351
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Marchi S, Patergnani S, Missiroli S, Morciano G, Rimessi A, Wieckowski MR, Giorgi C, Pinton P. Mitochondrial and endoplasmic reticulum calcium homeostasis and cell death. Cell Calcium 2017; 69:62-72. [PMID: 28515000 DOI: 10.1016/j.ceca.2017.05.003] [Citation(s) in RCA: 400] [Impact Index Per Article: 57.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 05/04/2017] [Accepted: 05/04/2017] [Indexed: 12/12/2022]
Abstract
The endoplasmic reticulum (ER) and mitochondria cannot be considered as static structures, as they intimately communicate, forming very dynamic platforms termed mitochondria-associated membranes (MAMs). In particular, the ER transmits proper Ca2+ signals to mitochondria, which decode them into specific inputs to regulate essential functions, including metabolism, energy production and apoptosis. Here, we will describe the different molecular players involved in the transfer of Ca2+ ions from the ER lumen to the mitochondrial matrix and how modifications in both ER-mitochondria contact sites and Ca2+ signaling can alter the cell death execution program.
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Affiliation(s)
- Saverio Marchi
- Dept. of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Simone Patergnani
- Dept. of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Sonia Missiroli
- Dept. of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Giampaolo Morciano
- Dept. of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Alessandro Rimessi
- Dept. of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | | | - Carlotta Giorgi
- Dept. of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Paolo Pinton
- Dept. of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy.
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352
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Hung V, Lam SS, Udeshi ND, Svinkina T, Guzman G, Mootha VK, Carr SA, Ting AY. Proteomic mapping of cytosol-facing outer mitochondrial and ER membranes in living human cells by proximity biotinylation. eLife 2017; 6:24463. [PMID: 28441135 PMCID: PMC5404927 DOI: 10.7554/elife.24463] [Citation(s) in RCA: 240] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 03/14/2017] [Indexed: 12/24/2022] Open
Abstract
The cytosol-facing membranes of cellular organelles contain proteins that enable signal transduction, regulation of morphology and trafficking, protein import and export, and other specialized processes. Discovery of these proteins by traditional biochemical fractionation can be plagued with contaminants and loss of key components. Using peroxidase-mediated proximity biotinylation, we captured and identified endogenous proteins on the outer mitochondrial membrane (OMM) and endoplasmic reticulum membrane (ERM) of living human fibroblasts. The proteomes of 137 and 634 proteins, respectively, are highly specific and highlight 94 potentially novel mitochondrial or ER proteins. Dataset intersection identified protein candidates potentially localized to mitochondria-ER contact sites. We found that one candidate, the tail-anchored, PDZ-domain-containing OMM protein SYNJ2BP, dramatically increases mitochondrial contacts with rough ER when overexpressed. Immunoprecipitation-mass spectrometry identified ribosome-binding protein 1 (RRBP1) as SYNJ2BP's ERM binding partner. Our results highlight the power of proximity biotinylation to yield insights into the molecular composition and function of intracellular membranes.
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Affiliation(s)
- Victoria Hung
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, United States
| | - Stephanie S Lam
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, United States
| | | | - Tanya Svinkina
- Broad Institute of MIT and Harvard, Cambridge, United States
| | - Gaelen Guzman
- Broad Institute of MIT and Harvard, Cambridge, United States
| | - Vamsi K Mootha
- Broad Institute of MIT and Harvard, Cambridge, United States.,Department of Molecular Biology, Howard Hughes Medical Institute, Massachusetts General Hospital, Harvard Medical School, Boston, United States
| | - Steven A Carr
- Broad Institute of MIT and Harvard, Cambridge, United States
| | - Alice Y Ting
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, United States.,Broad Institute of MIT and Harvard, Cambridge, United States
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353
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Eshima H, Miura S, Senoo N, Hatakeyama K, Poole DC, Kano Y. Improved skeletal muscle Ca 2+ regulation in vivo following contractions in mice overexpressing PGC-1α. Am J Physiol Regul Integr Comp Physiol 2017; 312:R1017-R1028. [PMID: 28438761 DOI: 10.1152/ajpregu.00032.2017] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 04/04/2017] [Accepted: 04/12/2017] [Indexed: 01/13/2023]
Abstract
In skeletal muscle, resting intracellular Ca2+ concentration ([Ca2+]i) homeostasis is exquisitely regulated by Ca2+ transport across the sarcolemmal, mitochondrial, and sarcoplasmic reticulum (SR) membranes. Of these three systems, the relative importance of the mitochondria in [Ca2+]i regulation remains poorly understood in in vivo skeletal muscle. We tested the hypothesis that the capacity for Ca2+ uptake by mitochondria is a primary factor in determining [Ca2+]i regulation in muscle at rest and following contractions. Tibialis anterior muscle of anesthetized peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α)-overexpressing (OE, increased mitochondria model) and wild-type (WT) littermate mice was exteriorized in vivo and loaded with the fluorescent probe fura 2-AM, and Rhod 2-AM Ca2+ buffering and mitochondrial [Ca2+] were evaluated at rest and during recovery from fatiguing tetanic contractions induced by electrical stimulation (120 s, 100 Hz). In addition, the effects of pharmacological inhibition of SR (thapsigargin) and mitochondrial [carbonyl cyanide-4-(trifluoromethoxy) phenylhydrazone (FCCP)] function were examined at rest. [Ca2+]i in WT remained elevated for the entire postcontraction recovery period (+6 ± 1% at 450 s), but in PGC-1α OE [Ca2+]i returned to resting baseline within 150 s. Thapsigargin immediately and substantially increased resting [Ca2+]i in WT, whereas in PGC-1α OE this effect was delayed and markedly diminished (WT, +12 ± 3; PGC-1α OE, +1 ± 2% at 600 s after thapsigargin treatment, P < 0.05). FCCP abolished this improvement of [Ca2+]i regulation in PGC-1α OE. Mitochondrial [Ca2+] accumulation was observed in PGC-1α OE following contractions and thapsigargin treatment. In the SR, PGC-1α OE downregulated SR Ca2+-ATPase 1 (Ca2+ uptake) and parvalbumin (Ca2+ buffering) protein levels, whereas mitochondrial Ca2+ uptake-related proteins (Mfn1, Mfn2, and mitochondrial Ca2+ uniporter) were upregulated. These data demonstrate a heretofore unappreciated role for skeletal muscle mitochondria in [Ca2+]i regulation in vivo following fatiguing tetanic contractions and at rest.
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Affiliation(s)
- Hiroaki Eshima
- Department of Engineering Science, Bioscience and Technology Program, University of Electro-Communications, Tokyo, Japan
| | - Shinji Miura
- Laboratory of Nutritional Biochemistry, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka, Japan; and
| | - Nanami Senoo
- Laboratory of Nutritional Biochemistry, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka, Japan; and
| | - Koji Hatakeyama
- Department of Engineering Science, Bioscience and Technology Program, University of Electro-Communications, Tokyo, Japan
| | - David C Poole
- Departments of Anatomy and Physiology and Kinesiology, Kansas State University, Manhattan, Kansas
| | - Yutaka Kano
- Department of Engineering Science, Bioscience and Technology Program, University of Electro-Communications, Tokyo, Japan;
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354
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The abundance of the ARL2 GTPase and its GAP, ELMOD2, at mitochondria are modulated by the fusogenic activity of mitofusins and stressors. PLoS One 2017; 12:e0175164. [PMID: 28380071 PMCID: PMC5381910 DOI: 10.1371/journal.pone.0175164] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 03/21/2017] [Indexed: 12/05/2022] Open
Abstract
Mitochondria are essential, dynamic organelles that respond to a number of stressors with changes in morphology that are linked to several mitochondrial functions, though the mechanisms involved are poorly understood. We show that the levels of the regulatory GTPase ARL2 and its GAP, ELMOD2, are specifically increased at mitochondria in immortalized mouse embryo fibroblasts deleted for Mitofusin 2 (MFN2), but not MFN1. Elevated ARL2 and ELMOD2 in MEFs deleted for MFN2 could be reversed by re-introduction of MFN2, but only when the mitochondrial fragmentation in these MEFs was also reversed, demonstrating that reversal of elevated ARL2 and ELMOD2 requires the fusogenic activity of MFN2. Other stressors with links to mitochondrial morphology were investigated and several, including glucose or serum deprivation, also caused increases in ARL2 and ELMOD2. In contrast, a number of pharmacological inhibitors of energy metabolism caused increases in ARL2 without affecting ELMOD2 levels. Together we interpret these data as evidence of two ARL2-sensitive pathways in mitochondria, one affecting ATP levels that is independent of ELMOD2 and the other leading to mitochondrial fusion involving MFN2 that does involve ELMOD2.
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355
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Giardia intestinalis mitosomes undergo synchronized fission but not fusion and are constitutively associated with the endoplasmic reticulum. BMC Biol 2017; 15:27. [PMID: 28372543 DOI: 10.1186/s12915-017-0361-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 03/01/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Mitochondria of opisthokonts undergo permanent fission and fusion throughout the cell cycle. Here, we investigated the dynamics of the mitosomes, the simplest forms of mitochondria, in the anaerobic protist parasite Giardia intestinalis, a member of the Excavata supergroup of eukaryotes. The mitosomes have abandoned typical mitochondrial traits such as the mitochondrial genome and aerobic respiration and their single role known to date is the formation of iron-sulfur clusters. RESULTS In live experiments, no fusion events were observed between the mitosomes in G. intestinalis. Moreover, the organelles were highly prone to becoming heterogeneous. This suggests that fusion is either much less frequent or even absent in mitosome dynamics. Unlike in mitochondria, division of the mitosomes was absolutely synchronized and limited to mitosis. The association of the nuclear and the mitosomal division persisted during the encystation of the parasite. During the segregation of the divided mitosomes, the subset of the organelles between two G. intestinalis nuclei had a prominent role. Surprisingly, the sole dynamin-related protein of the parasite seemed not to be involved in mitosomal division. However, throughout the cell cycle, mitosomes associated with the endoplasmic reticulum (ER), although none of the known ER-tethering complexes was present. Instead, the ER-mitosome interface was occupied by the lipid metabolism enzyme long-chain acyl-CoA synthetase 4. CONCLUSIONS This study provides the first report on the dynamics of mitosomes. We show that together with the loss of metabolic complexity of mitochondria, mitosomes of G. intestinalis have uniquely streamlined their dynamics by harmonizing their division with mitosis. We propose that this might be a strategy of G. intestinalis to maintain a stable number of organelles during cell propagation. The lack of mitosomal fusion may also be related to the secondary reduction of the organelles. However, as there are currently no reports on mitochondrial fusion in the whole Excavata supergroup, it is possible that the absence of mitochondrial fusion is an ancestral trait common to all excavates.
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356
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Carreras-Sureda A, Pihán P, Hetz C. The Unfolded Protein Response: At the Intersection between Endoplasmic Reticulum Function and Mitochondrial Bioenergetics. Front Oncol 2017; 7:55. [PMID: 28421160 PMCID: PMC5377016 DOI: 10.3389/fonc.2017.00055] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 03/13/2017] [Indexed: 02/04/2023] Open
Abstract
Endoplasmic reticulum (ER) to mitochondria communication has emerged in recent years as a signaling hub regulating cellular physiology with a relevant contribution to diseases including cancer and neurodegeneration. This functional integration is exerted through discrete interorganelle structures known as mitochondria-associated membranes (MAMs). At these domains, ER/mitochondria physically associate to dynamically adjust metabolic demands and the response to stress stimuli. Here, we provide a focused overview of how the ER shapes the function of the mitochondria, giving a special emphasis to the significance of local signaling of the unfolded protein response at MAMs. The implications to cell fate control and the progression of cancer are also discussed.
