and undergo constant membrane remodeling during mitochondrial fusion and fission. It has remained enigmatic how these membrane curvatures are generated and maintained, and specific factors involved in these processes are largely unknown. This review focuses on the current understanding of the molecular mechanism of mitochondrial membrane architectural organization and factors critical for mitochondrial morphogenesis, as well as their functional link to human diseases.
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Affiliation(s)
- Ziyun Yang
- School of Life Sciences, Guangxi Normal University, Guilin, China.,Guangxi Universities, Key Laboratory of Stem Cell and Biopharmaceutical Technology, Guangxi Normal University, Guilin, China.,Research Center for Biomedical Sciences, Guangxi Normal University, Guilin, China
| | - Liang Wang
- National Chengdu Center for Safety Evaluation of Drugs, State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, West China Hospital, West China Medical School, Sichuan University, High-Tech Development Zone, Chengdu, China
| | - Cheng Yang
- School of Life Sciences, Guangxi Normal University, Guilin, China.,Guangxi Universities, Key Laboratory of Stem Cell and Biopharmaceutical Technology, Guangxi Normal University, Guilin, China.,Research Center for Biomedical Sciences, Guangxi Normal University, Guilin, China
| | - Shiming Pu
- School of Life Sciences, Guangxi Normal University, Guilin, China.,Guangxi Universities, Key Laboratory of Stem Cell and Biopharmaceutical Technology, Guangxi Normal University, Guilin, China.,Research Center for Biomedical Sciences, Guangxi Normal University, Guilin, China
| | - Ziqi Guo
- School of Life Sciences, Guangxi Normal University, Guilin, China.,Guangxi Universities, Key Laboratory of Stem Cell and Biopharmaceutical Technology, Guangxi Normal University, Guilin, China.,Research Center for Biomedical Sciences, Guangxi Normal University, Guilin, China
| | - Qiong Wu
- School of Life Sciences, Guangxi Normal University, Guilin, China.,Guangxi Universities, Key Laboratory of Stem Cell and Biopharmaceutical Technology, Guangxi Normal University, Guilin, China.,Research Center for Biomedical Sciences, Guangxi Normal University, Guilin, China
| | - Zuping Zhou
- School of Life Sciences, Guangxi Normal University, Guilin, China.,Guangxi Universities, Key Laboratory of Stem Cell and Biopharmaceutical Technology, Guangxi Normal University, Guilin, China.,Research Center for Biomedical Sciences, Guangxi Normal University, Guilin, China
| | - Hongxia Zhao
- School of Life Sciences, Guangxi Normal University, Guilin, China.,Guangxi Universities, Key Laboratory of Stem Cell and Biopharmaceutical Technology, Guangxi Normal University, Guilin, China.,Research Center for Biomedical Sciences, Guangxi Normal University, Guilin, China.,Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
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7
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Abstract
Mitochondria are complex organelles with two membranes. Their architecture is determined by characteristic folds of the inner membrane, termed cristae. Recent studies in yeast and other organisms led to the identification of four major pathways that cooperate to shape cristae membranes. These include dimer formation of the mitochondrial ATP synthase, assembly of the mitochondrial contact site and cristae organizing system (MICOS), inner membrane remodelling by a dynamin-related GTPase (Mgm1/OPA1), and modulation of the mitochondrial lipid composition. In this review, we describe the function of the evolutionarily conserved machineries involved in mitochondrial cristae biogenesis with a focus on yeast and present current models to explain how their coordinated activities establish mitochondrial membrane architecture.
