51
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Simmen T, Herrera-Cruz MS. Plastic mitochondria-endoplasmic reticulum (ER) contacts use chaperones and tethers to mould their structure and signaling. Curr Opin Cell Biol 2018; 53:61-69. [DOI: 10.1016/j.ceb.2018.04.014] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 04/10/2018] [Accepted: 04/30/2018] [Indexed: 12/19/2022]
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52
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Eisner V, Picard M, Hajnóczky G. Mitochondrial dynamics in adaptive and maladaptive cellular stress responses. Nat Cell Biol 2018; 20:755-765. [PMID: 29950571 PMCID: PMC6716149 DOI: 10.1038/s41556-018-0133-0] [Citation(s) in RCA: 427] [Impact Index Per Article: 61.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 05/29/2018] [Indexed: 12/22/2022]
Abstract
Mitochondria sense and respond to many stressors and can support either cell survival or death through energy production and signaling pathways. Mitochondrial responses depend on fusion-fission dynamics that dilute and segregate damaged mitochondria. Mitochondrial motility and inter-organellar interactions, including with the endoplasmic reticulum, also function in cellular adaptation to stress. In this Review, we discuss how stressors influence these components, and how they contribute to the complex adaptive and pathological responses that lead to disease.
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Affiliation(s)
- Verónica Eisner
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Martin Picard
- Division of Behavioral Medicine, Departments of Psychiatry and Neurology, The Merritt Center, Columbia Translational Neuroscience Initiative, Columbia Aging Center, Columbia University Medical Center, New York, NY, USA
| | - György Hajnóczky
- MitoCare Center, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA.
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53
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Csordás G, Weaver D, Hajnóczky G. Endoplasmic Reticulum-Mitochondrial Contactology: Structure and Signaling Functions. Trends Cell Biol 2018; 28:523-540. [PMID: 29588129 DOI: 10.1016/j.tcb.2018.02.009] [Citation(s) in RCA: 426] [Impact Index Per Article: 60.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 02/23/2018] [Accepted: 02/23/2018] [Indexed: 02/08/2023]
Abstract
Interorganellar contacts are increasingly recognized as central to the control of cellular behavior. These contacts, which typically involve a small fraction of the endomembrane surface, are local communication hubs that resemble synapses. We propose the term contactology to denote the analysis of interorganellar contacts. Endoplasmic reticulum (ER) contacts with mitochondria were recognized several decades ago; major roles in ion and lipid transfer, signaling, and membrane dynamics have been established, while others continue to emerge. The functional diversity of ER-mitochondrial (ER-mito) contacts is mirrored in their structural heterogeneity, with subspecialization likely supported by multiple, different linker-forming protein structures. The nanoscale size of the contacts has made studying their structure, function, and dynamics difficult. This review focuses on the structure of the ER-mito contacts, methods for studying them, and the roles of contacts in Ca2+ and reactive oxygen species (ROS) signaling.
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Affiliation(s)
- György Csordás
- MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA.
| | - David Weaver
- MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA.
| | - György Hajnóczky
- MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA.
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54
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Delprat B, Maurice T, Delettre C. Wolfram syndrome: MAMs' connection? Cell Death Dis 2018; 9:364. [PMID: 29511163 PMCID: PMC5840383 DOI: 10.1038/s41419-018-0406-3] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 02/13/2018] [Accepted: 02/13/2018] [Indexed: 12/28/2022]
Abstract
Wolfram syndrome (WS) is a rare neurodegenerative disease, the main pathological hallmarks of which associate with diabetes, optic atrophy, and deafness. Other symptoms may be identified in some but not all patients. Prognosis is poor, with death occurring around 35 years of age. To date, no treatment is available. WS was first described as a mitochondriopathy. However, the localization of the protein on the endoplasmic reticulum (ER) membrane challenged this hypothesis. ER contacts mitochondria to ensure effective Ca2+ transfer, lipids transfer, and apoptosis within stabilized and functionalized microdomains, termed “mitochondria-associated ER membranes” (MAMs). Two types of WS are characterized so far and Wolfram syndrome type 2 is due to mutation in CISD2, a protein mostly expressed in MAMs. The aim of the present review is to collect evidences showing that WS is indeed a mitochondriopathy, with established MAM dysfunction, and thus share commonalities with several neurodegenerative diseases, including Alzheimer’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis, as well as metabolic diseases, such as diabetes.
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Affiliation(s)
- Benjamin Delprat
- INSERM UMR-S1198, 34095, Montpellier, France. .,University of Montpellier, 34095, Montpellier, France.
| | - Tangui Maurice
- INSERM UMR-S1198, 34095, Montpellier, France.,University of Montpellier, 34095, Montpellier, France
| | - Cécile Delettre
- University of Montpellier, 34095, Montpellier, France. .,INSERM UMR-S1051, Institute of Neurosciences of Montpellier, 34090, Montpellier, France.
