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Alsayyah C, Singh MK, Morcillo-Parra MA, Cavellini L, Shai N, Schmitt C, Schuldiner M, Zalckvar E, Mallet A, Belgareh-Touzé N, Zimmer C, Cohen MM. Mitofusin-mediated contacts between mitochondria and peroxisomes regulate mitochondrial fusion. PLoS Biol 2024; 22:e3002602. [PMID: 38669296 PMCID: PMC11078399 DOI: 10.1371/journal.pbio.3002602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 05/08/2024] [Accepted: 03/26/2024] [Indexed: 04/28/2024] Open
Abstract
Mitofusins are large GTPases that trigger fusion of mitochondrial outer membranes. Similarly to the human mitofusin Mfn2, which also tethers mitochondria to the endoplasmic reticulum (ER), the yeast mitofusin Fzo1 stimulates contacts between Peroxisomes and Mitochondria when overexpressed. Yet, the physiological significance and function of these "PerMit" contacts remain unknown. Here, we demonstrate that Fzo1 naturally localizes to peroxisomes and promotes PerMit contacts in physiological conditions. These contacts are regulated through co-modulation of Fzo1 levels by the ubiquitin-proteasome system (UPS) and by the desaturation status of fatty acids (FAs). Contacts decrease under low FA desaturation but reach a maximum during high FA desaturation. High-throughput genetic screening combined with high-resolution cellular imaging reveal that Fzo1-mediated PerMit contacts favor the transit of peroxisomal citrate into mitochondria. In turn, citrate enters the TCA cycle to stimulate the mitochondrial membrane potential and maintain efficient mitochondrial fusion upon high FA desaturation. These findings thus unravel a mechanism by which inter-organelle contacts safeguard mitochondrial fusion.
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Affiliation(s)
- Cynthia Alsayyah
- Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, Sorbonne Université, CNRS, UMR8226, Institut de Biologie Physico-Chimique, Paris, France
| | - Manish K. Singh
- Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, Sorbonne Université, CNRS, UMR8226, Institut de Biologie Physico-Chimique, Paris, France
- Institut Pasteur, Université Paris Cité, Imaging and Modeling Unit, F-75015 Paris, France
| | - Maria Angeles Morcillo-Parra
- Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, Sorbonne Université, CNRS, UMR8226, Institut de Biologie Physico-Chimique, Paris, France
| | - Laetitia Cavellini
- Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, Sorbonne Université, CNRS, UMR8226, Institut de Biologie Physico-Chimique, Paris, France
| | - Nadav Shai
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Christine Schmitt
- Ultrastructural BioImaging Core Facility, C2RT, Institut Pasteur, Université Paris Cité, Paris, France
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Einat Zalckvar
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Adeline Mallet
- Ultrastructural BioImaging Core Facility, C2RT, Institut Pasteur, Université Paris Cité, Paris, France
| | - Naïma Belgareh-Touzé
- Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, Sorbonne Université, CNRS, UMR8226, Institut de Biologie Physico-Chimique, Paris, France
| | - Christophe Zimmer
- Institut Pasteur, Université Paris Cité, Imaging and Modeling Unit, F-75015 Paris, France
- Rudolf Virchow Center for Integrative and Translational Bioimaging, University of Würzburg, Würzburg, Germany
| | - Mickaël M. Cohen
- Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, Sorbonne Université, CNRS, UMR8226, Institut de Biologie Physico-Chimique, Paris, France
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2
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Maruyama T, Hama Y, Noda NN. Mechanisms of mitochondrial reorganization. J Biochem 2024; 175:167-178. [PMID: 38016932 DOI: 10.1093/jb/mvad098] [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: 08/30/2023] [Revised: 10/27/2023] [Accepted: 11/09/2023] [Indexed: 11/30/2023] Open
Abstract
The cytoplasm of eukaryotes is dynamically zoned by membrane-bound and membraneless organelles. Cytoplasmic zoning allows various biochemical reactions to take place at the right time and place. Mitochondrion is a membrane-bound organelle that provides a zone for intracellular energy production and metabolism of lipids and iron. A key feature of mitochondria is their high dynamics: mitochondria constantly undergo fusion and fission, and excess or damaged mitochondria are selectively eliminated by mitophagy. Therefore, mitochondria are appropriate model systems to understand dynamic cytoplasmic zoning by membrane organelles. In this review, we summarize the molecular mechanisms of mitochondrial fusion and fission as well as mitophagy unveiled through studies using yeast and mammalian models.
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Affiliation(s)
- Tatsuro Maruyama
- Institute of Microbial Chemistry (BIKAKEN), 3-14-23 Kamiosaki, Shinagawa-ku, Tokyo 141-0021, Japan
| | - Yutaro Hama
- Institute of Microbial Chemistry (BIKAKEN), 3-14-23 Kamiosaki, Shinagawa-ku, Tokyo 141-0021, Japan
- Institute for Genetic Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo 060-0815, Japan
| | - Nobuo N Noda
- Institute of Microbial Chemistry (BIKAKEN), 3-14-23 Kamiosaki, Shinagawa-ku, Tokyo 141-0021, Japan
- Institute for Genetic Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo 060-0815, Japan
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3
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Anton V, Buntenbroich I, Simões T, Joaquim M, Müller L, Buettner R, Odenthal M, Hoppe T, Escobar-Henriques M. E4 ubiquitin ligase promotes mitofusin turnover and mitochondrial stress response. Mol Cell 2023; 83:2976-2990.e9. [PMID: 37595558 PMCID: PMC10434984 DOI: 10.1016/j.molcel.2023.07.021] [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: 07/08/2022] [Revised: 05/31/2023] [Accepted: 07/18/2023] [Indexed: 08/20/2023]
Abstract
Ubiquitin-dependent control of mitochondrial dynamics is important for protein quality and neuronal integrity. Mitofusins, mitochondrial fusion factors, can integrate cellular stress through their ubiquitylation, which is carried out by multiple E3 enzymes in response to many different stimuli. However, the molecular mechanisms that enable coordinated responses are largely unknown. Here we show that yeast Ufd2, a conserved ubiquitin chain-elongating E4 enzyme, is required for mitochondrial shape adjustments. Under various stresses, Ufd2 translocates to mitochondria and triggers mitofusin ubiquitylation. This elongates ubiquitin chains on mitofusin and promotes its proteasomal degradation, leading to mitochondrial fragmentation. Ufd2 and its human homologue UBE4B also target mitofusin mutants associated with Charcot-Marie-Tooth disease, a hereditary sensory and motor neuropathy characterized by progressive loss of the peripheral nerves. This underscores the pathophysiological importance of E4-mediated ubiquitylation in neurodegeneration. In summary, we identify E4-dependent mitochondrial stress adaptation by linking various metabolic processes to mitochondrial fusion and fission dynamics.
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Affiliation(s)
- Vincent Anton
- Institute for Genetics, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Cologne, Germany
| | - Ira Buntenbroich
- Institute for Genetics, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Cologne, Germany
| | - Tânia Simões
- Institute for Genetics, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Cologne, Germany
| | - Mariana Joaquim
- Institute for Genetics, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Cologne, Germany; Center for Molecular Medicine Cologne (CMMC), Cologne, Germany
| | - Leonie Müller
- Institute for Genetics, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Cologne, Germany
| | - Reinhard Buettner
- Center for Molecular Medicine Cologne (CMMC), Cologne, Germany; Institute of Pathology, Medical Faculty, University Hospital, University of Cologne, Germany
| | - Margarete Odenthal
- Center for Molecular Medicine Cologne (CMMC), Cologne, Germany; Institute of Pathology, Medical Faculty, University Hospital, University of Cologne, Germany
| | - Thorsten Hoppe
- Institute for Genetics, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Cologne, Germany; Center for Molecular Medicine Cologne (CMMC), Cologne, Germany
| | - Mafalda Escobar-Henriques
- Institute for Genetics, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Cologne, Germany; Center for Molecular Medicine Cologne (CMMC), Cologne, Germany.
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4
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Buntenbroich I, Anton V, Perez-Hernandez D, Simões T, Gaedke F, Schauss A, Dittmar G, Riemer J, Escobar-Henriques M. Docking and stability defects in mitofusin highlight the proteasome as a potential therapeutic target. iScience 2023; 26:107014. [PMID: 37416455 PMCID: PMC10320088 DOI: 10.1016/j.isci.2023.107014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 04/23/2023] [Accepted: 05/29/2023] [Indexed: 07/08/2023] Open
Abstract
Defects in mitochondrial fusion are at the base of many diseases. Mitofusins power membrane-remodeling events via self-interaction and GTP hydrolysis. However, how exactly mitofusins mediate fusion of the outer membrane is still unclear. Structural studies enable tailored design of mitofusin variants, providing valuable tools to dissect this stepwise process. Here, we found that the two cysteines conserved between yeast and mammals are required for mitochondrial fusion, revealing two novel steps of the fusion cycle. C381 is dominantly required for the formation of the trans-tethering complex, before GTP hydrolysis. C805 allows stabilizing the Fzo1 protein and the trans-tethering complex, just prior to membrane fusion. Moreover, proteasomal inhibition rescued Fzo1 C805S levels and membrane fusion, suggesting a possible application for clinically approved drugs. Together, our study provides insights into how assembly or stability defects in mitofusins might cause mitofusin-associated diseases and uncovers potential therapeutic intervention by proteasomal inhibition.
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Affiliation(s)
- Ira Buntenbroich
- Institute for Genetics,University of Cologne, Cologne 50931, Germany
| | - Vincent Anton
- Institute for Genetics,University of Cologne, Cologne 50931, Germany
| | - Daniel Perez-Hernandez
- Proteomics of Cellular Signaling, Luxembourg Institute of Health, Strassen 1445, Luxembourg
| | - Tânia Simões
- Institute for Genetics,University of Cologne, Cologne 50931, Germany
| | - Felix Gaedke
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne 50931, Germany
| | - Astrid Schauss
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne 50931, Germany
| | - Gunnar Dittmar
- Proteomics of Cellular Signaling, Luxembourg Institute of Health, Strassen 1445, Luxembourg
| | - Jan Riemer
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne 50931, Germany
- Institute for Biochemistry, University of Cologne, Cologne 50931, Germany
| | - Mafalda Escobar-Henriques
- Institute for Genetics,University of Cologne, Cologne 50931, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne 50931, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne 50931, Germany
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5
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Schuettpelz J, Janer A, Antonicka H, Shoubridge EA. The role of the mitochondrial outer membrane protein SLC25A46 in mitochondrial fission and fusion. Life Sci Alliance 2023; 6:e202301914. [PMID: 36977595 PMCID: PMC10052876 DOI: 10.26508/lsa.202301914] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 03/08/2023] [Accepted: 03/10/2023] [Indexed: 03/30/2023] Open
Abstract
Mutations in SLC25A46 underlie a wide spectrum of neurodegenerative diseases associated with alterations in mitochondrial morphology. We established an SLC25A46 knock-out cell line in human fibroblasts and studied the pathogenicity of three variants (p.T142I, p.R257Q, and p.E335D). Mitochondria were fragmented in the knock-out cell line and hyperfused in all pathogenic variants. The loss of SLC25A46 led to abnormalities in the mitochondrial cristae ultrastructure that were not rescued by the expression of the variants. SLC25A46 was present in discrete puncta at mitochondrial branch points and tips of mitochondrial tubules, co-localizing with DRP1 and OPA1. Virtually, all fission/fusion events were demarcated by a SLC25A46 focus. SLC25A46 co-immunoprecipitated with the fusion machinery, and loss of function altered the oligomerization state of OPA1 and MFN2. Proximity interaction mapping identified components of the ER membrane, lipid transfer proteins, and mitochondrial outer membrane proteins, indicating that it is present at interorganellar contact sites. SLC25A46 loss of function led to altered mitochondrial lipid composition, suggesting that it may facilitate interorganellar lipid flux or play a role in membrane remodeling associated with mitochondrial fusion and fission.