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Affiliation(s)
- Amado Carreras-Sureda
- Center for Geroscience, Brain Health and Metabolism, Faculty of Medicine, University of Chile, Santiago, Chile.,Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile.,Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, University of Chile, Santiago, Chile
| | - Philippe Pihán
- Center for Geroscience, Brain Health and Metabolism, Faculty of Medicine, University of Chile, Santiago, Chile.,Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile.,Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, University of Chile, Santiago, Chile
| | - Claudio Hetz
- Center for Geroscience, Brain Health and Metabolism, Faculty of Medicine, University of Chile, Santiago, Chile.,Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile.,Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, University of Chile, Santiago, Chile.,Buck Institute for Research on Aging, Novato, CA, USA.,Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA, USA
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357
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Boutant M, Kulkarni SS, Joffraud M, Ratajczak J, Valera-Alberni M, Combe R, Zorzano A, Cantó C. Mfn2 is critical for brown adipose tissue thermogenic function. EMBO J 2017; 36:1543-1558. [PMID: 28348166 PMCID: PMC5452040 DOI: 10.15252/embj.201694914] [Citation(s) in RCA: 174] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 02/16/2017] [Accepted: 02/28/2017] [Indexed: 01/19/2023] Open
Abstract
Mitochondrial fusion and fission events, collectively known as mitochondrial dynamics, act as quality control mechanisms to ensure mitochondrial function and fine‐tune cellular bioenergetics. Defective mitofusin 2 (Mfn2) expression and enhanced mitochondrial fission in skeletal muscle are hallmarks of insulin‐resistant states. Interestingly, Mfn2 is highly expressed in brown adipose tissue (BAT), yet its role remains unexplored. Using adipose‐specific Mfn2 knockout (Mfn2‐adKO) mice, we demonstrate that Mfn2, but not Mfn1, deficiency in BAT leads to a profound BAT dysfunction, associated with impaired respiratory capacity and a blunted response to adrenergic stimuli. Importantly, Mfn2 directly interacts with perilipin 1, facilitating the interaction between the mitochondria and the lipid droplet in response to adrenergic stimulation. Surprisingly, Mfn2‐adKO mice were protected from high‐fat diet‐induced insulin resistance and hepatic steatosis. Altogether, these results demonstrate that Mfn2 is a mediator of mitochondria to lipid droplet interactions, influencing lipolytic processes and whole‐body energy homeostasis.
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Affiliation(s)
- Marie Boutant
- Nestlé Institute of Health Sciences, Lausanne, Switzerland
| | | | | | - Joanna Ratajczak
- Nestlé Institute of Health Sciences, Lausanne, Switzerland.,School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Miriam Valera-Alberni
- Nestlé Institute of Health Sciences, Lausanne, Switzerland.,School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Roy Combe
- Center of PhenoGenomics (CPG), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Antonio Zorzano
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain.,Departament de Bioquímica i Biologia Molecular, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain.,Instituto de Salud Carlos III, Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain
| | - Carles Cantó
- Nestlé Institute of Health Sciences, Lausanne, Switzerland .,School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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358
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Naon D, Zaninello M, Giacomello M, Varanita T, Grespi F, Lakshminaranayan S, Serafini A, Semenzato M, Herkenne S, Hernández-Alvarez MI, Zorzano A, De Stefani D, Dorn GW, Scorrano L. Reply to Filadi et al.: Does Mitofusin 2 tether or separate endoplasmic reticulum and mitochondria? Proc Natl Acad Sci U S A 2017; 114:E2268-E2269. [PMID: 28289205 PMCID: PMC5373396 DOI: 10.1073/pnas.1618610114] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Deborah Naon
- Department of Biology, University of Padua, 35121 Padua, Italy
- Department of Biomedical Sciences, University of Padua, 35121 Padua, Italy
| | - Marta Zaninello
- Department of Biology, University of Padua, 35121 Padua, Italy
- Dulbecco-Telethon Institute, Venetian Institute of Molecular Medicine, 35129 Padua, Italy
- Fondazione S. Lucia Istituto di Recovero e Cura a Carattere Scientifico, 00161 Rome, Italy
| | - Marta Giacomello
- Department of Biology, University of Padua, 35121 Padua, Italy
- Dulbecco-Telethon Institute, Venetian Institute of Molecular Medicine, 35129 Padua, Italy
| | - Tatiana Varanita
- Department of Biology, University of Padua, 35121 Padua, Italy
- Dulbecco-Telethon Institute, Venetian Institute of Molecular Medicine, 35129 Padua, Italy
| | - Francesca Grespi
- Department of Biology, University of Padua, 35121 Padua, Italy
- Dulbecco-Telethon Institute, Venetian Institute of Molecular Medicine, 35129 Padua, Italy
| | - Sowmya Lakshminaranayan
- Department of Biology, University of Padua, 35121 Padua, Italy
- Fondazione S. Lucia Istituto di Recovero e Cura a Carattere Scientifico, 00161 Rome, Italy
| | - Annalisa Serafini
- Department of Biology, University of Padua, 35121 Padua, Italy
- Dulbecco-Telethon Institute, Venetian Institute of Molecular Medicine, 35129 Padua, Italy
| | - Martina Semenzato
- Department of Biology, University of Padua, 35121 Padua, Italy
- Dulbecco-Telethon Institute, Venetian Institute of Molecular Medicine, 35129 Padua, Italy
| | - Stephanie Herkenne
- Department of Biology, University of Padua, 35121 Padua, Italy
- Dulbecco-Telethon Institute, Venetian Institute of Molecular Medicine, 35129 Padua, Italy
| | | | - Antonio Zorzano
- Institute for Research in Biomedicine, 08028 Barcelona, Spain
| | - Diego De Stefani
- Department of Biomedical Sciences, University of Padua, 35121 Padua, Italy
| | - Gerald W Dorn
- Department of Internal Medicine, Center for Pharmacogenomics, Washington University School of Medicine, St. Louis, MO 63110
| | - Luca Scorrano
- Department of Biology, University of Padua, 35121 Padua, Italy;
- Dulbecco-Telethon Institute, Venetian Institute of Molecular Medicine, 35129 Padua, Italy
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359
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Ong SB, Kalkhoran SB, Hernández-Reséndiz S, Samangouei P, Ong SG, Hausenloy DJ. Mitochondrial-Shaping Proteins in Cardiac Health and Disease - the Long and the Short of It! Cardiovasc Drugs Ther 2017; 31:87-107. [PMID: 28190190 PMCID: PMC5346600 DOI: 10.1007/s10557-016-6710-1] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Mitochondrial health is critically dependent on the ability of mitochondria to undergo changes in mitochondrial morphology, a process which is regulated by mitochondrial shaping proteins. Mitochondria undergo fission to generate fragmented discrete organelles, a process which is mediated by the mitochondrial fission proteins (Drp1, hFIS1, Mff and MiD49/51), and is required for cell division, and to remove damaged mitochondria by mitophagy. Mitochondria undergo fusion to form elongated interconnected networks, a process which is orchestrated by the mitochondrial fusion proteins (Mfn1, Mfn2 and OPA1), and which enables the replenishment of damaged mitochondrial DNA. In the adult heart, mitochondria are relatively static, are constrained in their movement, and are characteristically arranged into 3 distinct subpopulations based on their locality and function (subsarcolemmal, myofibrillar, and perinuclear). Although the mitochondria are arranged differently, emerging data supports a role for the mitochondrial shaping proteins in cardiac health and disease. Interestingly, in the adult heart, it appears that the pleiotropic effects of the mitochondrial fusion proteins, Mfn2 (endoplasmic reticulum-tethering, mitophagy) and OPA1 (cristae remodeling, regulation of apoptosis, and energy production) may play more important roles than their pro-fusion effects. In this review article, we provide an overview of the mitochondrial fusion and fission proteins in the adult heart, and highlight their roles as novel therapeutic targets for treating cardiac disease.
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Affiliation(s)
- Sang-Bing Ong
- Cardiovascular and Metabolic Disorders Program, Duke-National University of Singapore Medical School, 8 College Road, Singapore, 169857, Singapore.,National Heart Research Institute Singapore, National Heart Centre Singapore, Singapore, Singapore
| | - Siavash Beikoghli Kalkhoran
- The Hatter Cardiovascular Institute, Institute of Cardiovascular Science, University College London, London, UK
| | - Sauri Hernández-Reséndiz
- Cardiovascular and Metabolic Disorders Program, Duke-National University of Singapore Medical School, 8 College Road, Singapore, 169857, Singapore.,National Heart Research Institute Singapore, National Heart Centre Singapore, Singapore, Singapore
| | - Parisa Samangouei
- The Hatter Cardiovascular Institute, Institute of Cardiovascular Science, University College London, London, UK
| | - Sang-Ging Ong
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, USA
| | - Derek John Hausenloy
- Cardiovascular and Metabolic Disorders Program, Duke-National University of Singapore Medical School, 8 College Road, Singapore, 169857, Singapore. .,National Heart Research Institute Singapore, National Heart Centre Singapore, Singapore, Singapore. .,The Hatter Cardiovascular Institute, Institute of Cardiovascular Science, University College London, London, UK. .,The National Institute of Health Research, University College London Hospitals Biomedical Research Centre, London, UK.
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360
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Potential Roles of Mitochondria-Associated ER Membranes (MAMs) in Traumatic Brain Injury. Cell Mol Neurobiol 2017; 37:1349-1357. [PMID: 28324201 DOI: 10.1007/s10571-017-0484-2] [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: 12/11/2016] [Accepted: 03/13/2017] [Indexed: 12/12/2022]
Abstract
The endoplasmic reticulum (ER) and mitochondria have both been shown to be critical in cellular homeostasis. The functions of the ER and mitochondria are independent but interrelated. These two organelles could form physical interactions, known as MAMs, to regulate physiological functions between ER and mitochondria to maintain Ca2+, lipid, and metabolite exchange. Several proteins are located in MAMs, including RNA-dependent protein kinase (PKR)-like ER kinase, inositol 1,4,5-trisphosphate receptors, phosphofurin acidic cluster sorting protein-2 and sigma-1 receptor to ensure regulation. Recent studies indicated that MAMs participate in inflammation and apoptosis in various conditions. All of these functions are crucial in determining cell fate following traumatic brain injury (TBI). We hypothesized that MAMs may associate with TBI and could contribute to mitochondrial dysfunction, ER stress, autophagy dysregulation, dysregulation of Ca2+ homeostasis, and oxidative stress. In this review, we summarize the latest understanding of MAM formation and their potential regulatory role in TBI pathophysiology.
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361
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On the role of Mitofusin 2 in endoplasmic reticulum-mitochondria tethering. Proc Natl Acad Sci U S A 2017; 114:E2266-E2267. [PMID: 28289206 DOI: 10.1073/pnas.1616040114] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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362
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Lopez-Crisosto C, Pennanen C, Vasquez-Trincado C, Morales PE, Bravo-Sagua R, Quest AFG, Chiong M, Lavandero S. Sarcoplasmic reticulum-mitochondria communication in cardiovascular pathophysiology. Nat Rev Cardiol 2017; 14:342-360. [PMID: 28275246 DOI: 10.1038/nrcardio.2017.23] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Repetitive, calcium-mediated contractile activity renders cardiomyocytes critically dependent on a sustained energy supply and adequate calcium buffering, both of which are provided by mitochondria. Moreover, in vascular smooth muscle cells, mitochondrial metabolism modulates cell growth and proliferation, whereas cytosolic calcium levels regulate the arterial vascular tone. Physical and functional communication between mitochondria and sarco/endoplasmic reticulum and balanced mitochondrial dynamics seem to have a critical role for optimal calcium transfer to mitochondria, which is crucial in calcium homeostasis and mitochondrial metabolism in both types of muscle cells. Moreover, mitochondrial dysfunction has been associated with myocardial damage and dysregulation of vascular smooth muscle proliferation. Therefore, sarco/endoplasmic reticulum-mitochondria coupling and mitochondrial dynamics are now viewed as relevant factors in the pathogenesis of cardiac and vascular diseases, including coronary artery disease, heart failure, and pulmonary arterial hypertension. In this Review, we summarize the evidence related to the role of sarco/endoplasmic reticulum-mitochondria communication in cardiac and vascular muscle physiology, with a focus on how perturbations contribute to the pathogenesis of cardiovascular disorders.