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55
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Bcl-2 inhibitors as anti-cancer therapeutics: The impact of and on calcium signaling. Cell Calcium 2018; 70:102-116. [DOI: 10.1016/j.ceca.2017.05.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 05/24/2017] [Accepted: 05/24/2017] [Indexed: 01/08/2023]
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56
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Redox crosstalk at endoplasmic reticulum (ER) membrane contact sites (MCS) uses toxic waste to deliver messages. Cell Death Dis 2018; 9:331. [PMID: 29491367 PMCID: PMC5832433 DOI: 10.1038/s41419-017-0033-4] [Citation(s) in RCA: 169] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 09/29/2017] [Accepted: 10/03/2017] [Indexed: 12/17/2022]
Abstract
Many cellular redox reactions housed within mitochondria, peroxisomes and the endoplasmic reticulum (ER) generate hydrogen peroxide (H2O2) and other reactive oxygen species (ROS). The contribution of each organelle to the total cellular ROS production is considerable, but varies between cell types and also over time. Redox-regulatory enzymes are thought to assemble at a “redox triangle” formed by mitochondria, peroxisomes and the ER, assembling “redoxosomes” that sense ROS accumulations and redox imbalances. The redoxosome enzymes use ROS, potentially toxic by-products made by some redoxosome members themselves, to transmit inter-compartmental signals via chemical modifications of downstream proteins and lipids. Interestingly, important components of the redoxosome are ER chaperones and oxidoreductases, identifying ER oxidative protein folding as a key ROS producer and controller of the tri-organellar membrane contact sites (MCS) formed at the redox triangle. At these MCS, ROS accumulations could directly facilitate inter-organellar signal transmission, using ROS transporters. In addition, ROS influence the flux of Ca2+ ions, since many Ca2+ handling proteins, including inositol 1,4,5 trisphosphate receptors (IP3Rs), SERCA pumps or regulators of the mitochondrial Ca2+ uniporter (MCU) are redox-sensitive. Fine-tuning of these redox and ion signaling pathways might be difficult in older organisms, suggesting a dysfunctional redox triangle may accompany the aging process.
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57
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Kerkhofs M, Bittremieux M, Morciano G, Giorgi C, Pinton P, Parys JB, Bultynck G. Emerging molecular mechanisms in chemotherapy: Ca 2+ signaling at the mitochondria-associated endoplasmic reticulum membranes. Cell Death Dis 2018; 9:334. [PMID: 29491433 PMCID: PMC5832420 DOI: 10.1038/s41419-017-0179-0] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 10/27/2017] [Accepted: 11/03/2017] [Indexed: 12/13/2022]
Abstract
Inter-organellar communication often takes the form of Ca2+ signals. These Ca2+ signals originate from the endoplasmic reticulum (ER) and regulate different cellular processes like metabolism, fertilization, migration, and cell fate. A prime target for Ca2+ signals are the mitochondria. ER-mitochondrial Ca2+ transfer is possible through the existence of mitochondria-associated ER membranes (MAMs), ER structures that are in the proximity of the mitochondria. This creates a micro-domain in which the Ca2+ concentrations are manifold higher than in the cytosol, allowing for rapid mitochondrial Ca2+ uptake. In the mitochondria, the Ca2+ signal is decoded differentially depending on its spatiotemporal characteristics. While Ca2+ oscillations stimulate metabolism and constitute pro-survival signaling, mitochondrial Ca2+ overload results in apoptosis. Many chemotherapeutics depend on efficient ER-mitochondrial Ca2+ signaling to exert their function. However, several oncogenes and tumor suppressors present in the MAMs can alter Ca2+ signaling in cancer cells, rendering chemotherapeutics ineffective. In this review, we will discuss recent studies that connect ER-mitochondrial Ca2+ transfer, tumor suppressors and oncogenes at the MAMs, and chemotherapy.
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Affiliation(s)
- Martijn Kerkhofs
- Department of Cellular and Molecular Medicine and Leuven Kanker Instituut, KU Leuven, Laboratory of Molecular and Cellular Signaling, Leuven, Belgium
| | - Mart Bittremieux
- Department of Cellular and Molecular Medicine and Leuven Kanker Instituut, KU Leuven, Laboratory of Molecular and Cellular Signaling, Leuven, Belgium
| | - Giampaolo Morciano
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
- Cecilia Hospital, GVM Care & Research, E.S: Health Science Foundation, Cotignola, Italy
| | - Carlotta Giorgi
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Paolo Pinton
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
- Cecilia Hospital, GVM Care & Research, E.S: Health Science Foundation, Cotignola, Italy
- CNR Institute of Cell Biology and Neurobiology, Monterotondo, Italy
| | - Jan B Parys
- Department of Cellular and Molecular Medicine and Leuven Kanker Instituut, KU Leuven, Laboratory of Molecular and Cellular Signaling, Leuven, Belgium
| | - Geert Bultynck
- Department of Cellular and Molecular Medicine and Leuven Kanker Instituut, KU Leuven, Laboratory of Molecular and Cellular Signaling, Leuven, Belgium.
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58
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Bergmann TJ, Fregno I, Fumagalli F, Rinaldi A, Bertoni F, Boersema PJ, Picotti P, Molinari M. Chemical stresses fail to mimic the unfolded protein response resulting from luminal load with unfolded polypeptides. J Biol Chem 2018; 293:5600-5612. [PMID: 29453283 DOI: 10.1074/jbc.ra117.001484] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 01/23/2018] [Indexed: 12/16/2022] Open
Abstract
The stress sensors ATF6, IRE1, and PERK monitor deviations from homeostatic conditions in the endoplasmic reticulum (ER), a protein biogenesis compartment of eukaryotic cells. Their activation elicits unfolded protein responses (UPR) to re-establish proteostasis. UPR have been extensively investigated in cells exposed to chemicals that activate ER stress sensors by perturbing calcium, N-glycans, or redox homeostasis. Cell responses to variations in luminal load with unfolded proteins are, in contrast, poorly characterized. Here, we compared gene and protein expression profiles in HEK293 cells challenged with ER stress-inducing drugs or expressing model polypeptides. Drug titration to limit up-regulation of the endogenous ER stress reporters heat shock protein family A (Hsp70) member 5 (BiP/HSPA5) and homocysteine-inducible ER protein with ubiquitin-like domain 1 (HERP/HERPUD1) to levels comparable with luminal accumulation of unfolded proteins substantially reduced the amplitude of both transcriptional and translational responses. However, these drug-induced changes remained pleiotropic and failed to recapitulate responses to ER load with unfolded proteins. These required unfolded protein association with BiP and induced a much smaller subset of genes participating in a chaperone complex that binds unfolded peptide chains. In conclusion, UPR resulting from ER load with unfolded proteins proceed via a well-defined and fine-tuned pathway, whereas even mild chemical stresses caused by compounds often used to stimulate UPR induce cellular responses largely unrelated to the UPR or ER-mediated protein secretion.