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Affiliation(s)
- Till Klecker
- Institut für Zellbiologie, Universität Bayreuth, 95440 Bayreuth, Germany
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8
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Del Dotto V, Carelli V. Dominant Optic Atrophy (DOA): Modeling the Kaleidoscopic Roles of OPA1 in Mitochondrial Homeostasis. Front Neurol 2021; 12:681326. [PMID: 34177786 PMCID: PMC8220150 DOI: 10.3389/fneur.2021.681326] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 04/22/2021] [Indexed: 02/05/2023] Open
Abstract
In the year 2000, the discovery of OPA1 mutations as causative for dominant optic atrophy (DOA) was pivotal to rapidly expand the field of mitochondrial dynamics and describe the complex machinery governing this pathway, with a multitude of other genes and encoded proteins involved in neurodegenerative disorders of the optic nerve. OPA1 turned out to be a much more complex protein than initially envisaged, connecting multiple pathways beyond its strict role in mitochondrial fusion, such as sensing of OXPHOS needs and mitochondrial DNA maintenance. As a consequence, an increasing need to investigate OPA1 functions at multiple levels has imposed the development of multiple tools and models that are here reviewed. Translational mitochondrial medicine, with the ultimate objective of translating basic science necessary to understand pathogenic mechanisms into therapeutic strategies, requires disease modeling at multiple levels: from the simplest, like in yeast, to cell models, including the increasing use of reprogrammed stem cells (iPSCs) from patients, to animal models. In the present review, we thoroughly examine and provide the state of the art of all these approaches.
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Affiliation(s)
- Valentina Del Dotto
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Valerio Carelli
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy.,Istituto di Ricovero e Cura a Carattere Scientifico Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna, Italy
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9
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Gao S, Hu J. Mitochondrial Fusion: The Machineries In and Out. Trends Cell Biol 2020; 31:62-74. [PMID: 33092941 DOI: 10.1016/j.tcb.2020.09.008] [Citation(s) in RCA: 175] [Impact Index Per Article: 43.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 09/10/2020] [Accepted: 09/14/2020] [Indexed: 11/15/2022]
Abstract
Mitochondria are highly dynamic organelles that constantly undergo fission and fusion. Disruption of mitochondrial dynamics undermines their function and causes several human diseases. The fusion of the outer (OMM) and inner mitochondrial membranes (IMM) is mediated by two classes of dynamin-like protein (DLP): mitofusin (MFN)/fuzzy onions 1 (Fzo1) and optic atrophy 1/mitochondria genome maintenance 1 (OPA1/Mgm1). Given the lack of structural information on these fusogens, the molecular mechanisms underlying mitochondrial fusion remain unclear, even after 20 years. Here, we review recent advances in structural studies of the mitochondrial fusion machinery, discuss their implication for DLPs, and summarize the pathogenic mechanisms of disease-causing mutations in mitochondrial fusion DLPs.
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Affiliation(s)
- Song Gao
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, 510060 Guangzhou, China; Guangzhou Regenerative Medicine and Health Guangdong Laboratory, 510530 Guangzhou, China.
| | - Junjie Hu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
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10
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Khosravi S, Harner ME. The MICOS complex, a structural element of mitochondria with versatile functions. Biol Chem 2020; 401:765-778. [DOI: 10.1515/hsz-2020-0103] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 03/16/2020] [Indexed: 01/01/2023]
Abstract
AbstractMitochondria perform a plethora of functions in various cells of different tissues. Their architecture differs remarkably, for instance in neurons versus steroidogenic cells. Furthermore, aberrant mitochondrial architecture results in mitochondrial dysfunction. This indicates strongly that mitochondrial architecture and function are intimately linked. Therefore, a deep knowledge about the determinants of mitochondrial architecture and their function on a molecular level is of utmost importance. In the past decades, various proteins and protein complexes essential for formation of mitochondrial architecture have been identified. Here we will review the current knowledge of the MICOS complex, one of the major structural elements of mitochondria. MICOS is a multi-subunit complex present in the inner mitochondrial membrane. Multiple interaction partners in the inner and outer mitochondrial membrane point to participation in a multitude of important processes, such as generation of mitochondrial architecture, lipid metabolism, and protein import into mitochondria. Since the MICOS complex is highly conserved in form and function throughout evolution, we will highlight the importance of MICOS for mammals. We will emphasize in particular the current knowledge of the association of MICOS with severe human diseases, including Charcot–Marie–Tooth disease type 2, Alzheimer's disease, Parkinson's disease, Frontotemporal Dementia and Amyotrophic Lateral Sclerosis.