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Affiliation(s)
- Jana Schuettpelz
- Department of Human Genetics, Montreal Neurological Institute, McGill University, Montreal, Canada
| | - Alexandre Janer
- Department of Human Genetics, Montreal Neurological Institute, McGill University, Montreal, Canada
| | - Hana Antonicka
- Department of Human Genetics, Montreal Neurological Institute, McGill University, Montreal, Canada
| | - Eric A Shoubridge
- Department of Human Genetics, Montreal Neurological Institute, McGill University, Montreal, Canada
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6
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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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7
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Sloat SR, Hoppins S. A dominant negative mitofusin causes mitochondrial perinuclear clusters because of aberrant tethering. Life Sci Alliance 2022; 6:6/1/e202101305. [PMID: 36229071 PMCID: PMC9568670 DOI: 10.26508/lsa.202101305] [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: 11/19/2021] [Revised: 09/27/2022] [Accepted: 09/28/2022] [Indexed: 11/29/2022] Open
Abstract
In vertebrates, mitochondrial outer membrane fusion is mediated by two mitofusin paralogs, Mfn1 and Mfn2, conserved dynamin superfamily proteins. Here, we characterize a variant of mitofusin reported in patients with CMT2A where a serine is replaced with a proline (Mfn2-S350P and the equivalent in Mfn1, S329P). This serine is in a hinge domain (Hinge 2) that connects the globular GTPase domain to the adjacent extended helical bundle. We find that expression of this variant results in prolific and stable mitochondrial tethering that also blocks mitochondrial fusion by endogenous wild-type mitofusin. The formation of mitochondrial perinuclear clusters by this CMT2A variant requires normal GTPase domain function and formation of a mitofusin complex across two membranes. We propose that conformational dynamics mediated by Hinge 2 and regulated by GTP hydrolysis are disrupted by the substitution of proline at S329/S350 and this prevents progression from tethering to membrane fusion. Thus, our data are consistent with a model for mitofusin-mediated membrane fusion where Hinge 2 supports a power stroke to progress from the tethering complex to membrane fusion.
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8
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Buntenbroich I, Simões T, Escobar-Henriques M. Analysis of Protein Stability by Synthesis Shutoff. Bio Protoc 2021; 11:e4225. [PMID: 34909446 DOI: 10.21769/bioprotoc.4225] [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: 07/19/2018] [Revised: 10/02/2018] [Accepted: 10/18/2018] [Indexed: 11/02/2022] Open
Abstract
In this protocol, we describe the analysis of protein stability over time, using synthesis shutoff. As an example, we express HA-tagged yeast mitofusin Fzo1 in Saccharomyces cerevisiae and inhibit translation via cycloheximide (CHX). Proteasomal inhibition with MG132 is performed, as an optional step, before the addition of CHX. Proteins are extracted via trichloroacetic acid (TCA) precipitation and subsequently separated via SDS-PAGE. Immunoblotting and antibody-decoration are performed to detect Fzo1 using HA-specific antibodies. We have adapted the method of blocking protein translation with cycloheximide to analyze the stability of high molecular weight proteins, including post-translational modifications and their impact on protein turnover.
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Affiliation(s)
- Ira Buntenbroich
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany
| | - Tânia Simões
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany
| | - Mafalda Escobar-Henriques
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany
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9
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Cdk8 Kinase Module: A Mediator of Life and Death Decisions in Times of Stress. Microorganisms 2021; 9:microorganisms9102152. [PMID: 34683473 PMCID: PMC8540245 DOI: 10.3390/microorganisms9102152] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Revised: 10/06/2021] [Accepted: 10/08/2021] [Indexed: 01/18/2023] Open
Abstract
The Cdk8 kinase module (CKM) of the multi-subunit mediator complex plays an essential role in cell fate decisions in response to different environmental cues. In the budding yeast S. cerevisiae, the CKM consists of four conserved subunits (cyclin C and its cognate cyclin-dependent kinase Cdk8, Med13, and Med12) and predominantly negatively regulates a subset of stress responsive genes (SRG’s). Derepression of these SRG’s is accomplished by disassociating the CKM from the mediator, thus allowing RNA polymerase II-directed transcription. In response to cell death stimuli, cyclin C translocates to the mitochondria where it induces mitochondrial hyper-fission and promotes regulated cell death (RCD). The nuclear release of cyclin C requires Med13 destruction by the ubiquitin-proteasome system (UPS). In contrast, to protect the cell from RCD following SRG induction induced by nutrient deprivation, cyclin C is rapidly destroyed by the UPS before it reaches the cytoplasm. This enables a survival response by two mechanisms: increased ATP production by retaining reticular mitochondrial morphology and relieving CKM-mediated repression on autophagy genes. Intriguingly, nitrogen starvation also stimulates Med13 destruction but through a different mechanism. Rather than destruction via the UPS, Med13 proteolysis occurs in the vacuole (yeast lysosome) via a newly identified Snx4-assisted autophagy pathway. Taken together, these findings reveal that the CKM regulates cell fate decisions by both transcriptional and non-transcriptional mechanisms, placing it at a convergence point between cell death and cell survival pathways.
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10
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Shvetsova A, Masud AJ, Schneider L, Bergmann U, Monteuuis G, Miinalainen IJ, Hiltunen JK, Kastaniotis AJ. A hunt for OM45 synthetic petite interactions in Saccharomyces cerevisiae reveals a role for Miro GTPase Gem1p in cristae structure maintenance. Microbiologyopen 2021; 10:e1238. [PMID: 34713605 PMCID: PMC8501180 DOI: 10.1002/mbo3.1238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 09/09/2021] [Accepted: 09/09/2021] [Indexed: 11/28/2022] Open
Abstract
Om45 is a major protein of the yeast's outer mitochondrial membrane under respiratory conditions. However, the cellular role of the protein has remained obscure. Previously, deletion mutant phenotypes have not been found, and clear amino acid sequence similarities that would allow inferring its functional role are not available. In this work, we describe synthetic petite mutants of GEM1 and UGO1 that depend on the presence of OM45 for respiratory growth, as well as the identification of several multicopy suppressors of the synthetic petite phenotypes. In the analysis of our mutants, we demonstrate that Om45p and Gem1p have a collaborative role in the maintenance of mitochondrial morphology, cristae structure, and mitochondrial DNA maintenance. A group of multicopy suppressors rescuing the synthetic lethal phenotypes of the mutants on non-fermentable carbon sources additionally supports this result. Our results imply that the synthetic petite phenotypes we observed are due to the disturbance of the inner mitochondrial membrane and point to this mitochondrial sub-compartment as the main target of action of Om45p, Ugo1p, and the yeast Miro GTPase Gem1p.
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Affiliation(s)
- Antonina Shvetsova
- Faculty of Biochemistry and Molecular Medicine and Biocenter OuluUniversity of OuluOuluFinland
| | - Ali J. Masud
- Faculty of Biochemistry and Molecular Medicine and Biocenter OuluUniversity of OuluOuluFinland
| | - Laura Schneider
- Faculty of Biochemistry and Molecular Medicine and Biocenter OuluUniversity of OuluOuluFinland
| | - Ulrich Bergmann
- Faculty of Biochemistry and Molecular Medicine and Biocenter OuluUniversity of OuluOuluFinland
| | - Geoffray Monteuuis
- Faculty of Biochemistry and Molecular Medicine and Biocenter OuluUniversity of OuluOuluFinland
- Present address:
Department of Biochemistry and Developmental BiologyUniversity of HelsinkiHelsinkiFinland
| | - Ilkka J. Miinalainen
- Faculty of Biochemistry and Molecular Medicine and Biocenter OuluUniversity of OuluOuluFinland
| | - J. Kalervo Hiltunen
- Faculty of Biochemistry and Molecular Medicine and Biocenter OuluUniversity of OuluOuluFinland
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11
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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: 13] [Impact Index Per Article: 3.3] [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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12
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Suresh HG, Pascoe N, Andrews B. The structure and function of deubiquitinases: lessons from budding yeast. Open Biol 2020; 10:200279. [PMID: 33081638 PMCID: PMC7653365 DOI: 10.1098/rsob.200279] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Protein ubiquitination is a key post-translational modification that regulates diverse cellular processes in eukaryotic cells. The specificity of ubiquitin (Ub) signalling for different bioprocesses and pathways is dictated by the large variety of mono-ubiquitination and polyubiquitination events, including many possible chain architectures. Deubiquitinases (DUBs) reverse or edit Ub signals with high sophistication and specificity, forming an integral arm of the Ub signalling machinery, thus impinging on fundamental cellular processes including DNA damage repair, gene expression, protein quality control and organellar integrity. In this review, we discuss the many layers of DUB function and regulation, with a focus on insights gained from budding yeast. Our review provides a framework to understand key aspects of DUB biology.
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Affiliation(s)
- Harsha Garadi Suresh
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada M5S 3E1
| | - Natasha Pascoe
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada M5S 3E1.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 3E1
| | - Brenda Andrews
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada M5S 3E1.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 3E1
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13
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Escobar-Henriques M, Anton V. Mitochondrial Surveillance by Cdc48/p97: MAD vs. Membrane Fusion. Int J Mol Sci 2020; 21:E6841. [PMID: 32961852 PMCID: PMC7555132 DOI: 10.3390/ijms21186841] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 09/07/2020] [Accepted: 09/08/2020] [Indexed: 11/16/2022] Open
Abstract
Cdc48/p97 is a ring-shaped, ATP-driven hexameric motor, essential for cellular viability. It specifically unfolds and extracts ubiquitylated proteins from membranes or protein complexes, mostly targeting them for proteolytic degradation by the proteasome. Cdc48/p97 is involved in a multitude of cellular processes, reaching from cell cycle regulation to signal transduction, also participating in growth or death decisions. The role of Cdc48/p97 in endoplasmic reticulum-associated degradation (ERAD), where it extracts proteins targeted for degradation from the ER membrane, has been extensively described. Here, we present the roles of Cdc48/p97 in mitochondrial regulation. We discuss mitochondrial quality control surveillance by Cdc48/p97 in mitochondrial-associated degradation (MAD), highlighting the potential pathologic significance thereof. Furthermore, we present the current knowledge of how Cdc48/p97 regulates mitofusin activity in outer membrane fusion and how this may impact on neurodegeneration.
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Affiliation(s)
- Mafalda Escobar-Henriques
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center for Molecular Medicine Cologne (CMMC), University of Cologne, Joseph-Stelzmann-Straße 26, 50931 Cologne, Germany;
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14
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Sabouny R, Shutt TE. Reciprocal Regulation of Mitochondrial Fission and Fusion. Trends Biochem Sci 2020; 45:564-577. [DOI: 10.1016/j.tibs.2020.03.009] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 03/03/2020] [Accepted: 03/16/2020] [Indexed: 12/24/2022]
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15
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Ma L, Chen X, Zhao B, Shi Y, Han F. Enhanced apoptosis and decreased ampa receptors are involved in deficit in fear memory in rin1 knockout rats. J Affect Disord 2020; 268:173-182. [PMID: 32174475 DOI: 10.1016/j.jad.2020.02.040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 02/20/2020] [Accepted: 02/26/2020] [Indexed: 11/28/2022]
Abstract
BACKGROUND Ras and Rab interactor 1 (Rin1) is predominantly expressed in memory-related brain regions, and has been reported to play an important role in fear memory. Increased expression of Rin1 in an animal model of posttraumatic stress disorder (PTSD) has been associated with enhanced acquisition of fear memories, but the exact mechanism of Rin1 in memory regulation are not clear. METHODS Here, we used Rin1-knockout rats to examine the effect of Rin1 on fear memories by fear conditional test and the molecular mechanisms that regulate these effects by immunofluorescence, western blotting and TUNEL. RESULTS Our results show that Rin1-knockout rats have a deficit in formation and extinction of Auditory fear memories. Lack of Rin1 results in enhanced apoptosis in the hippocampus through a pathway related to the mitochondria rather than the endoplasmic reticulum-related pathway. Importantly, the lack of Rin1 induces a decrease in α-amino-3‑hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPAR) found in the cytoplasm, but not in those found in the membrane. Expression of CaMKII (which is important for insertion of cytoplasmic AMPAR into the membrane) and stargazin (which is important for immobilization of AMPAR in the membrane) was not changed. The lack of Rin1 also induced changes in AMPAR distribution, from diffuse spread in the cells to clusters around the edge of the cell. Additionally, clustered AMPAR distribution showed a high degree of overlap with actin distribution. CONCLUSION These findings indicate that Rin1 affects not only apoptosis, but also the concentration and distribution pattern of AMPAR, which are important in the formation and extinction of fear memory.