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Affiliation(s)
- Timothy J Bergmann
- From the Università della Svizzera italiana, 6900 Lugano, Switzerland.,the Institute for Research in Biomedicine, 6500 Bellinzona, Switzerland.,the Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Ilaria Fregno
- From the Università della Svizzera italiana, 6900 Lugano, Switzerland.,the Institute for Research in Biomedicine, 6500 Bellinzona, Switzerland.,the Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Fiorenza Fumagalli
- From the Università della Svizzera italiana, 6900 Lugano, Switzerland.,the Institute for Research in Biomedicine, 6500 Bellinzona, Switzerland.,the Graduate School for Cellular and Biomedical Sciences, University of Bern, 3001 Bern, Switzerland
| | - Andrea Rinaldi
- From the Università della Svizzera italiana, 6900 Lugano, Switzerland.,the Istituto Oncologico di Ricerca, 6500 Bellinzona, Switzerland, and
| | - Francesco Bertoni
- From the Università della Svizzera italiana, 6900 Lugano, Switzerland.,the Istituto Oncologico di Ricerca, 6500 Bellinzona, Switzerland, and
| | - Paul J Boersema
- the Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Paola Picotti
- the Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Maurizio Molinari
- From the Università della Svizzera italiana, 6900 Lugano, Switzerland, .,the Institute for Research in Biomedicine, 6500 Bellinzona, Switzerland.,the École Polytechnique Fédérale de Lausanne, School of Life Sciences, 1015 Lausanne, Switzerland
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59
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Radif Y, Ndiaye H, Kalantzi V, Jacobs R, Hall A, Minogue S, Waugh MG. The endogenous subcellular localisations of the long chain fatty acid-activating enzymes ACSL3 and ACSL4 in sarcoma and breast cancer cells. Mol Cell Biochem 2018; 448:275-286. [PMID: 29450800 PMCID: PMC6182735 DOI: 10.1007/s11010-018-3332-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 02/09/2018] [Indexed: 12/22/2022]
Abstract
Fatty acid uptake and metabolism are often dysregulated in cancer cells. Fatty acid activation is a critical step that allows these biomolecules to enter cellular metabolic pathways such as mitochondrial β-oxidation for ATP generation or the lipogenic routes that generate bioactive lipids such as the inositol phospholipids. Fatty acid activation by the addition of coenzyme A is catalysed by a family of enzymes called the acyl CoA synthetase ligases (ACSL). Furthermore, enhanced expression of particular ACSL isoforms, such as ACSL4, is a feature of some more aggressive cancers and may contribute to the oncogenic phenotype. This study focuses on ACSL3 and ACSL4, closely related structural homologues that preferentially activate palmitate and arachidonate fatty acids, respectively. In this study, immunohistochemical screening of multiple soft tissue tumour arrays revealed that ACSL3 and ACSL4 were highly, but differentially, expressed in a subset of leiomyosarcomas, fibrosarcomas and rhabdomyosarcomas, with consistent cytoplasmic and granular stainings of tumour cells. The intracellular localisations of endogenously expressed ACSL3 and ACSL4 were further investigated by detailed subcellular fractionation analyses of HT1080 fibrosarcoma and MCF-7 breast cancer cells. ACSL3 distribution closely overlapped with proteins involved in trafficking from the trans-Golgi network and endosomes. In contrast, the ACSL4 localisation pattern more closely followed that of calnexin which is an endoplasmic reticulum resident chaperone. Confocal immunofluorescence imaging of MCF-7 cells confirmed the intracellular localisations of both enzymes. These observations reveal new information regarding the compartmentation of fatty acid metabolism in cancer cells.
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Affiliation(s)
- Yassmeen Radif
- Lipid & Membrane Biology Group, University College London, Floor U3, Royal Free Hospital Campus, Rowland Hill Street, London, NW3 2PF, UK
| | - Haarith Ndiaye
- Lipid & Membrane Biology Group, University College London, Floor U3, Royal Free Hospital Campus, Rowland Hill Street, London, NW3 2PF, UK
| | - Vasiliki Kalantzi
- Lipid & Membrane Biology Group, University College London, Floor U3, Royal Free Hospital Campus, Rowland Hill Street, London, NW3 2PF, UK
| | - Ruth Jacobs
- Lipid & Membrane Biology Group, University College London, Floor U3, Royal Free Hospital Campus, Rowland Hill Street, London, NW3 2PF, UK
| | - Andrew Hall
- Sheila Sherlock Liver Centre, Royal Free London NHS Foundation Trust and UCL Institute for Liver and Digestive Health, University College London, London, UK
| | - Shane Minogue
- Lipid & Membrane Biology Group, University College London, Floor U3, Royal Free Hospital Campus, Rowland Hill Street, London, NW3 2PF, UK
| | - Mark G Waugh
- Lipid & Membrane Biology Group, University College London, Floor U3, Royal Free Hospital Campus, Rowland Hill Street, London, NW3 2PF, UK.
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60
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Jiang H, Zhang X, Chen X, Aramsangtienchai P, Tong Z, Lin H. Protein Lipidation: Occurrence, Mechanisms, Biological Functions, and Enabling Technologies. Chem Rev 2018; 118:919-988. [PMID: 29292991 DOI: 10.1021/acs.chemrev.6b00750] [Citation(s) in RCA: 331] [Impact Index Per Article: 47.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Protein lipidation, including cysteine prenylation, N-terminal glycine myristoylation, cysteine palmitoylation, and serine and lysine fatty acylation, occurs in many proteins in eukaryotic cells and regulates numerous biological pathways, such as membrane trafficking, protein secretion, signal transduction, and apoptosis. We provide a comprehensive review of protein lipidation, including descriptions of proteins known to be modified and the functions of the modifications, the enzymes that control them, and the tools and technologies developed to study them. We also highlight key questions about protein lipidation that remain to be answered, the challenges associated with answering such questions, and possible solutions to overcome these challenges.