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Affiliation(s)
- Siavash Khosravi
- Department of Cell Biology, Biomedical Center, Ludwig-Maximilians University Munich, Großhaderner Str. 9, Planegg/Martinsried, MunichD-82152, Germany
| | - Max E. Harner
- Institute of Cardiovascular Physiology and Pathophysiology, Biomedical Center, Ludwig-Maximilians University Munich, Großhaderner Str. 9, Planegg/Martinsried, MunichD-82152, Germany
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11
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Structural analysis of a trimeric assembly of the mitochondrial dynamin-like GTPase Mgm1. Proc Natl Acad Sci U S A 2020; 117:4061-4070. [PMID: 32041880 PMCID: PMC7049166 DOI: 10.1073/pnas.1919116117] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Mitochondria are dynamic double-membraned organelles, which undergo cycles of division and fusion mediated by dynamin-related GTPases. How dynamins mediate mitochondrial inner membrane fusion is not understood. In humans, defective inner membrane fusion causes a degenerative form of blindness termed dominant optic atrophy. Here, we solve the structure of a trimer assembly of an inner membrane fusion dynamin. Our observations underscore the structural plasticity of dynamins and suggest a previously unidentified mode of how they might mediate membrane fusion events. The fusion of inner mitochondrial membranes requires dynamin-like GTPases, Mgm1 in yeast and OPA1 in mammals, but how they mediate membrane fusion is poorly understood. Here, we determined the crystal structure of Saccharomyces cerevisiae short Mgm1 (s-Mgm1) in complex with GDP. It revealed an N-terminal GTPase (G) domain followed by two helix bundles (HB1 and HB2) and a unique C-terminal lipid-interacting stalk (LIS). Dimers can form through antiparallel HB interactions. Head-to-tail trimers are built by intermolecular interactions between the G domain and HB2-LIS. Biochemical and in vivo analyses support the idea that the assembly interfaces observed here are native and critical for Mgm1 function. We also found that s-Mgm1 interacts with negatively charged lipids via both the G domain and LIS. Based on these observations, we propose that membrane targeting via the G domain and LIS facilitates the in cis assembly of Mgm1, potentially generating a highly curved membrane tip to allow inner membrane fusion.
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12
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Huddleston ME, Xiao N, Both AP, Gordon DM. Single amino acid mutations in the Saccharomyces cerevisiae rhomboid peptidase, Pcp1p, alter mitochondrial morphology. Cell Biol Int 2020; 44:200-215. [PMID: 31441130 PMCID: PMC6972574 DOI: 10.1002/cbin.11219] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 08/18/2019] [Indexed: 01/24/2023]
Abstract
Key to mitochondrial activities is the maintenance of mitochondrial morphology, specifically cristae structures formed by the invagination of the inner membrane that are enriched in proteins of the electron transport chain. In Saccharomyces cerevisiae , these cristae folds are a result of the membrane fusion activities of Mgm1p and the membrane-bending properties of adenosine triphosphate (ATP) synthase oligomerization. An additional protein linked to mitochondrial morphology is Pcp1p, a serine protease responsible for the proteolytic processing of Mgm1p. Here, we have used hydroxylamine-based random mutagenesis to identify amino acids important for Pcp1p peptidase activity. Using this approach we have isolated five single amino acid mutants that exhibit respiratory growth defects that correlate with loss of mitochondrial genome stability. Reduced Pcp1p protease activity was confirmed by immunoblotting with the accumulation of improperly processed Mgm1p. Ultra-structural analysis of mitochondrial morphology in these mutants found a varying degree of defects in cristae organization. However, not all of the mutants presented with decreased ATP synthase complex assembly as determined by blue native polyacrylamide gel electrophoresis. Together, these data suggest that there is a threshold level of processed Mgm1p required to maintain ATP synthase super-complex assembly and mitochondrial cristae organization.
