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Gamuyao R, Chang CL. Imaging and proteomics toolkits for studying organelle contact sites. Front Cell Dev Biol 2024; 12:1466915. [PMID: 39381373 PMCID: PMC11458464 DOI: 10.3389/fcell.2024.1466915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2024] [Accepted: 09/05/2024] [Indexed: 10/10/2024] Open
Abstract
Organelle contact sites are regions where two heterologous membranes are juxtaposed by molecular tethering complexes. These contact sites are important in inter-organelle communication and cellular functional integration. However, visualizing these minute foci and identifying contact site proteomes have been challenging. In recent years, fluorescence-based methods have been developed to visualize the dynamic physical interaction of organelles while proximity labeling approaches facilitate the profiling of proteomes at contact sites. In this review, we explain the design principle for these contact site reporters: a dual-organelle interaction mechanism based on how endogenous tethers and/or tethering complexes localize to contact sites. We classify the contact site reporters into three categories: (i) single-protein systems, (ii) two-component systems with activated reporter signal upon organelle proximity, and (iii) reporters for contact site proteomes. We also highlight advanced imaging analysis with high temporal-spatial resolution and the use of machine-learning algorithms for detecting contact sites.
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Affiliation(s)
| | - Chi-Lun Chang
- Department of Cell and Molecular Biology, St. Jude Children’s Research Hospital, Memphis, TN, United States
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2
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Saukko-Paavola AJ, Klemm RW. Remodelling of mitochondrial function by import of specific lipids at multiple membrane-contact sites. FEBS Lett 2024; 598:1274-1291. [PMID: 38311340 DOI: 10.1002/1873-3468.14813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 12/14/2023] [Accepted: 12/28/2023] [Indexed: 02/08/2024]
Abstract
Organelles form physical and functional contact between each other to exchange information, metabolic intermediates, and signaling molecules. Tethering factors and contact site complexes bring partnering organelles into close spatial proximity to establish membrane contact sites (MCSs), which specialize in unique functions like lipid transport or Ca2+ signaling. Here, we discuss how MCSs form dynamic platforms that are important for lipid metabolism. We provide a perspective on how import of specific lipids from the ER and other organelles may contribute to remodeling of mitochondria during nutrient starvation. We speculate that mitochondrial adaptation is achieved by connecting several compartments into a highly dynamic organelle network. The lipid droplet appears to be a central hub in coordinating the function of these organelle neighborhoods.
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Affiliation(s)
| | - Robin W Klemm
- Department of Physiology, Anatomy and Genetics, University of Oxford, UK
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3
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Skalka GL, Tsakovska M, Murphy DJ. Kinase signalling adaptation supports dysfunctional mitochondria in disease. Front Mol Biosci 2024; 11:1354682. [PMID: 38434478 PMCID: PMC10906720 DOI: 10.3389/fmolb.2024.1354682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 01/15/2024] [Indexed: 03/05/2024] Open
Abstract
Mitochondria form a critical control nexus which are essential for maintaining correct tissue homeostasis. An increasing number of studies have identified dysregulation of mitochondria as a driver in cancer. However, which pathways support and promote this adapted mitochondrial function? A key hallmark of cancer is perturbation of kinase signalling pathways. These pathways include mitogen activated protein kinases (MAPK), lipid secondary messenger networks, cyclic-AMP-activated (cAMP)/AMP-activated kinases (AMPK), and Ca2+/calmodulin-dependent protein kinase (CaMK) networks. These signalling pathways have multiple substrates which support initiation and persistence of cancer. Many of these are involved in the regulation of mitochondrial morphology, mitochondrial apoptosis, mitochondrial calcium homeostasis, mitochondrial associated membranes (MAMs), and retrograde ROS signalling. This review will aim to both explore how kinase signalling integrates with these critical mitochondrial pathways and highlight how these systems can be usurped to support the development of disease. In addition, we will identify areas which require further investigation to fully understand the complexities of these regulatory interactions. Overall, this review will emphasize how studying the interaction between kinase signalling and mitochondria improves our understanding of mitochondrial homeostasis and can yield novel therapeutic targets to treat disease.
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Affiliation(s)
- George L. Skalka
- School of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Mina Tsakovska
- School of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Daniel J. Murphy
- School of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom
- CRUK Scotland Institute, Glasgow, United Kingdom
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4
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Voeltz GK, Sawyer EM, Hajnóczky G, Prinz WA. Making the connection: How membrane contact sites have changed our view of organelle biology. Cell 2024; 187:257-270. [PMID: 38242082 DOI: 10.1016/j.cell.2023.11.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 11/13/2023] [Accepted: 11/29/2023] [Indexed: 01/21/2024]
Abstract
The view of organelles and how they operate together has changed dramatically over the last two decades. The textbook view of organelles was that they operated largely independently and were connected by vesicular trafficking and the diffusion of signals through the cytoplasm. We now know that all organelles make functional close contacts with one another, often called membrane contact sites. The study of these sites has moved to center stage in cell biology as it has become clear that they play critical roles in healthy and developing cells and during cell stress and disease states. Contact sites have important roles in intracellular signaling, lipid metabolism, motor-protein-mediated membrane dynamics, organelle division, and organelle biogenesis. Here, we summarize the major conceptual changes that have occurred in cell biology as we have come to appreciate how contact sites integrate the activities of organelles.
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Affiliation(s)
- G K Voeltz
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Boulder, CO 80309, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA.
| | - E M Sawyer
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Boulder, CO 80309, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - G Hajnóczky
- MitoCare Center, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - W A Prinz
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA.
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5
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Makio T, Simmen T. Not So Rare: Diseases Based on Mutant Proteins Controlling Endoplasmic Reticulum-Mitochondria Contact (MERC) Tethering. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2024; 7:25152564241261228. [PMID: 39070058 PMCID: PMC11273598 DOI: 10.1177/25152564241261228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 04/12/2024] [Accepted: 05/27/2024] [Indexed: 07/30/2024]
Abstract
Mitochondria-endoplasmic reticulum contacts (MERCs), also called endoplasmic reticulum (ER)-mitochondria contact sites (ERMCS), are the membrane domains, where these two organelles exchange lipids, Ca2+ ions, and reactive oxygen species. This crosstalk is a major determinant of cell metabolism, since it allows the ER to control mitochondrial oxidative phosphorylation and the Krebs cycle, while conversely, it allows the mitochondria to provide sufficient ATP to control ER proteostasis. MERC metabolic signaling is under the control of tethers and a multitude of regulatory proteins. Many of these proteins have recently been discovered to give rise to rare diseases if their genes are mutated. Surprisingly, these diseases share important hallmarks and cause neurological defects, sometimes paired with, or replaced by skeletal muscle deficiency. Typical symptoms include developmental delay, intellectual disability, facial dysmorphism and ophthalmologic defects. Seizures, epilepsy, deafness, ataxia, or peripheral neuropathy can also occur upon mutation of a MERC protein. Given that most MERC tethers and regulatory proteins have secondary functions, some MERC protein-based diseases do not fit into this categorization. Typically, however, the proteins affected in those diseases have dominant functions unrelated to their roles in MERCs tethering or their regulation. We are discussing avenues to pharmacologically target genetic diseases leading to MERC defects, based on our novel insight that MERC defects lead to common characteristics in rare diseases. These shared characteristics of MERCs disorders raise the hope that they may allow for similar treatment options.
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Affiliation(s)
- Tadashi Makio
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Thomas Simmen
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
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6
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Cardoen B, Vandevoorde KR, Gao G, Ortiz-Silva M, Alan P, Liu W, Tiliakou E, Vogl AW, Hamarneh G, Nabi IR. Membrane contact site detection (MCS-DETECT) reveals dual control of rough mitochondria-ER contacts. J Cell Biol 2024; 223:e202206109. [PMID: 37948126 PMCID: PMC10638097 DOI: 10.1083/jcb.202206109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 09/20/2022] [Accepted: 10/23/2023] [Indexed: 11/12/2023] Open
Abstract
Identification and morphological analysis of mitochondria-ER contacts (MERCs) by fluorescent microscopy is limited by subpixel resolution interorganelle distances. Here, the membrane contact site (MCS) detection algorithm, MCS-DETECT, reconstructs subpixel resolution MERCs from 3D super-resolution image volumes. MCS-DETECT shows that elongated ribosome-studded riboMERCs, present in HT-1080 but not COS-7 cells, are morphologically distinct from smaller smooth contacts and larger contacts induced by mitochondria-ER linker expression in COS-7 cells. RiboMERC formation is associated with increased mitochondrial potential, reduced in Gp78 knockout HT-1080 cells and induced by Gp78 ubiquitin ligase activity in COS-7 and HeLa cells. Knockdown of riboMERC tether RRBP1 eliminates riboMERCs in both wild-type and Gp78 knockout HT-1080 cells. By MCS-DETECT, Gp78-dependent riboMERCs present complex tubular shapes that intercalate between and contact multiple mitochondria. MCS-DETECT of 3D whole-cell super-resolution image volumes, therefore, identifies novel dual control of tubular riboMERCs, whose formation is dependent on RRBP1 and size modulated by Gp78 E3 ubiquitin ligase activity.
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Affiliation(s)
- Ben Cardoen
- School of Computing Science, Simon Fraser University, Burnaby, Canada
| | - Kurt R. Vandevoorde
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, Canada
| | - Guang Gao
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, Canada
| | - Milene Ortiz-Silva
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, Canada
| | - Parsa Alan
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, Canada
| | - William Liu
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, Canada
| | - Ellie Tiliakou
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, Canada
| | - A. Wayne Vogl
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, Canada
| | - Ghassan Hamarneh
- School of Computing Science, Simon Fraser University, Burnaby, Canada
| | - Ivan R. Nabi
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, Canada
- School of Biomedical Engineering, University of British Columbia, Vancouver, Canada
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7
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Yepuri G, Ramirez LM, Theophall GG, Reverdatto SV, Quadri N, Hasan SN, Bu L, Thiagarajan D, Wilson R, Díez RL, Gugger PF, Mangar K, Narula N, Katz SD, Zhou B, Li H, Stotland AB, Gottlieb RA, Schmidt AM, Shekhtman A, Ramasamy R. DIAPH1-MFN2 interaction regulates mitochondria-SR/ER contact and modulates ischemic/hypoxic stress. Nat Commun 2023; 14:6900. [PMID: 37903764 PMCID: PMC10616211 DOI: 10.1038/s41467-023-42521-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 10/13/2023] [Indexed: 11/01/2023] Open
Abstract
Inter-organelle contact and communication between mitochondria and sarco/endoplasmic reticulum (SR/ER) maintain cellular homeostasis and are profoundly disturbed during tissue ischemia. We tested the hypothesis that the formin Diaphanous-1 (DIAPH1), which regulates actin dynamics, signal transduction and metabolic functions, contributes to these processes. We demonstrate that DIAPH1 interacts directly with Mitofusin-2 (MFN2) to shorten mitochondria-SR/ER distance, thereby enhancing mitochondria-ER contact in cells including cardiomyocytes, endothelial cells and macrophages. Solution structure studies affirm the interaction between the Diaphanous Inhibitory Domain and the cytosolic GTPase domain of MFN2. In male rodent and human cardiomyocytes, DIAPH1-MFN2 interaction regulates mitochondrial turnover, mitophagy, and oxidative stress. Introduction of synthetic linker construct, which shorten the mitochondria-SR/ER distance, mitigated the molecular and functional benefits of DIAPH1 silencing in ischemia. This work establishes fundamental roles for DIAPH1-MFN2 interaction in the regulation of mitochondria-SR/ER contact networks. We propose that targeting pathways that regulate DIAPH1-MFN2 interactions may facilitate recovery from tissue ischemia.