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Affiliation(s)
- Camila Lopez-Crisosto
- Advanced Center for Chronic Diseases (ACCDiS), Facultad de Ciencias Quimicas y Farmaceuticas &Facultad de Medicina, Universidad de Chile, Sergio Livingstone 1007, Santiago 8380492, Chile
| | - Christian Pennanen
- Advanced Center for Chronic Diseases (ACCDiS), Facultad de Ciencias Quimicas y Farmaceuticas &Facultad de Medicina, Universidad de Chile, Sergio Livingstone 1007, Santiago 8380492, Chile
| | - Cesar Vasquez-Trincado
- Advanced Center for Chronic Diseases (ACCDiS), Facultad de Ciencias Quimicas y Farmaceuticas &Facultad de Medicina, Universidad de Chile, Sergio Livingstone 1007, Santiago 8380492, Chile
| | - Pablo E Morales
- Advanced Center for Chronic Diseases (ACCDiS), Facultad de Ciencias Quimicas y Farmaceuticas &Facultad de Medicina, Universidad de Chile, Sergio Livingstone 1007, Santiago 8380492, Chile
| | - Roberto Bravo-Sagua
- Advanced Center for Chronic Diseases (ACCDiS), Facultad de Ciencias Quimicas y Farmaceuticas &Facultad de Medicina, Universidad de Chile, Sergio Livingstone 1007, Santiago 8380492, Chile.,Instituto de Nutricion y Tecnologia de los Alimentos (INTA), Universidad de Chile, Avenida El Líbano 5524, Santiago 7830490, Chile
| | - Andrew F G Quest
- Advanced Center for Chronic Diseases (ACCDiS), Facultad de Ciencias Quimicas y Farmaceuticas &Facultad de Medicina, Universidad de Chile, Sergio Livingstone 1007, Santiago 8380492, Chile.,Centro de Estudios Moleculares de la Celula (CEMC), Instituto de Ciencias Biomedicas, Facultad de Medicina, Universidad de Chile, Independencia 1027, Santiago 8380453, Chile
| | - Mario Chiong
- Advanced Center for Chronic Diseases (ACCDiS), Facultad de Ciencias Quimicas y Farmaceuticas &Facultad de Medicina, Universidad de Chile, Sergio Livingstone 1007, Santiago 8380492, Chile
| | - Sergio Lavandero
- Advanced Center for Chronic Diseases (ACCDiS), Facultad de Ciencias Quimicas y Farmaceuticas &Facultad de Medicina, Universidad de Chile, Sergio Livingstone 1007, Santiago 8380492, Chile.,Centro de Estudios Moleculares de la Celula (CEMC), Instituto de Ciencias Biomedicas, Facultad de Medicina, Universidad de Chile, Independencia 1027, Santiago 8380453, Chile.,Department of Internal Medicine (Cardiology Division), University of Texas Southwestern Medical Center, 6000 Harry Hines Boulevard, Dallas, Texas 75235, USA
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363
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Federico M, Portiansky EL, Sommese L, Alvarado FJ, Blanco PG, Zanuzzi CN, Dedman J, Kaetzel M, Wehrens XHT, Mattiazzi A, Palomeque J. Calcium-calmodulin-dependent protein kinase mediates the intracellular signalling pathways of cardiac apoptosis in mice with impaired glucose tolerance. J Physiol 2017; 595:4089-4108. [PMID: 28105734 DOI: 10.1113/jp273714] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Accepted: 01/17/2017] [Indexed: 01/01/2023] Open
Abstract
KEY POINTS Spontaneous sarcoplasmic reticulum (SR) Ca2+ release events increased in fructose-rich diet mouse (FRD) myocytes vs. control diet (CD) mice, in the absence of significant changes in SR Ca2+ load. In HEK293 cells, hyperglycaemia significantly enhanced [3 H]ryanodine binding and Ca2+ /calmodulin-dependent protein kinase II (CaMKII) phosphorylation of RyR2-S2814 residue vs. normoglycaemia. These increases were prevented by CaMKII inhibition. FRD significantly augmented cardiac apoptosis in WT vs. CD-WT mice, which was prevented by co-treatment with the reactive oxygen species scavenger Tempol. Oxidative stress was also increased in FRD-SR-autocamide inhibitory peptide (AIP) mice, expressing the SR-targeted CaMKII inhibitor AIP, without any significant enhancement of apoptosis vs. CD-SR-AIP mice. FRD produced mitochondrial swelling and membrane depolarization in FRD-WT mice but not in FRD-S2814A mice, in which the CaMKII site on ryanodine receptor 2 was ablated. FRD decreased mitochondrial area, mean Feret diameter and the mean distance between SR and the outer mitochondrial membrane vs. CD hearts. This remodelling was prevented in AC3I mice, with cardiac-targeted CaMKII inhibition. ABSTRACT The impact of cardiac apoptosis in pre-diabetic stages of diabetic cardiomyopathy is unknown. We show that myocytes from fructose-rich diet (FRD) animals exhibit arrhythmias produced by exacerbated Ca2+ /calmodulin-protein kinase (CaMKII) activity, ryanodine receptor 2 (RyR2) phosphorylation and sarcoplasmic reticulum (SR) Ca2+ leak. We tested the hypothesis that this mechanism also underlies cardiac apoptosis in pre-diabetes. We generated a pre-diabetic model in FRD mice. FRD mice showed an increase in oxidative stress, hypertrophy and systolic dysfunction. FRD myocytes exhibited enhanced SR Ca2+ spontaneous events in the absence of SR Ca2+ load alterations vs. control-diet (CD) myocytes. In HEK293 cells, hyperglycaemia significantly enhanced [3 H]ryanodine binding and CaMKII phosphorylation of RyR2-S2814 residue vs. normoglycaemia. CaMKII inhibition prevented hyperglycaemia-induced alterations. FRD also evoked cardiac apoptosis in WT mice vs. CD-WT mice. Co-treatment with the reactive oxygen species scavenger Tempol prevented FRD-induced apoptosis in WT mice. In contrast, FRD enhanced oxidative stress but not apoptosis in FRD-SR-AIP mice, in which a CaMKII inhibitor is targeted to the SR. FRD produced mitochondrial membrane depolarization in WT mice but not in S2814A mice, in which the CaMKII phosphorylation site on RyR2 was ablated. Furthermore, FRD decreased mitochondrial area, mean Feret diameter and mean SR-mitochondrial distance vs. CD-WT hearts. This remodelling was prevented in AC3I mice, with cardiac-targeted CaMKII inhibition. CaMKII phosphorylation of RyR2, SR Ca2+ leak and mitochondrial membrane depolarization are critically involved in the apoptotic pathway of the pre-diabetic heart. The FRD-induced decrease in SR-mitochondrial distance is likely to additionally favour Ca2+ transit between the two organelles.
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Affiliation(s)
- Marilen Federico
- Centro de Investigaciones Cardiovasculares, CCT-La Plata-CONICET, Facultad de Cs. Médicas, UNLP, La Plata, Argentina
| | - Enrique L Portiansky
- Laboratorio de Análisis de Imágenes, Facultad de Cs. Veterinarias, UNLP, La Plata, Argentina
| | - Leandro Sommese
- Centro de Investigaciones Cardiovasculares, CCT-La Plata-CONICET, Facultad de Cs. Médicas, UNLP, La Plata, Argentina
| | - Francisco J Alvarado
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Paula G Blanco
- Servicio de Ecocardiografía, Facultad de Veterinaria, UNLP, La Plata, Argentina
| | - Carolina N Zanuzzi
- Laboratorio de Análisis de Imágenes, Facultad de Cs. Veterinarias, UNLP, La Plata, Argentina
| | - John Dedman
- Department of Genome Science, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Marcia Kaetzel
- Department of Genome Science, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Xander H T Wehrens
- Cardiovascular Research Institute, Departments of Molecular Physiology and Biophysics, Medicine (in Cardiology), Pediatrics; and Center for Space Medicine, Baylor College of Medicine, Houston, TX, USA
| | - Alicia Mattiazzi
- Centro de Investigaciones Cardiovasculares, CCT-La Plata-CONICET, Facultad de Cs. Médicas, UNLP, La Plata, Argentina
| | - Julieta Palomeque
- Centro de Investigaciones Cardiovasculares, CCT-La Plata-CONICET, Facultad de Cs. Médicas, UNLP, La Plata, Argentina
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364
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Demetriadou A, Morales-Sanfrutos J, Nearchou M, Baba O, Kyriacou K, Tate EW, Drousiotou A, Petrou PP. Mouse Stbd1 is N-myristoylated and affects ER-mitochondria association and mitochondrial morphology. J Cell Sci 2017; 130:903-915. [PMID: 28137759 PMCID: PMC5358331 DOI: 10.1242/jcs.195263] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 01/16/2017] [Indexed: 12/17/2022] Open
Abstract
Starch binding domain-containing protein 1 (Stbd1) is a carbohydrate-binding protein that has been proposed to be a selective autophagy receptor for glycogen. Here, we show that mouse Stbd1 is a transmembrane endoplasmic reticulum (ER)-resident protein with the capacity to induce the formation of organized ER structures in HeLa cells. In addition to bulk ER, Stbd1 was found to localize to mitochondria-associated membranes (MAMs), which represent regions of close apposition between the ER and mitochondria. We demonstrate that N-myristoylation and binding of Stbd1 to glycogen act as major determinants of its subcellular targeting. Moreover, overexpression of non-myristoylated Stbd1 enhanced the association between ER and mitochondria, and further induced prominent mitochondrial fragmentation and clustering. Conversely, shRNA-mediated Stbd1 silencing resulted in an increase in the spacing between ER and mitochondria, and an altered morphology of the mitochondrial network, suggesting elevated fusion and interconnectivity of mitochondria. Our data unravel the molecular mechanism underlying Stbd1 subcellular targeting, support and expand its proposed function as a selective autophagy receptor for glycogen and uncover a new role for the protein in the physical association between ER and mitochondria.
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Affiliation(s)
- Anthi Demetriadou
- Department of Biochemical Genetics, The Cyprus Institute of Neurology and Genetics, P. O. Box 23462, Nicosia 1683, Cyprus
- The Cyprus School of Molecular Medicine, P. O. Box 23462, Nicosia 1683, Cyprus
| | | | - Marianna Nearchou
- Department of Electron Microscopy / Molecular Pathology, The Cyprus Institute of Neurology and Genetics, P. O. Box 23462, Nicosia 1683, Cyprus
| | - Otto Baba
- Oral and Maxillofacial Anatomy, Faculty of Dentistry, Tokushima University, Tokushima 770-8504, Japan
| | - Kyriacos Kyriacou
- The Cyprus School of Molecular Medicine, P. O. Box 23462, Nicosia 1683, Cyprus
- Department of Electron Microscopy / Molecular Pathology, The Cyprus Institute of Neurology and Genetics, P. O. Box 23462, Nicosia 1683, Cyprus
| | - Edward W Tate
- Department of Chemistry, Imperial College London, Exhibition Road, London SW7 2AZ, UK
| | - Anthi Drousiotou
- Department of Biochemical Genetics, The Cyprus Institute of Neurology and Genetics, P. O. Box 23462, Nicosia 1683, Cyprus
- The Cyprus School of Molecular Medicine, P. O. Box 23462, Nicosia 1683, Cyprus
| | - Petros P Petrou
- Department of Biochemical Genetics, The Cyprus Institute of Neurology and Genetics, P. O. Box 23462, Nicosia 1683, Cyprus
- The Cyprus School of Molecular Medicine, P. O. Box 23462, Nicosia 1683, Cyprus
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365
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Gelmetti V, De Rosa P, Torosantucci L, Marini ES, Romagnoli A, Di Rienzo M, Arena G, Vignone D, Fimia GM, Valente EM. PINK1 and BECN1 relocalize at mitochondria-associated membranes during mitophagy and promote ER-mitochondria tethering and autophagosome formation. Autophagy 2017; 13:654-669. [PMID: 28368777 DOI: 10.1080/15548627.2016.1277309] [Citation(s) in RCA: 229] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Mitophagy is a highly specialized process to remove dysfunctional or superfluous mitochondria through the macroautophagy/autophagy pathway, aimed at protecting cells from the damage of disordered mitochondrial metabolism and apoptosis induction. PINK1, a neuroprotective protein mutated in autosomal recessive Parkinson disease, has been implicated in the activation of mitophagy by selectively accumulating on depolarized mitochondria, and promoting PARK2/Parkin translocation to them. While these steps have been characterized in depth, less is known about the process and site of autophagosome formation upon mitophagic stimuli. A previous study reported that, in starvation-induced autophagy, the proautophagic protein BECN1/Beclin1 (which we previously showed to interact with PINK1) relocalizes at specific regions of contact between the endoplasmic reticulum (ER) and mitochondria called mitochondria-associated membranes (MAM), from which the autophagosome originates. Here we show that, following mitophagic stimuli, autophagosomes also form at MAM; moreover, endogenous PINK1 and BECN1 were both found to relocalize at MAM, where they promoted the enhancement of ER-mitochondria contact sites and the formation of omegasomes, that represent autophagosome precursors. PARK2 was also enhanced at MAM following mitophagy induction. However, PINK1 silencing impaired BECN1 enrichment at MAM independently of PARK2, suggesting a novel role for PINK1 in regulating mitophagy. MAM have been recently implicated in many key cellular events. In this light, the observed prevalent localization of PINK1 at MAM may well explain other neuroprotective activities of this protein, such as modulation of mitochondrial calcium levels, mitochondrial dynamics, and apoptosis.