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Affiliation(s)
- Hong Jiang
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Xiaoyu Zhang
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Xiao Chen
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Pornpun Aramsangtienchai
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Zhen Tong
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
| | - Hening Lin
- Howard Hughes Medical Institute, Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States
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61
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McMichael TM, Zhang L, Chemudupati M, Hach JC, Kenney AD, Hang HC, Yount JS. The palmitoyltransferase ZDHHC20 enhances interferon-induced transmembrane protein 3 (IFITM3) palmitoylation and antiviral activity. J Biol Chem 2017; 292:21517-21526. [PMID: 29079573 DOI: 10.1074/jbc.m117.800482] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2017] [Revised: 10/23/2017] [Indexed: 01/21/2023] Open
Abstract
Interferon-induced transmembrane protein 3 (IFITM3) is a cellular endosome- and lysosome-localized protein that restricts numerous virus infections. IFITM3 is activated by palmitoylation, a lipid posttranslational modification. Palmitoylation of proteins is primarily mediated by zinc finger DHHC domain-containing palmitoyltransferases (ZDHHCs), but which members of this enzyme family can modify IFITM3 is not known. Here, we screened a library of human cell lines individually lacking ZDHHCs 1-24 and found that IFITM3 palmitoylation and its inhibition of influenza virus infection remained strong in the absence of any single ZDHHC, suggesting functional redundancy of these enzymes in the IFITM3-mediated antiviral response. In an overexpression screen with 23 mammalian ZDHHCs, we unexpectedly observed that more than half of the ZDHHCs were capable of increasing IFITM3 palmitoylation with ZDHHCs 3, 7, 15, and 20 having the greatest effect. Among these four enzymes, ZDHHC20 uniquely increased IFITM3 antiviral activity when both proteins were overexpressed. ZDHHC20 colocalized extensively with IFITM3 at lysosomes unlike ZDHHCs 3, 7, and 15, which showed a defined perinuclear localization pattern, suggesting that the location at which IFITM3 is palmitoylated may influence its activity. Unlike knock-out of individual ZDHHCs, siRNA-mediated knockdown of both ZDHHC3 and ZDHHC7 in ZDHHC20 knock-out cells decreased endogenous IFITM3 palmitoylation. Overall, our results demonstrate that multiple ZDHHCs can palmitoylate IFITM3 to ensure a robust antiviral response and that ZDHHC20 may serve as a particularly useful tool for understanding and enhancing IFITM3 activity.
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Affiliation(s)
- Temet M McMichael
- From the Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio 43210 and
| | - Lizhi Zhang
- From the Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio 43210 and
| | - Mahesh Chemudupati
- From the Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio 43210 and
| | - Jocelyn C Hach
- From the Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio 43210 and
| | - Adam D Kenney
- From the Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio 43210 and
| | - Howard C Hang
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, New York 10065
| | - Jacob S Yount
- From the Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio 43210 and
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62
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Myrum C, Soulé J, Bittins M, Cavagnini K, Goff K, Ziemek SK, Eriksen MS, Patil S, Szum A, Nair RR, Bramham CR. Arc Interacts with the Integral Endoplasmic Reticulum Protein, Calnexin. Front Cell Neurosci 2017; 11:294. [PMID: 28979192 PMCID: PMC5611444 DOI: 10.3389/fncel.2017.00294] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 09/05/2017] [Indexed: 11/13/2022] Open
Abstract
Activity-regulated cytoskeleton-associated protein, Arc, is a major regulator of long-term synaptic plasticity and memory formation. Here we reveal a novel interaction partner of Arc, a resident endoplasmic reticulum transmembrane protein, calnexin. We show an interaction between recombinantly-expressed GST-tagged Arc and endogenous calnexin in HEK293, SH-SY5Y neuroblastoma and PC12 cells. The interaction was dependent on the central linker region of the Arc protein that is also required for endocytosis of AMPA-type glutamate receptors. High-resolution proximity-ligation assays (PLAs) demonstrate molecular proximity of endogenous Arc with the cytosolic C-terminus, but not the lumenal N-terminus of calnexin. In hippocampal neuronal cultures treated with brain-derived neurotrophic factor (BDNF), Arc interacted with calnexin in the perinuclear cytoplasm and dendritic shaft. Arc also interacted with C-terminal calnexin in the adult rat dentate gyrus (DG). After induction of long-term potentiation (LTP) in the perforant path projection to the DG of adult anesthetized rats, enhanced interaction between Arc and calnexin was obtained in the dentate granule cell layer (GCL). Although Arc and calnexin are both implicated in the regulation of receptor endocytosis, no modulation of endocytosis was detected in transferrin uptake assays. Previous work showed that Arc interacts with multiple protein partners to regulate synaptic transmission and nuclear signaling. The identification of calnexin as a binding partner further supports the role of Arc as a hub protein and extends the range of Arc function to the endoplasmic reticulum, though the function of the Arc/calnexin interaction remains to be defined.