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Affiliation(s)
- Gautham Yepuri
- Diabetes Research Program, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, NYU Grossman School of Medicine, New York, New York, 10016, USA
| | - Lisa M Ramirez
- Department of Chemistry, University of Albany, State University of New York, Albany, NY, 12222, USA
| | - Gregory G Theophall
- Department of Chemistry, University of Albany, State University of New York, Albany, NY, 12222, USA
| | - Sergei V Reverdatto
- Department of Chemistry, University of Albany, State University of New York, Albany, NY, 12222, USA
| | - Nosirudeen Quadri
- Diabetes Research Program, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, NYU Grossman School of Medicine, New York, New York, 10016, USA
| | - Syed Nurul Hasan
- Diabetes Research Program, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, NYU Grossman School of Medicine, New York, New York, 10016, USA
| | - Lei Bu
- Department of Medicine, Leon H. Charney Division of Cardiology, NYU Grossman School of Medicine, New York, NY, 10016, USA
| | - Devi Thiagarajan
- Diabetes Research Program, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, NYU Grossman School of Medicine, New York, New York, 10016, USA
| | - Robin Wilson
- Diabetes Research Program, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, NYU Grossman School of Medicine, New York, New York, 10016, USA
| | - Raquel López Díez
- Diabetes Research Program, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, NYU Grossman School of Medicine, New York, New York, 10016, USA
| | - Paul F Gugger
- Diabetes Research Program, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, NYU Grossman School of Medicine, New York, New York, 10016, USA
| | - Kaamashri Mangar
- Diabetes Research Program, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, NYU Grossman School of Medicine, New York, New York, 10016, USA
| | - Navneet Narula
- Department of Pathology, NYU Grossman School of Medicine, New York, NY, 10016, USA
| | - Stuart D Katz
- Department of Medicine, Leon H. Charney Division of Cardiology, NYU Grossman School of Medicine, New York, NY, 10016, USA
| | - Boyan Zhou
- Department of Population Health, NYU Grossman School of Medicine, New York, NY, 10016, USA
| | - Huilin Li
- Department of Population Health, NYU Grossman School of Medicine, New York, NY, 10016, USA
| | - Aleksandr B Stotland
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, 90048, USA
| | - Roberta A Gottlieb
- Department of Biomedical Sciences, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, 90048, USA
| | - Ann Marie Schmidt
- Diabetes Research Program, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, NYU Grossman School of Medicine, New York, New York, 10016, USA
| | - Alexander Shekhtman
- Department of Chemistry, University of Albany, State University of New York, Albany, NY, 12222, USA
| | - Ravichandran Ramasamy
- Diabetes Research Program, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, NYU Grossman School of Medicine, New York, New York, 10016, USA.
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8
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Wozny MR, Di Luca A, Morado DR, Picco A, Khaddaj R, Campomanes P, Ivanović L, Hoffmann PC, Miller EA, Vanni S, Kukulski W. In situ architecture of the ER-mitochondria encounter structure. Nature 2023:10.1038/s41586-023-06050-3. [PMID: 37165187 DOI: 10.1038/s41586-023-06050-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Accepted: 04/04/2023] [Indexed: 05/12/2023]
Abstract
The endoplasmic reticulum and mitochondria are main hubs of eukaryotic membrane biogenesis that rely on lipid exchange via membrane contact sites1-3, but the underpinning mechanisms remain poorly understood. In yeast, tethering and lipid transfer between the two organelles is mediated by the endoplasmic reticulum-mitochondria encounter structure (ERMES), a four-subunit complex of unresolved stoichiometry and architecture4-6. Here we determined the molecular organization of ERMES within Saccharomyces cerevisiae cells using integrative structural biology by combining quantitative live imaging, cryo-correlative microscopy, subtomogram averaging and molecular modelling. We found that ERMES assembles into approximately 25 discrete bridge-like complexes distributed irregularly across a contact site. Each bridge consists of three synaptotagmin-like mitochondrial lipid binding protein domains oriented in a zig-zag arrangement. Our molecular model of ERMES reveals a pathway for lipids. These findings resolve the in situ supramolecular architecture of a major inter-organelle lipid transfer machinery and provide a basis for the mechanistic understanding of lipid fluxes in eukaryotic cells.
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Affiliation(s)
- Michael R Wozny
- MRC Laboratory of Molecular Biology, Cambridge, UK
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
| | - Andrea Di Luca
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Dustin R Morado
- MRC Laboratory of Molecular Biology, Cambridge, UK
- SciLifeLab, Solna, Sweden
- Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Andrea Picco
- Department of Biochemistry, University of Geneva, Geneva, Switzerland
| | - Rasha Khaddaj
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
| | - Pablo Campomanes
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Lazar Ivanović
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Patrick C Hoffmann
- MRC Laboratory of Molecular Biology, Cambridge, UK
- Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | | | - Stefano Vanni
- Department of Biology, University of Fribourg, Fribourg, Switzerland.
| | - Wanda Kukulski
- MRC Laboratory of Molecular Biology, Cambridge, UK.
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland.
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9
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Sassano ML, van Vliet AR, Vervoort E, Van Eygen S, Van den Haute C, Pavie B, Roels J, Swinnen JV, Spinazzi M, Moens L, Casteels K, Meyts I, Pinton P, Marchi S, Rochin L, Giordano F, Felipe-Abrio B, Agostinis P. PERK recruits E-Syt1 at ER-mitochondria contacts for mitochondrial lipid transport and respiration. J Cell Biol 2023; 222:e202206008. [PMID: 36821088 PMCID: PMC9998969 DOI: 10.1083/jcb.202206008] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 12/07/2022] [Accepted: 01/19/2023] [Indexed: 02/24/2023] Open
Abstract
The integrity of ER-mitochondria appositions ensures transfer of ions and phospholipids (PLs) between these organelles and exerts crucial effects on mitochondrial bioenergetics. Malfunctions within the ER-mitochondria contacts altering lipid trafficking homeostasis manifest in diverse pathologies, but the molecular effectors governing this process remain ill-defined. Here, we report that PERK promotes lipid trafficking at the ER-mitochondria contact sites (EMCS) through a non-conventional, unfolded protein response-independent, mechanism. PERK operates as an adaptor for the recruitment of the ER-plasma membrane tether and lipid transfer protein (LTP) Extended-Synaptotagmin 1 (E-Syt1), within the EMCS. In resting cells, the heterotypic E-Syt1-PERK interaction endorses transfer of PLs between the ER and mitochondria. Weakening the E-Syt1-PERK interaction or removing the lipid transfer SMP-domain of E-Syt1, compromises mitochondrial respiration. Our findings unravel E-Syt1 as a PERK interacting LTP and molecular component of the lipid trafficking machinery of the EMCS, which critically maintains mitochondrial homeostasis and fitness.
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Affiliation(s)
- Maria Livia Sassano
- Cell Death Research and Therapy Group, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
- VIB Center for Cancer Biology, Leuven, Belgium
| | - Alexander R. van Vliet
- Cell Death Research and Therapy Group, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Ellen Vervoort
- Cell Death Research and Therapy Group, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
- VIB Center for Cancer Biology, Leuven, Belgium
| | - Sofie Van Eygen
- Cell Death Research and Therapy Group, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
- VIB Center for Cancer Biology, Leuven, Belgium
| | - Chris Van den Haute
- Research Group for Neurobiology and Gene Therapy, Department of Neuroscience, Leuven Viral Vector Core, KU Leuven, Leuven, Belgium
| | | | - Joris Roels
- VIB-bioimaging Center UGent, Ghent, Belgium
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Johannes V. Swinnen
- Laboratory of Lipid Metabolism and Cancer, Department of Oncology, KU Leuven, Leuven, Belgium
| | - Marco Spinazzi
- Neuromuscular Reference Center, CHU Angers, Angers, France
| | - Leen Moens
- Laboratory for Inborn Errors of Immunity, Department of Microbiology, Immunology and Transplantation, KU Leuven, Department of Pediatrics, University Hospitals Leuven, Leuven, Belgium
| | - Kristina Casteels
- Woman and Child, Department for Development and Regeneration, KU Leuven, Department of Pediatrics, University Hospitals Leuven, Leuven, Belgium
| | - Isabelle Meyts
- Laboratory for Inborn Errors of Immunity, Department of Microbiology, Immunology and Transplantation, KU Leuven, Department of Pediatrics, University Hospitals Leuven, Leuven, Belgium
| | - Paolo Pinton
- Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | - Saverio Marchi
- Department of Clinical and Molecular Sciences, Marche Polytechnic University, Ancona, Italy
| | | | | | - Blanca Felipe-Abrio
- Cell Death Research and Therapy Group, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
- VIB Center for Cancer Biology, Leuven, Belgium
| | - Patrizia Agostinis
- Cell Death Research and Therapy Group, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
- VIB Center for Cancer Biology, Leuven, Belgium
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10
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Renne MF, Bao X, Hokken MWJ, Bierhuizen AS, Hermansson M, Sprenger RR, Ewing TA, Ma X, Cox RC, Brouwers JF, De Smet CH, Ejsing CS, de Kroon AIPM. Molecular species selectivity of lipid transport creates a mitochondrial sink for di-unsaturated phospholipids. EMBO J 2022; 41:e106837. [PMID: 34873731 PMCID: PMC8762554 DOI: 10.15252/embj.2020106837] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 10/22/2021] [Accepted: 10/26/2021] [Indexed: 11/09/2022] Open
Abstract
Mitochondria depend on the import of phospholipid precursors for the biosynthesis of phosphatidylethanolamine (PE) and cardiolipin, yet the mechanism of their transport remains elusive. A dynamic lipidomics approach revealed that mitochondria preferentially import di-unsaturated phosphatidylserine (PS) for subsequent conversion to PE by the mitochondrial PS decarboxylase Psd1p. Several protein complexes tethering mitochondria to the endomembrane system have been implicated in lipid transport in yeast, including the endoplasmic reticulum (ER)-mitochondrial encounter structure (ERMES), ER-membrane complex (EMC), and the vacuole and mitochondria patch (vCLAMP). By limiting the availability of unsaturated phospholipids, we created conditions to investigate the mechanism of lipid transfer and the contributions of the tethering complexes in vivo. Under these conditions, inactivation of ERMES components or of the vCLAMP component Vps39p exacerbated accumulation of saturated lipid acyl chains, indicating that ERMES and Vps39p contribute to the mitochondrial sink for unsaturated acyl chains by mediating transfer of di-unsaturated phospholipids. These results support the concept that intermembrane lipid flow is rate-limited by molecular species-dependent lipid efflux from the donor membrane and driven by the lipid species' concentration gradient between donor and acceptor membrane.