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Affiliation(s)
- Vania Gelmetti
- a Neurogenetics Unit, IRCCS Santa Lucia Foundation , Rome , Italy
| | - Priscilla De Rosa
- b IRCCS Casa Sollievo della Sofferenza, CSS-Mendel Institute , Rome , Italy
| | | | | | - Alessandra Romagnoli
- d National Institute for Infectious Diseases "LazzaroSpallanzani" IRCCS , Rome , Italy
| | - Martina Di Rienzo
- d National Institute for Infectious Diseases "LazzaroSpallanzani" IRCCS , Rome , Italy.,e Department of Biology , "Tor Vergata" University , Rome , Italy
| | - Giuseppe Arena
- f IRCM, Institut de Recherche en Cancérologie de Montpellier, INSERM U1194, Université Montpellier, Institutrégional du Cancer Montpellier , Montpellier , France
| | | | - Gian Maria Fimia
- d National Institute for Infectious Diseases "LazzaroSpallanzani" IRCCS , Rome , Italy.,h Department of Biological and Environmental Sciences and Technologies (DiSTeBA) , University of Salento , Lecce , Italy
| | - Enza Maria Valente
- a Neurogenetics Unit, IRCCS Santa Lucia Foundation , Rome , Italy.,i Department of Molecular Medicine , University of Pavia , Pavia , Italy
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366
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Doghman-Bouguerra M, Lalli E. The ER-mitochondria couple: In life and death from steroidogenesis to tumorigenesis. Mol Cell Endocrinol 2017; 441:176-184. [PMID: 27594532 DOI: 10.1016/j.mce.2016.08.050] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 08/29/2016] [Accepted: 08/31/2016] [Indexed: 02/07/2023]
Abstract
Steroidogenesis is a multistep process where interorganelle communications between the endoplasmic reticulum and mitochondria are critical. These intimate interactions physically occur through the Mitochondria-Associated ER membranes called MAMs. MAMs play important roles in mitochondrial morphology and in many cellular functions ranging from lipid metabolism, to calcium signaling and apoptosis together with a critical effect on steroidogenesis. Moreover, our recent characterization of new MAM resident proteins in adrenocortical cells extends the function of MAM in the mechanism of resistance of cancer cells to apoptotic stimuli and offers new perspectives in targeted therapeutic approaches for adrenocortical tumorigenesis.
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Affiliation(s)
- Mabrouka Doghman-Bouguerra
- Université Côte d'Azur, France; CNRS UMR 7275, France; NEOGENEX CNRS International Associated Laboratory, France; Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), France.
| | - Enzo Lalli
- Université Côte d'Azur, France; CNRS UMR 7275, France; NEOGENEX CNRS International Associated Laboratory, France; Inserm, France; Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), France
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367
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Flippo KH, Strack S. Mitochondrial dynamics in neuronal injury, development and plasticity. J Cell Sci 2017; 130:671-681. [PMID: 28154157 DOI: 10.1242/jcs.171017] [Citation(s) in RCA: 156] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Mitochondria fulfill numerous cellular functions including ATP production, Ca2+ buffering, neurotransmitter synthesis and degradation, ROS production and sequestration, apoptosis and intermediate metabolism. Mitochondrial dynamics, a collective term for the processes of mitochondrial fission, fusion and transport, governs mitochondrial function and localization within the cell. Correct balance of mitochondrial dynamics is especially important in neurons as mutations in fission and fusion enzymes cause peripheral neuropathies and impaired development of the nervous system in humans. Regulation of mitochondrial dynamics is partly accomplished through post-translational modification of mitochondrial fission and fusion enzymes, in turn influencing mitochondrial bioenergetics and transport. The importance of post-translational regulation is highlighted by numerous neurodegenerative disorders associated with post-translational modification of the mitochondrial fission enzyme Drp1. Not surprisingly, mitochondrial dynamics also play an important physiological role in the development of the nervous system and synaptic plasticity. Here, we highlight recent findings underlying the mechanisms and regulation of mitochondrial dynamics in relation to neurological disease, as well as the development and plasticity of the nervous system.
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Affiliation(s)
- Kyle H Flippo
- Department of Pharmacology, University of Iowa, Iowa City, USA
| | - Stefan Strack
- Department of Pharmacology, University of Iowa, Iowa City, USA
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368
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Superresolution Imaging Identifies That Conventional Trafficking Pathways Are Not Essential for Endoplasmic Reticulum to Outer Mitochondrial Membrane Protein Transport. Sci Rep 2017; 7:16. [PMID: 28154412 PMCID: PMC5428351 DOI: 10.1038/s41598-017-00039-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 12/20/2016] [Indexed: 11/23/2022] Open
Abstract
Most nuclear-encoded mitochondrial proteins traffic from the cytosol to mitochondria. Some of these proteins localize at mitochondria-associated membranes (MAM), where mitochondria are closely apposed with the endoplasmic reticulum (ER). We have previously shown that the human cytomegalovirus signal-anchored protein known as viral mitochondria-localized inhibitor of apoptosis (vMIA) traffics from the ER to mitochondria and clusters at the outer mitochondrial membrane (OMM). Here, we have examined the host pathways by which vMIA traffics from the ER to mitochondria and clusters at the OMM. By disruption of phosphofurin acidic cluster sorting protein 2 (PACS-2), mitofusins (Mfn1/2), and dynamin related protein 1 (Drp1), we find these conventional pathways for ER to the mitochondria trafficking are dispensable for vMIA trafficking to OMM. Instead, mutations in vMIA that change its hydrophobicity alter its trafficking to mitochondria. Superresolution imaging showed that PACS-2- and Mfn-mediated membrane apposition or hydrophobic interactions alter vMIA’s ability to organize in nanoscale clusters at the OMM. This shows that signal-anchored MAM proteins can make use of hydrophobic interactions independently of conventional ER-mitochondria pathways to traffic from the ER to mitochondria. Further, vMIA hydrophobic interactions and ER-mitochondria contacts facilitate proper organization of vMIA on the OMM.
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369
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Tubbs E, Rieusset J. Metabolic signaling functions of ER-mitochondria contact sites: role in metabolic diseases. J Mol Endocrinol 2017; 58:R87-R106. [PMID: 27965371 DOI: 10.1530/jme-16-0189] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 12/13/2016] [Indexed: 12/16/2022]
Abstract
Beyond the maintenance of cellular homeostasis and the determination of cell fate, ER-mitochondria contact sites, defined as mitochondria-associated membranes (MAM), start to emerge as an important signaling hub that integrates nutrient and hormonal stimuli and adapts cellular metabolism. Here, we summarize the established structural and functional features of MAM and mainly focus on the latest breakthroughs highlighting a crucial role of organelle crosstalk in the control of metabolic homeostasis. Lastly, we discuss recent studies that have revealed the importance of MAM in not only metabolic diseases but also in other pathologies with disrupted metabolism, shedding light on potential common molecular mechanisms and leading hopefully to novel treatment strategies.
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Affiliation(s)
- Emily Tubbs
- Department of Clinical SciencesLund University Diabetes Centre, Malmö, Sweden
| | - Jennifer Rieusset
- INSERM UMR-1060CarMeN Laboratory, Lyon 1 University, INRA U1235, INSA of Lyon, Charles Merieux Lyon-Sud medical Universities, Lyon, France
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370
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Gomez-Suaga P, Paillusson S, Stoica R, Noble W, Hanger DP, Miller CCJ. The ER-Mitochondria Tethering Complex VAPB-PTPIP51 Regulates Autophagy. Curr Biol 2017; 27:371-385. [PMID: 28132811 PMCID: PMC5300905 DOI: 10.1016/j.cub.2016.12.038] [Citation(s) in RCA: 274] [Impact Index Per Article: 39.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 11/24/2016] [Accepted: 12/16/2016] [Indexed: 01/07/2023]
Abstract
Mitochondria form close physical associations with the endoplasmic reticulum (ER) that regulate a number of physiological functions. One mechanism by which regions of ER are recruited to mitochondria involves binding of the ER protein VAPB to the mitochondrial protein PTPIP51, which act as scaffolds to tether the two organelles. Here, we show that the VAPB-PTPIP51 tethers regulate autophagy. We demonstrate that overexpression of VAPB or PTPIP51 to tighten ER-mitochondria contacts impairs, whereas small interfering RNA (siRNA)-mediated loss of VAPB or PTPIP51 to loosen contacts stimulates, autophagosome formation. Moreover, we show that expression of a synthetic linker protein that artificially tethers ER and mitochondria also reduces autophagosome formation, and that this artificial tether rescues the effects of siRNA loss of VAPB or PTPIP51 on autophagy. Thus, these effects of VAPB and PTPIP51 manipulation on autophagy are a consequence of their ER-mitochondria tethering function. Interestingly, we discovered that tightening of ER-mitochondria contacts by overexpression of VAPB or PTPIP51 impairs rapamycin- and torin 1-induced, but not starvation-induced, autophagy. This suggests that the regulation of autophagy by ER-mitochondria signaling is at least partly dependent upon the nature of the autophagic stimulus. Finally, we demonstrate that the mechanism by which the VAPB-PTPIP51 tethers regulate autophagy involves their role in mediating delivery of Ca2+ to mitochondria from ER stores. Thus, our findings reveal a new molecular mechanism for regulating autophagy. Loosening ER-mitochondria contacts by loss of VAPB-PTPIP51 stimulates autophagy Tightening ER-mitochondria contacts by increased VAPB-PTPIP51 inhibits autophagy Artificial ER-mitochondria tethers rescue VAPB-PTPIP51 loss effects on autophagy The effects of VAPB-PTPIP51 involve their role in ER-mitochondria Ca2+ delivery
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Affiliation(s)
- Patricia Gomez-Suaga
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 9RX, UK
| | - Sebastien Paillusson
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 9RX, UK
| | - Radu Stoica
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 9RX, UK
| | - Wendy Noble
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 9RX, UK
| | - Diane P Hanger
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 9RX, UK
| | - Christopher C J Miller
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE5 9RX, UK.
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371
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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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372
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Morciano G, Pedriali G, Sbano L, Iannitti T, Giorgi C, Pinton P. Intersection of mitochondrial fission and fusion machinery with apoptotic pathways: Role of Mcl-1. Biol Cell 2017; 108:279-293. [PMID: 27234233 DOI: 10.1111/boc.201600019] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 05/24/2016] [Indexed: 01/10/2023]
Abstract
Mitochondria actively contribute to apoptotic cell death through mechanisms including the loss of integrity of the outer mitochondrial membrane, the release of intermembrane space proteins, such as cytochrome c, in the cytosol and the caspase cascade activation. This process is the result of careful cooperation not only among members of the Bcl-2 family but also dynamin-related proteins. These events are often accompanied by fission of the organelle, thus linking mitochondrial dynamics to apoptosis. Emerging evidences are suggesting a fine regulation of mitochondrial morphology by Bcl-2 family members and active participation of fission-fusion proteins in apoptosis. The debate whether in mitochondrial morphogenesis the role of Bcl-2 family members is functionally distinct from their role in apoptosis is still open and, above all, which morphological changes are associated with cell death sensitisation. This review will cover the findings on how the mitochondrial fission and fusion machinery may intersect apoptotic pathways focusing on recent advances on the key role played by Mcl-1.