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Affiliation(s)
- Linchuan Ma
- PTSD laboratory, Department of Histology and Embryology, Basic Medical College, China Medical University, Shenyang 110122, China.
| | - Xinzhao Chen
- PTSD laboratory, Department of Histology and Embryology, Basic Medical College, China Medical University, Shenyang 110122, China.
| | - Beiying Zhao
- PTSD laboratory, Department of Histology and Embryology, Basic Medical College, China Medical University, Shenyang 110122, China.
| | - Yuxiu Shi
- PTSD laboratory, Department of Histology and Embryology, Basic Medical College, China Medical University, Shenyang 110122, China
| | - Fang Han
- PTSD laboratory, Department of Histology and Embryology, Basic Medical College, China Medical University, Shenyang 110122, China.
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16
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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: 29] [Impact Index Per Article: 7.3] [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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17
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Galkina KV, Zyrina AN, Golyshev SA, Kashko ND, Markova OV, Sokolov SS, Severin FF, Knorre DA. Mitochondrial dynamics in yeast with repressed adenine nucleotide translocator AAC2. Eur J Cell Biol 2020; 99:151071. [PMID: 32057484 DOI: 10.1016/j.ejcb.2020.151071] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Revised: 01/30/2020] [Accepted: 01/30/2020] [Indexed: 12/25/2022] Open
Abstract
The mitochondrial network structure dynamically adapts to cellular metabolic challenges. Mitochondrial depolarisation, particularly, induces fragmentation of the network. This fragmentation may be a result of either a direct regulation of the mitochondrial fusion machinery by transmembrane potential or an indirect effect of metabolic remodelling. Activities of ATP synthase and adenine nucleotide translocator (ANT) link the mitochondrial transmembrane potential with the cytosolic NTP/NDP ratio. Given that mitochondrial fusion requires cytosolic GTP, a decrease in the NTP/NDP ratio might also account for protonophore-induced mitochondrial fragmentation. For evaluating the contributions of direct and indirect mechanisms to mitochondrial remodelling, we assessed the morphology of the mitochondrial network in yeast cells with inhibited ANT. We showed that the repression of AAC2 (PET9), a major ANT gene in yeast, increases mitochondrial transmembrane potential. However, the mitochondrial network in this strain was fragmented. Meanwhile, AAC2 repression did not prevent mitochondrial fusion in zygotes; nor did it inhibit mitochondrial hyperfusion induced by Dnm1p inhibitor mdivi-1. These results suggest that the inhibition of ANT, rather than preventing mitochondrial fusion, facilitates mitochondrial fission. The protonophores were not able to induce additional mitochondrial fragmentation in an AAC2-repressed strain and in yeast cells with inhibited ATP synthase. Importantly, treatment with the ATP synthase inhibitor oligomycin A also induced mitochondrial fragmentation and hyperpolarization. Taken together, our data suggest that ATP/ADP translocation plays a crucial role in shaping of the mitochondrial network and exemplify that an increase in mitochondrial membrane potential does not necessarily oppose mitochondrial fragmentation.
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Affiliation(s)
- Kseniia V Galkina
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Leninskiye Gory 1-73, Moscow, 119991, Russia; Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskiye Gory 1-40, Moscow, 119991, Russia
| | - Anna N Zyrina
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskiye Gory 1-40, Moscow, 119991, Russia
| | - Sergey A Golyshev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskiye Gory 1-40, Moscow, 119991, Russia
| | - Nataliia D Kashko
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Leninskiye Gory 1-73, Moscow, 119991, Russia
| | - Olga V Markova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskiye Gory 1-40, Moscow, 119991, Russia
| | - Svyatoslav S Sokolov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskiye Gory 1-40, Moscow, 119991, Russia
| | - Fedor F Severin
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskiye Gory 1-40, Moscow, 119991, Russia
| | - Dmitry A Knorre
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskiye Gory 1-40, Moscow, 119991, Russia; Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, 119991, Russia.
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18
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Schuster R, Anton V, Simões T, Altin S, den Brave F, Hermanns T, Hospenthal M, Komander D, Dittmar G, Dohmen RJ, Escobar-Henriques M. Dual role of a GTPase conformational switch for membrane fusion by mitofusin ubiquitylation. Life Sci Alliance 2020; 3:e201900476. [PMID: 31857350 PMCID: PMC6925385 DOI: 10.26508/lsa.201900476] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 12/11/2019] [Accepted: 12/11/2019] [Indexed: 12/13/2022] Open
Abstract
Mitochondria are essential organelles whose function is upheld by their dynamic nature. This plasticity is mediated by large dynamin-related GTPases, called mitofusins in the case of fusion between two mitochondrial outer membranes. Fusion requires ubiquitylation, attached to K398 in the yeast mitofusin Fzo1, occurring in atypical and conserved forms. Here, modelling located ubiquitylation to α4 of the GTPase domain, a critical helix in Ras-mediated events. Structure-driven analysis revealed a dual role of K398. First, it is required for GTP-dependent dynamic changes of α4. Indeed, mutations designed to restore the conformational switch, in the absence of K398, rescued wild-type-like ubiquitylation on Fzo1 and allowed fusion. Second, K398 is needed for Fzo1 recognition by the pro-fusion factors Cdc48 and Ubp2. Finally, the atypical ubiquitylation pattern is stringently required bilaterally on both involved mitochondria. In contrast, exchange of the conserved pattern with conventional ubiquitin chains was not sufficient for fusion. In sum, α4 lysines from both small and large GTPases could generally have an electrostatic function for membrane interaction, followed by posttranslational modifications, thus driving membrane fusion events.
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Affiliation(s)
- Ramona Schuster
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Vincent Anton
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Tânia Simões
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Selver Altin
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Fabian den Brave
- Department of Molecular Cell Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Thomas Hermanns
- Institute for Genetics, University of Cologne, Cologne, Germany
| | - Manuela Hospenthal
- Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule Zürich, Zürich, Switzerland
| | - David Komander
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
- Ubiquitin Signalling Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Australia
| | - Gunnar Dittmar
- Proteomics of Cellular Signalling, Luxembourg Institute of Health, Strassen, Luxembourg
| | - R Jürgen Dohmen
- Institute for Genetics, University of Cologne, Cologne, Germany
| | - Mafalda Escobar-Henriques
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
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19
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Yu R, Lendahl U, Nistér M, Zhao J. Regulation of Mammalian Mitochondrial Dynamics: Opportunities and Challenges. Front Endocrinol (Lausanne) 2020; 11:374. [PMID: 32595603 PMCID: PMC7300174 DOI: 10.3389/fendo.2020.00374] [Citation(s) in RCA: 92] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 05/12/2020] [Indexed: 01/01/2023] Open
Abstract
Mitochondria are highly dynamic organelles and important for a variety of cellular functions. They constantly undergo fission and fusion events, referred to as mitochondrial dynamics, which affects the shape, size, and number of mitochondria in the cell, as well as mitochondrial subcellular transport, mitochondrial quality control (mitophagy), and programmed cell death (apoptosis). Dysfunctional mitochondrial dynamics is associated with various human diseases. Mitochondrial dynamics is mediated by a set of mitochondria-shaping proteins in both yeast and mammals. In this review, we describe recent insights into the potential molecular mechanisms underlying mitochondrial fusion and fission, particularly highlighting the coordinating roles of different mitochondria-shaping proteins in the processes, as well as the roles of the endoplasmic reticulum (ER), the actin cytoskeleton and membrane phospholipids in the regulation of mitochondrial dynamics. We particularly focus on emerging roles for the mammalian mitochondrial proteins Fis1, Mff, and MIEFs (MIEF1 and MIEF2) in regulating the recruitment of the cytosolic Drp1 to the surface of mitochondria and how these proteins, especially Fis1, mediate crosstalk between the mitochondrial fission and fusion machineries. In summary, this review provides novel insights into the molecular mechanisms of mammalian mitochondrial dynamics and the involvement of these mechanisms in apoptosis and autophagy.
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Affiliation(s)
- Rong Yu
- Department of Oncology-Pathology, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden
| | - Urban Lendahl
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Monica Nistér
- Department of Oncology-Pathology, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden
- *Correspondence: Monica Nistér
| | - Jian Zhao
- Department of Oncology-Pathology, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden
- Jian Zhao
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20
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Truong T, Zeng G, Lim TK, Cao T, Pang LM, Lee YM, Lin Q, Wang Y, Seneviratne CJ. Proteomics Analysis ofCandida albicans dnm1Haploid Mutant Unraveled the Association between Mitochondrial Fission and Antifungal Susceptibility. Proteomics 2019; 20:e1900240. [DOI: 10.1002/pmic.201900240] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 11/05/2019] [Indexed: 12/16/2022]
Affiliation(s)
- Thuyen Truong
- Oral Sciences, Faculty of DentistryNational University of Singapore 9 Lower Kent Ridge Road Singapore 119085
| | - Guisheng Zeng
- Institute of Molecular and Cell BiologyAgency for Science, Technology and Research 61 Biopolis Drive, Proteos Singapore 138673
| | - Teck Kwang Lim
- Department of Biological SciencesFaculty of Science, National University of Singapore 16 Science Drive 4, S2 Singapore 117558
| | - Tong Cao
- Oral Sciences, Faculty of DentistryNational University of Singapore 9 Lower Kent Ridge Road Singapore 119085
| | - Li Mei Pang
- National Dental Research Institute SingaporeSinghealth Duke NUS, Singapore 5 Second Hospital Ave Singapore 168938
| | - Yew Mun Lee
- Department of Biological SciencesFaculty of Science, National University of Singapore 16 Science Drive 4, S2 Singapore 117558
| | - Qingsong Lin
- Department of Biological SciencesFaculty of Science, National University of Singapore 16 Science Drive 4, S2 Singapore 117558
| | - Yue Wang
- Institute of Molecular and Cell BiologyAgency for Science, Technology and Research 61 Biopolis Drive, Proteos Singapore 138673
- Department of Biochemistry, Yong Loo Lin School of MedicineNational University of Singapore 10 Medical Dr Singapore 117597
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21
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Anton V, Buntenbroich I, Schuster R, Babatz F, Simões T, Altin S, Calabrese G, Riemer J, Schauss A, Escobar-Henriques M. Plasticity in salt bridge allows fusion-competent ubiquitylation of mitofusins and Cdc48 recognition. Life Sci Alliance 2019; 2:e201900491. [PMID: 31740565 PMCID: PMC6861704 DOI: 10.26508/lsa.201900491] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 11/06/2019] [Accepted: 11/07/2019] [Indexed: 01/08/2023] Open
Abstract
Mitofusins are dynamin-related GTPases that drive mitochondrial fusion by sequential events of oligomerization and GTP hydrolysis, followed by their ubiquitylation. Here, we show that fusion requires a trilateral salt bridge at a hinge point of the yeast mitofusin Fzo1, alternatingly forming before and after GTP hydrolysis. Mutations causative of Charcot-Marie-Tooth disease massively map to this hinge point site, underlining the disease relevance of the trilateral salt bridge. A triple charge swap rescues the activity of Fzo1, emphasizing the close coordination of the hinge residues with GTP hydrolysis. Subsequently, ubiquitylation of Fzo1 allows the AAA-ATPase ubiquitin-chaperone Cdc48 to resolve Fzo1 clusters, releasing the dynamin for the next fusion round. Furthermore, cross-complementation within the oligomer unexpectedly revealed ubiquitylated but fusion-incompetent Fzo1 intermediates. However, Cdc48 did not affect the ubiquitylated but fusion-incompetent variants, indicating that Fzo1 ubiquitylation is only controlled after membrane merging. Together, we present an integrated model on how mitochondrial outer membranes fuse, a critical process for their respiratory function but also putatively relevant for therapeutic interventions.