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Affiliation(s)
- Mike F Renne
- Membrane Biochemistry & BiophysicsDepartment of ChemistryUtrecht UniversityUtrechtThe Netherlands
- Present address:
Sir William Dunn School of PathologyUniversity of OxfordOxfordUK
| | - Xue Bao
- Membrane Biochemistry & BiophysicsDepartment of ChemistryUtrecht UniversityUtrechtThe Netherlands
| | - Margriet WJ Hokken
- Membrane Biochemistry & BiophysicsDepartment of ChemistryUtrecht UniversityUtrechtThe Netherlands
- Present address:
Department of Medical MicrobiologyRadboud University Medical CenterRadboud Institute for Molecular Life SciencesNijmegenThe Netherlands
| | - Adolf S Bierhuizen
- Membrane Biochemistry & BiophysicsDepartment of ChemistryUtrecht UniversityUtrechtThe Netherlands
| | - Martin Hermansson
- Department of Biochemistry and Molecular BiologyVILLUM Center for Bioanalytical SciencesUniversity of Southern DenmarkOdenseDenmark
| | - Richard R Sprenger
- Department of Biochemistry and Molecular BiologyVILLUM Center for Bioanalytical SciencesUniversity of Southern DenmarkOdenseDenmark
| | - Tom A Ewing
- Membrane Biochemistry & BiophysicsDepartment of ChemistryUtrecht UniversityUtrechtThe Netherlands
- Present address:
Wageningen Food & Biobased ResearchWageningen University & ResearchWageningenThe Netherlands
| | - Xiao Ma
- Membrane Biochemistry & BiophysicsDepartment of ChemistryUtrecht UniversityUtrechtThe Netherlands
| | - Ruud C Cox
- Membrane Biochemistry & BiophysicsDepartment of ChemistryUtrecht UniversityUtrechtThe Netherlands
| | - Jos F Brouwers
- Biochemistry and Cell BiologyDepartment of Veterinary MedicineUtrecht UniversityUtrechtThe Netherlands
- Present address:
Center for Molecular MedicineUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Cedric H De Smet
- Membrane Biochemistry & BiophysicsDepartment of ChemistryUtrecht UniversityUtrechtThe Netherlands
| | - Christer S Ejsing
- Department of Biochemistry and Molecular BiologyVILLUM Center for Bioanalytical SciencesUniversity of Southern DenmarkOdenseDenmark
- Cell Biology and Biophysics UnitEuropean Molecular Biology LaboratoryHeidelbergGermany
| | - Anton IPM de Kroon
- Membrane Biochemistry & BiophysicsDepartment of ChemistryUtrecht UniversityUtrechtThe Netherlands
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11
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Means RE, Katz SG. Balancing life and death: BCL-2 family members at diverse ER-mitochondrial contact sites. FEBS J 2022; 289:7075-7112. [PMID: 34668625 DOI: 10.1111/febs.16241] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 10/11/2021] [Accepted: 10/19/2021] [Indexed: 01/13/2023]
Abstract
The outer mitochondrial membrane is a busy place. One essential activity for cellular survival is the regulation of membrane integrity by the BCL-2 family of proteins. Another critical facet of the outer mitochondrial membrane is its close approximation with the endoplasmic reticulum. These mitochondrial-associated membranes (MAMs) occupy a significant fraction of the mitochondrial surface and serve as key signaling hubs for multiple cellular processes. Each of these pathways may be considered as forming their own specialized MAM subtype. Interestingly, like membrane permeabilization, most of these pathways play critical roles in regulating cellular survival and death. Recently, the pro-apoptotic BCL-2 family member BOK has been found within MAMs where it plays important roles in their structure and function. This has led to a greater appreciation that multiple BCL-2 family proteins, which are known to participate in numerous functions throughout the cell, also have roles within MAMs. In this review, we evaluate several MAM subsets, their role in cellular homeostasis, and the contribution of BCL-2 family members to their functions.
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Affiliation(s)
- Robert E Means
- Department of Pathology, Yale University School of Medicine, New Haven, CT, USA
| | - Samuel G Katz
- Department of Pathology, Yale University School of Medicine, New Haven, CT, USA
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12
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Dentoni G, Naia L, Portal B, Leal NS, Nilsson P, Lindskog M, Ankarcrona M. Mitochondrial Alterations in Neurons Derived from the Murine AppNL-F Knock-In Model of Alzheimer’s Disease. J Alzheimers Dis 2022; 90:565-583. [DOI: 10.3233/jad-220383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Background: Alzheimer’s disease (AD) research has relied on mouse models overexpressing human mutant A βPP; however, newer generation knock-in models allow for physiological expression of amyloid-β protein precursor (AβPP) containing familial AD mutations where murine AβPP is edited with a humanized amyloid-β (Aβ) sequence. The AppNL-F mouse model has shown substantial similarities to AD brains developing late onset cognitive impairment. Objective: In this study, we aimed to characterize mature primary cortical neurons derived from homozygous AppNL-F embryos, especially to identify early mitochondrial alterations in this model. Methods: Primary cultures of AppNL-F neurons kept in culture for 12–15 days were used to measure Aβ levels, secretase activity, mitochondrial functions, mitochondrial-ER contacts, synaptic function, and cell death. Results: We detected higher levels of Aβ42 released from AppNL-F neurons as compared to wild-type neurons. AppNL-F neurons, also displayed an increased Aβ42/Aβ40 ratio, similar to adult AppNL-F mouse brain. Interestingly, we found an upregulation in mitochondrial oxygen consumption with concomitant downregulation in glycolytic reserve. Furthermore, AppNL-F neurons were more susceptible to cell death triggered by mitochondrial electron transport chain inhibition. Juxtaposition between ER and mitochondria was found to be substantially upregulated, which may account for upregulated mitochondrial-derived ATP production. However, anterograde mitochondrial movement was severely impaired in this model along with loss in synaptic vesicle protein and impairment in pre- and post-synaptic function. Conclusion: We show that widespread mitochondrial alterations can be detected in AppNL-F neurons in vitro, where amyloid plaque deposition does not occur, suggesting soluble and oligomeric Aβ-species being responsible for these alterations.
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Affiliation(s)
- Giacomo Dentoni
- Department of Neurobiology, Karolinska Institutet, Care Science and Society, Division of Neurogeriatrics, Stockholm, Sweden
| | - Luana Naia
- Department of Neurobiology, Karolinska Institutet, Care Science and Society, Division of Neurogeriatrics, Stockholm, Sweden
| | - Benjamin Portal
- Department of Neuroscience, Uppsala University, Uppsala, Sweden
| | - Nuno Santos Leal
- Department of Neurobiology, Karolinska Institutet, Care Science and Society, Division of Neurogeriatrics, Stockholm, Sweden
| | - Per Nilsson
- Department of Neurobiology, Karolinska Institutet, Care Science and Society, Division of Neurogeriatrics, Stockholm, Sweden
| | - Maria Lindskog
- Department of Neuroscience, Uppsala University, Uppsala, Sweden
| | - Maria Ankarcrona
- Department of Neurobiology, Karolinska Institutet, Care Science and Society, Division of Neurogeriatrics, Stockholm, Sweden
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13
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Dentoni G, Castro-Aldrete L, Naia L, Ankarcrona M. The Potential of Small Molecules to Modulate the Mitochondria-Endoplasmic Reticulum Interplay in Alzheimer's Disease. Front Cell Dev Biol 2022; 10:920228. [PMID: 36092728 PMCID: PMC9459385 DOI: 10.3389/fcell.2022.920228] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 06/08/2022] [Indexed: 11/13/2022] Open
Abstract
Alzheimer's disease (AD) is the most common neurodegenerative disease affecting a growing number of elderly individuals. No disease-modifying drugs have yet been identified despite over 30 years of research on the topic, showing the need for further research on this multifactorial disease. In addition to the accumulation of amyloid β-peptide (Aβ) and hyperphosphorylated tau (p-tau), several other alterations have been associated with AD such as calcium (Ca2+) signaling, glucose-, fatty acid-, cholesterol-, and phospholipid metabolism, inflammation, and mitochondrial dysfunction. Interestingly, all these processes have been associated with the mitochondria-endoplasmic reticulum (ER) contact site (MERCS) signaling hub. We and others have hypothesized that the dysregulated MERCS function may be one of the main pathogenic pathways driving AD pathology. Due to the variety of biological processes overseen at the MERCS, we believe that they constitute unique therapeutic targets to boost the neuronal function and recover neuronal homeostasis. Thus, developing molecules with the capacity to correct and/or modulate the MERCS interplay can unleash unique therapeutic opportunities for AD. The potential pharmacological intervention using MERCS modulators in different models of AD is currently under investigation. Here, we survey small molecules with the potential to modulate MERCS structures and functions and restore neuronal homeostasis in AD. We will focus on recently reported examples and provide an overview of the current challenges and future perspectives to develop MERCS modulators in the context of translational research.
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Affiliation(s)
| | | | | | - Maria Ankarcrona
- Division of Neurogeriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Science and Society (NVS), Karolinska Institutet, Stockholm, Sweden
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14
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Carreras-Sureda A, Kroemer G, Cardenas JC, Hetz C. Balancing energy and protein homeostasis at ER-mitochondria contact sites. Sci Signal 2022; 15:eabm7524. [DOI: 10.1126/scisignal.abm7524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The endoplasmic reticulum (ER) is the largest organelle of the cell and participates in multiple essential functions, including the production of secretory proteins, lipid synthesis, and calcium storage. Sustaining proteostasis requires an intimate coupling with energy production. Mitochondrial respiration evolved to be functionally connected to ER physiology through a physical interface between both organelles known as mitochondria-associated membranes. This quasi-synaptic structure acts as a signaling hub that tunes the function of both organelles in a bidirectional manner and controls proteostasis, cell death pathways, and mitochondrial bioenergetics. Here, we discuss the main signaling mechanisms governing interorganellar communication and their putative role in diseases including cancer and neurodegeneration.
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Affiliation(s)
- Amado Carreras-Sureda
- Department of Cell Physiology and Metabolism, University of Geneva, 1, rue Michel-Servet, 1211 Geneva, Switzerland
| | - Guido Kroemer
- Centre de Recherche des Cordeliers, Equipe labellisée par la Ligue contre le cancer, Université de Paris, Sorbonne Université, Inserm U1138, Institut Universitaire de France, 75006 Paris, France
- Metabolomics and Cell Biology Platforms, Institut Gustave Roussy, 94805 Villejuif, France
- Department of Biology, Institut du Cancer Paris CARPEM, Hôpital Européen Georges Pompidou, AP-HP, 75015 Paris, France
| | - Julio Cesar Cardenas
- Center for Integrative Biology, Mayor University, 7510041 Santiago, Chile
- Center for Geroscience, Brain Health, and Metabolism, 70086 Santiago, Chile
- Buck Institute for Research on Aging, Novato, CA 94945, USA
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Claudio Hetz
- Center for Geroscience, Brain Health, and Metabolism, 70086 Santiago, Chile
- Buck Institute for Research on Aging, Novato, CA 94945, USA
- Faculty of Medicine, Biomedical Neuroscience Institute, University of Chile, 70086 Santiago, Chile
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, University of Chile, 70086 Santiago, Chile
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15
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Degechisa ST, Dabi YT, Gizaw ST. The mitochondrial associated endoplasmic reticulum membranes: A platform for the pathogenesis of inflammation-mediated metabolic diseases. Immun Inflamm Dis 2022; 10:e647. [PMID: 35759226 PMCID: PMC9168553 DOI: 10.1002/iid3.647] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 05/13/2022] [Accepted: 05/16/2022] [Indexed: 01/03/2023] Open
Abstract
Mitochondria-associated endoplasmic reticulum membranes (MAM) are specialized subcellular compartments that are shaped by endoplasmic reticulum (ER) subdomains placed side by side to the outer membrane of mitochondria (OMM) being connected by tethering proteins in mammalian cells. Studies showed that MAM has multiple physiological functions. These include regulation of lipid synthesis and transport, Ca2+ transport and signaling, mitochondrial dynamics, apoptosis, autophagy, and formation and activation of an inflammasome. However, alterations of MAM integrity lead to deleterious effects due to an increased generation of mitochondrial reactive oxygen species (ROS) via increased Ca2+ transfer from the ER to mitochondria. This, in turn, causes mitochondrial damage and release of mitochondrial components into the cytosol as damage-associated molecular patterns which rapidly activate MAM-resident Nod-like receptor protein-3 (NLRP3) inflammasome components. This complex induces the release of pro-inflammatory cytokines that initiate low-grade chronic inflammation that subsequently causes the development of metabolic diseases. But, the mechanisms of how MAM is involved in the pathogenesis of these diseases are not exhaustively reviewed. Therefore, this review was aimed to highlight the contribution of MAM to a variety of cellular functions and consider its significance pertaining to the pathogenesis of inflammation-mediated metabolic diseases.