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Affiliation(s)
- Giampaolo Morciano
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Gaia Pedriali
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Luigi Sbano
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Tommaso Iannitti
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, UK
| | - Carlotta Giorgi
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy.
| | - Paolo Pinton
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy.
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373
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Filadi R, Theurey P, Pizzo P. The endoplasmic reticulum-mitochondria coupling in health and disease: Molecules, functions and significance. Cell Calcium 2017; 62:1-15. [PMID: 28108029 DOI: 10.1016/j.ceca.2017.01.003] [Citation(s) in RCA: 154] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 01/09/2017] [Accepted: 01/09/2017] [Indexed: 12/14/2022]
Abstract
The close apposition between endoplasmic reticulum (ER) and mitochondria represents a key platform, capable to regulate different fundamental cellular pathways. Among these, Ca2+ signaling and lipid homeostasis have been demonstrated over the last years to be deeply modulated by ER-mitochondria cross-talk. Given its importance in cell life/death decisions, increasing evidence suggests that alterations of the ER-mitochondria axis could be responsible for the onset and progression of several diseases, including neurodegeneration, cancer and obesity. However, the molecular identity of the proteins controlling this inter-organelle apposition is still debated. In this review, we summarize the main cellular pathways controlled by ER-mitochondria appositions, focusing on the principal molecules reported to be involved in this interplay and on those diseases for which alterations in organelles communication have been reported.
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Affiliation(s)
- Riccardo Filadi
- Department of Biomedical Sciences, University of Padova, Italy
| | - Pierre Theurey
- Department of Biomedical Sciences, University of Padova, Italy
| | - Paola Pizzo
- Department of Biomedical Sciences, University of Padova, Italy; Neuroscience Institute, National Research Council (CNR), Padova, Italy.
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374
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Missiroli S, Danese A, Iannitti T, Patergnani S, Perrone M, Previati M, Giorgi C, Pinton P. Endoplasmic reticulum-mitochondria Ca 2+ crosstalk in the control of the tumor cell fate. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:858-864. [PMID: 28064002 DOI: 10.1016/j.bbamcr.2016.12.024] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 12/19/2016] [Accepted: 12/21/2016] [Indexed: 12/28/2022]
Abstract
Mitochondria-associated membranes are juxtaposed between the endoplasmic reticulum and mitochondria and have been identified as a critical hub in the regulation of apoptosis and tumor growth. One key function of mitochondria-associated membranes is to provide asylum to a number of proteins with tumor suppressor and oncogenic properties. In this review, we discuss how Ca2+ flux manipulation represents the primary mechanism underlying the action of several oncogenes and tumor-suppressor genes and how these networks might be manipulated to provide novel therapies for cancer. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.
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Affiliation(s)
- Sonia Missiroli
- Dept. of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Alberto Danese
- Dept. of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Tommaso Iannitti
- KWS BioTest, Marine View Office Park, Portishead, Somerset BS20 7AW, UK
| | - Simone Patergnani
- Dept. of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Mariasole Perrone
- Dept. of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Maurizio Previati
- Department of Morphology, Surgery and Experimental Medicine, Section of Human Anatomy and Histology, Laboratory for Technologies of Advanced Therapies(LTTA), University of Ferrara, Ferrara, Italy
| | - Carlotta Giorgi
- Dept. of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Paolo Pinton
- Dept. of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy.
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375
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Marchi S, Bittremieux M, Missiroli S, Morganti C, Patergnani S, Sbano L, Rimessi A, Kerkhofs M, Parys JB, Bultynck G, Giorgi C, Pinton P. Endoplasmic Reticulum-Mitochondria Communication Through Ca 2+ Signaling: The Importance of Mitochondria-Associated Membranes (MAMs). ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 997:49-67. [PMID: 28815521 DOI: 10.1007/978-981-10-4567-7_4] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The execution of proper Ca2+ signaling requires close apposition between the endoplasmic reticulum (ER) and mitochondria. Hence, Ca2+ released from the ER is "quasi-synaptically" transferred to mitochondrial matrix, where Ca2+ stimulates mitochondrial ATP synthesis by activating the tricarboxylic acid (TCA) cycle. However, when the Ca2+ transfer is excessive and sustained, mitochondrial Ca2+ overload induces apoptosis by opening the mitochondrial permeability transition pore. A large number of regulatory proteins reside at mitochondria-associated ER membranes (MAMs) to maintain the optimal distance between the organelles and to coordinate the functionality of both ER and mitochondrial Ca2+ transporters or channels. In this chapter, we discuss the different pathways involved in the regulation of ER-mitochondria Ca2+ flux and describe the activities of the various Ca2+ players based on their primary intra-organelle localization.
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Affiliation(s)
- Saverio Marchi
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Mart Bittremieux
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut, KU Leuven, Campus Gasthuisberg O&N-I box 802, Herestraat 49, B-3000, Leuven, Belgium
| | - Sonia Missiroli
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Claudia Morganti
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Simone Patergnani
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Luigi Sbano
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Alessandro Rimessi
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Martijn Kerkhofs
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut, KU Leuven, Campus Gasthuisberg O&N-I box 802, Herestraat 49, B-3000, Leuven, Belgium
| | - Jan B Parys
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut, KU Leuven, Campus Gasthuisberg O&N-I box 802, Herestraat 49, B-3000, Leuven, Belgium
| | - Geert Bultynck
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut, KU Leuven, Campus Gasthuisberg O&N-I box 802, Herestraat 49, B-3000, Leuven, Belgium
| | - Carlotta Giorgi
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy.
| | - Paolo Pinton
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy.
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376
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Kerkhofs M, Giorgi C, Marchi S, Seitaj B, Parys JB, Pinton P, Bultynck G, Bittremieux M. Alterations in Ca 2+ Signalling via ER-Mitochondria Contact Site Remodelling in Cancer. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 997:225-254. [PMID: 28815534 DOI: 10.1007/978-981-10-4567-7_17] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Inter-organellar contact sites establish microdomains for localised Ca2+-signalling events. One of these microdomains is established between the ER and the mitochondria. Importantly, the so-called mitochondria-associated ER membranes (MAMs) contain, besides structural proteins and proteins involved in lipid exchange, several Ca2+-transport systems, mediating efficient Ca2+ transfer from the ER to the mitochondria. These Ca2+ signals critically control several mitochondrial functions, thereby impacting cell metabolism, cell death and survival, proliferation and migration. Hence, the MAMs have emerged as critical signalling hubs in physiology, while their dysregulation is an important factor that drives or at least contributes to oncogenesis and tumour progression. In this book chapter, we will provide an overview of the role of the MAMs in cell function and how alterations in the MAM composition contribute to oncogenic features and behaviours.
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Affiliation(s)
- Martijn Kerkhofs
- Laboratory Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut (LKI), KU Leuven, Campus Gasthuisberg O&N 1 Box 802, Herestraat 49, 3000, Leuven, Belgium
| | - Carlotta Giorgi
- Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, University of Ferrara, Ferrara, Italy
| | - Saverio Marchi
- Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, University of Ferrara, Ferrara, Italy
| | - Bruno Seitaj
- Laboratory Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut (LKI), KU Leuven, Campus Gasthuisberg O&N 1 Box 802, Herestraat 49, 3000, Leuven, Belgium
| | - Jan B Parys
- Laboratory Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut (LKI), KU Leuven, Campus Gasthuisberg O&N 1 Box 802, Herestraat 49, 3000, Leuven, Belgium
| | - Paolo Pinton
- Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, University of Ferrara, Ferrara, Italy
| | - Geert Bultynck
- Laboratory Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut (LKI), KU Leuven, Campus Gasthuisberg O&N 1 Box 802, Herestraat 49, 3000, Leuven, Belgium.
| | - Mart Bittremieux
- Laboratory Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut (LKI), KU Leuven, Campus Gasthuisberg O&N 1 Box 802, Herestraat 49, 3000, Leuven, Belgium
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377
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Theurey P, Rieusset J. Mitochondria-Associated Membranes Response to Nutrient Availability and Role in Metabolic Diseases. Trends Endocrinol Metab 2017; 28:32-45. [PMID: 27670636 DOI: 10.1016/j.tem.2016.09.002] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 08/31/2016] [Accepted: 09/01/2016] [Indexed: 12/13/2022]
Abstract
Metabolic diseases are associated with nutrient excess and metabolic inflexibility. Mitochondria and endoplasmic reticulum are important organelles and nutrient sensors, and their dysfunction has been extensively and independently implicated in metabolic diseases. Both organelles interact at sites known as mitochondria-associated membranes (MAMs), in order to exchange metabolites and calcium. Recent evidence indicates that MAM could be a hub of hepatic insulin signaling and nutrient sensing. In this review, we discuss the roles organelle function and communication play in the cell's adaptation to nutrient availability, in both physiology and metabolic diseases. We highlight how dynamic regulation of MAM affects mitochondria physiology and adaptation of cellular metabolism to nutrient availability, and how chronic MAM disruption participates in the metabolic inflexibility associated with metabolic disorders.
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Affiliation(s)
- Pierre Theurey
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Jennifer Rieusset
- INSERM UMR-1060, CarMeN Laboratory, Lyon 1 University, INRA U1397, F-69921 Oullins, France.
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378
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Mitochondrial Calcium Handling in Physiology and Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 982:25-47. [PMID: 28551780 DOI: 10.1007/978-3-319-55330-6_2] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Calcium (Ca2+) accumulation inside mitochondria represents a pleiotropic signal controlling a wide range of cellular functions, including key metabolic pathways and life/death decisions. This phenomenon has been first described in the 1960s, but the identity of the molecules controlling this process remained a mystery until just few years ago, when both mitochondrial Ca2+ uptake and release systems were genetically dissected. This finally opened the possibility to develop genetic models to directly test the contribution of mitochondrial Ca2+ homeostasis to cellular functions. Here we summarize our current understanding of the molecular machinery that controls mitochondrial Ca2+ handling and critically evaluate the physiopathological role of mitochondrial Ca2+ signaling, based on recent evidences obtained through in vitro and in vivo models.
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379
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Abstract
The endoplasmic reticulum (ER) is a crucial organelle for coordinating cellular Ca2+ signaling and protein synthesis and folding. Moreover, the dynamic and complex membranous structures constituting the ER allow the formation of contact sites with other organelles and structures, including among others the mitochondria and the plasma membrane (PM). The contact sites that the ER form with mitochondria is a hot topic in research, and the nature of the so-called mitochondria-associated membranes (MAMs) is continuously evolving. The MAMs consist of a proteinaceous tether that physically connects the ER with mitochondria. The MAMs harness the main functions of both organelles to form a specialized subcompartment at the interface of the ER and mitochondria. Under homeostatic conditions, MAMs are crucial for the efficient transfer of Ca2+ from the ER to mitochondria, and for proper mitochondria bioenergetics and lipid synthesis. MAMs are also believed to be the master regulators of mitochondrial shape and motility, and to form a crucial site for autophagosome assembly. Not surprisingly, MAMs have been shown to be a hot spot for the transfer of stress signals from the ER to mitochondria, most notably under the conditions of loss of ER proteostasis, by engaging the unfolded protein response (UPR). In this chapter after an introduction on ER biology and ER stress, we will review the emerging and key signaling roles of the MAMs, which have a root in cellular processes and signaling cascades coordinated by the ER.