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Affiliation(s)
- Vincent Anton
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Ira Buntenbroich
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Ramona Schuster
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | | | - Tânia Simões
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Selver Altin
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Gaetano Calabrese
- Institute for Biochemistry, Department of Chemistry, University of Cologne, Cologne, Germany
| | - Jan Riemer
- Institute for Biochemistry, Department of Chemistry, University of Cologne, Cologne, Germany
| | | | - Mafalda Escobar-Henriques
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
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22
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Cell organelles and yeast longevity: an intertwined regulation. Curr Genet 2019; 66:15-41. [PMID: 31535186 DOI: 10.1007/s00294-019-01035-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 09/12/2019] [Accepted: 09/12/2019] [Indexed: 12/16/2022]
Abstract
Organelles are dynamic structures of a eukaryotic cell that compartmentalize various essential functions and regulate optimum functioning. On the other hand, ageing is an inevitable phenomenon that leads to irreversible cellular damage and affects optimum functioning of cells. Recent research shows compelling evidence that connects organelle dysfunction to ageing-related diseases/disorders. Studies in several model systems including yeast have led to seminal contributions to the field of ageing in uncovering novel pathways, proteins and their functions, identification of pro- and anti-ageing factors and so on. In this review, we present a comprehensive overview of findings that highlight the role of organelles in ageing and ageing-associated functions/pathways in yeast.
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De Vecchis D, Brandner A, Baaden M, Cohen MM, Taly A. A Molecular Perspective on Mitochondrial Membrane Fusion: From the Key Players to Oligomerization and Tethering of Mitofusin. J Membr Biol 2019; 252:293-306. [PMID: 31485701 DOI: 10.1007/s00232-019-00089-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 08/14/2019] [Indexed: 12/29/2022]
Abstract
Mitochondria are dynamic organelles characterized by an ultrastructural organization which is essential in maintaining their quality control and ensuring functional efficiency. The complex mitochondrial network is the result of the two ongoing forces of fusion and fission of inner and outer membranes. Understanding the functional details of mitochondrial dynamics is physiologically relevant as perturbations of this delicate equilibrium have critical consequences and involved in several neurological disorders. Molecular actors involved in this process are large GTPases from the dynamin-related protein family. They catalyze nucleotide-dependent membrane remodeling and are widely conserved from bacteria to higher eukaryotes. Although structural characterization of different family members has contributed in understanding molecular mechanisms of mitochondrial dynamics in more detail, the complete structure of some members as well as the precise assembly of functional oligomers remains largely unknown. As increasing structural data become available, the domain modularity across the dynamin superfamily emerged as a foundation for transfering the knowledge towards less characterized members. In this review, we will first provide an overview of the main actors involved in mitochondrial dynamics. We then discuss recent example of computational methodologies for the study of mitofusin oligomers, and present how the usage of integrative modeling in conjunction with biochemical data can be an asset in progressing the still challenging field of membrane dynamics.
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Affiliation(s)
- Dario De Vecchis
- School of Medicine, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, LIGHT Building, Leeds, LS2 9JT, UK.
| | - Astrid Brandner
- CNRS, Université de Paris, UPR 9080, Laboratoire de Biochimie Théorique, 13 Rue Pierre et Marie Curie, 75005, Paris, France.,Institut de Biologie Physico-Chimique - Fondation Edmond de Rothschild, PSL Research University, Paris, France
| | - Marc Baaden
- CNRS, Université de Paris, UPR 9080, Laboratoire de Biochimie Théorique, 13 Rue Pierre et Marie Curie, 75005, Paris, France.,Institut de Biologie Physico-Chimique - Fondation Edmond de Rothschild, PSL Research University, Paris, France
| | - Mickael M Cohen
- Institut de Biologie Physico-Chimique - Fondation Edmond de Rothschild, PSL Research University, Paris, France.,Laboratoire de Biologie Cellulaire et Moléculaire des Eucaryotes, Sorbonne Université, CNRS, UMR 8226, Paris, France
| | - Antoine Taly
- CNRS, Université de Paris, UPR 9080, Laboratoire de Biochimie Théorique, 13 Rue Pierre et Marie Curie, 75005, Paris, France. .,Institut de Biologie Physico-Chimique - Fondation Edmond de Rothschild, PSL Research University, Paris, France.
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Brandner A, De Vecchis D, Baaden M, Cohen MM, Taly A. Physics-based oligomeric models of the yeast mitofusin Fzo1 at the molecular scale in the context of membrane docking. Mitochondrion 2019; 49:234-244. [PMID: 31306768 DOI: 10.1016/j.mito.2019.06.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 06/07/2019] [Accepted: 06/24/2019] [Indexed: 11/17/2022]
Abstract
Tethering and homotypic fusion of mitochondrial outer membranes is mediated by large GTPases of the dynamin-related proteins family called the mitofusins. The yeast mitofusin Fzo1 forms high molecular weight complexes and its assembly during membrane fusion likely involves the formation of high order complexes. Consistent with this possibility, mitofusins form oligomers in both cis (on the same lipid bilayer) and trans to mediate membrane attachment and fusion. Here, we utilize our recent Fzo1 model to investigate and discuss the formation of cis and trans mitofusin oligomers. We have built three distinct cis-assembly Fzo1 models that gave rise to three distinct trans-oligomeric models of mitofusin constructs. Each model involves two main components of mitofusin oligomerization: the GTPase and the trunk domains. The oligomeric models proposed in this study were further assessed for stability and dynamics in a membrane environment using a coarse-grained molecular dynamics (MD) simulation approach. A narrow opening 'head-to-head' cis-oligomerization (via the GTPase domain) followed by the antiparallel 'back-to-back' trans-associations (via the trunk domain) appears to be in agreement with all of the available experimental data. More broadly, this study opens new possibilities to start exploring cis and trans conformations for Fzo1 and mitofusins in general.
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Affiliation(s)
- Astrid Brandner
- CNRS, Université de Paris, UPR 9080, Laboratoire de Biochimie Théorique, UPR 9080, 13 rue Pierre et Marie Curie, F-75005, Paris, France; Institut de Biologie Physico-Chimique-Fondation Edmond de Rothschild, PSL Research University, Paris, France
| | - Dario De Vecchis
- CNRS, Université de Paris, UPR 9080, Laboratoire de Biochimie Théorique, UPR 9080, 13 rue Pierre et Marie Curie, F-75005, Paris, France; Institut de Biologie Physico-Chimique-Fondation Edmond de Rothschild, PSL Research University, Paris, France
| | - Marc Baaden
- CNRS, Université de Paris, UPR 9080, Laboratoire de Biochimie Théorique, UPR 9080, 13 rue Pierre et Marie Curie, F-75005, Paris, France; Institut de Biologie Physico-Chimique-Fondation Edmond de Rothschild, PSL Research University, Paris, France
| | - Mickael M Cohen
- Laboratoire de Biologie Cellulaire et Moléculaire des Eucaryotes, Sorbonne Université, CNRS, UMR 8226, France; Institut de Biologie Physico-Chimique-Fondation Edmond de Rothschild, PSL Research University, Paris, France.
| | - Antoine Taly
- CNRS, Université de Paris, UPR 9080, Laboratoire de Biochimie Théorique, UPR 9080, 13 rue Pierre et Marie Curie, F-75005, Paris, France; Institut de Biologie Physico-Chimique-Fondation Edmond de Rothschild, PSL Research University, Paris, France.
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25
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Dederer V, Khmelinskii A, Huhn AG, Okreglak V, Knop M, Lemberg MK. Cooperation of mitochondrial and ER factors in quality control of tail-anchored proteins. eLife 2019; 8:45506. [PMID: 31172943 PMCID: PMC6586462 DOI: 10.7554/elife.45506] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 06/06/2019] [Indexed: 01/04/2023] Open
Abstract
Tail-anchored (TA) proteins insert post-translationally into the endoplasmic reticulum (ER), the outer mitochondrial membrane (OMM) and peroxisomes. Whereas the GET pathway controls ER-targeting, no dedicated factors are known for OMM insertion, posing the question of how accuracy is achieved. The mitochondrial AAA-ATPase Msp1 removes mislocalized TA proteins from the OMM, but it is unclear, how Msp1 clients are targeted for degradation. Here we screened for factors involved in degradation of TA proteins mislocalized to mitochondria. We show that the ER-associated degradation (ERAD) E3 ubiquitin ligase Doa10 controls cytoplasmic level of Msp1 clients. Furthermore, we identified the uncharacterized OMM protein Fmp32 and the ectopically expressed subunit of the ER-mitochondria encounter structure (ERMES) complex Gem1 as native clients for Msp1 and Doa10. We propose that productive localization of TA proteins to the OMM is ensured by complex assembly, while orphan subunits are extracted by Msp1 and eventually degraded by Doa10.
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Affiliation(s)
- Verena Dederer
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Anton Khmelinskii
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany.,Institute of Molecular Biology (IMB), Mainz, Germany
| | - Anna Gesine Huhn
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Voytek Okreglak
- Calico Life Sciences LLC, South San Francisco, United States
| | - Michael Knop
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany.,Cell Morphogenesis and Signal Transduction, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Marius K Lemberg
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
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26
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Escobar-Henriques M, Joaquim M. Mitofusins: Disease Gatekeepers and Hubs in Mitochondrial Quality Control by E3 Ligases. Front Physiol 2019; 10:517. [PMID: 31156446 PMCID: PMC6533591 DOI: 10.3389/fphys.2019.00517] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 04/11/2019] [Indexed: 02/06/2023] Open
Abstract
Mitochondria are dynamic organelles engaged in quality control and aging processes. They constantly undergo fusion, fission, transport, and anchoring events, which empower mitochondria with a very interactive behavior. The membrane remodeling processes needed for fusion require conserved proteins named mitofusins, MFN1 and MFN2 in mammals and Fzo1 in yeast. They are the first determinants deciding on whether communication and content exchange between different mitochondrial populations should occur. Importantly, each cell possesses hundreds of mitochondria, with a different severity of mitochondrial mutations or dysfunctional proteins, which potentially spread damage to the entire network. Therefore, the degree of their merging capacity critically influences cellular fitness. In turn, the mitochondrial network rapidly and dramatically changes in response to metabolic and environmental cues. Notably, cancer or obesity conditions, and stress experienced by neurons and cardiomyocytes, for example, triggers the downregulation of mitofusins and thus fragmentation of mitochondria. This places mitofusins upfront in sensing and transmitting stress. In fact, mitofusins are almost entirely exposed to the cytoplasm, a topology suitable for a critical relay point in information exchange between mitochondria and their cellular environment. Consistent with their topology, mitofusins are either activated or repressed by cytosolic post-translational modifiers, mainly by ubiquitin. Ubiquitin is a ubiquitous small protein orchestrating multiple quality control pathways, which is covalently attached to lysine residues in its substrates, or in ubiquitin itself. Importantly, from a chain of events also mediated by E1 and E2 enzymes, E3 ligases perform the ultimate and determinant step in substrate choice. Here, we review the ubiquitin E3 ligases that modify mitofusins. Two mitochondrial E3 enzymes—March5 and MUL1—one ligase located to the ER—Gp78—and finally three cytosolic enzymes—MGRN1, HUWE1, and Parkin—were shown to ubiquitylate mitofusins, in response to a variety of cellular inputs. The respective outcomes on mitochondrial morphology, on contact sites to the endoplasmic reticulum and on destructive processes, like mitophagy or apoptosis, are presented. Ultimately, understanding the mechanisms by which E3 ligases and mitofusins sense and bi-directionally signal mitochondria-cytosolic dysfunctions could pave the way for therapeutic approaches in neurodegenerative, cardiovascular, and obesity-linked diseases.