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Affiliation(s)
- Craig Myrum
- Dr. Einar Martens Research Group for Biological Psychiatry, Center for Medical Genetics and Molecular Medicine, Haukeland University HospitalBergen, Norway.,Department of Biomedicine and the K.G. Jebsen Center for Research on Neuropsychiatric Disorders, University of BergenBergen, Norway
| | - Jonathan Soulé
- Department of Biomedicine and the K.G. Jebsen Center for Research on Neuropsychiatric Disorders, University of BergenBergen, Norway
| | - Margarethe Bittins
- Department of Biomedicine and the K.G. Jebsen Center for Research on Neuropsychiatric Disorders, University of BergenBergen, Norway
| | - Kyle Cavagnini
- Department of Biomedicine and the K.G. Jebsen Center for Research on Neuropsychiatric Disorders, University of BergenBergen, Norway
| | - Kevin Goff
- Department of Biomedicine and the K.G. Jebsen Center for Research on Neuropsychiatric Disorders, University of BergenBergen, Norway
| | - Silje K Ziemek
- Department of Biomedicine and the K.G. Jebsen Center for Research on Neuropsychiatric Disorders, University of BergenBergen, Norway
| | - Maria S Eriksen
- Department of Biomedicine and the K.G. Jebsen Center for Research on Neuropsychiatric Disorders, University of BergenBergen, Norway
| | - Sudarshan Patil
- Department of Biomedicine and the K.G. Jebsen Center for Research on Neuropsychiatric Disorders, University of BergenBergen, Norway
| | - Adrian Szum
- Department of Biomedicine and the K.G. Jebsen Center for Research on Neuropsychiatric Disorders, University of BergenBergen, Norway
| | - Rajeevkumar R Nair
- Department of Biomedicine and the K.G. Jebsen Center for Research on Neuropsychiatric Disorders, University of BergenBergen, Norway
| | - Clive R Bramham
- Department of Biomedicine and the K.G. Jebsen Center for Research on Neuropsychiatric Disorders, University of BergenBergen, Norway
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63
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Maternal intake of trans-unsaturated or interesterified fatty acids during pregnancy and lactation modifies mitochondrial bioenergetics in the liver of adult offspring in mice. Br J Nutr 2017; 118:41-52. [DOI: 10.1017/s0007114517001817] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
AbstractThe quality of dietary lipids in the maternal diet can programme the offspring to diseases in later life. We investigated whether the maternal intake of palm oil or interesterified fat, substitutes for trans-unsaturated fatty acids (FA), induces metabolic changes in the adult offspring. During pregnancy and lactation, C57BL/6 female mice received normolipidic diets containing partially hydrogenated vegetable fat rich in trans-unsaturated fatty acids (TG), palm oil (PG), interesterified fat (IG) or soyabean oil (CG). After weaning, male offspring from all groups received the control diet until day 110. Plasma glucose and TAG and liver FA profiles were ascertained. Liver mitochondrial function was accessed with high-resolution respirometry by measuring VO2, fluorimetry for detection of hydrogen peroxide (H2O2) production and mitochondrial Ca2+ uptake. The results showed that the IG offspring presented a 20 % increase in plasma glucose and both the IG and TG offspring presented a 2- and 1·9-fold increase in TAG, respectively, when compared with CG offspring. Liver MUFA and PUFA contents decreased in the TG and IG offspring when compared with CG offspring. Liver MUFA content also decreased in the PG offspring. These modifications in FA composition possibly affected liver mitochondrial function, as respiration was impaired in the TG offspring and H2O2 production was higher in the IG offspring. In addition, mitochondrial Ca2+ retention capacity was reduced by approximately 40 and 55 % in the TG and IG offspring, respectively. In conclusion, maternal consumption of trans-unsaturated and interesterified fat affected offspring health by compromising mitochondrial bioenergetics and lipid metabolism in the liver.
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The Lectin Chaperone Calnexin Is Involved in the Endoplasmic Reticulum Stress Response by Regulating Ca 2+ Homeostasis in Aspergillus nidulans. Appl Environ Microbiol 2017; 83:AEM.00673-17. [PMID: 28550061 DOI: 10.1128/aem.00673-17] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 05/18/2017] [Indexed: 12/23/2022] Open
Abstract
The Ca2+-mediated signaling pathway is crucial for environmental adaptation in fungi. Here we show that calnexin, a molecular chaperone located in the endoplasmic reticulum (ER), plays an important role in regulating the cytosolic free calcium concentration ([Ca2+]c) in Aspergillus nidulans Inactivation of calnexin (ClxA) in A. nidulans caused severe defects in hyphal growth and conidiation under ER stress caused by the ER stress-inducing agent dithiothreitol (DTT) or high temperature. Importantly, defects in the ΔclxA mutant were restored by the addition of extracellular calcium. Furthermore, the CchA/MidA complex (the high-affinity Ca2+ channels), calcineurin (calcium/calmodulin-dependent protein phosphatase), and PmrA (secretory pathway Ca2+ ATPase) were required for extracellular calcium-based restoration of the DTT/thermal stress sensitivity in the ΔclxA mutant. Interestingly, the ΔclxA mutant exhibited markedly reduced conidium formation and hyphal growth defects under the low-calcium condition, which is similar to defects caused by mutations in MidA/CchA. Moreover, the phenotypic defects were further exacerbated in the ΔclxA ΔmidA ΔcchA mutant, which suggested that ClxA and MidA/CchA are both required under the calcium-limiting condition. Using the calcium-sensitive photoprotein aequorin to monitor [Ca2+]c in living cells, we found that ClxA and MidA/CchA complex synergistically coordinate transient increase in [Ca2+]c in response to extracellular calcium. Moreover, ClxA, in particular its luminal domain, plays a role in mediating the transient [Ca2+]c in response to DTT-induced ER stress in the absence of extracellular calcium, indicating ClxA may mediate calcium release from internal calcium stores. Our findings provide new insights into the role of calnexin in the regulation of calcium-mediated response in fungal ER stress adaptation.IMPORTANCE Calnexin is a well-known molecular chaperone conserved from yeast to humans. Although it contains calcium binding domains, little is known about the role of calnexin in Ca2+ regulation. In this study, we demonstrate that calnexin (ClxA) in the filamentous fungus Aspergillus nidulans, similar to the high-affinity calcium uptake system (HACS), is required for normal growth and conidiation under the calcium-limiting condition. The ClxA dysfunction decreases the transient cytosolic free calcium concentration ([Ca2+]c) induced by a high extracellular calcium or DTT-induced ER stress. Our findings provide the direct evidence that calnexin plays important roles in regulating Ca2+ homeostasis in addition to its role as a molecular chaperone in fungi. These results provide new insights into the roles of calnexin and expand knowledge of fungal stress adaptation.