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380
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Malli R, Graier WF. The Role of Mitochondria in the Activation/Maintenance of SOCE: The Contribution of Mitochondrial Ca 2+ Uptake, Mitochondrial Motility, and Location to Store-Operated Ca 2+ Entry. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 993:297-319. [PMID: 28900921 DOI: 10.1007/978-3-319-57732-6_16] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In most cell types, the depletion of internal Ca2+ stores triggers the activation of Ca2+ entry. This crucial phenomenon is known since the 1980s and referred to as store-operated Ca2+ entry (SOCE). With the discoveries of the stromal-interacting molecules (STIMs) and the Ca2+-permeable Orai channels as the long-awaited molecular constituents of SOCE, the role of mitochondria in controlling the activity of this particular Ca2+ entry pathway is kind of buried in oblivion. However, the capability of mitochondria to locally sequester Ca2+ at sites of Ca2+ release and entry was initially supposed to rule SOCE by facilitating the Ca2+ depletion of the endoplasmic reticulum and removing entering Ca2+ from the Ca2+-inhibitable channels, respectively. Moreover, the central role of these organelles in controlling the cellular energy metabolism has been linked to the activity of SOCE. Nevertheless, the exact molecular mechanisms by which mitochondria actually determine SOCE are still pretty obscure. In this essay we describe the complexity of the mitochondrial Ca2+ uptake machinery and its regulation, molecular components, and properties, which open new ways for scrutinizing the contribution of mitochondria to SOCE. Moreover, data concerning the variability of the morphology and cellular distribution of mitochondria as putative determinants of SOCE activation, maintenance, and termination are summarized.
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Affiliation(s)
- Roland Malli
- Institute of Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstrasse 6/6, 8010, Graz, Austria
| | - Wolfgang F Graier
- Institute of Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstrasse 6/6, 8010, Graz, Austria.
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381
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Over Six Decades of Discovery and Characterization of the Architecture at Mitochondria-Associated Membranes (MAMs). ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 997:13-31. [PMID: 28815519 DOI: 10.1007/978-981-10-4567-7_2] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The discovery of proteins regulating ER-mitochondria tethering including phosphofurin acidic cluster sorting protein 2 (PACS-2) and mitofusin-2 has pushed contact sites between the endoplasmic reticulum (ER) and mitochondria into the spotlight of cell biology. While the field is developing rapidly and controversies have come and gone multiple times during its history, it is sometimes overlooked that significant research has been done decades ago with the original discovery of these structures in the 1950s and the first characterization of their function (and coining of the term mitochondria-associated membrane, MAM) in 1990. Today, an ever-increasing array of proteins localize to the MAM fraction of the endoplasmic reticulum (ER) to regulate the interaction of this organelle with mitochondria. These mitochondria-ER contacts, sometimes referred to as MERCs, regulate a multitude of biological functions, including lipid metabolism, Ca2+ signaling, bioenergetics, inflammation, autophagy, mitochondrial structure, and apoptosis.
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382
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383
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When under pressure, get closer: PERKing up membrane contact sites during ER stress. Biochem Soc Trans 2016; 44:499-504. [PMID: 27068961 DOI: 10.1042/bst20150272] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Indexed: 02/06/2023]
Abstract
The endoplasmic reticulum (ER) is the main hub of cellular Ca(2+)signalling and protein synthesis and folding. The ER moreover is the central player in the formation of contact sites with other organelles and structures, including mitochondria, plasma membrane (PM) and endosomes. The most studied of these, the ER-mitochondria contact sites, are crucial regulators of cellular Ca(2+)homoeostasis, metabolism and cell death signalling. Protein kinase RNA-like ER kinase (PERK), an ER stress kinase and crucial signalling protein in the unfolded protein response (UPR), was found to be able to orchestrate contact sites between the ER and mitochondria and to be indispensable for the pre-apoptotic trafficking of calreticulin (CRT) at the PM during immunogenic cell death (ICD). Furthermore, PERK has recently been linked with ER and PM contact sites through the mechanism of store-operated Ca(2+)entry (SOCE). Here we discuss emerging findings disclosing novel roles of the ER stress sensor PERK in orchestrating inter-organellar communication in the context of ER stress.
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384
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Bonneau B, Ando H, Kawaai K, Hirose M, Takahashi-Iwanaga H, Mikoshiba K. IRBIT controls apoptosis by interacting with the Bcl-2 homolog, Bcl2l10, and by promoting ER-mitochondria contact. eLife 2016; 5. [PMID: 27995898 PMCID: PMC5173324 DOI: 10.7554/elife.19896] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 11/24/2016] [Indexed: 12/15/2022] Open
Abstract
IRBIT is a molecule that interacts with the inositol 1,4,5-trisphosphate (IP3)-binding pocket of the IP3 receptor (IP3R), whereas the antiapoptotic protein, Bcl2l10, binds to another part of the IP3-binding domain. Here we show that Bcl2l10 and IRBIT interact and exert an additive inhibition of IP3R in the physiological state. Moreover, we found that these proteins associate in a complex in mitochondria-associated membranes (MAMs) and that their interplay is involved in apoptosis regulation. MAMs are a hotspot for Ca2+ transfer between endoplasmic reticulum (ER) and mitochondria, and massive Ca2+ release through IP3R in mitochondria induces cell death. We found that upon apoptotic stress, IRBIT is dephosphorylated, becoming an inhibitor of Bcl2l10. Moreover, IRBIT promotes ER mitochondria contact. Our results suggest that by inhibiting Bcl2l10 activity and promoting contact between ER and mitochondria, IRBIT facilitates massive Ca2+ transfer to mitochondria and promotes apoptosis. This work then describes IRBIT as a new regulator of cell death.
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Affiliation(s)
- Benjamin Bonneau
- Laboratory for Developmental Neurobiology, RIKEN Brain Science institute, Wako-shi, Japan
| | - Hideaki Ando
- Laboratory for Developmental Neurobiology, RIKEN Brain Science institute, Wako-shi, Japan
| | - Katsuhiro Kawaai
- Laboratory for Developmental Neurobiology, RIKEN Brain Science institute, Wako-shi, Japan
| | - Matsumi Hirose
- Laboratory for Developmental Neurobiology, RIKEN Brain Science institute, Wako-shi, Japan
| | | | - Katsuhiko Mikoshiba
- Laboratory for Developmental Neurobiology, RIKEN Brain Science institute, Wako-shi, Japan
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385
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Role of Mitochondria-Associated Endoplasmic Reticulum Membrane in Inflammation-Mediated Metabolic Diseases. Mediators Inflamm 2016; 2016:1851420. [PMID: 28074080 PMCID: PMC5198184 DOI: 10.1155/2016/1851420] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 11/17/2016] [Indexed: 12/11/2022] Open
Abstract
Inflammation is considered to be one of the most critical factors involved in the development of complex metabolic diseases such as type 2 diabetes, cancer, and cardiovascular disease. A few decades ago, the discovery of mitochondria-associated endoplasmic reticulum (ER) membrane (MAM) was followed by the identification of its roles in regulating cellular homeostatic processes, ranging from cellular bioenergetics to apoptosis. MAM provides an excellent platform for numerous signaling pathways; among them, inflammatory signaling pathways associated with MAM play a critical role in cellular defense during pathogenic infections and metabolic disorders. However, induction of MAM causes deleterious effects by amplifying mitochondrial reactive oxygen species generation through increased calcium transfer from the ER to mitochondria, thereby causing mitochondrial damage and release of mitochondrial components into the cytosol as damage-associated molecular patterns (DAMPs). These mitochondrial DAMPs rapidly activate MAM-resident inflammasome components and other inflammatory factors, which promote inflammasome complex formation and release of proinflammatory cytokines in pathological conditions. Long-term stimulation of the inflammasome instigates chronic inflammation, leading to the pathogenesis of metabolic diseases. In this review, we summarize the current understanding of MAM and its association with inflammation-mediated metabolic diseases.
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386
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Kulkarni SS, Joffraud M, Boutant M, Ratajczak J, Gao AW, Maclachlan C, Hernandez-Alvarez MI, Raymond F, Metairon S, Descombes P, Houtkooper RH, Zorzano A, Cantó C. Mfn1 Deficiency in the Liver Protects Against Diet-Induced Insulin Resistance and Enhances the Hypoglycemic Effect of Metformin. Diabetes 2016; 65:3552-3560. [PMID: 27613809 DOI: 10.2337/db15-1725] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 09/05/2016] [Indexed: 11/13/2022]
Abstract
Mitochondrial function can be influenced by mitochondrial shape and connectivity with other cellular organelles through fusion and fission processes. Disturbances in mitochondrial architecture and mitochondrial fusion-related genes are observed in situations of type 2 diabetes and obesity, leading to a highly fissioned mitochondrial network. To directly test the effect of reduced mitochondrial fusion on hepatic metabolism, we generated mice with a liver-specific deletion of the Mfn1 gene (Mfn1LKO) and monitored their energy homeostasis, mitochondrial function, and susceptibility to diet-induced insulin resistance. Livers from Mfn1LKO mice displayed a highly fragmented mitochondrial network. This was coupled to an enhanced mitochondrial respiration capacity and a preference for the use of lipids as the main energy source. Although Mfn1LKO mice are similar to control mice fed a low-fat diet, they are protected against insulin resistance induced by a high-fat diet. Importantly, Mfn1 deficiency increased complex I abundance and sensitized animals to the hypoglycemic effect of metformin. Our results suggest that targeting Mfn1 could provide novel avenues to ameliorate glucose homeostasis in obese patients and improve the effectiveness of metformin.
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Affiliation(s)
| | | | - Marie Boutant
- Nestlé Institute of Health Sciences, Lausanne, Switzerland
| | - Joanna Ratajczak
- Nestlé Institute of Health Sciences, Lausanne, Switzerland
- École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Arwen W Gao
- Laboratory Genetic Metabolic Diseases, Academic Medical Center, Amsterdam, the Netherlands
| | | | - Maria Isabel Hernandez-Alvarez
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
- Departament de Bioquímica i Biologia Molecular, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
- Instituto de Salud Carlos III, CIBERDEM, Madrid, Spain
| | | | | | | | - Riekelt H Houtkooper
- Laboratory Genetic Metabolic Diseases, Academic Medical Center, Amsterdam, the Netherlands
| | - Antonio Zorzano
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
- Departament de Bioquímica i Biologia Molecular, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
- Instituto de Salud Carlos III, CIBERDEM, Madrid, Spain
| | - Carles Cantó
- Nestlé Institute of Health Sciences, Lausanne, Switzerland
- École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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387
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Dengue virus induces mitochondrial elongation through impairment of Drp1-triggered mitochondrial fission. Virology 2016; 500:149-160. [PMID: 27816895 DOI: 10.1016/j.virol.2016.10.022] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 10/18/2016] [Accepted: 10/24/2016] [Indexed: 02/08/2023]
Abstract
Mitochondria are highly dynamic organelles that undergo continuous cycles of fission and fusion to maintain essential cellular functions. An imbalance between these two processes can result in many pathophysiological outcomes. Dengue virus (DENV) interacts with cellular organelles, including mitochondria, to successfully replicate in cells. This study used live-cell imaging and found an increase in mitochondrial length and respiration during DENV infection. The level of mitochondrial fission protein, Dynamin-related protein 1 (Drp1), was decreased on mitochondria during DENV infection, as well as Drp1 phosphorylated on serine 616, which is important for mitochondrial fission. DENV proteins NS4b and NS3 were also associated with subcellular fractions of mitochondria. Induction of fission through uncoupling of mitochondria or overexpression of Drp1 wild-type and Drp1 with a phosphomimetic mutation (S616D) significantly reduced viral replication. These results demonstrate that DENV infection causes an imbalance in mitochondrial dynamics by inhibiting Drp1-triggered mitochondrial fission, which promotes viral replication.