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Affiliation(s)
- Sisay T. Degechisa
- Department of Medical Biochemistry, School of MedicineCollege of Health Sciences, Addis Ababa UniversityAddis AbabaEthiopia
- Department of Medical Laboratory SciencesCollege of Medicine and Health Sciences, Arba Minch UniversityArba MinchEthiopia
| | - Yosef T. Dabi
- Department of Medical Biochemistry, School of MedicineCollege of Health Sciences, Addis Ababa UniversityAddis AbabaEthiopia
- Department of Medical Laboratory ScienceWollega UniversityNekemteEthiopia
| | - Solomon T. Gizaw
- Department of Medical Biochemistry, School of MedicineCollege of Health Sciences, Addis Ababa UniversityAddis AbabaEthiopia
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16
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Jain A, Zoncu R. Organelle transporters and inter-organelle communication as drivers of metabolic regulation and cellular homeostasis. Mol Metab 2022; 60:101481. [PMID: 35342037 PMCID: PMC9043965 DOI: 10.1016/j.molmet.2022.101481] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 03/14/2022] [Accepted: 03/21/2022] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Spatial compartmentalization of metabolic pathways within membrane-separated organelles is key to the ability of eukaryotic cells to precisely regulate their biochemical functions. Membrane-bound organelles such as mitochondria, endoplasmic reticulum (ER) and lysosomes enable the concentration of metabolic precursors within optimized chemical environments, greatly accelerating the efficiency of both anabolic and catabolic reactions, enabling division of labor and optimal utilization of resources. However, metabolic compartmentalization also poses a challenge to cells because it creates spatial discontinuities that must be bridged for reaction cascades to be connected and completed. To do so, cells employ different methods to coordinate metabolic fluxes occurring in different organelles, such as membrane-localized transporters to facilitate regulated metabolite exchange between mitochondria and lysosomes, non-vesicular transport pathways via physical contact sites connecting the ER with both mitochondria and lysosomes, as well as localized regulatory signaling processes that coordinately regulate the activity of all these organelles. SCOPE OF REVIEW This review covers how cells use membrane transporters, membrane contact sites, and localized signaling pathways to mediate inter-organelle communication and coordinate metabolism. We also describe how disruption of inter-organelle communication is an emerging driver in a multitude of diseases, from cancer to neurodegeneration. MAJOR CONCLUSIONS Effective communication among organelles is essential to cellular health and function. Identifying the major molecular players involved in mediating metabolic coordination between organelles will further our understanding of cellular metabolism in health and lead us to design better therapeutics against dysregulated metabolism in disease.
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Affiliation(s)
- Aakriti Jain
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Roberto Zoncu
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
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17
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Mitochondria-Endoplasmic Reticulum Interplay Regulates Exo-Cytosis in Human Neuroblastoma Cells. Cells 2022; 11:cells11030514. [PMID: 35159324 PMCID: PMC8834387 DOI: 10.3390/cells11030514] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 01/23/2022] [Accepted: 01/27/2022] [Indexed: 02/04/2023] Open
Abstract
Mitochondria–endoplasmic reticulum (ER) contact sites (MERCS) have been emerging as a multifaceted subcellular region of the cell which affects several physiological and pathological mechanisms. A thus far underexplored aspect of MERCS is their contribution to exocytosis. Here, we set out to understand the role of these contacts in exocytosis and find potential mechanisms linking these structures to vesicle release in human neuroblastoma SH-SY5Y cells. We show that increased mitochondria to ER juxtaposition through Mitofusin 2 (Mfn2) knock-down resulted in a substantial upregulation of the number of MERCS, confirming the role of Mfn2 as a negative regulator of these structures. Furthermore, we report that both vesicle numbers and vesicle protein levels were decreased, while a considerable upregulation in exocytotic events upon cellular depolarization was detected. Interestingly, in Mfn2 knock-down cells, the inhibition of the inositol 1,4,5-trisphosphate receptor (IP3R) and the mitochondrial calcium (Ca2+) uniporter (MCU) restored vesicle protein content and attenuated exocytosis. We thus suggest that MERCS could be targeted to prevent increased exocytosis in conditions in which ER to mitochondria proximity is upregulated.
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18
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Intertwined and Finely Balanced: Endoplasmic Reticulum Morphology, Dynamics, Function, and Diseases. Cells 2021; 10:cells10092341. [PMID: 34571990 PMCID: PMC8472773 DOI: 10.3390/cells10092341] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 09/02/2021] [Accepted: 09/04/2021] [Indexed: 02/07/2023] Open
Abstract
The endoplasmic reticulum (ER) is an organelle that is responsible for many essential subcellular processes. Interconnected narrow tubules at the periphery and thicker sheet-like regions in the perinuclear region are linked to the nuclear envelope. It is becoming apparent that the complex morphology and dynamics of the ER are linked to its function. Mutations in the proteins involved in regulating ER structure and movement are implicated in many diseases including neurodegenerative diseases such as Alzheimer’s, Parkinson’s, and amyotrophic lateral sclerosis (ALS). The ER is also hijacked by pathogens to promote their replication. Bacteria such as Legionella pneumophila and Chlamydia trachomatis, as well as the Zika virus, bind to ER morphology and dynamics-regulating proteins to exploit the functions of the ER to their advantage. This review covers our understanding of ER morphology, including the functional subdomains and membrane contact sites that the organelle forms. We also focus on ER dynamics and the current efforts to quantify ER motion and discuss the diseases related to ER morphology and dynamics.
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19
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Bassot A, Prip-Buus C, Alves A, Berdeaux O, Perrier J, Lenoir V, Ji-Cao J, Berger MA, Loizon E, Cabaret S, Panthu B, Rieusset J, Morio B. Loss and gain of function of Grp75 or mitofusin 2 distinctly alter cholesterol metabolism, but all promote triglyceride accumulation in hepatocytes. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1866:159030. [PMID: 34419589 DOI: 10.1016/j.bbalip.2021.159030] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 08/03/2021] [Accepted: 08/13/2021] [Indexed: 12/15/2022]
Abstract
In the liver, contact sites between the endoplasmic reticulum (ER) and mitochondria (named MAMs) may be crucial hubs for the regulation of lipid metabolism, thus contributing to the exacerbation or prevention of fatty liver. We hypothesized that tether proteins located at MAMs could play a key role in preventing triglyceride accumulation in hepatocytes and nonalcoholic fatty liver disease (NAFLD) occurrence. To test this, we explored the role of two key partners in building MAM integrity and functionality, the glucose-regulated protein 75 (Grp75) and mitofusin 2 (Mfn2), which liver contents are altered in obesity and NAFLD. Grp75 or Mfn2 expression was either silenced using siRNA or overexpressed with adenoviruses in Huh7 cells. Silencing of Grp75 and Mfn2 resulted in decreased ER-mitochondria interactions, mitochondrial network fusion state and mitochondrial oxidative capacity, while overexpression of the two proteins induced mirror impacts on these parameters. Furthermore, Grp75 or Mfn2 silencing decreased cellular cholesterol content and enhanced triglyceride secretion in ApoB100 lipoproteins, while their overexpression led to reverse effects. Cellular phosphatidylcholine/phosphatidylethanolamine ratio was decreased only upon overexpression of the proteins, potentially contributing to altered ApoB100 assembly and secretion. Despite the opposite differences, both silencing and overexpression of Grp75 or Mfn2 induced triglyceride storage, although a fatty acid challenge was required to express the alteration upon protein silencing. Among the mechanisms potentially involved in this phenotype, ER stress was closely associated with altered triglyceride metabolism after Grp75 or Mfn2 overexpression, while blunted mitochondrial FA oxidation capacity may be the main defect causing triglyceride accumulation upon Grp75 or Mfn2 silencing. Further studies are required to decipher the link between modulation of Grp75 or Mfn2 expression, change in MAM integrity and alteration of cholesterol content of the cell. In conclusion, Grp75 or Mfn2 silencing and overexpression in Huh7 cells contribute to altering MAM integrity and cholesterol storage in opposite directions, but all promote triglyceride accumulation through distinct cellular pathways. This study also highlights that besides Mfn2, Grp75 could play a central role in hepatic lipid and cholesterol metabolism in obesity and NAFLD.
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Affiliation(s)
- Arthur Bassot
- CarMeN Laboratory, INSERM U1060, INRAE U1397, Université Lyon 1, 69008 Lyon, France.
| | - Carina Prip-Buus
- Institut Cochin, Département d'Endocrinologie, Métabolisme et Diabète, INSERM U1016/CNRS UMR8104/Université de Paris, 75014 Paris, France.
| | - Anaïs Alves
- CarMeN Laboratory, INSERM U1060, INRAE U1397, Université Lyon 1, 69008 Lyon, France.
| | - Olivier Berdeaux
- ChemoSens Platform, Centre des Sciences du Goût et de l'Alimentation, CNRS, INRA, Université Bourgogne Franche-Comté, Agrosup Dijon, F-21000 Dijon, France.
| | - Johan Perrier
- CarMeN Laboratory, INSERM U1060, INRAE U1397, Université Lyon 1, 69008 Lyon, France.
| | - Véronique Lenoir
- Institut Cochin, Département d'Endocrinologie, Métabolisme et Diabète, INSERM U1016/CNRS UMR8104/Université de Paris, 75014 Paris, France.
| | - Jingwei Ji-Cao
- CarMeN Laboratory, INSERM U1060, INRAE U1397, Université Lyon 1, 69008 Lyon, France.
| | - Marie-Agnès Berger
- CarMeN Laboratory, INSERM U1060, INRAE U1397, Université Lyon 1, 69008 Lyon, France.
| | - Emmanuelle Loizon
- CarMeN Laboratory, INSERM U1060, INRAE U1397, Université Lyon 1, 69008 Lyon, France.
| | - Stephanie Cabaret
- ChemoSens Platform, Centre des Sciences du Goût et de l'Alimentation, CNRS, INRA, Université Bourgogne Franche-Comté, Agrosup Dijon, F-21000 Dijon, France.
| | - Baptiste Panthu
- CarMeN Laboratory, INSERM U1060, INRAE U1397, Université Lyon 1, 69008 Lyon, France.
| | - Jennifer Rieusset
- CarMeN Laboratory, INSERM U1060, INRAE U1397, Université Lyon 1, 69008 Lyon, France.
| | - Béatrice Morio
- CarMeN Laboratory, INSERM U1060, INRAE U1397, Université Lyon 1, 69008 Lyon, France.
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20
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Phospholipids: Identification and Implication in Muscle Pathophysiology. Int J Mol Sci 2021; 22:ijms22158176. [PMID: 34360941 PMCID: PMC8347011 DOI: 10.3390/ijms22158176] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 07/24/2021] [Accepted: 07/26/2021] [Indexed: 12/29/2022] Open
Abstract
Phospholipids (PLs) are amphiphilic molecules that were essential for life to become cellular. PLs have not only a key role in compartmentation as they are the main components of membrane, but they are also involved in cell signaling, cell metabolism, and even cell pathophysiology. Considered for a long time to simply be structural elements of membranes, phospholipids are increasingly being viewed as sensors of their environment and regulators of many metabolic processes. After presenting their main characteristics, we expose the increasing methods of PL detection and identification that help to understand their key role in life processes. Interest and importance of PL homeostasis is growing as pathogenic variants in genes involved in PL biosynthesis and/or remodeling are linked to human diseases. We here review diseases that involve deregulation of PL homeostasis and present a predominantly muscular phenotype.