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Affiliation(s)
- Mafalda Escobar-Henriques
- Center for Molecular Medicine Cologne (CMMC), Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Mariana Joaquim
- Center for Molecular Medicine Cologne (CMMC), Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
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27
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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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28
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Schuster R, Simões T, Brave FD, Escobar-Henriques M. Separation and Visualization of Low Abundant Ubiquitylated Forms. Bio Protoc 2018; 8:e3081. [PMID: 34532539 DOI: 10.21769/bioprotoc.3081] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 10/29/2018] [Accepted: 11/02/2018] [Indexed: 11/02/2022] Open
Abstract
In this protocol we describe the separation and visualization of ubiquitylated forms of the yeast mitofusin Fzo1 by Western blot. To this aim, we express HA-tagged Fzo1 in Saccharomyces cerevisiae, break the cells to extract a membrane-enriched fraction, solubilize the membranes using detergent and then specifically immunoprecipitate the tagged protein using anti-HA affinity beads. Subsequently, we separate the higher molecular weight (ubiquitylated) forms of Fzo1 via SDS-PAGE. Finally, immunoblotting and immunodecoration are used to detect the protein and its ubiquitylated forms using an HA-specific antibody. By using this protocol, it is possible to separate and visualize higher molecular weight forms of low abundant proteins such as Fzo1 and detect sharp and distinct bands above the unmodified protein by Western blot.
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Affiliation(s)
- Ramona Schuster
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany
| | - Tânia Simões
- Institute for Genetics, 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, Am Klopferspitz 18, Martinsried, Germany
| | - Mafalda Escobar-Henriques
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany
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29
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Chowdhury A, Ogura T, Esaki M. Two Cdc48 cofactors Ubp3 and Ubx2 regulate mitochondrial morphology and protein turnover. J Biochem 2018; 164:349-358. [PMID: 29924334 DOI: 10.1093/jb/mvy057] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 06/13/2018] [Indexed: 12/22/2022] Open
Abstract
Mitochondria continuously undergo coordinated fusion and fission during vegetative growth to keep their homogeneity and to remove damaged components. A cytosolic AAA ATPase, Cdc48, is implicated in the mitochondrial fusion event and turnover of a fusion-responsible GTPase in the mitochondrial outer membrane, Fzo1, suggesting a possible linkage of mitochondrial fusion and Fzo1 turnover. Here, we identified two Cdc48 cofactor proteins, Ubp3 and Ubx2, involving mitochondria regulation. In the absence of UBP3, mitochondrial fragmentation and aggregation were observed. The turnover of Fzo1 was not affected in Δubp3, but instead a deubiquitylase Ubp12 that removes fusion-required polyubiquitin chains from Fzo1 was stabilized. Thus, excess amount of Ubp12 may lead to mitochondrial fragmentation by removal of fusion-competent ubiquitylated Fzo1. In contrast, deletion of UBX2 perturbed disassembly of Fzo1 oligomers and their degradation without alteration of mitochondrial morphology. The UBX2 deletion led to destabilization of Ubp2 that negatively regulates Fzo1 turnover by removing degradation-signalling polyubiquitin chains, suggesting that Ubx2 would directly facilitate Fzo1 degradation. These results indicated that two different Cdc48-cofactor complexes independently regulate mitochondrial fusion and Fzo1 turnover.
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Affiliation(s)
- Abhijit Chowdhury
- Department of Molecular Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, Honjo 2-2-1, Chuo-ku, Kumamoto, Japan.,Program for Leading Graduate Schools "HIGO Program", Kumamoto University, Honjo 1-1-1, Chuo-ku, Kumamoto, Japan
| | - Teru Ogura
- Department of Molecular Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, Honjo 2-2-1, Chuo-ku, Kumamoto, Japan.,Program for Leading Graduate Schools "HIGO Program", Kumamoto University, Honjo 1-1-1, Chuo-ku, Kumamoto, Japan.,Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Honcho 4-1-8, Kawaguchi-shi, Saitama, Japan
| | - Masatoshi Esaki
- Department of Molecular Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, Honjo 2-2-1, Chuo-ku, Kumamoto, Japan.,Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Honcho 4-1-8, Kawaguchi-shi, Saitama, Japan
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30
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Systematic mapping of contact sites reveals tethers and a function for the peroxisome-mitochondria contact. Nat Commun 2018; 9:1761. [PMID: 29720625 PMCID: PMC5932058 DOI: 10.1038/s41467-018-03957-8] [Citation(s) in RCA: 194] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 03/22/2018] [Indexed: 12/15/2022] Open
Abstract
The understanding that organelles are not floating in the cytosol, but rather held in an organized yet dynamic interplay through membrane contact sites, is altering the way we grasp cell biological phenomena. However, we still have not identified the entire repertoire of contact sites, their tethering molecules and functions. To systematically characterize contact sites and their tethering molecules here we employ a proximity detection method based on split fluorophores and discover four potential new yeast contact sites. We then focus on a little-studied yet highly disease-relevant contact, the Peroxisome-Mitochondria (PerMit) proximity, and uncover and characterize two tether proteins: Fzo1 and Pex34. We genetically expand the PerMit contact site and demonstrate a physiological function in β-oxidation of fatty acids. Our work showcases how systematic analysis of contact site machinery and functions can deepen our understanding of these structures in health and disease.
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31
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Bagli E, Zikou AK, Agnantis N, Kitsos G. Mitochondrial Membrane Dynamics and Inherited Optic Neuropathies. ACTA ACUST UNITED AC 2018; 31:511-525. [PMID: 28652416 DOI: 10.21873/invivo.11090] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 04/14/2017] [Accepted: 04/19/2017] [Indexed: 12/12/2022]
Abstract
Inherited optic neuropathies are a genetically diverse group of disorders mainly characterized by visual loss and optic atrophy. Since the first recognition of Leber's hereditary optic neuropathy, several genetic defects altering primary mitochondrial respiration have been proposed to contribute to the development of syndromic and non-syndromic optic neuropathies. Moreover, the genomics and imaging revolution in the past decade has increased diagnostic efficiency and accuracy, allowing recognition of a link between mitochondrial dynamics machinery and a broad range of inherited neurodegenerative diseases involving the optic nerve. Mutations of novel genes modifying mainly the balance between mitochondrial fusion and fission have been shown to lead to overlapping clinical phenotypes ranging from isolated optic atrophy to severe, sometimes lethal multisystem disorders, and are reviewed herein. Given the particular vulnerability of retinal ganglion cells to mitochondrial dysfunction, the accessibility of the eye as a part of the central nervous system and improvements in technical imaging concerning assessment of the retinal nerve fiber layer, optic nerve evaluation becomes critical - even in asymptomatic patients - for correct diagnosis, understanding and early treatment of these complex and enigmatic clinical entities.
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Affiliation(s)
- Eleni Bagli
- Institute of Molecular Biology and Biotechnology-FORTH, Division of Biomedical Research, Ioannina, Greece.,Department of Ophthalmology, University of Ioannina, Ioannina, Greece
| | - Anastasia K Zikou
- Department of Clinical Radiology, University of Ioannina, Ioannina, Greece
| | - Niki Agnantis
- Department of Pathology, University of Ioannina, Ioannina, Greece
| | - Georgios Kitsos
- Department of Ophthalmology, University of Ioannina, Ioannina, Greece
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32
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Simões T, Schuster R, den Brave F, Escobar-Henriques M. Cdc48 regulates a deubiquitylase cascade critical for mitochondrial fusion. eLife 2018; 7:30015. [PMID: 29309037 PMCID: PMC5798933 DOI: 10.7554/elife.30015] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 01/04/2018] [Indexed: 12/27/2022] Open
Abstract
Cdc48/p97, a ubiquitin-selective chaperone, orchestrates the function of E3 ligases and deubiquitylases (DUBs). Here, we identify a new function of Cdc48 in ubiquitin-dependent regulation of mitochondrial dynamics. The DUBs Ubp12 and Ubp2 exert opposing effects on mitochondrial fusion and cleave different ubiquitin chains on the mitofusin Fzo1. We demonstrate that Cdc48 integrates the activities of these two DUBs, which are themselves ubiquitylated. First, Cdc48 promotes proteolysis of Ubp12, stabilizing pro-fusion ubiquitylation on Fzo1. Second, loss of Ubp12 stabilizes Ubp2 and thereby facilitates removal of ubiquitin chains on Fzo1 inhibiting fusion. Thus, Cdc48 synergistically regulates the ubiquitylation status of Fzo1, allowing to control the balance between activation or repression of mitochondrial fusion. In conclusion, we unravel a new cascade of ubiquitylation events, comprising Cdc48 and two DUBs, fine-tuning the fusogenic activity of Fzo1. Mitochondria are little compartments within a cell that produce the energy needed for most biological processes. Each cell possesses several mitochondria, which can fuse together and then break again into smaller units. This fusion process is essential for cellular health. Two proteins in the cell have a major role in controlling mitochondrial fusion: Ubp12 and Ubp2. Ubp12 prevents fusion, while Ubp2 activates it. These molecules carry out their roles by acting on a third protein called mitofusin, which is a key gatekeeper of the fusion mechanism. Cells often ‘tag’ proteins with small molecules called ubiquitin to change the protein’s role and how it interacts with other cellular structures. Depending on how they are ‘tagged’, mitofusins can exist in two forms. One type of tagging means that the protein then promotes fusion of the mitochondria; the other leads to the mitofusin being destroyed by the cell. It is still unclear how Ubp12, Ubp2 and the different forms of mitofusins interact with each other to finely control mitochondrial fusion. Here, Simões, Schuster et al. clarify these interactions in yeast and show how these proteins are themselves regulated. Ubp2 promotes fusion by attaching to the mitofusin that is labeled to be destroyed, and removing this tag: the mitofusin will then not be degraded, and can promote fusion. Ubp12 prevents fusion through two mechanisms. First, it can remove the ‘pro-fusion’ tag on the mitofusin that prompts mitochondrial fusion. Second, Simões, Schuster et al. now show that Ubp12 also inhibits Ubp2 and its fusion-promoting activity. In turn, the experiments reveal that a master protein called Cdc48 can control the entire Ubp12-Ubp2-mitofusin pathway. Cdc48 directly represses Ubp12 and therefore its anti-fusion activity. This inhibition also leaves Ubp2 free to stimulate fusion through its action on mitofusin. The molecules involved in controlling mitochondrial fusion in yeast are very similar to the ones in people. In humans, improper regulation of mitofusins causes an incurable disease of the nerves and the brain called Charcot-Marie-Tooth 2A. Understanding how the fusion of mitochondria is controlled can lead to new drug discoveries.
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Affiliation(s)
- Tânia Simões
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany
| | - Ramona Schuster
- Institute for Genetics, 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, Am Klopferspitz 18, Martinsried, Germany
| | - Mafalda Escobar-Henriques
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany
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33
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A membrane-inserted structural model of the yeast mitofusin Fzo1. Sci Rep 2017; 7:10217. [PMID: 28860650 PMCID: PMC5578988 DOI: 10.1038/s41598-017-10687-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 08/14/2017] [Indexed: 01/23/2023] Open
Abstract
Mitofusins are large transmembrane GTPases of the dynamin-related protein family, and are required for the tethering and fusion of mitochondrial outer membranes. Their full-length structures remain unknown, which is a limiting factor in the study of outer membrane fusion. We investigated the structure and dynamics of the yeast mitofusin Fzo1 through a hybrid computational and experimental approach, combining molecular modelling and all-atom molecular dynamics simulations in a lipid bilayer with site-directed mutagenesis and in vivo functional assays. The predicted architecture of Fzo1 improves upon the current domain annotation, with a precise description of the helical spans linked by flexible hinges, which are likely of functional significance. In vivo site-directed mutagenesis validates salient aspects of this model, notably, the long-distance contacts and residues participating in hinges. GDP is predicted to interact with Fzo1 through the G1 and G4 motifs of the GTPase domain. The model reveals structural determinants critical for protein function, including regions that may be involved in GTPase domain-dependent rearrangements.