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Affiliation(s)
| | - Ningyu Xiao
- Department of Biological SciencesMississippi State UniversityMississippi StateMississippi39762USA
| | - Andries Pieter Both
- Department of Biological SciencesMississippi State UniversityMississippi StateMississippi39762USA
| | - Donna M. Gordon
- Department of Biological SciencesMississippi State UniversityMississippi StateMississippi39762USA
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13
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Faelber K, Dietrich L, Noel JK, Wollweber F, Pfitzner AK, Mühleip A, Sánchez R, Kudryashev M, Chiaruttini N, Lilie H, Schlegel J, Rosenbaum E, Hessenberger M, Matthaeus C, Kunz S, von der Malsburg A, Noé F, Roux A, van der Laan M, Kühlbrandt W, Daumke O. Structure and assembly of the mitochondrial membrane remodelling GTPase Mgm1. Nature 2019; 571:429-433. [PMID: 31292547 DOI: 10.1038/s41586-019-1372-3] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 06/13/2019] [Indexed: 12/25/2022]
Abstract
Balanced fusion and fission are key for the proper function and physiology of mitochondria1,2. Remodelling of the mitochondrial inner membrane is mediated by the dynamin-like protein mitochondrial genome maintenance 1 (Mgm1) in fungi or the related protein optic atrophy 1 (OPA1) in animals3-5. Mgm1 is required for the preservation of mitochondrial DNA in yeast6, whereas mutations in the OPA1 gene in humans are a common cause of autosomal dominant optic atrophy-a genetic disorder that affects the optic nerve7,8. Mgm1 and OPA1 are present in mitochondria as a membrane-integral long form and a short form that is soluble in the intermembrane space. Yeast strains that express temperature-sensitive mutants of Mgm19,10 or mammalian cells that lack OPA1 display fragmented mitochondria11,12, which suggests that Mgm1 and OPA1 have an important role in inner-membrane fusion. Consistently, only the mitochondrial outer membrane-not the inner membrane-fuses in the absence of functional Mgm113. Mgm1 and OPA1 have also been shown to maintain proper cristae architecture10,14; for example, OPA1 prevents the release of pro-apoptotic factors by tightening crista junctions15. Finally, the short form of OPA1 localizes to mitochondrial constriction sites, where it presumably promotes mitochondrial fission16. How Mgm1 and OPA1 perform their diverse functions in membrane fusion, scission and cristae organization is at present unknown. Here we present crystal and electron cryo-tomography structures of Mgm1 from Chaetomium thermophilum. Mgm1 consists of a GTPase (G) domain, a bundle signalling element domain, a stalk, and a paddle domain that contains a membrane-binding site. Biochemical and cell-based experiments demonstrate that the Mgm1 stalk mediates the assembly of bent tetramers into helical filaments. Electron cryo-tomography studies of Mgm1-decorated lipid tubes and fluorescence microscopy experiments on reconstituted membrane tubes indicate how the tetramers assemble on positively or negatively curved membranes. Our findings convey how Mgm1 and OPA1 filaments dynamically remodel the mitochondrial inner membrane.
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Affiliation(s)
- Katja Faelber
- Crystallography, Max-Delbrück-Centrum for Molecular Medicine, Berlin, Germany.
| | - Lea Dietrich
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Jeffrey K Noel
- Crystallography, Max-Delbrück-Centrum for Molecular Medicine, Berlin, Germany
| | - Florian Wollweber
- Medical Biochemistry & Molecular Biology, Center for Molecular Signaling, PZMS, Saarland University Medical School, Homburg, Germany
| | | | - Alexander Mühleip
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Ricardo Sánchez
- Alexander von Humboldt - Sofja Kovalevskaja Research Group, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Misha Kudryashev
- Alexander von Humboldt - Sofja Kovalevskaja Research Group, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | | | - Hauke Lilie
- Institute of Biochemistry and Biotechnology, Section of Protein Biochemistry, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Jeanette Schlegel
- Crystallography, Max-Delbrück-Centrum for Molecular Medicine, Berlin, Germany
| | - Eva Rosenbaum
- Crystallography, Max-Delbrück-Centrum for Molecular Medicine, Berlin, Germany
| | - Manuel Hessenberger
- Crystallography, Max-Delbrück-Centrum for Molecular Medicine, Berlin, Germany
| | - Claudia Matthaeus
- Crystallography, Max-Delbrück-Centrum for Molecular Medicine, Berlin, Germany
| | - Séverine Kunz
- EM facility, Max-Delbrück-Centrum for Molecular Medicine, Berlin, Germany
| | - Alexander von der Malsburg
- Medical Biochemistry & Molecular Biology, Center for Molecular Signaling, PZMS, Saarland University Medical School, Homburg, Germany
| | - Frank Noé
- Institute for Mathematics, Freie Universität Berlin, Berlin, Germany
| | - Aurélien Roux
- Biochemistry Department, University of Geneva, Geneva, Switzerland
| | - Martin van der Laan
- Medical Biochemistry & Molecular Biology, Center for Molecular Signaling, PZMS, Saarland University Medical School, Homburg, Germany
| | - Werner Kühlbrandt
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany.
| | - Oliver Daumke
- Crystallography, Max-Delbrück-Centrum for Molecular Medicine, Berlin, Germany. .,Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany.