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388
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Rodríguez-Arribas M, Yakhine-Diop SMS, Pedro JMBS, Gómez-Suaga P, Gómez-Sánchez R, Martínez-Chacón G, Fuentes JM, González-Polo RA, Niso-Santano M. Mitochondria-Associated Membranes (MAMs): Overview and Its Role in Parkinson's Disease. Mol Neurobiol 2016; 54:6287-6303. [PMID: 27714635 DOI: 10.1007/s12035-016-0140-8] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 09/19/2016] [Indexed: 12/21/2022]
Abstract
Mitochondria-associated membranes (MAMs) are structures that regulate physiological functions between endoplasmic reticulum (ER) and mitochondria in order to maintain calcium signaling and mitochondrial biogenesis. Several proteins located in MAMs, including those encoded by PARK genes and some of neurodegeneration-related proteins (huntingtin, presenilin, etc.), ensure this regulation. In this regard, MAM alteration is associated with neurodegenerative diseases such as Parkinson's (PD), Alzheimer's (AD), and Huntington's diseases (HD) and contributes to the appearance of the pathogenesis features, i.e., autophagy dysregulation, mitochondrial dysfunction, oxidative stress, and lately, neuronal death. Moreover,, ER stress and/or damaged mitochondria can be the cause of these disruptions. Therefore, ER-mitochondria contact structure and function are crucial to multiple cellular processes. This review is focused on the molecular interaction between ER and mitochondria indispensable to MAM formation and on MAM alteration-induced etiology of neurodegenerative diseases.
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Affiliation(s)
- M Rodríguez-Arribas
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Universidad de Extremadura, Avda. De la Universidad S/N, C.P, 10003, Cáceres, Cáceres, Spain.,Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, Avda. de la Universidad s/n, C.P, 10003, Cáceres, Cáceres, Spain
| | - S M S Yakhine-Diop
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Universidad de Extremadura, Avda. De la Universidad S/N, C.P, 10003, Cáceres, Cáceres, Spain.,Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, Avda. de la Universidad s/n, C.P, 10003, Cáceres, Cáceres, Spain
| | - J M Bravo-San Pedro
- Equipe 11 labellisée Ligue contre le Cancer, Centre de Recherche des Cordeliers, 75006, Paris, France.,INSERM U1138, 75006, Paris, France.,Université Paris Descartes/Paris V, Sorbonne Paris Cité, 75006, Paris, France.,Université Pierre et Marie Curie/Paris VI, 75006, Paris, France.,Gustave Roussy Comprehensive Cancer Institute, 94805, Villejuif, France
| | - P Gómez-Suaga
- Department Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute Kings College London, London, SE5 9RX, UK
| | - R Gómez-Sánchez
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - G Martínez-Chacón
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Universidad de Extremadura, Avda. De la Universidad S/N, C.P, 10003, Cáceres, Cáceres, Spain.,Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, Avda. de la Universidad s/n, C.P, 10003, Cáceres, Cáceres, Spain
| | - J M Fuentes
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Universidad de Extremadura, Avda. De la Universidad S/N, C.P, 10003, Cáceres, Cáceres, Spain.,Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, Avda. de la Universidad s/n, C.P, 10003, Cáceres, Cáceres, Spain
| | - R A González-Polo
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Universidad de Extremadura, Avda. De la Universidad S/N, C.P, 10003, Cáceres, Cáceres, Spain. .,Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, Avda. de la Universidad s/n, C.P, 10003, Cáceres, Cáceres, Spain.
| | - M Niso-Santano
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Universidad de Extremadura, Avda. De la Universidad S/N, C.P, 10003, Cáceres, Cáceres, Spain. .,Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, Avda. de la Universidad s/n, C.P, 10003, Cáceres, Cáceres, Spain.
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389
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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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390
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Piecing Together the Patchwork of Contact Sites. Trends Cell Biol 2016; 27:214-229. [PMID: 27717534 DOI: 10.1016/j.tcb.2016.08.010] [Citation(s) in RCA: 120] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 08/10/2016] [Accepted: 08/25/2016] [Indexed: 11/23/2022]
Abstract
Contact sites are places where two organelles join together to carry out a shared activity requiring nonvesicular communication. A large number of contact sites have been discovered, and almost any two organelles can contact each other. General rules about contacts include constraints on bridging proteins, with only a minority of bridges physically creating contacts by acting as 'tethers'. The downstream effects of contacts include changing the physical behaviour of organelles, and also forming biochemically heterogeneous subdomains. However, some functions typically localized to contact sites, such as lipid transfer, have no absolute requirement to be situated there. Therefore, the key aspect of contacts is the directness of communication, which allows metabolic channelling and collective regulation.
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391
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Horibata Y, Ando H, Zhang P, Vergnes L, Aoyama C, Itoh M, Reue K, Sugimoto H. StarD7 Protein Deficiency Adversely Affects the Phosphatidylcholine Composition, Respiratory Activity, and Cristae Structure of Mitochondria. J Biol Chem 2016; 291:24880-24891. [PMID: 27694445 DOI: 10.1074/jbc.m116.736793] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 08/30/2016] [Indexed: 12/17/2022] Open
Abstract
Phosphatidylcholine (PC) is a major phospholipid of mitochondria, comprising 40-50% of both the outer and the inner membranes. However, PC must be imported from its production organelles because mitochondria lack the enzymes essential for PC biosynthesis. In a previous study, we found that StarD7 mediates the intracellular transfer of PC to mitochondria. Therefore, in this study, we analyzed the contribution of StarD7 to the maintenance of mitochondrial phospholipid content and function using siRNA-mediated knockdown and knock-out (KO) of the StarD7 gene in HEPA-1 cells. Real time analysis of respiratory activity demonstrated that the oxygen consumption rate and activity of mitochondrial complexes were impaired in StarD7-KD cells. To confirm these results, we established StarD7-KO HEPA-1 cells by double nicking using CRISPR/Cas9n. As expected, StarD7-KD and -KO cells showed a significant reduction in mitochondrial PC content. The ATP level and growth rate of KO cells were notably lower compared with wild-type cells when cultured in glucose-free galactose-containing medium to force cells to rely on mitochondrial ATP production. In KO cells, the level of the MTCO1 protein, a primary subunit of complex IV, was reduced without a concomitant decrease in its mRNA, but the level was restored when StarD7-I was overexpressed. StarD7-KO cells showed impaired formation of the mitochondrial supercomplexes and exhibited a disorganized cristae structure, with no changes in optic atrophy 1 protein. These findings indicate that StarD7 plays important roles in maintaining the proper composition of mitochondrial phospholipids as well as mitochondrial function and morphogenesis.
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Affiliation(s)
- Yasuhiro Horibata
- From the Department of Biochemistry, Dokkyo Medical University School of Medicine, 880 Kitakobayashi, Mibu, Tochigi, Japan and
| | - Hiromi Ando
- From the Department of Biochemistry, Dokkyo Medical University School of Medicine, 880 Kitakobayashi, Mibu, Tochigi, Japan and
| | - Peixiang Zhang
- the Department of Human Genetics, David Geffen School of Medicine and
| | - Laurent Vergnes
- the Department of Human Genetics, David Geffen School of Medicine and
| | - Chieko Aoyama
- From the Department of Biochemistry, Dokkyo Medical University School of Medicine, 880 Kitakobayashi, Mibu, Tochigi, Japan and
| | - Masahiko Itoh
- From the Department of Biochemistry, Dokkyo Medical University School of Medicine, 880 Kitakobayashi, Mibu, Tochigi, Japan and
| | - Karen Reue
- the Department of Human Genetics, David Geffen School of Medicine and.,the Molecular Biology Institute at UCLA, Los Angeles, California 90095
| | - Hiroyuki Sugimoto
- From the Department of Biochemistry, Dokkyo Medical University School of Medicine, 880 Kitakobayashi, Mibu, Tochigi, Japan and
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392
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Raffaello A, Mammucari C, Gherardi G, Rizzuto R. Calcium at the Center of Cell Signaling: Interplay between Endoplasmic Reticulum, Mitochondria, and Lysosomes. Trends Biochem Sci 2016; 41:1035-1049. [PMID: 27692849 DOI: 10.1016/j.tibs.2016.09.001] [Citation(s) in RCA: 349] [Impact Index Per Article: 43.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 08/31/2016] [Accepted: 09/07/2016] [Indexed: 12/29/2022]
Abstract
In recent years, rapid discoveries have been made relating to Ca2+ handling at specific organelles that have important implications for whole-cell Ca2+ homeostasis. In particular, the structures of the endoplasmic reticulum (ER) Ca2+ channels revealed by electron cryomicroscopy (cryo-EM), continuous updates on the structure, regulation, and role of the mitochondrial calcium uniporter (MCU) complex, and the analysis of lysosomal Ca2+ signaling are milestones on the route towards a deeper comprehension of the complexity of global Ca2+ signaling. In this review we summarize recent discoveries on the regulation of interorganellar Ca2+ homeostasis and its role in pathophysiology.
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Affiliation(s)
- Anna Raffaello
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy.
| | - Cristina Mammucari
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy.
| | - Gaia Gherardi
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy
| | - Rosario Rizzuto
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; Neuroscience Institute, National Research Council, 35131 Padua, Italy.
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393
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Critical reappraisal confirms that Mitofusin 2 is an endoplasmic reticulum-mitochondria tether. Proc Natl Acad Sci U S A 2016; 113:11249-11254. [PMID: 27647893 DOI: 10.1073/pnas.1606786113] [Citation(s) in RCA: 367] [Impact Index Per Article: 45.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The discovery of the multiple roles of mitochondria-endoplasmic reticulum (ER) juxtaposition in cell biology often relied upon the exploitation of Mitofusin (Mfn) 2 as an ER-mitochondria tether. However, this established Mfn2 function was recently questioned, calling for a critical re-evaluation of Mfn2's role in ER-mitochondria cross-talk. Electron microscopy and fluorescence-based probes of organelle proximity confirmed that ER-mitochondria juxtaposition was reduced by constitutive or acute Mfn2 deletion. Functionally, mitochondrial uptake of Ca2+ released from the ER was reduced following acute Mfn2 ablation, as well as in Mfn2-/- cells overexpressing the mitochondrial calcium uniporter. Mitochondrial Ca2+ uptake rate and extent were normal in isolated Mfn2-/- liver mitochondria, consistent with the finding that acute or chronic Mfn2 ablation or overexpression did not alter mitochondrial calcium uniporter complex component levels. Hence, Mfn2 stands as a bona fide ER-mitochondria tether whose ablation decreases interorganellar juxtaposition and communication.
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394
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De La Fuente S, Fernandez-Sanz C, Vail C, Agra EJ, Holmstrom K, Sun J, Mishra J, Williams D, Finkel T, Murphy E, Joseph SK, Sheu SS, Csordás G. Strategic Positioning and Biased Activity of the Mitochondrial Calcium Uniporter in Cardiac Muscle. J Biol Chem 2016; 291:23343-23362. [PMID: 27637331 DOI: 10.1074/jbc.m116.755496] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Indexed: 11/06/2022] Open
Abstract
Control of myocardial energetics by Ca2+ signal propagation to the mitochondrial matrix includes local Ca2+ delivery from sarcoplasmic reticulum (SR) ryanodine receptors (RyR2) to the inner mitochondrial membrane (IMM) Ca2+ uniporter (mtCU). mtCU activity in cardiac mitochondria is relatively low, whereas the IMM surface is large, due to extensive cristae folding. Hence, stochastically distributed mtCU may not suffice to support local Ca2+ transfer. We hypothesized that mtCU concentrated at mitochondria-SR associations would promote the effective Ca2+ transfer. mtCU distribution was determined by tracking MCU and EMRE, the proteins essential for channel formation. Both proteins were enriched in the IMM-outer mitochondrial membrane (OMM) contact point submitochondrial fraction and, as super-resolution microscopy revealed, located more to the mitochondrial periphery (inner boundary membrane) than inside the cristae, indicating high accessibility to cytosol-derived Ca2+ inputs. Furthermore, MCU immunofluorescence distribution was biased toward the mitochondria-SR interface (RyR2), and this bias was promoted by Ca2+ signaling activity in intact cardiomyocytes. The SR fraction of heart homogenate contains mitochondria with extensive SR associations, and these mitochondria are highly enriched in EMRE. Size exclusion chromatography suggested for EMRE- and MCU-containing complexes a wide size range and also revealed MCU-containing complexes devoid of EMRE (thus disabled) in the mitochondrial but not the SR fraction. Functional measurements suggested more effective mtCU-mediated Ca2+ uptake activity by the mitochondria of the SR than of the mitochondrial fraction. Thus, mtCU "hot spots" can be formed at the cardiac muscle mitochondria-SR associations via localization and assembly bias, serving local Ca2+ signaling and the excitation-energetics coupling.