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34
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An ubiquitin-dependent balance between mitofusin turnover and fatty acids desaturation regulates mitochondrial fusion. Nat Commun 2017; 8:15832. [PMID: 28607491 PMCID: PMC5474747 DOI: 10.1038/ncomms15832] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 04/27/2017] [Indexed: 01/22/2023] Open
Abstract
Mitochondrial integrity relies on homotypic fusion between adjacent outer membranes, which is mediated by large GTPases called mitofusins. The regulation of this process remains nonetheless elusive. Here, we report a crosstalk between the ubiquitin protease Ubp2 and the ubiquitin ligases Mdm30 and Rsp5 that modulates mitochondrial fusion. Ubp2 is an antagonist of Rsp5, which promotes synthesis of the fatty acids desaturase Ole1. We show that Ubp2 also counteracts Mdm30-mediated turnover of the yeast mitofusin Fzo1 and that Mdm30 targets Ubp2 for degradation thereby inducing Rsp5-mediated desaturation of fatty acids. Exogenous desaturated fatty acids inhibit Ubp2 degradation resulting in higher levels of Fzo1 and maintenance of efficient mitochondrial fusion. Our results demonstrate that the Mdm30-Ubp2-Rsp5 crosstalk regulates mitochondrial fusion by coordinating an intricate balance between Fzo1 turnover and the status of fatty acids saturation. This pathway may link outer membrane fusion to lipids homeostasis. Mitochondrial fusion is crucial for cellular homeostasis but its regulation is still not fully understood. Here the authors report that a cross-talk between ubiquitin protease Ubp2 and ligases Mdm30 and Rsp5 modulates mitofusin Fzo1 levels and fatty acids saturation and thus mitochondrial fusion.
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35
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Bovine and murine models highlight novel roles for SLC25A46 in mitochondrial dynamics and metabolism, with implications for human and animal health. PLoS Genet 2017; 13:e1006597. [PMID: 28376083 PMCID: PMC5380314 DOI: 10.1371/journal.pgen.1006597] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 01/21/2017] [Indexed: 12/11/2022] Open
Abstract
Neuropathies are neurodegenerative diseases affecting humans and other mammals. Many genetic causes have been identified so far, including mutations of genes encoding proteins involved in mitochondrial dynamics. Recently, the “Turning calves syndrome”, a novel sensorimotor polyneuropathy was described in the French Rouge-des-Prés cattle breed. In the present study, we determined that this hereditary disease resulted from a single nucleotide substitution in SLC25A46, a gene encoding a protein of the mitochondrial carrier family. This mutation caused an apparent damaging amino-acid substitution. To better understand the function of this protein, we knocked out the Slc25a46 gene in a mouse model. This alteration affected not only the nervous system but also altered general metabolism, resulting in premature mortality. Based on optic microscopy examination, electron microscopy and on biochemical, metabolic and proteomic analyses, we showed that the Slc25a46 disruption caused a fusion/fission imbalance and an abnormal mitochondrial architecture that disturbed mitochondrial metabolism. These data extended the range of phenotypes associated with Slc25a46 dysfunction. Moreover, this Slc25a46 knock-out mouse model should be useful to further elucidate the role of SLC25A46 in mitochondrial dynamics. Mitochondria are essential organelles, the site of numerous biochemical reactions, with a critical role in delivering energy to cells, particularly in the nervous system. Consequently, disrupted mitochondrial function often results in neurodegenerative diseases, in humans and in other mammals. Herein, we determined that the “Turning calves syndrome”, a new hereditary sensorimotor polyneuropathy in the French Rouge-des-Prés cattle breed was due to a single substitution in SLC25A46, a gene encoding a protein of the mitochondrial carrier family. We created a mouse knock-out model and determined that disruption of this gene dramatically disturbed mitochondrial dynamics in various organs that resulted in altered metabolism and early death, indirectly confirming the gene identification in cattle. Moreover, our novel findings extended the range of phenotypes associated with polymorphisms of this gene and help to elucidate the role of SLC25A46 in mitochondrial function.
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36
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Karavaeva IE, Golyshev SA, Smirnova EA, Sokolov SS, Severin FF, Knorre DA. Mitochondrial depolarization in yeast zygotes inhibits clonal expansion of selfish mtDNA. J Cell Sci 2017; 130:1274-1284. [PMID: 28193734 DOI: 10.1242/jcs.197269] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 02/09/2017] [Indexed: 12/15/2022] Open
Abstract
Non-identical copies of mitochondrial DNA (mtDNA) compete with each other within a cell and the ultimate variant of mtDNA present depends on their relative replication rates. Using yeast Saccharomyces cerevisiae cells as a model, we studied the effects of mitochondrial inhibitors on the competition between wild-type mtDNA and mutant selfish mtDNA in heteroplasmic zygotes. We found that decreasing mitochondrial transmembrane potential by adding uncouplers or valinomycin changes the competition outcomes in favor of the wild-type mtDNA. This effect was significantly lower in cells with disrupted mitochondria fission or repression of the autophagy-related genes ATG8, ATG32 or ATG33, implying that heteroplasmic zygotes activate mitochondrial degradation in response to the depolarization. Moreover, the rate of mitochondrially targeted GFP turnover was higher in zygotes treated with uncoupler than in haploid cells or untreated zygotes. Finally, we showed that vacuoles of zygotes with uncoupler-activated autophagy contained DNA. Taken together, our data demonstrate that mitochondrial depolarization inhibits clonal expansion of selfish mtDNA and this effect depends on mitochondrial fission and autophagy. These observations suggest an activation of mitochondria quality control mechanisms in heteroplasmic yeast zygotes.
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Affiliation(s)
- Iuliia E Karavaeva
- Faculty of Bioengineering and Bioinformatics, Moscow State University, Leninskiye Gory 1-73, Moscow 119991, Russia
| | - Sergey A Golyshev
- Belozersky Institute of Physico-Chemical Biology, Moscow State University, Leninskiye Gory 1-40, Moscow 119991, Russia
| | - Ekaterina A Smirnova
- Belozersky Institute of Physico-Chemical Biology, Moscow State University, Leninskiye Gory 1-40, Moscow 119991, Russia
| | - Svyatoslav S Sokolov
- Belozersky Institute of Physico-Chemical Biology, Moscow State University, Leninskiye Gory 1-40, Moscow 119991, Russia
| | - Fedor F Severin
- Belozersky Institute of Physico-Chemical Biology, Moscow State University, Leninskiye Gory 1-40, Moscow 119991, Russia
| | - Dmitry A Knorre
- Belozersky Institute of Physico-Chemical Biology, Moscow State University, Leninskiye Gory 1-40, Moscow 119991, Russia
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37
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Herrera-Cruz MS, Simmen T. Of yeast, mice and men: MAMs come in two flavors. Biol Direct 2017; 12:3. [PMID: 28122638 PMCID: PMC5267431 DOI: 10.1186/s13062-017-0174-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 01/18/2017] [Indexed: 12/15/2022] Open
Abstract
The past decade has seen dramatic progress in our understanding of membrane contact sites (MCS). Important examples of these are endoplasmic reticulum (ER)-mitochondria contact sites. ER-mitochondria contacts have originally been discovered in mammalian tissue, where they have been designated as mitochondria-associated membranes (MAMs). It is also in this model system, where the first critical MAM proteins have been identified, including MAM tethering regulators such as phospho-furin acidic cluster sorting protein 2 (PACS-2) and mitofusin-2. However, the past decade has seen the discovery of the MAM also in the powerful yeast model system Saccharomyces cerevisiae. This has led to the discovery of novel MAM tethers such as the yeast ER-mitochondria encounter structure (ERMES), absent in the mammalian system, but whose regulators Gem1 and Lam6 are conserved. While MAMs, sometimes referred to as mitochondria-ER contacts (MERCs), regulate lipid metabolism, Ca2+ signaling, bioenergetics, inflammation, autophagy and apoptosis, not all of these functions exist in both systems or operate differently. This biological difference has led to puzzling discrepancies on findings obtained in yeast or mammalian cells at the moment. Our review aims to shed some light onto mechanistic differences between yeast and mammalian MAM and their underlying causes. Reviewers: This article was reviewed by Paola Pizzo (nominated by Luca Pellegrini), Maya Schuldiner and György Szabadkai (nominated by Luca Pellegrini).
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Affiliation(s)
- Maria Sol Herrera-Cruz
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G2H7, Canada
| | - Thomas Simmen
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G2H7, Canada.
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38
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Drp1-Dependent Mitochondrial Fission Plays Critical Roles in Physiological and Pathological Progresses in Mammals. Int J Mol Sci 2017; 18:ijms18010144. [PMID: 28098754 PMCID: PMC5297777 DOI: 10.3390/ijms18010144] [Citation(s) in RCA: 172] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 12/28/2016] [Accepted: 01/09/2017] [Indexed: 12/22/2022] Open
Abstract
Current research has demonstrated that mitochondrial morphology, distribution, and function are maintained by the balanced regulation of mitochondrial fission and fusion, and perturbation of the homeostasis between these processes has been related to cell or organ dysfunction and abnormal mitochondrial redistribution. Abnormal mitochondrial fusion induces the fragmentation of mitochondria from a tubular morphology into pieces; in contrast, perturbed mitochondrial fission results in the fusion of adjacent mitochondria. A member of the dynamin family of large GTPases, dynamin-related protein 1 (Drp1), effectively influences cell survival and apoptosis by mediating the mitochondrial fission process in mammals. Drp1-dependent mitochondrial fission is an intricate process regulating both cellular and organ dynamics, including development, apoptosis, acute organ injury, and various diseases. Only after clarification of the regulative mechanisms of this critical protein in vivo and in vitro will it set a milestone for preventing mitochondrial fission related pathological processes and refractory diseases.
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Steffen J, Vashisht AA, Wan J, Jen JC, Claypool SM, Wohlschlegel JA, Koehler CM. Rapid degradation of mutant SLC25A46 by the ubiquitin-proteasome system results in MFN1/2-mediated hyperfusion of mitochondria. Mol Biol Cell 2017; 28:600-612. [PMID: 28057766 PMCID: PMC5328619 DOI: 10.1091/mbc.e16-07-0545] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 12/12/2016] [Accepted: 12/30/2016] [Indexed: 11/29/2022] Open
Abstract
SCL25A46 is a mitochondrial carrier protein that localizes to the outer membrane. Mutation L341P causes rapid degradation of SLC25A46 by the ubiquitin-proteasome system, independent of activated stress pathways, including mitophagy and apoptosis. SLC25A46 regulates oligomerization of MFN1/2 and mitochondrial dynamics. SCL25A46 is a mitochondrial carrier protein that surprisingly localizes to the outer membrane and is distantly related to Ugo1. Here we show that a subset of SLC25A46 interacts with mitochondrial dynamics components and the MICOS complex. Decreased expression of SLC25A46 results in increased stability and oligomerization of MFN1 and MFN2 on mitochondria, promoting mitochondrial hyperfusion. A mutation at L341P causes rapid degradation of SLC25A46, which manifests as a rare disease, pontocerebellar hypoplasia. The E3 ubiquitin ligases MULAN and MARCH5 coordinate ubiquitylation of SLC25A46 L341P, leading to degradation by organized activities of P97 and the proteasome. Whereas outer mitochondrial membrane–associated degradation is typically associated with apoptosis or a specialized type of autophagy termed mitophagy, SLC25A46 degradation operates independently of activation of outer membrane stress pathways. Thus SLC25A46 is a new component in mitochondrial dynamics that serves as a regulator for MFN1/2 oligomerization. Moreover, SLC25A46 is selectively degraded from the outer membrane independently of mitophagy and apoptosis, providing a framework for mechanistic studies in the proteolysis of outer membrane proteins.