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14
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Dietz JV, Bohovych I, Viana MP, Khalimonchuk O. Proteolytic regulation of mitochondrial dynamics. Mitochondrion 2019; 49:289-304. [PMID: 31029640 DOI: 10.1016/j.mito.2019.04.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 04/19/2019] [Indexed: 12/23/2022]
Abstract
Spatiotemporal changes in the abundance, shape, and cellular localization of the mitochondrial network, also known as mitochondrial dynamics, are now widely recognized to play a key role in mitochondrial and cellular physiology as well as disease states. This process involves coordinated remodeling of the outer and inner mitochondrial membranes by conserved dynamin-like guanosine triphosphatases and their partner molecules in response to various physiological and stress stimuli. Although the core machineries that mediate fusion and partitioning of the mitochondrial network have been extensively characterized, many aspects of their function and regulation are incompletely understood and only beginning to emerge. In the present review we briefly summarize current knowledge about how the key mitochondrial dynamics-mediating factors are regulated via selective proteolysis by mitochondrial and cellular proteolytic machineries.
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Affiliation(s)
- Jonathan V Dietz
- Department of Biochemistry, University of Nebraska, Lincoln, NE 68588, United States of America
| | - Iryna Bohovych
- Department of Biochemistry, University of Nebraska, Lincoln, NE 68588, United States of America
| | - Martonio Ponte Viana
- Department of Biochemistry, University of Nebraska, Lincoln, NE 68588, United States of America
| | - Oleh Khalimonchuk
- Department of Biochemistry, University of Nebraska, Lincoln, NE 68588, United States of America; Nebraska Redox Biology Center, University of Nebraska, Lincoln, NE 68588, United States of America; Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, United States of America.
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15
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Abstract
Mitochondria undergo frequent fusion and fission events to adapt their morphology to cellular needs. Homotypic docking and fusion of outer mitochondrial membranes are controlled by Mitofusins, a set of large membrane-anchored GTPase proteins belonging to the dynamin superfamily. Mitofusins include, in addition to their GTPase and transmembrane domains, two heptad repeat domains, HR1 and HR2. All four regions are crucial for Mitofusin function, but their precise contribution to mitochondrial docking and fusion events has remained elusive until very recently. In this commentary, we first give an overview of the established strategies employed by various protein machineries distinct from Mitofusins to mediate membrane fusion. We then present recent structure–function data on Mitofusins that provide important novel insights into their mode of action in mitochondrial fusion.
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Affiliation(s)
- Mickael M Cohen
- Sorbonne Université, CNRS UMR8226, Institut de Biologie Physico-Chimique, Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, Paris, France
| | - David Tareste
- Université Paris Descartes, Sorbonne Paris Cité, INSERM ERL U950, Trafic Membranaire dans le Cerveau Normal et Pathologique, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, INSERM UMR 894, Institut de Psychiatrie et Neurosciences de Paris, Paris, France
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16
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Mo GCH, Yip CM. Structural templating of J-aggregates: Visualizing bis(monoacylglycero)phosphate domains in live cells. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2017; 1865:1687-1695. [PMID: 28844737 DOI: 10.1016/j.bbapap.2017.07.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 07/13/2017] [Accepted: 07/24/2017] [Indexed: 12/23/2022]
Abstract
Identifying the key structural and dynamical determinants that drive the association of biomolecules, whether in solution, or perhaps more importantly in a membrane environment, has critical implications for our understanding of cellular dynamics, processes, and signaling. With recent advances in high-resolution imaging techniques, from the development of new molecular labels to technical advances in imaging methodologies and platforms, researchers are now reaping the benefits of being able to directly characterize and quantify local dynamics, structures, and conformations in live cells and tissues. These capabilities are providing unique insights into association stoichiometries, interactions, and structures on sub-micron length scales. We previously examined the role of lipid headgroup chemistry and phase state in guiding the formation of pseudoisocyanine (PIC) dye J-aggregates on supported planar bilayers [Langmuir, 25, 10719]. We describe here how these same J-aggregates can report on the in situ formation of organellar membrane domains in live cells. Live cell hyperspectral confocal microscopy using GFP-conjugated GTPase markers of early (Rab5) and late (Rab7) endosomes revealed that the PIC J-aggregates were confined to domains on either the limiting membrane or intralumenal vesicles (ILV) of late endosomes, known to be enriched in the anionic lipid bis(monoacylglycero)phosphate (BMP). Correlated confocal fluorescence - atomic force microscopy performed on endosomal membrane-mimetic supported planar lipid bilayers confirmed BMP-specific templating of the PIC J-aggregates. These data provide strong evidence for the formation of BMP-rich lipid domains during multivesicular body formation and portend the application of structured dye aggregates as markers of cellular membrane domain structure, size, and formation.