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21
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Chen J, Bassot A, Giuliani F, Simmen T. Amyotrophic Lateral Sclerosis (ALS): Stressed by Dysfunctional Mitochondria-Endoplasmic Reticulum Contacts (MERCs). Cells 2021; 10:cells10071789. [PMID: 34359958 PMCID: PMC8304209 DOI: 10.3390/cells10071789] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 07/12/2021] [Accepted: 07/13/2021] [Indexed: 02/06/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease for which there is currently no cure. Progress in the characterization of other neurodegenerative mechanisms has shifted the spotlight onto an intracellular structure called mitochondria-endoplasmic reticulum (ER) contacts (MERCs) whose ER portion can be biochemically isolated as mitochondria-associated membranes (MAMs). Within the central nervous system (CNS), these structures control the metabolic output of mitochondria and keep sources of oxidative stress in check via autophagy. The most relevant MERC controllers in the ALS pathogenesis are vesicle-associated membrane protein-associated protein B (VAPB), a mitochondria-ER tether, and the ubiquitin-specific chaperone valosin containing protein (VCP). These two systems cooperate to maintain mitochondrial energy output and prevent oxidative stress. In ALS, mutant VAPB and VCP take a central position in the pathology through MERC dysfunction that ultimately alters or compromises mitochondrial bioenergetics. Intriguingly, both proteins are targets themselves of other ALS mutant proteins, including C9orf72, FUS, or TDP-43. Thus, a new picture emerges, where different triggers cause MERC dysfunction in ALS, subsequently leading to well-known pathological changes including endoplasmic reticulum (ER) stress, inflammation, and motor neuron death.
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Affiliation(s)
- Junsheng Chen
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G2H7, Canada; (J.C.); (A.B.)
| | - Arthur Bassot
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G2H7, Canada; (J.C.); (A.B.)
| | - Fabrizio Giuliani
- Department of Medicine (Neurology), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G2H7, Canada;
| | - Thomas Simmen
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G2H7, Canada; (J.C.); (A.B.)
- Correspondence: ; Tel.: +1-780-492-1546
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22
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Bustos G, Ahumada-Castro U, Silva-Pavez E, Puebla A, Lovy A, Cesar Cardenas J. The ER-mitochondria Ca 2+ signaling in cancer progression: Fueling the monster. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 363:49-121. [PMID: 34392932 DOI: 10.1016/bs.ircmb.2021.03.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cancer is a leading cause of death worldwide. All major tumor suppressors and oncogenes are now recognized to have fundamental connections with metabolic pathways. A hallmark feature of cancer cells is a reprogramming of their metabolism even when nutrients are available. Increasing evidence indicates that most cancer cells rely on mitochondrial metabolism to sustain their energetic and biosynthetic demands. Mitochondria are functionally and physically coupled to the endoplasmic reticulum (ER), the major calcium (Ca2+) storage organelle in mammalian cells, through special domains known as mitochondria-ER contact sites (MERCS). In this domain, the release of Ca2+ from the ER is mainly regulated by inositol 1,4,5-trisphosphate (IP3) receptors (IP3Rs), a family of Ca2+ release channels activated by the ligand IP3. IP3R mediated Ca2+ release is transferred to mitochondria through the mitochondrial Ca2+ uniporter (MCU). Once in the mitochondrial matrix, Ca2+ activates several proteins that stimulate mitochondrial performance. The role of IP3R and MCU in cancer, as well as the other proteins that enable the Ca2+ communication between these two organelles is just beginning to be understood. Here, we describe the function of the main players of the ER mitochondrial Ca2+ communication and discuss how this particular signal may contribute to the rise and development of cancer traits.
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Affiliation(s)
- Galdo Bustos
- Faculty of Sciences, Universidad Mayor, Center for Integrative Biology, Santiago, Chile; Geroscience Center for Brain Health and Metabolism, Santiago, Chile
| | - Ulises Ahumada-Castro
- Faculty of Sciences, Universidad Mayor, Center for Integrative Biology, Santiago, Chile; Geroscience Center for Brain Health and Metabolism, Santiago, Chile
| | - Eduardo Silva-Pavez
- Faculty of Sciences, Universidad Mayor, Center for Integrative Biology, Santiago, Chile; Geroscience Center for Brain Health and Metabolism, Santiago, Chile
| | - Andrea Puebla
- Faculty of Sciences, Universidad Mayor, Center for Integrative Biology, Santiago, Chile; Geroscience Center for Brain Health and Metabolism, Santiago, Chile
| | - Alenka Lovy
- Faculty of Sciences, Universidad Mayor, Center for Integrative Biology, Santiago, Chile; Geroscience Center for Brain Health and Metabolism, Santiago, Chile; Department of Neuroscience, Center for Neuroscience Research, Tufts School of Medicine, Boston, MA, United States.
| | - J Cesar Cardenas
- Faculty of Sciences, Universidad Mayor, Center for Integrative Biology, Santiago, Chile; Geroscience Center for Brain Health and Metabolism, Santiago, Chile; Buck Institute for Research on Aging, Novato, CA, United States; Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, United States.
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23
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Sam PN, Calzada E, Acoba MG, Zhao T, Watanabe Y, Nejatfard A, Trinidad JC, Shutt TE, Neal SE, Claypool SM. Impaired phosphatidylethanolamine metabolism activates a reversible stress response that detects and resolves mutant mitochondrial precursors. iScience 2021; 24:102196. [PMID: 33718843 PMCID: PMC7921845 DOI: 10.1016/j.isci.2021.102196] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 01/27/2021] [Accepted: 02/10/2021] [Indexed: 02/06/2023] Open
Abstract
Phosphatidylethanolamine (PE) made in mitochondria has long been recognized as an important precursor for phosphatidylcholine production that occurs in the endoplasmic reticulum (ER). Recently, the strict mitochondrial localization of the enzyme that makes PE in the mitochondrion, phosphatidylserine decarboxylase 1 (Psd1), was questioned. Since a dual localization of Psd1 to the ER would have far-reaching implications, we initiated our study to independently re-assess the subcellular distribution of Psd1. Our results support the unavoidable conclusion that the vast majority, if not all, of functional Psd1 resides in the mitochondrion. Through our efforts, we discovered that mutant forms of Psd1 that impair a self-processing step needed for it to become functional are dually localized to the ER when expressed in a PE-limiting environment. We conclude that severely impaired cellular PE metabolism provokes an ER-assisted adaptive response that is capable of identifying and resolving nonfunctional mitochondrial precursors.
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Affiliation(s)
- Pingdewinde N. Sam
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Elizabeth Calzada
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Michelle Grace Acoba
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Tian Zhao
- Departments of Medical Genetics and Biochemistry & Molecular Biology, Cumming School of Medicine, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Yasunori Watanabe
- Faculty of Science, Yamagata University, 1-4-12 Kojirakawa-machi, Yamagata, Yamagata 990-8560, Japan
| | - Anahita Nejatfard
- Division of Biological Sciences, The Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA, USA
| | | | - Timothy E. Shutt
- Faculty of Science, Yamagata University, 1-4-12 Kojirakawa-machi, Yamagata, Yamagata 990-8560, Japan
| | - Sonya E. Neal
- Division of Biological Sciences, The Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA, USA
| | - Steven M. Claypool
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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24
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Dynamic Remodeling of Membranes and Their Lipids during Acute Hormone-Induced Steroidogenesis in MA-10 Mouse Leydig Tumor Cells. Int J Mol Sci 2021; 22:ijms22052554. [PMID: 33806352 PMCID: PMC7961408 DOI: 10.3390/ijms22052554] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 02/24/2021] [Accepted: 02/27/2021] [Indexed: 12/14/2022] Open
Abstract
Lipids play essential roles in numerous cellular processes, including membrane remodeling, signal transduction, the modulation of hormone activity, and steroidogenesis. We chose steroidogenic MA-10 mouse tumor Leydig cells to investigate subcellular lipid localization during steroidogenesis. Electron microscopy showed that cAMP stimulation increased associations between the plasma membrane (PM) and the endoplasmic reticulum (ER) and between the ER and mitochondria. cAMP stimulation also increased the movement of cholesterol from the PM compared to untreated cells, which was partially inhibited when ATPase family AAA-domain containing protein 3 A (ATAD3A), which functions in ER and mitochondria interactions, was knocked down. Mitochondria, ER, cytoplasm, PM, PM-associated membranes (PAMs), and mitochondria-associated membranes (MAMs) were isolated from control and hormone-stimulated cells. Lipidomic analyses revealed that each isolated compartment had a unique lipid composition, and the induction of steroidogenesis caused the significant remodeling of its lipidome. cAMP-induced changes in lipid composition included an increase in phosphatidylserine and cardiolipin levels in PAM and PM compartments, respectively; an increase in phosphatidylinositol in the ER, mitochondria, and MAMs; and a reorganization of phosphatidic acid, cholesterol ester, ceramide, and phosphatidylethanolamine. Abundant lipids, such as phosphatidylcholine, were not affected by hormone treatment. Our data suggested that PM–ER–mitochondria tethering may be involved in lipid trafficking between organelles and indicated that hormone-induced acute steroid production involves extensive organelle remodeling.
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25
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Carpio MA, Means RE, Brill AL, Sainz A, Ehrlich BE, Katz SG. BOK controls apoptosis by Ca 2+ transfer through ER-mitochondrial contact sites. Cell Rep 2021; 34:108827. [PMID: 33691099 PMCID: PMC7995216 DOI: 10.1016/j.celrep.2021.108827] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 11/20/2020] [Accepted: 02/16/2021] [Indexed: 12/11/2022] Open
Abstract
Calcium transfer from the endoplasmic reticulum (ER) to mitochondria is a critical contributor to apoptosis. B cell lymphoma 2 (BCL-2) ovarian killer (BOK) localizes to the ER and binds the inositol 1,4,5-trisphosophate receptor (IP3R). Here, we show that BOK is necessary for baseline mitochondrial calcium levels and stimulus-induced calcium transfer from the ER to the mitochondria. Murine embryonic fibroblasts deficient for BOK have decreased proximity of the ER to the mitochondria and altered protein composition of mitochondria-associated membranes (MAMs), which form essential calcium microdomains. Rescue of the ER-mitochondrial juxtaposition with drug-inducible interorganelle linkers reveals a kinetic disruption, which when overcome in Bok−/− cells is still insufficient to rescue thapsigargin-induced calcium transfer and apoptosis. Likewise, a BOK mutant unable to interact with IP3R restores ER-mitochondrial proximity, but not ER-mitochondrial calcium transfer, MAM protein composition, or apoptosis. This work identifies the dynamic coordination of ER-mitochondrial contact by BOK as an important control point for apoptosis. Carpio et al. demonstrate that the proapoptotic BCL-2 family member BOK is present in mitochondrial associated membranes (MAMs). The interaction of BOK with the IP3Rs is critical for its regulation of Ca2+ transfer to the mitochondria, ER-mitochondrial contact sites, and apoptosis.
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Affiliation(s)
- Marcos A Carpio
- Department of Pathology, Yale School of Medicine, New Haven, CT 06525, USA
| | - Robert E Means
- Department of Pathology, Yale School of Medicine, New Haven, CT 06525, USA
| | - Allison L Brill
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT 06525, USA
| | - Alva Sainz
- Department of Pathology, Yale School of Medicine, New Haven, CT 06525, USA
| | - Barbara E Ehrlich
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT 06525, USA; Department of Pharmacology, Yale School of Medicine, New Haven, CT 06525, USA
| | - Samuel G Katz
- Department of Pathology, Yale School of Medicine, New Haven, CT 06525, USA.
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26
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Leal NS, Martins LM. Mind the Gap: Mitochondria and the Endoplasmic Reticulum in Neurodegenerative Diseases. Biomedicines 2021; 9:biomedicines9020227. [PMID: 33672391 PMCID: PMC7926795 DOI: 10.3390/biomedicines9020227] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 02/17/2021] [Accepted: 02/18/2021] [Indexed: 12/16/2022] Open
Abstract
The way organelles are viewed by cell biologists is quickly changing. For many years, these cellular entities were thought to be unique and singular structures that performed specific roles. However, in recent decades, researchers have discovered that organelles are dynamic and form physical contacts. In addition, organelle interactions modulate several vital biological functions, and the dysregulation of these contacts is involved in cell dysfunction and different pathologies, including neurodegenerative diseases. Mitochondria–ER contact sites (MERCS) are among the most extensively studied and understood juxtapositioned interorganelle structures. In this review, we summarise the major biological and ultrastructural dysfunctions of MERCS in neurodegeneration, with a particular focus on Alzheimer’s disease as well as Parkinson’s disease, amyotrophic lateral sclerosis and frontotemporal dementia. We also propose an updated version of the MERCS hypothesis in Alzheimer’s disease based on new findings. Finally, we discuss the possibility of MERCS being used as possible drug targets to halt cell death and neurodegeneration.