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Affiliation(s)
- Janos Steffen
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095
| | - Ajay A Vashisht
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095
| | - Jijun Wan
- Department of Neurology, University of California, Los Angeles, Los Angeles, CA 90095
| | - Joanna C Jen
- Department of Neurology, University of California, Los Angeles, Los Angeles, CA 90095
| | - Steven M Claypool
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - James A Wohlschlegel
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095.,Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095
| | - Carla M Koehler
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095 .,Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095.,Jonsson Comprehensive Cancer Center, University of California, Los Angeles, Los Angeles, CA 90095
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Mukherjee R, Chakrabarti O. Regulation of Mitofusin1 by Mahogunin Ring Finger-1 and the proteasome modulates mitochondrial fusion. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:3065-3083. [PMID: 27713096 DOI: 10.1016/j.bbamcr.2016.09.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 09/27/2016] [Accepted: 09/29/2016] [Indexed: 10/20/2022]
Abstract
Health and homoeostasis are maintained by a dynamic balance between mitochondrial fission and fusion. Mitochondrial fusion machinery is largely unknown in mammals. Only a few reports have illustrated the role of Fzo1 in mitochondrial fusion known in Saccharomyces cerevisiae. We demonstrate that the ubiquitin ligase Mahogunin Ring Finger-1 (MGRN1) interacts with and constitutively ubiquitinates the mammalian homolog, Mitofusin1 (Mfn1) via K63 linkages. In mice models, loss of Mgrn1 function leads to severe developmental defects and adult-onset spongiform neurodegeneration, similar to prion diseases. The tethering of mitochondria to form the ~180kDa Mfn1 complex is independent of MGRN1-mediated ubiquitination. However, successful mitochondrial fusion requires formation of higher oligomers of Mfn1 which in turn needs GTPase activity, intact heptad repeats of Mfn1 and ubiquitination by MGRN1. Following ubiquitination, proteasomal processing of Mfn1 completes the mitochondrial fusion process. This step requires functional p97 activity. These findings suggest a sequence of events where GTPase activity of Mfn1 and tethering of adjacent mitochondria precedes its MGRN1-mediated ubiquitination and proteasomal degradation culminating in mitochondrial fusion.
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Affiliation(s)
- Rukmini Mukherjee
- Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata, 700064, India
| | - Oishee Chakrabarti
- Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata, 700064, India.
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Janer A, Prudent J, Paupe V, Fahiminiya S, Majewski J, Sgarioto N, Des Rosiers C, Forest A, Lin ZY, Gingras AC, Mitchell G, McBride HM, Shoubridge EA. SLC25A46 is required for mitochondrial lipid homeostasis and cristae maintenance and is responsible for Leigh syndrome. EMBO Mol Med 2016; 8:1019-38. [PMID: 27390132 PMCID: PMC5009808 DOI: 10.15252/emmm.201506159] [Citation(s) in RCA: 127] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Mitochondria form a dynamic network that responds to physiological signals and metabolic stresses by altering the balance between fusion and fission. Mitochondrial fusion is orchestrated by conserved GTPases MFN1/2 and OPA1, a process coordinated in yeast by Ugo1, a mitochondrial metabolite carrier family protein. We uncovered a homozygous missense mutation in SLC25A46, the mammalian orthologue of Ugo1, in a subject with Leigh syndrome. SLC25A46 is an integral outer membrane protein that interacts with MFN2, OPA1, and the mitochondrial contact site and cristae organizing system (MICOS) complex. The subject mutation destabilizes the protein, leading to mitochondrial hyperfusion, alterations in endoplasmic reticulum (ER) morphology, impaired cellular respiration, and premature cellular senescence. The MICOS complex is disrupted in subject fibroblasts, resulting in strikingly abnormal mitochondrial architecture, with markedly shortened cristae. SLC25A46 also interacts with the ER membrane protein complex EMC, and phospholipid composition is altered in subject mitochondria. These results show that SLC25A46 plays a role in a mitochondrial/ER pathway that facilitates lipid transfer, and link altered mitochondrial dynamics to early‐onset neurodegenerative disease and cell fate decisions.
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Affiliation(s)
- Alexandre Janer
- Department of Human Genetics, McGill University, Montreal, QC, Canada Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Julien Prudent
- Montreal Neurological Institute, McGill University, Montreal, QC, Canada Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
| | - Vincent Paupe
- Department of Human Genetics, McGill University, Montreal, QC, Canada Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | | | - Jacek Majewski
- Department of Human Genetics, McGill University, Montreal, QC, Canada
| | - Nicolas Sgarioto
- Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Christine Des Rosiers
- Department of Nutrition, Université de Montréal, Montreal, QC, Canada Research Centre, Montreal Heart Institute, Montreal, QC, Canada
| | - Anik Forest
- Department of Nutrition, Université de Montréal, Montreal, QC, Canada Research Centre, Montreal Heart Institute, Montreal, QC, Canada
| | - Zhen-Yuan Lin
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | - Anne-Claude Gingras
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Grant Mitchell
- Division of Medical Genetics, Department of Pediatrics, CHU Sainte-Justine and Université de Montréal, Montreal, QC, Canada
| | - Heidi M McBride
- Montreal Neurological Institute, McGill University, Montreal, QC, Canada Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
| | - Eric A Shoubridge
- Department of Human Genetics, McGill University, Montreal, QC, Canada Montreal Neurological Institute, McGill University, Montreal, QC, Canada
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Daumke O, Praefcke GJK. Invited review: Mechanisms of GTP hydrolysis and conformational transitions in the dynamin superfamily. Biopolymers 2016; 105:580-93. [PMID: 27062152 PMCID: PMC5084822 DOI: 10.1002/bip.22855] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 03/31/2016] [Accepted: 04/01/2016] [Indexed: 12/29/2022]
Abstract
Dynamin superfamily proteins are multidomain mechano-chemical GTPases which are implicated in nucleotide-dependent membrane remodeling events. A prominent feature of these proteins is their assembly- stimulated mechanism of GTP hydrolysis. The molecular basis for this reaction has been initially clarified for the dynamin-related guanylate binding protein 1 (GBP1) and involves the transient dimerization of the GTPase domains in a parallel head-to-head fashion. A catalytic arginine finger from the phosphate binding (P-) loop is repositioned toward the nucleotide of the same molecule to stabilize the transition state of GTP hydrolysis. Dynamin uses a related dimerization-dependent mechanism, but instead of the catalytic arginine, a monovalent cation is involved in catalysis. Still another variation of the GTP hydrolysis mechanism has been revealed for the dynamin-like Irga6 which bears a glycine at the corresponding position in the P-loop. Here, we highlight conserved and divergent features of GTP hydrolysis in dynamin superfamily proteins and show how nucleotide binding and hydrolysis are converted into mechano-chemical movements. We also describe models how the energy of GTP hydrolysis can be harnessed for diverse membrane remodeling events, such as membrane fission or fusion. © 2016 Wiley Periodicals, Inc. Biopolymers 105: 580-593, 2016.
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Affiliation(s)
- Oliver Daumke
- Kristallographie, Max-Delbrück Centrum Für Molekulare Medizin, Robert-Rössle-Straße 10, Berlin, 13125, Germany
- Institut Für Chemie und Biochemie, Freie Universität Berlin, Takustraße 3, Berlin, 14195, Germany
| | - Gerrit J K Praefcke
- Abteilung Hämatologie/Transfusionsmedizin, Paul-Ehrlich-Institut, Paul-Ehrlich-Straße 51-59, Langen, 63225, Germany
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Brandt T, Cavellini L, Kühlbrandt W, Cohen MM. A mitofusin-dependent docking ring complex triggers mitochondrial fusion in vitro. eLife 2016; 5. [PMID: 27253069 PMCID: PMC4929004 DOI: 10.7554/elife.14618] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 06/01/2016] [Indexed: 01/19/2023] Open
Abstract
Fusion of mitochondrial outer membranes is crucial for proper organelle function and involves large GTPases called mitofusins. The discrete steps that allow mitochondria to attach to one another and merge their outer membranes are unknown. By combining an in vitro mitochondrial fusion assay with electron cryo-tomography (cryo-ET), we visualize the junction between attached mitochondria isolated from Saccharomyces cerevisiae and observe complexes that mediate this attachment. We find that cycles of GTP hydrolysis induce progressive formation of a docking ring structure around extended areas of contact. Further GTP hydrolysis triggers local outer membrane fusion at the periphery of the contact region. These findings unravel key features of mitofusin-dependent fusion of outer membranes and constitute an important advance in our understanding of how mitochondria connect and merge. DOI:http://dx.doi.org/10.7554/eLife.14618.001 Yeast and other eukaryotic cells contain distinct compartments that have specific roles. For example, compartments called mitochondria – which are surrounded by two layers of membrane – provide the energy needed for many cell processes. The organization of the network of mitochondria in a cell has a large effect on their capacity to provide energy. Mitochondria can fuse together to make larger compartments or divide to make smaller ones. Defects in fusion or division of mitochondria can reduce the amount of energy that is provided, which, in humans and animals can lead to diseases that affect various organs, especially those in the nervous system. When two mitochondria fuse they must first attach to each other and then merge their outer membranes. Proteins called mitofusins are known to be involved in these processes, but the molecular details of how they take place were not clear. Brandt, Cavellini et al. investigated how mitochondria isolated from budding yeast cells attach to each other. The experiments found that two mitochondria first become loosely attached by mitofusins. These proteins then promote a tighter attachment in which the outer membranes of the two mitochondria come into contact over a larger area. This contact area is determined by a linear arrangement of proteins referred to as the docking ring. Brandt, Cavellini et al. further observed that local fusion between the outer membranes takes place at the edge of the contact area in the path of the docking ring. Future research will need to address how mitochondria attach to each other in living cells and how the process is regulated. DOI:http://dx.doi.org/10.7554/eLife.14618.002
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Affiliation(s)
- Tobias Brandt
- Max Planck Institute of Biophysics, Frankfurt, Germany
| | - Laetitia Cavellini
- Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, Institut de Biologie Physico-Chimique, Sorbonne Universités, Paris, France
| | | | - Mickaël M Cohen
- Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, Institut de Biologie Physico-Chimique, Sorbonne Universités, Paris, France
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Kumar S, Pan CC, Shah N, Wheeler SE, Hoyt KR, Hempel N, Mythreye K, Lee NY. Activation of Mitofusin2 by Smad2-RIN1 Complex during Mitochondrial Fusion. Mol Cell 2016; 62:520-31. [PMID: 27184078 DOI: 10.1016/j.molcel.2016.04.010] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 02/04/2016] [Accepted: 04/07/2016] [Indexed: 01/11/2023]
Abstract
Smads are nuclear-shuttling transcriptional mediators of transforming growth factor-β (TGF-β) signaling. Although their essential nuclear roles in gene regulation during development and carcinogenesis are well established, whether they have important cytoplasmic functions remains unclear. Here we report that Smad2 is a critical determinant of mitochondrial dynamics. We identified mitofusin2 (MFN2) and Rab and Ras Interactor 1 (RIN1) as new Smad2 binding partners required for mitochondrial fusion. Unlike TGF-β-induced Smad2/3 transcriptional responses underlying mitochondrial fragmentation and apoptosis, inactive cytoplasmic Smad2 rapidly promotes mitochondrial fusion by recruiting RIN1 into a complex with MFN2. We demonstrate that Smad2 is a key scaffold, allowing RIN1 to act as a GTP exchange factor for MFN2-GTPase activation to promote mitochondrial ATP synthesis and suppress superoxide production. These results reveal functional implications between Smads and mitochondrial dysfunction in cancer and metabolic and neurodegenerative disorders.
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Affiliation(s)
- Sanjay Kumar
- Division of Pharmacology, College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA
| | - Christopher C Pan
- Division of Pharmacology, College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA
| | - Nirav Shah
- Division of Pharmacology, College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA
| | - Sarah E Wheeler
- Division of Pharmacology, College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA
| | - Kari R Hoyt
- Division of Pharmacology, College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA
| | - Nadine Hempel
- Department of Pharmacology, Penn State University, Hershey, PA 17033, USA
| | - Karthikeyan Mythreye
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA
| | - Nam Y Lee
- Division of Pharmacology, College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA; Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA; James Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA.