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65
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Chemaly ER, Troncone L, Lebeche D. SERCA control of cell death and survival. Cell Calcium 2017; 69:46-61. [PMID: 28747251 DOI: 10.1016/j.ceca.2017.07.001] [Citation(s) in RCA: 132] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 07/03/2017] [Accepted: 07/03/2017] [Indexed: 12/31/2022]
Abstract
Intracellular calcium (Ca2+) is a critical coordinator of various aspects of cellular physiology. It is increasingly apparent that changes in cellular Ca2+ dynamics contribute to the regulation of normal and pathological signal transduction that controls cell growth and survival. Aberrant perturbations in Ca2+ homeostasis have been implicated in a range of pathological conditions, such as cardiovascular diseases, diabetes, tumorigenesis and steatosis hepatitis. Intracellular Ca2+ concentrations are therefore tightly regulated by a number of Ca2+ handling enzymes, proteins, channels and transporters located in the plasma membrane and in Ca2+ storage organelles, which work in concert to fine tune a temporally and spatially precise Ca2+ signal. Chief amongst them is the sarco/endoplasmic reticulum (SR/ER) Ca2+ ATPase pump (SERCA) which actively re-accumulates released Ca2+ back into the SR/ER, therefore maintaining Ca2+ homeostasis. There are at least 14 different SERCA isoforms encoded by three ATP2A1-3 genes whose expressions are species- and tissue-specific. Altered SERCA expression and activity results in cellular malignancy and induction of ER stress and ER stress-associated apoptosis. The role of SERCA misregulation in the control of apoptosis in various cell types and disease setting with prospective therapeutic implications is the focus of this review. Ca2+ is a double edge sword for both life as well as death, and current experimental evidence supports a model in which Ca2+ homeostasis and SERCA activity represent a nodal point that controls cell survival. Pharmacological or genetic targeting of this axis constitutes an incredible therapeutic potential to treat different diseases sharing similar biological disorders.
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Affiliation(s)
- Elie R Chemaly
- Division of Nephrology and Hypertension, Department of Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Luca Troncone
- Cardiovascular Research Institute, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Djamel Lebeche
- Cardiovascular Research Institute, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA; Diabetes, Obesity and Metabolism Institute, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA; Graduate School of Biological Sciences, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
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66
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Chen JJ, Boehning D. Protein Lipidation As a Regulator of Apoptotic Calcium Release: Relevance to Cancer. Front Oncol 2017; 7:138. [PMID: 28706877 PMCID: PMC5489567 DOI: 10.3389/fonc.2017.00138] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 06/16/2017] [Indexed: 12/16/2022] Open
Abstract
Calcium is a critical regulator of cell death pathways. One of the most proximal events leading to cell death is activation of plasma membrane and endoplasmic reticulum-resident calcium channels. A large body of evidence indicates that defects in this pathway contribute to cancer development. Although we have a thorough understanding of how downstream elevations in cytosolic and mitochondrial calcium contribute to cell death, it is much less clear how calcium channels are activated upstream of the apoptotic stimulus. Recently, it has been shown that protein lipidation is a potent regulator of apoptotic signaling. Although classically thought of as a static modification, rapid and reversible protein acylation has emerged as a new signaling paradigm relevant to many pathways, including calcium release and cell death. In this review, we will discuss the role of protein lipidation in regulating apoptotic calcium signaling with direct therapeutic relevance to cancer.
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Affiliation(s)
- Jessica J Chen
- Department of Biochemistry and Molecular Biology, McGovern Medical School, UTHealth, Houston, TX, United States
| | - Darren Boehning
- Department of Biochemistry and Molecular Biology, McGovern Medical School, UTHealth, Houston, TX, United States
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67
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Gutiérrez T, Simmen T. Endoplasmic reticulum chaperones tweak the mitochondrial calcium rheostat to control metabolism and cell death. Cell Calcium 2017; 70:64-75. [PMID: 28619231 DOI: 10.1016/j.ceca.2017.05.015] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 05/24/2017] [Accepted: 05/24/2017] [Indexed: 12/16/2022]
Abstract
The folding of secretory proteins is a well-understood mechanism, based on decades of research on endoplasmic reticulum (ER) chaperones. These chaperones interact with newly imported polypeptides close to the ER translocon. Classic examples for these proteins include the immunoglobulin binding protein (BiP/GRP78), and the lectins calnexin and calreticulin. Although not considered chaperones per se, the ER oxidoreductases of the protein disulfide isomerase (PDI) family complete the folding job by catalyzing the formation of disulfide bonds through cysteine oxidation. Research from the past decade has demonstrated that ER chaperones are multifunctional proteins. The regulation of ER-mitochondria Ca2+ crosstalk is one of their additional functions, as shown for calnexin, BiP/GRP78 or the oxidoreductases Ero1α and TMX1. This function depends on interactions of this group of proteins with the ER Ca2+ handling machinery. This novel function makes perfect sense for two reasons: i. It allows ER chaperones to control mitochondrial apoptosis instantly without a lengthy bypass involving the upregulation of pro-apoptotic transcription factors via the unfolded protein response (UPR); and ii. It allows the ER protein folding machinery to fine-tune ATP import via controlling the speed of mitochondrial oxidative phosphorylation. Therefore, the role of ER chaperones in regulating ER-mitochondria Ca2+ flux identifies the progression of secretory protein folding as a central regulator of cell survival and death, at least in cell types that secrete large amount of proteins. In other cell types, ER protein folding might serve as a sentinel mechanism that monitors cellular well-being to control cell metabolism and apoptosis. The selenoprotein SEPN1 is a classic example for such a role. Through the control of ER-mitochondria Ca2+-flux, ER chaperones and folding assistants guide cellular apoptosis and mitochondrial metabolism.