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Affiliation(s)
- Gary C H Mo
- Department of Chemical Engineering and Applied Chemistry, Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College St., Toronto M5S 3E1, Canada; Department of Pharmacology, University of California San Diego, La Jolla, CA 92093, USA
| | - Christopher M Yip
- Department of Biochemistry, Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College St., Toronto M5S 3E1, Canada; Department of Chemical Engineering and Applied Chemistry, Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College St., Toronto M5S 3E1, Canada; Institute of Biomaterials and Biomedical Engineering, Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College St., Toronto M5S 3E1, Canada.
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17
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Ramachandran R. Mitochondrial dynamics: The dynamin superfamily and execution by collusion. Semin Cell Dev Biol 2017; 76:201-212. [PMID: 28754444 DOI: 10.1016/j.semcdb.2017.07.039] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2017] [Revised: 07/20/2017] [Accepted: 07/24/2017] [Indexed: 11/25/2022]
Abstract
Distinct dynamin superfamily GTPases catalyze the constant fission and fusion of the elaborate mitochondrial networks that navigate the eukaryotic cytoplasm. Long believed to be the singular handiwork of dynamin-related protein 1 (Drp1), a cytosolic family member that transiently localizes to the mitochondrial surface, the execution of mitochondrial fission is now arguably believed to entail membrane remodeling events that are initiated upstream of Drp1 by ER-associated cytoskeletal networks and completed downstream by the prototypical dynamin, dynamin 2 (Dyn2). Recent developments in the field have also placed a sharp focus on the membrane microenvironment around the division apparatus and the potential facilitatory role of specific lipids in mitochondrial fission. Here, I will review current progress, as well as highlight the most visible gaps in knowledge, in elucidating the varied functions of the dynamin superfamily in the coordinated events of mitochondrial fission and fusion. The essential roles of protein and lipid cofactors are also highlighted.
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Affiliation(s)
- Rajesh Ramachandran
- Department of Physiology & Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106-4970, USA.
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18
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Mitochondrial fission and fusion. Biochem Soc Trans 2017; 44:1725-1735. [PMID: 27913683 DOI: 10.1042/bst20160129] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 09/15/2016] [Accepted: 10/05/2016] [Indexed: 01/27/2023]
Abstract
Mitochondrial fission and fusion have been recognized as critical processes in the health of mitochondria and cells. Two decades of studies have generated a great deal of information about mitochondrial fission and fusion; however, still much needs to be understood for the basic molecular mechanisms of these important cellular processes. The core protein factors for mitochondrial fission and fusion are dynamin proteins that possess membrane-remodeling properties. This short review covers a recent development and understanding of the mechanisms by which these mechanochemical enzymes mediate mitochondrial fission and fusion.