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Affiliation(s)
- Sergio De La Fuente
- From the MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Celia Fernandez-Sanz
- the Center for Translational Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, and
| | - Caitlin Vail
- From the MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Elorm J Agra
- From the MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Kira Holmstrom
- the Center for Molecular Medicine, Laboratory of Molecular Biology, and
| | - Junhui Sun
- the Systems Biology Center, Laboratory of Cardiac Physiology, NHLBI, National Institutes of Health, Bethesda, Maryland 20892
| | - Jyotsna Mishra
- the Center for Translational Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, and
| | - Dewight Williams
- the Penn EM Resource Laboratory, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Toren Finkel
- the Center for Molecular Medicine, Laboratory of Molecular Biology, and
| | - Elizabeth Murphy
- the Systems Biology Center, Laboratory of Cardiac Physiology, NHLBI, National Institutes of Health, Bethesda, Maryland 20892
| | - Suresh K Joseph
- From the MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Shey-Shing Sheu
- the Center for Translational Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, and
| | - György Csordás
- From the MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107,
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395
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Doghman-Bouguerra M, Granatiero V, Sbiera S, Sbiera I, Lacas-Gervais S, Brau F, Fassnacht M, Rizzuto R, Lalli E. FATE1 antagonizes calcium- and drug-induced apoptosis by uncoupling ER and mitochondria. EMBO Rep 2016; 17:1264-80. [PMID: 27402544 PMCID: PMC5007562 DOI: 10.15252/embr.201541504] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 06/10/2016] [Accepted: 06/16/2016] [Indexed: 11/09/2022] Open
Abstract
Several stimuli induce programmed cell death by increasing Ca(2+) transfer from the endoplasmic reticulum (ER) to mitochondria. Perturbation of this process has a special relevance in pathologies as cancer and neurodegenerative disorders. Mitochondrial Ca(2+) uptake mainly takes place in correspondence of mitochondria-associated ER membranes (MAM), specialized contact sites between the two organelles. Here, we show the important role of FATE1, a cancer-testis antigen, in the regulation of ER-mitochondria distance and Ca(2+) uptake by mitochondria. FATE1 is localized at the interface between ER and mitochondria, fractionating into MAM FATE1 expression in adrenocortical carcinoma (ACC) cells under the control of the transcription factor SF-1 decreases ER-mitochondria contact and mitochondrial Ca(2+) uptake, while its knockdown has an opposite effect. FATE1 also decreases sensitivity to mitochondrial Ca(2+)-dependent pro-apoptotic stimuli and to the chemotherapeutic drug mitotane. In patients with ACC, FATE1 expression in their tumor is inversely correlated with their overall survival. These results show that the ER-mitochondria uncoupling activity of FATE1 is harnessed by cancer cells to escape apoptotic death and resist the action of chemotherapeutic drugs.
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Affiliation(s)
- Mabrouka Doghman-Bouguerra
- Institut de Pharmacologie Moléculaire et Cellulaire CNRS UMR 7275 Sophia Antipolis, Valbonne, France NEOGENEX CNRS International Associated Laboratory, Valbonne, France University of Nice - Sophia Antipolis, Valbonne, France
| | - Veronica Granatiero
- Department of Biomedical Sciences, University of Padova, Padova, Italy CNR Neuroscience Institute, Padova, Italy
| | - Silviu Sbiera
- Department of Internal Medicine I - Endocrine Unit, University Hospital University of Würzburg, Würzburg, Germany
| | - Iuliu Sbiera
- Department of Internal Medicine I - Endocrine Unit, University Hospital University of Würzburg, Würzburg, Germany
| | | | - Frédéric Brau
- Institut de Pharmacologie Moléculaire et Cellulaire CNRS UMR 7275 Sophia Antipolis, Valbonne, France University of Nice - Sophia Antipolis, Valbonne, France
| | - Martin Fassnacht
- Comprehensive Cancer Center Mainfranken, University of Würzburg, Würzburg, Germany
| | - Rosario Rizzuto
- Department of Biomedical Sciences, University of Padova, Padova, Italy CNR Neuroscience Institute, Padova, Italy
| | - Enzo Lalli
- Institut de Pharmacologie Moléculaire et Cellulaire CNRS UMR 7275 Sophia Antipolis, Valbonne, France NEOGENEX CNRS International Associated Laboratory, Valbonne, France University of Nice - Sophia Antipolis, Valbonne, France
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396
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Interfaces between mitochondrial dynamics and disease. Cell Calcium 2016; 60:190-8. [DOI: 10.1016/j.ceca.2016.05.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 05/16/2016] [Accepted: 05/17/2016] [Indexed: 12/17/2022]
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397
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Fang D, Yan S, Yu Q, Chen D, Yan SS. Mfn2 is Required for Mitochondrial Development and Synapse Formation in Human Induced Pluripotent Stem Cells/hiPSC Derived Cortical Neurons. Sci Rep 2016; 6:31462. [PMID: 27535796 PMCID: PMC4989148 DOI: 10.1038/srep31462] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Accepted: 07/18/2016] [Indexed: 02/07/2023] Open
Abstract
Mitochondria are essential dynamic organelles for energy production. Mitochondria dynamically change their shapes tightly coupled to fission and fusion. Imbalance of fission and fusion can cause deficits in mitochondrial respiration, morphology and motility. Mfn2 (mitofusin 2), a mitochondrial membrane protein that participates in mitochondrial fusion in mammalian cells, contributes to the maintenance and operation of the mitochondrial network. Due to lack of applicable model systems, the mechanisms and involvement of mitochondria in neurogenesis in human brain cells have not been well explored. Here, by employing the human induced pluripotent stem cells (hiPSCs) differentiation system, we fully characterized mitochondrial development, neurogenesis and synapse formation in hiPSCs-derived cortical neurons. Differentiation of hiPSCs to cortical neurons with extended period demonstrates mature neurophysiology characterization and functional synaptic network formation. Mitochondrial respiration, morphology and motility in the differentiated neurons also exhibit pronounced development during differentiation. Mfn2 knock-down results in deficits in mitochondrial metabolism and network, neurogenesis and synapse formation, while Mfn2 overexpression enhances mitochondrial bioenergetics and functions, and promotes the differentiation and maturation of neurons. Together, our data indicate that Mfn2 is essential for human mitochondrial development in neuronal maturation and differentiation, which will enhance our understanding of the role of Mfn2 in neurogenesis.
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Affiliation(s)
- Du Fang
- Department of Pharmacology and Toxicology, and Higuchi Bioscience Center, School of Pharmacology, University of Kansas, Lawrence, KS, USA
| | - Shijun Yan
- Department of Pharmacology and Toxicology, and Higuchi Bioscience Center, School of Pharmacology, University of Kansas, Lawrence, KS, USA
| | - Qing Yu
- Department of Pharmacology and Toxicology, and Higuchi Bioscience Center, School of Pharmacology, University of Kansas, Lawrence, KS, USA
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Cheng Du, China
| | - Doris Chen
- Department of Pharmacology and Toxicology, and Higuchi Bioscience Center, School of Pharmacology, University of Kansas, Lawrence, KS, USA
| | - Shirley ShiDu Yan
- Department of Pharmacology and Toxicology, and Higuchi Bioscience Center, School of Pharmacology, University of Kansas, Lawrence, KS, USA
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398
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Raturi A, Gutiérrez T, Ortiz-Sandoval C, Ruangkittisakul A, Herrera-Cruz MS, Rockley JP, Gesson K, Ourdev D, Lou PH, Lucchinetti E, Tahbaz N, Zaugg M, Baksh S, Ballanyi K, Simmen T. TMX1 determines cancer cell metabolism as a thiol-based modulator of ER-mitochondria Ca2+ flux. J Cell Biol 2016; 214:433-44. [PMID: 27502484 PMCID: PMC4987292 DOI: 10.1083/jcb.201512077] [Citation(s) in RCA: 100] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 07/15/2016] [Indexed: 12/31/2022] Open
Abstract
Cancer cells are critically dependent on ER–mitochondria Ca2+ flux that regulates their bioenergetics. Here, Raturi et al. identify the ER oxidoreductase TMX1 as a thiol-dependent regulator of this intracellular signaling mechanism within cancer cells. The flux of Ca2+ from the endoplasmic reticulum (ER) to mitochondria regulates mitochondria metabolism. Within tumor tissue, mitochondria metabolism is frequently repressed, leading to chemotherapy resistance and increased growth of the tumor mass. Therefore, altered ER–mitochondria Ca2+ flux could be a cancer hallmark, but only a few regulatory proteins of this mechanism are currently known. One candidate is the redox-sensitive oxidoreductase TMX1 that is enriched on the mitochondria-associated membrane (MAM), the site of ER–mitochondria Ca2+ flux. Our findings demonstrate that cancer cells with low TMX1 exhibit increased ER Ca2+, accelerated cytosolic Ca2+ clearance, and reduced Ca2+ transfer to mitochondria. Thus, low levels of TMX1 reduce ER–mitochondria contacts, shift bioenergetics away from mitochondria, and accelerate tumor growth. For its role in intracellular ER–mitochondria Ca2+ flux, TMX1 requires its thioredoxin motif and palmitoylation to target to the MAM. As a thiol-based tumor suppressor, TMX1 increases mitochondrial ATP production and apoptosis progression.
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Affiliation(s)
- Arun Raturi
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada
| | - Tomás Gutiérrez
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada
| | - Carolina Ortiz-Sandoval
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada
| | - Araya Ruangkittisakul
- Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada
| | - Maria Sol Herrera-Cruz
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada
| | - Jeremy P Rockley
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada
| | - Kevin Gesson
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada
| | - Dimitar Ourdev
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada
| | - Phing-How Lou
- Department of Anesthesiology and Pain Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada
| | - Eliana Lucchinetti
- Department of Anesthesiology and Pain Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada
| | - Nasser Tahbaz
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada
| | - Michael Zaugg
- Department of Anesthesiology and Pain Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada
| | - Shairaz Baksh
- Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada Department of Biochemistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada Alberta Inflammatory Bowel Disease Consortium, University of Alberta, Edmonton, Alberta T6G2H7, Canada
| | - Klaus Ballanyi
- Department of Physiology, 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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399
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Bioenergetic roles of mitochondrial fusion. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1277-1283. [DOI: 10.1016/j.bbabio.2016.04.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 03/18/2016] [Accepted: 04/05/2016] [Indexed: 11/17/2022]
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400
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Dimmer KS, Rapaport D. Mitochondrial contact sites as platforms for phospholipid exchange. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1862:69-80. [PMID: 27477677 DOI: 10.1016/j.bbalip.2016.07.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 07/21/2016] [Accepted: 07/22/2016] [Indexed: 12/15/2022]
Abstract
Mitochondria are unique organelles that contain their own - although strongly reduced - genome, and are surrounded by two membranes. While most cellular phospholipid biosynthesis takes place in the ER, mitochondria harbor the whole spectrum of glycerophospholipids common to biological membranes. Mitochondria also contribute to overall phospholipid biosynthesis in cells by producing phosphatidylethanolamine, phosphatidylglycerol, and cardiolipin. Considering these features, it is not surprising that mitochondria maintain highly active exchange of phospholipids with other cellular compartments. In this contribution we describe the transport of phospholipids between mitochondria and other organelles, and discuss recent developments in our understanding of the molecular functions of the protein complexes that mediate these processes. This article is part of a Special Issue entitled: Lipids of Mitochondria edited by Guenther Daum.
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Affiliation(s)
- Kai Stefan Dimmer
- Interfaculty Institute of Biochemistry, University of Tübingen, Hoppe-Seyler-Str. 4, 72076 Tübingen, Germany.
| | - Doron Rapaport
- Interfaculty Institute of Biochemistry, University of Tübingen, Hoppe-Seyler-Str. 4, 72076 Tübingen, Germany
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