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27
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Axonal Organelles as Molecular Platforms for Axon Growth and Regeneration after Injury. Int J Mol Sci 2021; 22:ijms22041798. [PMID: 33670312 PMCID: PMC7918155 DOI: 10.3390/ijms22041798] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 02/06/2021] [Accepted: 02/08/2021] [Indexed: 02/06/2023] Open
Abstract
Investigating the molecular mechanisms governing developmental axon growth has been a useful approach for identifying new strategies for boosting axon regeneration after injury, with the goal of treating debilitating conditions such as spinal cord injury and vision loss. The picture emerging is that various axonal organelles are important centers for organizing the molecular mechanisms and machinery required for growth cone development and axon extension, and these have recently been targeted to stimulate robust regeneration in the injured adult central nervous system (CNS). This review summarizes recent literature highlighting a central role for organelles such as recycling endosomes, the endoplasmic reticulum, mitochondria, lysosomes, autophagosomes and the proteasome in developmental axon growth, and describes how these organelles can be targeted to promote axon regeneration after injury to the adult CNS. This review also examines the connections between these organelles in developing and regenerating axons, and finally discusses the molecular mechanisms within the axon that are required for successful axon growth.
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28
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Kumar V, Maity S. ER Stress-Sensor Proteins and ER-Mitochondrial Crosstalk-Signaling Beyond (ER) Stress Response. Biomolecules 2021; 11:173. [PMID: 33525374 PMCID: PMC7911976 DOI: 10.3390/biom11020173] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/14/2021] [Accepted: 01/19/2021] [Indexed: 02/07/2023] Open
Abstract
Recent studies undoubtedly show the importance of inter organellar connections to maintain cellular homeostasis. In normal physiological conditions or in the presence of cellular and environmental stress, each organelle responds alone or in coordination to maintain cellular function. The Endoplasmic reticulum (ER) and mitochondria are two important organelles with very specialized structural and functional properties. These two organelles are physically connected through very specialized proteins in the region called the mitochondria-associated ER membrane (MAM). The molecular foundation of this relationship is complex and involves not only ion homeostasis through the shuttling of calcium but also many structural and apoptotic proteins. IRE1alpha and PERK are known for their canonical function as an ER stress sensor controlling unfolded protein response during ER stress. The presence of these transmembrane proteins at the MAM indicates its potential involvement in other biological functions beyond ER stress signaling. Many recent studies have now focused on the non-canonical function of these sensors. In this review, we will focus on ER mitochondrial interdependence with special emphasis on the non-canonical role of ER stress sensors beyond ER stress.
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29
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Bassot A, Chen J, Simmen T. Post-Translational Modification of Cysteines: A Key Determinant of Endoplasmic Reticulum-Mitochondria Contacts (MERCs). CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2021; 4:25152564211001213. [PMID: 37366382 PMCID: PMC10243593 DOI: 10.1177/25152564211001213] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 01/18/2021] [Accepted: 02/08/2021] [Indexed: 06/28/2023]
Abstract
Cells must adjust their redox state to an ever-changing environment that could otherwise result in compromised homeostasis. An obvious way to adapt to changing redox conditions depends on cysteine post-translational modifications (PTMs) to adapt conformation, localization, interactions and catalytic activation of proteins. Such PTMs should occur preferentially in the proximity of oxidative stress sources. A particular concentration of these sources is found near membranes where the endoplasmic reticulum (ER) and the mitochondria interact on domains called MERCs (Mitochondria-Endoplasmic Reticulum Contacts). Here, fine inter-organelle communication controls metabolic homeostasis. MERCs achieve this goal through fluxes of Ca2+ ions and inter-organellar lipid exchange. Reactive oxygen species (ROS) that cause PTMs of mitochondria-associated membrane (MAM) proteins determine these intertwined MERC functions. Chronic changes of the pattern of these PTMs not only control physiological processes such as the circadian clock but could also lead to or worsen many human disorders such as cancer and neurodegenerative diseases.
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Affiliation(s)
| | | | - Thomas Simmen
- Thomas Simmen, Department of Cell
Biology, Faculty of Medicine and Dentistry, University of Alberta,
Edmonton, Alberta, Canada T6G2H7.
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30
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Xu J, Huang X. Lipid Metabolism at Membrane Contacts: Dynamics and Functions Beyond Lipid Homeostasis. Front Cell Dev Biol 2020; 8:615856. [PMID: 33425923 PMCID: PMC7786193 DOI: 10.3389/fcell.2020.615856] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 11/30/2020] [Indexed: 01/12/2023] Open
Abstract
Membrane contact sites (MCSs), regions where the membranes of two organelles are closely apposed, play critical roles in inter-organelle communication, such as lipid trafficking, intracellular signaling, and organelle biogenesis and division. First identified as “fraction X” in the early 90s, MCSs are now widely recognized to facilitate local lipid synthesis and inter-organelle lipid transfer, which are important for maintaining cellular lipid homeostasis. In this review, we discuss lipid metabolism and related cellular and physiological functions in MCSs. We start with the characteristics of lipid synthesis and breakdown at MCSs. Then we focus on proteins involved in lipid synthesis and turnover at these sites. Lastly, we summarize the cellular function of lipid metabolism at MCSs beyond mere lipid homeostasis, including the physiological meaning and relevance of MCSs regarding systemic lipid metabolism. This article is part of an article collection entitled: Coupling and Uncoupling: Dynamic Control of Membrane Contacts.
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Affiliation(s)
- Jiesi Xu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China
| | - Xun Huang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China.,College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
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31
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Human VAPome Analysis Reveals MOSPD1 and MOSPD3 as Membrane Contact Site Proteins Interacting with FFAT-Related FFNT Motifs. Cell Rep 2020; 33:108475. [DOI: 10.1016/j.celrep.2020.108475] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 10/05/2020] [Accepted: 11/12/2020] [Indexed: 12/21/2022] Open
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32
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Audano M, Pedretti S, Ligorio S, Crestani M, Caruso D, De Fabiani E, Mitro N. "The Loss of Golden Touch": Mitochondria-Organelle Interactions, Metabolism, and Cancer. Cells 2020; 9:cells9112519. [PMID: 33233365 PMCID: PMC7700504 DOI: 10.3390/cells9112519] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 11/18/2020] [Accepted: 11/20/2020] [Indexed: 02/06/2023] Open
Abstract
Mitochondria represent the energy hub of cells and their function is under the constant influence of their tethering with other subcellular organelles. Mitochondria interact with the endoplasmic reticulum, lysosomes, cytoskeleton, peroxisomes, and nucleus in several ways, ranging from signal transduction, vesicle transport, and membrane contact sites, to regulate energy metabolism, biosynthetic processes, apoptosis, and cell turnover. Tumorigenesis is often associated with mitochondrial dysfunction, which could likely be the result of an altered interaction with different cell organelles or structures. The purpose of the present review is to provide an updated overview of the links between inter-organellar communications and interactions and metabolism in cancer cells, with a focus on mitochondria. The very recent publication of several reviews on these aspects testifies the great interest in the area. Here, we aim at (1) summarizing recent evidence supporting that the metabolic rewiring and adaptation observed in tumors deeply affect organelle dynamics and cellular functions and vice versa; (2) discussing insights on the underlying mechanisms, when available; and (3) critically presenting the gaps in the field that need to be filled, for a comprehensive understanding of tumor cells’ biology. Chemo-resistance and druggable vulnerabilities of cancer cells related to the aspects mentioned above is also outlined.
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Affiliation(s)
| | | | | | | | | | - Emma De Fabiani
- Correspondence: (E.D.F.); (N.M.); Tel.: +39-02-503-18329 (E.D.F.); +39-02-503-18253 (N.M.)
| | - Nico Mitro
- Correspondence: (E.D.F.); (N.M.); Tel.: +39-02-503-18329 (E.D.F.); +39-02-503-18253 (N.M.)
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33
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Kimura AK, Kimura T. Phosphatidylserine biosynthesis pathways in lipid homeostasis: Toward resolution of the pending central issue for decades. FASEB J 2020; 35:e21177. [PMID: 33205488 DOI: 10.1096/fj.202001802r] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 10/17/2020] [Accepted: 10/26/2020] [Indexed: 12/28/2022]
Abstract
Enzymatic control of lipid homeostasis in the cell is a vital element in the complex organization of life. Phosphatidylserine (PS) is an essential anionic phospholipid of cell membranes, and conducts numerous roles for their structural and functional integrity. In mammalian cells, two distinct enzymes phosphatidylserine synthases-1 (PSS1) and -2 (PSS2) in the mitochondria-associated membrane (MAM) in the ER perform de novo synthesis of PS. It is based on base-exchange reactions of the preexisting dominant phospholipids phosphatidylcholine (PC) and phosphatidylethanolamine (PE). While PSS2 specifically catalyzes the reaction "PE → PS," whether or not PSS1 is responsible for the same reaction along with the reaction "PC → PS" remains unsettled despite its fundamental impact on the major stoichiometry. We propose here that a key but the only report that appeared to have put scientists on hold for decades in answering to this issue may be viewed consistently with other available research reports; PSS1 utilizes the two dominant phospholipid classes at a similar intrinsic rate. In this review, we discuss the issue in view of the current information for the enzyme machineries, membrane structure and dynamics, intracellular network of lipid transport, and PS synthesis in health and disease. Resolution of the pending issue is thus critical in advancing our understanding of roles of the essential anionic lipid in biology, health, and disease.
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Affiliation(s)
- Atsuko K Kimura
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
| | - Tomohiro Kimura
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
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34
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Inter-organelle membrane contact sites: implications for lipid metabolism. Biol Direct 2020; 15:24. [PMID: 33176847 PMCID: PMC7661199 DOI: 10.1186/s13062-020-00279-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 10/30/2020] [Indexed: 11/10/2022] Open
Abstract
This article supplements a recent Perspective by Scorrano et al. in Nature Communications [10 [ (1)]:1287] in which the properties and functions of inter-organelle membrane contact sites were summarized. It is now clear that inter-organelle membrane contact sites are widespread in eukaryotic cells and that diverse pairs of organelles can be linked via unique protein tethers. An appropriate definition of what constitutes an inter-organelle membrane contact site was proposed in the Perspective. In addition, the various experimental approaches that are frequently used to study these organelle associations, as well as the advantages and disadvantages of each of these methods, were considered. The nature of the tethers that link the pairs of organelles at the contact sites was discussed in detail and some biological functions that have been ascribed to specific membrane contact sites were highlighted. Nevertheless, the functions of most types of organelle contact sites remain unclear. In the current article I have considered some of the points raised in the Perspective but have omitted detailed information on the roles of membrane contact sites in biological functions such as apoptosis, autophagy, calcium homeostasis and mitochondrial fusion. Instead, I have provided some background on the initial discovery of mitochondria-endoplasmic reticulum membrane contact sites, and have focussed on the known roles of membrane contact sites in inter-organelle lipid transport. In addition, potential roles for membrane contact sites in human diseases are briefly discussed.