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19
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Quintana-Cabrera R, Mehrotra A, Rigoni G, Soriano ME. Who and how in the regulation of mitochondrial cristae shape and function. Biochem Biophys Res Commun 2017; 500:94-101. [PMID: 28438601 DOI: 10.1016/j.bbrc.2017.04.088] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 04/17/2017] [Indexed: 12/19/2022]
Abstract
Mitochondrial adaptation to different physiological conditions highly relies on the regulation of mitochondrial ultrastructure, particularly at the level of cristae compartment. Cristae represent the membrane hub where most of the respiratory complexes embed to account for OXPHOS and energy production in the form of adenosine triphosphate (ATP). Changes in cristae number and shape define the respiratory capacity as well as cell viability. The identification of key regulators of cristae morphology and the understanding of their contribution to the mitochondrial ultrastructure and function have become an strategic goal to understand mitochondrial disorders and to exploit as therapeutic targets. This review summarizes the known regulators of cristae ultrastructure and discusses their contribution and implications for mitochondrial dysfunction.
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Affiliation(s)
- R Quintana-Cabrera
- Department of Biology, University of Padova, Padova, 35121, Italy; Venetian Institute of Molecular Medicine, Padova 35129, Italy
| | - A Mehrotra
- Department of Biology, University of Padova, Padova, 35121, Italy
| | - G Rigoni
- Department of Biology, University of Padova, Padova, 35121, Italy
| | - M E Soriano
- Department of Biology, University of Padova, Padova, 35121, Italy.
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20
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Rampelt H, Zerbes RM, van der Laan M, Pfanner N. Role of the mitochondrial contact site and cristae organizing system in membrane architecture and dynamics. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:737-746. [DOI: 10.1016/j.bbamcr.2016.05.020] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 05/12/2016] [Accepted: 05/17/2016] [Indexed: 12/22/2022]
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21
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Harner ME, Unger AK, Geerts WJ, Mari M, Izawa T, Stenger M, Geimer S, Reggiori F, Westermann B, Neupert W. An evidence based hypothesis on the existence of two pathways of mitochondrial crista formation. eLife 2016; 5. [PMID: 27849155 PMCID: PMC5138035 DOI: 10.7554/elife.18853] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 11/14/2016] [Indexed: 12/31/2022] Open
Abstract
Metabolic function and architecture of mitochondria are intimately linked. More than 60 years ago, cristae were discovered as characteristic elements of mitochondria that harbor the protein complexes of oxidative phosphorylation, but how cristae are formed, remained an open question. Here we present experimental results obtained with yeast that support a novel hypothesis on the existence of two molecular pathways that lead to the generation of lamellar and tubular cristae. Formation of lamellar cristae depends on the mitochondrial fusion machinery through a pathway that is required also for homeostasis of mitochondria and mitochondrial DNA. Tubular cristae are formed via invaginations of the inner boundary membrane by a pathway independent of the fusion machinery. Dimerization of the F1FO-ATP synthase and the presence of the MICOS complex are necessary for both pathways. The proposed hypothesis is suggested to apply also to higher eukaryotes, since the key components are conserved in structure and function throughout evolution. DOI:http://dx.doi.org/10.7554/eLife.18853.001 Cells contain compartments called mitochondria, which are often called the powerhouses of the cell because they provide energy that drives vital cellular processes. Mitochondria have two membranes: an outer and an inner membrane. The outer membrane separates the mitochondria from the rest of the cell. The inner membrane is elaborately folded and the folds – called cristae – create a larger space to accommodate all of the protein machinery involved in producing energy. The cristae can be shaped as flat sac-like structures called lamellar cristae or as tubes known as tubular cristae. Mitochondria are dynamic and are constantly fusing with other mitochondria and splitting up. Even though the internal architecture of mitochondria was first revealed around 60 years ago, it is still not clear how the cristae form. Harner et al. now address this question in yeast cells by combining imaging, biochemistry and genetic approaches. The experiments show that lamellar cristae form when two mitochondria fuse with each other. The outer membranes merge and then the inner membranes start to fuse around their edges to generate the sac-like structure of lamellar cristae. A yeast protein called Mgm1 (known as Opa1 in mammals) drives the fusion of the inner membranes, but this process only takes place when enzymes called F1FO-ATP synthases