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Affiliation(s)
- Tomas Gutiérrez
- Faculty of Medicine and Dentistry, Department of Cell Biology, University of Alberta, Edmonton, T6G2H7, Canada
| | - Thomas Simmen
- Faculty of Medicine and Dentistry, Department of Cell Biology, University of Alberta, Edmonton, T6G2H7, Canada,.
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68
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Krols M, Bultynck G, Janssens S. ER-Mitochondria contact sites: A new regulator of cellular calcium flux comes into play. J Cell Biol 2017; 214:367-70. [PMID: 27528654 PMCID: PMC4987300 DOI: 10.1083/jcb.201607124] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 07/29/2016] [Indexed: 12/19/2022] Open
Abstract
Endoplasmic reticulum (ER)-mitochondria membrane contacts are hotspots for calcium signaling. In this issue, Raturi et al. (2016. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201512077) show that the thioredoxin TMX1 inhibits the calcium pump SERCA2b at ER-mitochondria contact sites, thereby affecting ER-mitochondrial calcium transfer and mitochondrial bioenergetics.
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Affiliation(s)
- Michiel Krols
- Peripheral Neuropathy Group, VIB Department of Molecular Genetics, University of Antwerp, 2610 Antwerpen, Belgium Neurogenetics Laboratory, Institute Born-Bunge, 2610 Antwerpen, Belgium
| | - Geert Bultynck
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium Leuvens Kankerinstituut, KU Leuven, 3000 Leuven, Belgium
| | - Sophie Janssens
- Immunoregulation and Mucosal Immunology Unit, Inflammation Research Center, VIB-UGent, BE-9030 Ghent, Belgium Department of Internal Medicine, Universiteit Gent, BE-9030 Ghent, Belgium
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69
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Endoplasmic reticulum-resident selenoproteins as regulators of calcium signaling and homeostasis. Cell Calcium 2017; 70:76-86. [PMID: 28506443 DOI: 10.1016/j.ceca.2017.05.001] [Citation(s) in RCA: 111] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 04/30/2017] [Indexed: 01/07/2023]
Abstract
The human selenoprotein family contains 25 members that share the common feature of containing the amino acid, selenocysteine (Sec). Seven selenoproteins are localized to the endoplasmic reticulum (ER) and exhibit different structural features contributing to a range of cellular functions. Some of these functions are either directly or indirectly related to calcium (Ca2+) flux or homeostasis. The presence of the unique Sec residue within these proteins allows some to exert oxidoreductase activity, while the function of the Sec in other ER selenoproteins remains unclear. Some functional insight has been achieved by identifying domains within the ER selenoproteins or through the identification of binding partners. For example, selenoproteins K and N (SELENOK AND SELENON) have been characterized through interactions detected with the inositol 1,4,5-triphosphate receptors (IP3Rs) and the SERCA2b pump, respectively. Others have been linked to chaperone functions related to ER stress or Ca2+ homeostasis. This review summarizes the details gathered to date regarding the ER-resident selenoproteins and their effect on Ca2+ regulated pathways and outcomes in cells.
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70
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Lopez-Crisosto C, Pennanen C, Vasquez-Trincado C, Morales PE, Bravo-Sagua R, Quest AFG, Chiong M, Lavandero S. Sarcoplasmic reticulum-mitochondria communication in cardiovascular pathophysiology. Nat Rev Cardiol 2017; 14:342-360. [PMID: 28275246 DOI: 10.1038/nrcardio.2017.23] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Repetitive, calcium-mediated contractile activity renders cardiomyocytes critically dependent on a sustained energy supply and adequate calcium buffering, both of which are provided by mitochondria. Moreover, in vascular smooth muscle cells, mitochondrial metabolism modulates cell growth and proliferation, whereas cytosolic calcium levels regulate the arterial vascular tone. Physical and functional communication between mitochondria and sarco/endoplasmic reticulum and balanced mitochondrial dynamics seem to have a critical role for optimal calcium transfer to mitochondria, which is crucial in calcium homeostasis and mitochondrial metabolism in both types of muscle cells. Moreover, mitochondrial dysfunction has been associated with myocardial damage and dysregulation of vascular smooth muscle proliferation. Therefore, sarco/endoplasmic reticulum-mitochondria coupling and mitochondrial dynamics are now viewed as relevant factors in the pathogenesis of cardiac and vascular diseases, including coronary artery disease, heart failure, and pulmonary arterial hypertension. In this Review, we summarize the evidence related to the role of sarco/endoplasmic reticulum-mitochondria communication in cardiac and vascular muscle physiology, with a focus on how perturbations contribute to the pathogenesis of cardiovascular disorders.