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35
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Rossini M, Pizzo P, Filadi R. Better to keep in touch: investigating inter‐organelle cross‐talk. FEBS J 2020; 288:740-755. [DOI: 10.1111/febs.15451] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 05/28/2020] [Accepted: 06/11/2020] [Indexed: 12/14/2022]
Affiliation(s)
- Michela Rossini
- Department of Biomedical Sciences University of Padua Padua Italy
| | - Paola Pizzo
- Department of Biomedical Sciences University of Padua Padua Italy
- Neuroscience Institute National Research Council (CNR) Padua Italy
| | - Riccardo Filadi
- Department of Biomedical Sciences University of Padua Padua Italy
- Neuroscience Institute National Research Council (CNR) Padua Italy
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36
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Kohler V, Aufschnaiter A, Büttner S. Closing the Gap: Membrane Contact Sites in the Regulation of Autophagy. Cells 2020; 9:E1184. [PMID: 32397538 PMCID: PMC7290522 DOI: 10.3390/cells9051184] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 04/29/2020] [Accepted: 05/07/2020] [Indexed: 12/14/2022] Open
Abstract
In all eukaryotic cells, intracellular organization and spatial separation of incompatible biochemical processes is established by individual cellular subcompartments in form of membrane-bound organelles. Virtually all of these organelles are physically connected via membrane contact sites (MCS), allowing interorganellar communication and a functional integration of cellular processes. These MCS coordinate the exchange of diverse metabolites and serve as hubs for lipid synthesis and trafficking. While this of course indirectly impacts on a plethora of biological functions, including autophagy, accumulating evidence shows that MCS can also directly regulate autophagic processes. Here, we focus on the nexus between interorganellar contacts and autophagy in yeast and mammalian cells, highlighting similarities and differences. We discuss MCS connecting the ER to mitochondria or the plasma membrane, crucial for early steps of both selective and non-selective autophagy, the yeast-specific nuclear-vacuolar tethering system and its role in microautophagy, the emerging function of distinct autophagy-related proteins in organellar tethering as well as novel MCS transiently emanating from the growing phagophore and mature autophagosome.
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Affiliation(s)
- Verena Kohler
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden;
| | - Andreas Aufschnaiter
- Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden;
| | - Sabrina Büttner
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden;
- Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria
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37
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Dorn GW. Mitofusins as mitochondrial anchors and tethers. J Mol Cell Cardiol 2020; 142:146-153. [PMID: 32304672 DOI: 10.1016/j.yjmcc.2020.04.016] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 02/24/2020] [Accepted: 04/11/2020] [Indexed: 12/18/2022]
Abstract
Mitochondria have their own genomes and their own agendas. Like their primitive bacterial ancestors, mitochondria interact with their environment and organelle colleagues at their physical interfaces, the outer mitochondrial membrane. Among outer membrane proteins, mitofusins (MFN) are increasingly recognized for their roles as arbiters of mitochondria-mitochondria and mitochondria-reticular interactions. This review examines the roles of MFN1 and MFN2 in the heart and other organs as proteins that tether mitochondria to each other or to other organelles, and as mitochondrial anchoring proteins for various macromolecular complexes. The consequences of MFN-mediated tethering and anchoring on mitochondrial fusion, motility, mitophagy, and mitochondria-ER calcium cross-talk are reviewed. Pathophysiological implications are explored from the perspective of mitofusin common functioning as tethering and anchoring proteins, rather than as mediators of individual processes. Finally, some informed speculation is provided for why mouse MFN knockout studies show severe multi-system phenotypes whereas rare human diseases linked to MFN mutations are limited in scope.
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Affiliation(s)
- Gerald W Dorn
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO, USA.
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38
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Abstract
Owing to their ability to efficiently generate ATP required to sustain normal cell function, mitochondria are often considered the 'powerhouses of the cell'. However, our understanding of the role of mitochondria in cell biology recently expanded when we recognized that they are key platforms for a plethora of cell signalling cascades. This functional versatility is tightly coupled to constant reshaping of the cellular mitochondrial network in a series of processes, collectively referred to as mitochondrial membrane dynamics and involving organelle fusion and fission (division) as well as ultrastructural remodelling of the membrane. Accordingly, mitochondrial dynamics influence and often orchestrate not only metabolism but also complex cell signalling events, such as those involved in regulating cell pluripotency, division, differentiation, senescence and death. Reciprocally, mitochondrial membrane dynamics are extensively regulated by post-translational modifications of its machinery and by the formation of membrane contact sites between mitochondria and other organelles, both of which have the capacity to integrate inputs from various pathways. Here, we discuss mitochondrial membrane dynamics and their regulation and describe how bioenergetics and cellular signalling are linked to these dynamic changes of mitochondrial morphology.
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39
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Peretti D, Kim S, Tufi R, Lev S. Lipid Transfer Proteins and Membrane Contact Sites in Human Cancer. Front Cell Dev Biol 2020; 7:371. [PMID: 32039198 PMCID: PMC6989408 DOI: 10.3389/fcell.2019.00371] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 12/16/2019] [Indexed: 11/29/2022] Open
Abstract
Lipid-transfer proteins (LTPs) were initially discovered as cytosolic factors that facilitate lipid transport between membrane bilayers in vitro. Since then, many LTPs have been isolated from bacteria, plants, yeast, and mammals, and extensively studied in cell-free systems and intact cells. A major advance in the LTP field was associated with the discovery of intracellular membrane contact sites (MCSs), small cytosolic gaps between the endoplasmic reticulum (ER) and other cellular membranes, which accelerate lipid transfer by LTPs. As LTPs modulate the distribution of lipids within cellular membranes, and many lipid species function as second messengers in key signaling pathways that control cell survival, proliferation, and migration, LTPs have been implicated in cancer-associated signal transduction cascades. Increasing evidence suggests that LTPs play an important role in cancer progression and metastasis. This review describes how different LTPs as well as MCSs can contribute to cell transformation and malignant phenotype, and discusses how “aberrant” MCSs are associated with tumorigenesis in human.
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Affiliation(s)
- Diego Peretti
- UK Dementia Research Institute, Clinical Neurosciences Department, University of Cambridge, Cambridge, United Kingdom
| | - SoHui Kim
- Nakseongdae R&D Center, GPCR Therapeutics, Inc., Seoul, South Korea
| | - Roberta Tufi
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Sima Lev
- Molecular Cell Biology Department, Weizmann Institute of Science, Rehovot, Israel
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40
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Abstract
Alzheimer's disease (AD) is the most common form of dementia, most prevalent in the elderly population and has a significant impact on individuals and their family as well as the health care system and the economy. While the number of patients affected by various forms of dementia including AD is on the increase, there is currently no cure. Although genome-wide association studies have identified genetic markers for familial AD, the molecular mechanisms underlying the initiation and development of both familial and sporadic AD remain poorly understood. Most neurodegenerative diseases and in particular those associated with dementia have been defined as proteinopathies due to the presence of intra- and/or extracellular protein aggregates in the brain of affected individuals. Although loss of proteostasis in AD has been known for decades, it is only in recent years that we have come to appreciate the role of ubiquitin-dependent mechanisms in brain homeostasis and in brain diseases. Ubiquitin is a highly versatile post-translational modification which regulates many aspects of protein fate and function, including protein degradation by the Ubiquitin-Proteasome System (UPS), autophagy-mediated removal of damaged organelles and proteins, lysosomal turnover of membrane proteins and of extracellular molecules brought inside the cell through endocytosis. Amyloid-β (Aβ) fragments as well as hyperphosphorylation of Tau are hallmarks of AD, and these are found in extracellular plaques and intracellular fibrils in the brain of individuals with AD, respectively. Yet, whether it is the oligomeric or the soluble species of Aβ and Tau that mediate toxicity is still unclear. These proteins impact on mitochondrial energy metabolism, inflammation, as well as a number of housekeeping processes including protein degradation through the UPS and autophagy. In this chapter, we will discuss the role of ubiquitin in neuronal homeostasis as well as in AD; summarise crosstalks between the enzymes that regulate protein ubiquitination and the toxic proteins Tau and Aβ; highlight emerging molecular mechanisms in AD as well as future strategies which aim to exploit the ubiquitin system as a source for next-generation therapeutics.
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41
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Madreiter-Sokolowski CT, Ramadani-Muja J, Ziomek G, Burgstaller S, Bischof H, Koshenov Z, Gottschalk B, Malli R, Graier WF. Tracking intra- and inter-organelle signaling of mitochondria. FEBS J 2019; 286:4378-4401. [PMID: 31661602 PMCID: PMC6899612 DOI: 10.1111/febs.15103] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 08/19/2019] [Accepted: 10/22/2019] [Indexed: 12/15/2022]
Abstract
Mitochondria are as highly specialized organelles and masters of the cellular energy metabolism in a constant and dynamic interplay with their cellular environment, providing adenosine triphosphate, buffering Ca2+ and fundamentally contributing to various signaling pathways. Hence, such broad field of action within eukaryotic cells requires a high level of structural and functional adaptation. Therefore, mitochondria are constantly moving and undergoing fusion and fission processes, changing their shape and their interaction with other organelles. Moreover, mitochondrial activity gets fine-tuned by intra- and interorganelle H+ , K+ , Na+ , and Ca2+ signaling. In this review, we provide an up-to-date overview on mitochondrial strategies to adapt and respond to, as well as affect, their cellular environment. We also present cutting-edge technologies used to track and investigate subcellular signaling, essential to the understanding of various physiological and pathophysiological processes.
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Affiliation(s)
- Corina T Madreiter-Sokolowski
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Austria.,Department of Health Sciences and Technology, ETH Zurich, Schwerzenbach, Switzerland
| | - Jeta Ramadani-Muja
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Austria
| | - Gabriela Ziomek
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Austria
| | - Sandra Burgstaller
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Austria
| | - Helmut Bischof
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Austria
| | - Zhanat Koshenov
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Austria
| | - Benjamin Gottschalk
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Austria
| | - Roland Malli
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Austria.,BioTechMed, Graz, Austria
| | - Wolfgang F Graier
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Austria.,BioTechMed, Graz, Austria
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42
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ER-Mitochondria Communication in Cells of the Innate Immune System. Cells 2019; 8:cells8091088. [PMID: 31540165 PMCID: PMC6770024 DOI: 10.3390/cells8091088] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 09/11/2019] [Accepted: 09/13/2019] [Indexed: 01/06/2023] Open
Abstract
In cells the interorganelle communication comprises vesicular and non-vesicular mechanisms. Non-vesicular material transfer predominantly takes place at regions of close organelle apposition termed membrane contact sites and is facilitated by a growing number of specialized proteins. Contacts of the endoplasmic reticulum (ER) and mitochondria are now recognized to be essential for diverse biological processes such as calcium homeostasis, phospholipid biosynthesis, apoptosis, and autophagy. In addition to these universal roles, ER-mitochondria communication serves also cell type-specific functions. In this review, we summarize the current knowledge on ER-mitochondria contacts in cells of the innate immune system, especially in macrophages. We discuss ER- mitochondria communication in the context of macrophage fatty acid metabolism linked to inflammatory and ER stress responses, its roles in apoptotic cell engulfment, activation of the inflammasome, and antiviral defense.
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43
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Gordaliza‐Alaguero I, Cantó C, Zorzano A. Metabolic implications of organelle-mitochondria communication. EMBO Rep 2019; 20:e47928. [PMID: 31418169 PMCID: PMC6726909 DOI: 10.15252/embr.201947928] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 05/10/2019] [Accepted: 05/28/2019] [Indexed: 12/31/2022] Open
Abstract
Cellular organelles are not static but show dynamism-a property that is likely relevant for their function. In addition, they interact with other organelles in a highly dynamic manner. In this review, we analyze the proteins involved in the interaction between mitochondria and other cellular organelles, especially the endoplasmic reticulum, lipid droplets, and lysosomes. Recent results indicate that, on one hand, metabolic alterations perturb the interaction between mitochondria and other organelles, and, on the other hand, that deficiency in proteins involved in the tethering between mitochondria and the ER or in specific functions of the interaction leads to metabolic alterations in a variety of tissues. The interaction between organelles is an emerging field that will permit to identify key proteins, to delineate novel modulation pathways, and to elucidate their implications in human disease.