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45
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Wu X, Li L, Jiang H. Doa1 targets ubiquitinated substrates for mitochondria-associated degradation. J Cell Biol 2016; 213:49-63. [PMID: 27044889 PMCID: PMC4828692 DOI: 10.1083/jcb.201510098] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Accepted: 03/02/2016] [Indexed: 02/07/2023] Open
Abstract
Wu et al. show that Doa1 recognizes and recruits ubiquitinated mitochondrial outer-membrane proteins to the Cdc48–proteasome degradation pathway. Doa1 deficiency sensitizes cells to mitochondrial oxidative stress. Mitochondria-associated degradation (MAD) mediated by the Cdc48 complex and proteasome degrades ubiquitinated mitochondrial outer-membrane proteins. MAD is critical for mitochondrial proteostasis, but it remains poorly characterized. We identified several mitochondrial Cdc48 substrates and developed a genetic screen assay to uncover regulators of the Cdc48-dependent MAD pathway. Surprisingly, we identified Doa1, a substrate-processing factor of Cdc48 that inhibits the degradation of some Cdc48 substrates, as a critical mediator of the turnover of mitochondrial Cdc48 substrates. Deletion of DOA1 causes the accumulation and mislocalization of substrates on mitochondria. Profiling of Cdc48 cofactors shows that Doa1 and Cdc48-Ufd1-Npl4 form a functional complex mediating MAD. Biochemically, Doa1 interacts with ubiquitinated substrates and facilitates substrate recruitment to the Cdc48-Ufd1-Npl4 complex. Functionally, Doa1 is critical for cell survival under mitochondrial oxidative stress, but not ER stress, conditions. Collectively, our results demonstrate the essential role of the Doa1–Cdc48-Ufd1-Npl4 complex in mitochondrial proteostasis and suggest that Doa1 plays dual roles on the Cdc48 complex.
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Affiliation(s)
- Xi Wu
- National Institute of Biological Sciences, Beijing 102206, China
| | - Lanlan Li
- National Institute of Biological Sciences, Beijing 102206, China
| | - Hui Jiang
- National Institute of Biological Sciences, Beijing 102206, China
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46
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Karavaeva IE, Shekhireva KV, Severin FF, Knorre DA. Does Mitochondrial Fusion Require Transmembrane Potential? BIOCHEMISTRY (MOSCOW) 2016; 80:549-58. [PMID: 26071772 DOI: 10.1134/s0006297915050053] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Dissipation of transmembrane potential inhibits mitochondrial fusion and thus prevents reintegration of damaged mitochondria into the mitochondrial network. Consequently, damaged mitochondria are removed by autophagy. Does transmembrane potential directly regulate the mitochondrial fusion machinery? It was shown that inhibition of ATP-synthase induces fragmentation of mitochondria while preserving transmembrane potential. Moreover, mitochondria of the yeast Saccharomyces cerevisiae retain the ability to fuse even in the absence of transmembrane potential. Metazoan mitochondria in some cases retain ability to fuse for a short period even in a depolarized state. It also seems unlikely that transmembrane potential-based regulation of mitochondrial fusion would prevent reintegration of mitochondria with damaged ATP-synthase into the mitochondrial network. Such reintegration could lead to clonal expansion of mtDNAs harboring deleterious mutations in ATP synthase. We speculate that transmembrane potential is not directly involved in regulation of mitochondrial fusion but affects mitochondrial NTP/NDP ratio, which in turn regulates their fusion.
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Affiliation(s)
- I E Karavaeva
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119992, Russia
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47
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Cross Talk of Proteostasis and Mitostasis in Cellular Homeodynamics, Ageing, and Disease. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:4587691. [PMID: 26977249 PMCID: PMC4763003 DOI: 10.1155/2016/4587691] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Revised: 12/24/2015] [Accepted: 12/31/2015] [Indexed: 12/26/2022]
Abstract
Mitochondria are highly dynamic organelles that provide essential metabolic functions and represent the major bioenergetic hub of eukaryotic cell. Therefore, maintenance of mitochondria activity is necessary for the proper cellular function and survival. To this end, several mechanisms that act at different levels and time points have been developed to ensure mitochondria quality control. An interconnected highly integrated system of mitochondrial and cytosolic chaperones and proteases along with the fission/fusion machinery represents the surveillance scaffold of mitostasis. Moreover, nonreversible mitochondrial damage targets the organelle to a specific autophagic removal, namely, mitophagy. Beyond the organelle dynamics, the constant interaction with the ubiquitin-proteasome-system (UPS) has become an emerging aspect of healthy mitochondria. Dysfunction of mitochondria and UPS increases with age and correlates with many age-related diseases including cancer and neurodegeneration. In this review, we discuss the functional cross talk of proteostasis and mitostasis in cellular homeodynamics and the impairment of mitochondrial quality control during ageing, cancer, and neurodegeneration.
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48
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Proteasome Impairment Induces Recovery of Mitochondrial Membrane Potential and an Alternative Pathway of Mitochondrial Fusion. Mol Cell Biol 2015; 36:347-62. [PMID: 26552703 DOI: 10.1128/mcb.00920-15] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 11/04/2015] [Indexed: 12/18/2022] Open
Abstract
Mitochondria are vital and highly dynamic organelles that continuously fuse and divide to maintain mitochondrial quality. Mitochondrial dysfunction impairs cellular integrity and is known to be associated with various human diseases. However, the mechanism by which the quality of mitochondria is maintained remains largely unexplored. Here we show that impaired proteasome function recovers the growth of yeast cells lacking Fzo1, a pivotal protein for mitochondrial fusion. Decreased proteasome activity increased the mitochondrial oxidoreductase protein Mia40 and the ratio of the short isoform of mitochondrial intermembrane protein Mgm1 (s-Mgm1) to the long isoform (l-Mgm1). The increase in Mia40 restored mitochondrial membrane potential, while the increase in the s-Mgm1/l-Mgm1 ratio promoted mitochondrial fusion in an Fzo1-independent manner. Our findings demonstrate a new pathway for mitochondrial quality control that is induced by proteasome impairment.
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Vögtle FN, Keller M, Taskin AA, Horvath SE, Guan XL, Prinz C, Opalińska M, Zorzin C, van der Laan M, Wenk MR, Schubert R, Wiedemann N, Holzer M, Meisinger C. The fusogenic lipid phosphatidic acid promotes the biogenesis of mitochondrial outer membrane protein Ugo1. J Cell Biol 2015; 210:951-60. [PMID: 26347140 PMCID: PMC4576865 DOI: 10.1083/jcb.201506085] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 07/29/2015] [Indexed: 01/31/2023] Open
Abstract
Import and assembly of mitochondrial proteins depend on a complex interplay of proteinaceous translocation machineries. The role of lipids in this process has been studied only marginally and so far no direct role for a specific lipid in mitochondrial protein biogenesis has been shown. Here we analyzed a potential role of phosphatidic acid (PA) in biogenesis of mitochondrial proteins in Saccharomyces cerevisiae. In vivo remodeling of the mitochondrial lipid composition by lithocholic acid treatment or by ablation of the lipid transport protein Ups1, both leading to an increase of mitochondrial PA levels, specifically stimulated the biogenesis of the outer membrane protein Ugo1, a component of the mitochondrial fusion machinery. We reconstituted the import and assembly pathway of Ugo1 in protein-free liposomes, mimicking the outer membrane phospholipid composition, and found a direct dependency of Ugo1 biogenesis on PA. Thus, PA represents the first lipid that is directly involved in the biogenesis pathway of a mitochondrial membrane protein.
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Affiliation(s)
- F.-Nora Vögtle
- Institut für Biochemie und
Molekularbiologie, Center of Biochemistry and Molecular Cell Research (ZBMZ),
University of Freiburg, 79104 Freiburg,
Germany
| | - Michael Keller
- Department of Pharmaceutical Technology and
Biopharmacy, Institute of Pharmaceutical Sciences, University of
Freiburg, 79104 Freiburg, Germany
| | - Asli A. Taskin
- Institut für Biochemie und
Molekularbiologie, Center of Biochemistry and Molecular Cell Research (ZBMZ),
University of Freiburg, 79104 Freiburg,
Germany
- Faculty of Biology, University
of Freiburg, 79104 Freiburg, Germany
- Spemann Graduate School of Biology and
Medicine, University of Freiburg, 79104 Freiburg,
Germany
| | - Susanne E. Horvath
- Institut für Biochemie und
Molekularbiologie, Center of Biochemistry and Molecular Cell Research (ZBMZ),
University of Freiburg, 79104 Freiburg,
Germany
| | - Xue Li Guan
- Department of Biochemistry, Yong Loo Lin School
of Medicine, National University of Singapore, Singapore 117456,
Singapore
- Department of Biological Sciences, Yong Loo Lin
School of Medicine, National University of Singapore, Singapore
117456, Singapore
| | - Claudia Prinz
- Institut für Biochemie und
Molekularbiologie, Center of Biochemistry and Molecular Cell Research (ZBMZ),
University of Freiburg, 79104 Freiburg,
Germany
| | - Magdalena Opalińska
- Institut für Biochemie und
Molekularbiologie, Center of Biochemistry and Molecular Cell Research (ZBMZ),
University of Freiburg, 79104 Freiburg,
Germany
| | - Carina Zorzin
- Department of Pharmaceutical Technology and
Biopharmacy, Institute of Pharmaceutical Sciences, University of
Freiburg, 79104 Freiburg, Germany
| | - Martin van der Laan
- Institut für Biochemie und
Molekularbiologie, Center of Biochemistry and Molecular Cell Research (ZBMZ),
University of Freiburg, 79104 Freiburg,
Germany
- BIOSS Centre for Biological Signalling Studies,
University of Freiburg, 79104 Freiburg,
Germany
| | - Markus R. Wenk
- Department of Biochemistry, Yong Loo Lin School
of Medicine, National University of Singapore, Singapore 117456,
Singapore
- Department of Biological Sciences, Yong Loo Lin
School of Medicine, National University of Singapore, Singapore
117456, Singapore
| | - Rolf Schubert
- Department of Pharmaceutical Technology and
Biopharmacy, Institute of Pharmaceutical Sciences, University of
Freiburg, 79104 Freiburg, Germany
| | - Nils Wiedemann
- Institut für Biochemie und
Molekularbiologie, Center of Biochemistry and Molecular Cell Research (ZBMZ),
University of Freiburg, 79104 Freiburg,
Germany
- BIOSS Centre for Biological Signalling Studies,
University of Freiburg, 79104 Freiburg,
Germany
| | - Martin Holzer
- Department of Pharmaceutical Technology and
Biopharmacy, Institute of Pharmaceutical Sciences, University of
Freiburg, 79104 Freiburg, Germany
| | - Chris Meisinger
- Institut für Biochemie und
Molekularbiologie, Center of Biochemistry and Molecular Cell Research (ZBMZ),
University of Freiburg, 79104 Freiburg,
Germany
- BIOSS Centre for Biological Signalling Studies,
University of Freiburg, 79104 Freiburg,
Germany
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50
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Simultaneous impairment of mitochondrial fission and fusion reduces mitophagy and shortens replicative lifespan. Sci Rep 2015; 5:7885. [PMID: 25601284 PMCID: PMC4298727 DOI: 10.1038/srep07885] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Accepted: 12/18/2014] [Indexed: 12/23/2022] Open
Abstract
Aging of biological systems is accompanied by degeneration of mitochondrial functions. Different pathways are active to counteract the processes which lead to mitochondrial dysfunction. Mitochondrial dynamics, the fission and fusion of mitochondria, is one of these quality control pathways. Mitophagy, the controlled degradation of mitochondria, is another one. Here we show that these pathways are linked. A double deletion mutant of Saccharomyces cerevisiae in which two essential components of the fission and fusion machinery, Dnm1 and Mgm1, are simultaneously ablated, contain wild-type like filamentous mitochondria, but are characterized by impaired respiration, an increased sensitivity to different stressors, increased mitochondrial protein carbonylation, and a decrease in mitophagy and replicative lifespan. These data show that a balanced mitochondrial dynamics and not a filamentous mitochondrial morphotype per se is the key for a long lifespan and demonstrate a cross-talk between two different mitochondrial quality control pathways.
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