on the inner membrane form pairs with one another. These F1FO-ATP synthase pairs stabilize the cristae membranes as they curve to form the sac-like structure. Later on, the formation of a group of proteins called the MICOS complex halts the fusion process to prevent the lamellar cristae from completely separating from the rest of the inner membrane. Harner et al. also found that tubular cristae form using a different mechanism when the inner membrane of the mitochondria grows inwards. This process also requires pairs of F1FO-ATP synthases and the MICOS complex, but does not involve Mgm1/Opa1. Together, these findings show that lamellar and tubular cristae in yeast form using two different mechanisms. Since the key components of these mechanisms are also found in virtually all other eukaryotes, the findings of Harner et al. are also likely to apply to many other organisms including animals. DOI:http://dx.doi.org/10.7554/eLife.18853.002
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Affiliation(s)
- Max E Harner
- Max Planck Institute of Biochemistry, Martinsried, Germany.,Walter Brendel Centre of Experimental Medicine, Ludwig-Maximilians-Universität München, Martinsried, Germany
| | - Ann-Katrin Unger
- Cell Biology and Electron Microscopy, Universität Bayreuth, Bayreuth, Germany
| | - Willie Jc Geerts
- Biomolecular Imaging, Bijvoet Center, Universiteit Utrecht, Utrecht, Netherlands
| | - Muriel Mari
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Toshiaki Izawa
- Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Maria Stenger
- Cell Biology and Electron Microscopy, Universität Bayreuth, Bayreuth, Germany
| | - Stefan Geimer
- Cell Biology and Electron Microscopy, Universität Bayreuth, Bayreuth, Germany
| | - Fulvio Reggiori
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Benedikt Westermann
- Cell Biology and Electron Microscopy, Universität Bayreuth, Bayreuth, Germany
| | - Walter Neupert
- Max Planck Institute of Biochemistry, Martinsried, Germany.,Department of Anatomy and Cell Biology, Biomedical Center, Ludwig-Maximilians Universität München, Martinsried, Germany
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22
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Barbot M, Meinecke M. Reconstitutions of mitochondrial inner membrane remodeling. J Struct Biol 2016; 196:20-28. [DOI: 10.1016/j.jsb.2016.07.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 07/20/2016] [Accepted: 07/21/2016] [Indexed: 02/03/2023]
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23
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MacVicar T, Langer T. OPA1 processing in cell death and disease - the long and short of it. J Cell Sci 2016; 129:2297-306. [PMID: 27189080 DOI: 10.1242/jcs.159186] [Citation(s) in RCA: 256] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The regulation of mitochondrial dynamics by the GTPase OPA1, which is located at the inner mitochondrial membrane, is crucial for adapting mitochondrial function and preserving cellular health. OPA1 governs the delicate balance between fusion and fission in the dynamic mitochondrial network. A disturbance of this balance, often observed under stress and pathologic conditions, causes mitochondrial fragmentation and can ultimately result in cell death. As discussed in this Commentary, these morphological changes are regulated by proteolytic processing of OPA1 by the inner-membrane peptidases YME1L (also known as YME1L1) and OMA1. Long, membrane-bound forms of OPA1 are required for mitochondrial fusion, but their processing to short, soluble forms limits fusion and can facilitate mitochondrial fission. Excessive OPA1 processing by the stress-activated protease OMA1 promotes mitochondrial fragmentation and, if persistent, triggers cell death and tissue degeneration in vivo The prevention of OMA1-mediated OPA1 processing and mitochondrial fragmentation might thus offer exciting therapeutic potential for human diseases associated with mitochondrial dysfunction.
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Affiliation(s)
- Thomas MacVicar
- Institute of Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) and Center for Molecular Medicine (CMMC), University of Cologne, Cologne 50931, Germany
| | - Thomas Langer
- Institute of Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) and Center for Molecular Medicine (CMMC), University of Cologne, Cologne 50931, Germany
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24
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Schrempp SG, van der Laan M. Get Ready for Fusion: Insights into Mgm1-Mediated Membrane Remodeling. J Mol Biol 2015; 427:2595-8. [PMID: 26079069 DOI: 10.1016/j.jmb.2015.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Sandra G Schrempp
- Institut für Biochemie und Molekularbiologie, ZBMZ, Universität Freiburg, D-79104 Freiburg, Germany
| | - Martin van der Laan
- Institut für Biochemie und Molekularbiologie, ZBMZ, Universität Freiburg, D-79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, Universität Freiburg, D-79104 Freiburg, Germany.
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