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Affiliation(s)
- Isabel Gordaliza‐Alaguero
- Institute for Research in Biomedicine (IRB Barcelona)Barcelona Institute of Science and Technology (BIST)BarcelonaSpain
- CIBER de Diabetes y Enfermedades Metabolicas AsociadasBarcelonaSpain
- Departamento de Bioquimica i Biomedicina MolecularFacultat de BiologiaUniversitat de BarcelonaBarcelonaSpain
| | - Carlos Cantó
- Nestle Institute of Health Sciences (NIHS)LausanneSwitzerland
- School of Life SciencesEcole Polytechnique Fédérale de Lausanne (EPFL)LausanneSwitzerland
| | - Antonio Zorzano
- Institute for Research in Biomedicine (IRB Barcelona)Barcelona Institute of Science and Technology (BIST)BarcelonaSpain
- CIBER de Diabetes y Enfermedades Metabolicas AsociadasBarcelonaSpain
- Departamento de Bioquimica i Biomedicina MolecularFacultat de BiologiaUniversitat de BarcelonaBarcelonaSpain
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Nishimura T, Stefan CJ. Specialized ER membrane domains for lipid metabolism and transport. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1865:158492. [PMID: 31349025 DOI: 10.1016/j.bbalip.2019.07.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 07/02/2019] [Accepted: 07/03/2019] [Indexed: 11/15/2022]
Abstract
The endoplasmic reticulum (ER) is a highly organized organelle that performs vital functions including de novo membrane lipid synthesis and transport. Accordingly, numerous lipid biosynthesis enzymes are localized in the ER membrane. However, it is now evident that lipid metabolism is sub-compartmentalized within the ER and that lipid biosynthetic enzymes engage with lipid transfer proteins (LTPs) to rapidly shuttle newly synthesized lipids from the ER to other organelles. As such, intimate relationships between lipid metabolism and lipid transfer pathways exist within the ER network. Notably, certain LTPs enhance the activities of lipid metabolizing enzymes; likewise, lipid metabolism can ensure the specificity of LTP transfer/exchange reactions. Yet, our understanding of these mutual relationships is still emerging. Here, we highlight past and recent key findings on specialized ER membrane domains involved in efficient lipid metabolism and transport and consider unresolved issues in the field.
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Affiliation(s)
- Taki Nishimura
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK.
| | - Christopher J Stefan
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK.
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45
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van Vliet AR, Sassano ML, Agostinis P. The Unfolded Protein Response and Membrane Contact Sites: Tethering as a Matter of Life and Death? ACTA ACUST UNITED AC 2018. [DOI: 10.1177/2515256418770512] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The endoplasmic reticulum (ER) is the most extensive organelle of the eukaryotic cell and constitutes the major site of protein and lipid synthesis and regulation of intracellular Ca2+ levels. To exert these functions properly, the ER network is shaped in structurally and functionally distinct domains that dynamically remodel in response to intrinsic and extrinsic cues. Moreover, the ER establishes a tight communication with virtually all organelles of the cell through specific subdomains called membrane contact sites. These contact sites allow preferential, nonvesicular channeling of key biological mediators including lipids and Ca2+ between organelles and are harnessed by the ER to interface with and coregulate a variety of organellar functions that are vital to maintain homeostasis. When ER homeostasis is lost, a condition that triggers the activation of an evolutionarily conserved pathway called the unfolded protein response (UPR), the ER undergoes rapid remodeling. These dynamic changes in ER morphology are functionally coupled to the modulation or formation of contact sites with key organelles, such as mitochondria and the plasma membrane, which critically regulate cell fate decisions of the ER-stressed cells. Certain components of the UPR have been shown to facilitate the formation of contact sites through various mechanisms including remodeling of the actin cytoskeleton. In this review, we discuss old and emerging evidence linking the UPR machinery to contact site formation in mammalian cells and discuss their important role in cellular homeostasis.
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Affiliation(s)
- Alexander R. van Vliet
- Cell Death Research & Therapy Laboratory, Department of Cellular and Molecular Medicine, KU Leuven-University of Leuven, Belgium
| | - Maria Livia Sassano
- Cell Death Research & Therapy Laboratory, Department of Cellular and Molecular Medicine, KU Leuven-University of Leuven, Belgium
| | - Patrizia Agostinis
- Cell Death Research & Therapy Laboratory, Department of Cellular and Molecular Medicine, KU Leuven-University of Leuven, Belgium
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46
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Vance JE. Historical perspective: phosphatidylserine and phosphatidylethanolamine from the 1800s to the present. J Lipid Res 2018; 59:923-944. [PMID: 29661786 DOI: 10.1194/jlr.r084004] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 04/12/2018] [Indexed: 12/17/2022] Open
Abstract
This article provides a historical account of the discovery, chemistry, and biochemistry of two ubiquitous phosphoglycerolipids, phosphatidylserine (PS) and phosphatidylethanolamine (PE), including the ether lipids. In addition, the article describes the biosynthetic pathways for these phospholipids and how these pathways were elucidated. Several unique functions of PS and PE in mammalian cells in addition to their ability to define physical properties of membranes are discussed. For example, the translocation of PS from the inner to the outer leaflet of the plasma membrane of cells occurs during apoptosis and during some other specific physiological processes, and this translocation is responsible for profound life-or-death events. Moreover, mitochondrial function is severely impaired when the PE content of mitochondria is reduced below a threshold level. The discovery and implications of the existence of membrane contact sites between the endoplasmic reticulum and mitochondria and their relevance for PS and PE metabolism, as well as for mitochondrial function, are also discussed. Many of the recent advances in these fields are due to the use of isotope labeling for tracing biochemical pathways. In addition, techniques for disruption of specific genes in mice are now widely used and have provided major breakthroughs in understanding the roles and metabolism of PS and PE in vivo.
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Affiliation(s)
- Jean E Vance
- Department of Medicine and Group on the Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta T6G 2S2, Canada.
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Sassano ML, van Vliet AR, Agostinis P. Mitochondria-Associated Membranes As Networking Platforms and Regulators of Cancer Cell Fate. Front Oncol 2017; 7:174. [PMID: 28868254 PMCID: PMC5563315 DOI: 10.3389/fonc.2017.00174] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 07/31/2017] [Indexed: 01/05/2023] Open
Abstract
The tight cross talk between two essential organelles of the cell, the endoplasmic reticulum (ER) and mitochondria, is spatially and functionally regulated by specific microdomains known as the mitochondria-associated membranes (MAMs). MAMs are hot spots of Ca2+ transfer between the ER and mitochondria, and emerging data indicate their vital role in the regulation of fundamental physiological processes, chief among them mitochondria bioenergetics, proteostasis, cell death, and autophagy. Moreover, and perhaps not surprisingly, it has become clear that signaling events regulated at the ER-mitochondria intersection regulate key processes in oncogenesis and in the response of cancer cells to therapeutics. ER-mitochondria appositions have been shown to dynamically recruit oncogenes and tumor suppressors, modulating their activity and protein complex formation, adapt the bioenergetic demand of cancer cells and to regulate cell death pathways and redox signaling in cancer cells. In this review, we discuss some emerging players of the ER-mitochondria contact sites in mammalian cells, the key processes they regulate and recent evidence highlighting the role of MAMs in shaping cell-autonomous and non-autonomous signals that regulate cancer growth.
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Affiliation(s)
- Maria Livia Sassano
- Cell Death Research and Therapy (CDRT) Laboratory, Department of Cellular and Molecular Medicine, KU Leuven University of Leuven, Leuven, Belgium
| | - Alexander R. van Vliet
- Cell Death Research and Therapy (CDRT) Laboratory, Department of Cellular and Molecular Medicine, KU Leuven University of Leuven, Leuven, Belgium
| | - Patrizia Agostinis
- Cell Death Research and Therapy (CDRT) Laboratory, Department of Cellular and Molecular Medicine, KU Leuven University of Leuven, Leuven, Belgium
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48
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Schrader M, Pellegrini L. The making of a mammalian peroxisome, version 2.0: mitochondria get into the mix. Cell Death Differ 2017; 24:1148-1152. [PMID: 28409773 PMCID: PMC5520164 DOI: 10.1038/cdd.2017.23] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Accepted: 02/06/2017] [Indexed: 01/03/2023] Open
Abstract
A recent report from the Laboratory of Heidi McBride (McGill University) presents a role for mitochondria in the de novo biogenesis of peroxisomes in mammalian cells. Peroxisomes are essential organelles responsible for a wide variety of biochemical functions, from the generation of bile to plasmalogen synthesis, reduction of peroxides, and the oxidation of very-long-chain fatty acids. Like mitochondria, peroxisomes proliferate primarily through growth and division of pre-existing peroxisomes. However, unlike mitochondria, peroxisomes do not fuse; further, and perhaps most importantly, they can also be born de novo, a process thought to occur through the generation of pre-peroxisomal vesicles that originate from the endoplasmic reticulum. De novo peroxisome biogenesis has been extensively studied in yeast, with a major focus on the role of the ER in this process; however, in the mammalian system this field is much less explored. By exploiting patient cells lacking mature peroxisomes, the McBride laboratory now assigns a role to ER and mitochondria in de novo mammalian peroxisome biogenesis by showing that the formation of immature pre-peroxisomes occurs through the fusion of Pex3-/Pex14-containing mitochondria-derived vesicles with Pex16-containing ER-derived vesicles.
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Affiliation(s)
| | - Luca Pellegrini
- Faculty of Medicine, Department of Molecular Biology, Medical Biochemistry and Pathology, Universitè Laval, Quebec, QC, Canada
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49
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Herrera-Cruz MS, Simmen T. Cancer: Untethering Mitochondria from the Endoplasmic Reticulum? Front Oncol 2017; 7:105. [PMID: 28603693 PMCID: PMC5445141 DOI: 10.3389/fonc.2017.00105] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 05/05/2017] [Indexed: 01/18/2023] Open
Abstract
Following the discovery of the mitochondria-associated membrane (MAM) as a hub for lipid metabolism in 1990 and its description as one of the first examples for membrane contact sites at the turn of the century, the past decade has seen the emergence of this structure as a potential regulator of cancer growth and metabolism. The mechanistic basis for this hypothesis is that the MAM accommodates flux of Ca2+ from the endoplasmic reticulum (ER) to mitochondria. This flux then determines mitochondrial ATP production, known to be low in many tumors as part of the Warburg effect. However, low mitochondrial Ca2+ flux also reduces the propensity of tumor cells to undergo apoptosis, another cancer hallmark. Numerous regulators of this flux have been recently identified as MAM proteins. Not surprisingly, many fall into the groups of tumor suppressors and oncogenes. Given the important role that the MAM could play in cancer, it is expected that proteins mediating its formation are particularly implicated in tumorigenesis. Examples for such proteins are mitofusin-2 and phosphofurin acidic cluster sorting protein 2 that likely act as tumor suppressors. This review discusses how these proteins that mediate or regulate ER–mitochondria tethering are (or are not) promoting or inhibiting tumorigenesis. The emerging picture of MAMs in cancer seems to indicate that in addition to the downregulation of mitochondrial Ca2+ import, MAM defects are but one way how cancer cells control mitochondria metabolism and apoptosis.
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Affiliation(s)
- Maria Sol Herrera-Cruz
- Faculty of Medicine and Dentistry, Department of Cell Biology, University of Alberta, Edmonton, AB, Canada
| | - Thomas Simmen
- Faculty of Medicine and Dentistry, Department of Cell Biology, University of Alberta, Edmonton, AB, Canada
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50
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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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