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Affiliation(s)
- Camila Lopez-Crisosto
- Advanced Center for Chronic Diseases (ACCDiS), Facultad de Ciencias Quimicas y Farmaceuticas &Facultad de Medicina, Universidad de Chile, Sergio Livingstone 1007, Santiago 8380492, Chile
| | - Christian Pennanen
- Advanced Center for Chronic Diseases (ACCDiS), Facultad de Ciencias Quimicas y Farmaceuticas &Facultad de Medicina, Universidad de Chile, Sergio Livingstone 1007, Santiago 8380492, Chile
| | - Cesar Vasquez-Trincado
- Advanced Center for Chronic Diseases (ACCDiS), Facultad de Ciencias Quimicas y Farmaceuticas &Facultad de Medicina, Universidad de Chile, Sergio Livingstone 1007, Santiago 8380492, Chile
| | - Pablo E Morales
- Advanced Center for Chronic Diseases (ACCDiS), Facultad de Ciencias Quimicas y Farmaceuticas &Facultad de Medicina, Universidad de Chile, Sergio Livingstone 1007, Santiago 8380492, Chile
| | - Roberto Bravo-Sagua
- Advanced Center for Chronic Diseases (ACCDiS), Facultad de Ciencias Quimicas y Farmaceuticas &Facultad de Medicina, Universidad de Chile, Sergio Livingstone 1007, Santiago 8380492, Chile.,Instituto de Nutricion y Tecnologia de los Alimentos (INTA), Universidad de Chile, Avenida El Líbano 5524, Santiago 7830490, Chile
| | - Andrew F G Quest
- Advanced Center for Chronic Diseases (ACCDiS), Facultad de Ciencias Quimicas y Farmaceuticas &Facultad de Medicina, Universidad de Chile, Sergio Livingstone 1007, Santiago 8380492, Chile.,Centro de Estudios Moleculares de la Celula (CEMC), Instituto de Ciencias Biomedicas, Facultad de Medicina, Universidad de Chile, Independencia 1027, Santiago 8380453, Chile
| | - Mario Chiong
- Advanced Center for Chronic Diseases (ACCDiS), Facultad de Ciencias Quimicas y Farmaceuticas &Facultad de Medicina, Universidad de Chile, Sergio Livingstone 1007, Santiago 8380492, Chile
| | - Sergio Lavandero
- Advanced Center for Chronic Diseases (ACCDiS), Facultad de Ciencias Quimicas y Farmaceuticas &Facultad de Medicina, Universidad de Chile, Sergio Livingstone 1007, Santiago 8380492, Chile.,Centro de Estudios Moleculares de la Celula (CEMC), Instituto de Ciencias Biomedicas, Facultad de Medicina, Universidad de Chile, Independencia 1027, Santiago 8380453, Chile.,Department of Internal Medicine (Cardiology Division), University of Texas Southwestern Medical Center, 6000 Harry Hines Boulevard, Dallas, Texas 75235, USA
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71
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Hepatic stimulator substance inhibits calcium overflow through the mitochondria-associated membrane compartment during nonalcoholic steatohepatitis. J Transl Med 2017; 97:289-301. [PMID: 27991906 DOI: 10.1038/labinvest.2016.139] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 10/26/2016] [Accepted: 11/17/2016] [Indexed: 12/14/2022] Open
Abstract
Nonalcoholic fatty liver disease is considered a disorder of the endoplasmic reticulum (ER) and mitochondria. Recent studies have shown that the ER and mitochondrial membranes overlap by 15-20%, a region referred to as the 'mitochondria-associated ER membrane' (MAM). Some proteins, including sarco/ER calcium ATPase (SERCA), are located in the MAM and have an important role in Ca2+ signaling and homeostasis between the ER and the mitochondria. Our previous study showed that hepatic stimulator substance (HSS) inhibits the ER stress induced by reactive oxygen species, thus reducing mitochondrial damage. However, the mechanism underlying the protective effect of HSS on the ER and ER-mitochondrial interaction remains unclear. In this study, we confirmed that the exogenous expression of HSS protected the liver from steatosis in mice with nonalcoholic steatohepatitis. More importantly, the protection provided by HSS allowed SERCA in the MAM compartment to function well, preventing the extensive influx of cytosolic free Ca2+ to the mitochondria, thus preserving the mitochondrial functions from calcium overload and relieving palmitic-acid-induced hepatocyte steatosis. Our results suggest that the protective effect of HSS on SERCA expression is associated with the maintenance of calcium homeostasis within the MAM, thus ameliorating the disordered Ca2+ communication between the ER and mitochondria.
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72
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Calumenin contributes to ER-Ca 2+ homeostasis in bronchial epithelial cells expressing WT and F508del mutated CFTR and to F508del-CFTR retention. Cell Calcium 2017; 62:47-59. [PMID: 28189267 DOI: 10.1016/j.ceca.2017.01.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 01/20/2017] [Accepted: 01/20/2017] [Indexed: 11/22/2022]
Abstract
Cystic Fibrosis (CF) is the most frequent fatal genetic disease in Caucasian populations. Mutations in the chloride channel CF Transmembrane Conductance Regulator (CFTR) gene are responsible for functional defects of the protein and multiple associated dysregulations. The most common mutation in patients with CF, F508del-CFTR, causes defective CFTR protein folding. Thus minimal levels of the receptor are expressed at the cell surface as the mutated CFTR is retained in the endoplasmic reticulum (ER) where it correlates with defective calcium (Ca2+) homeostasis. In this study, we discovered that the Ca2+ binding protein Calumenin (CALU) is a key regulator in the maintenance of ER-Ca2+ calcium homeostasis in both wild type and F508del-CFTR expressing cells. Calumenin modulates SERCA pump activity without drastically affecting ER-Ca2+ concentration. In addition, reducing Calumenin expression in CF cells results in a partial restoration of CFTR activity, highlighting a potential function of Calumenin in CFTR maturation. These findings demonstrate a pivotal role for Calumenin in CF cells, providing insights into how modulation of Calumenin expression or activity may be used as a potential therapeutic tool to correct defects in F508del-CFTR.
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73
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Regulation of Calcium Homeostasis by ER Redox: A Close-Up of the ER/Mitochondria Connection. J Mol Biol 2017; 429:620-632. [PMID: 28137421 DOI: 10.1016/j.jmb.2017.01.017] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 01/20/2017] [Accepted: 01/20/2017] [Indexed: 01/17/2023]
Abstract
Calcium signaling plays an important role in cell survival by influencing mitochondria-related processes such as energy production and apoptosis. The endoplasmic reticulum (ER) is the main storage compartment for cell calcium (Ca2+; ~60-500μM), and the Ca2+ released by the ER has a prompt effect on the homeostasis of the juxtaposed mitochondria. Recent findings have highlighted a close connection between ER redox and Ca2+ signaling that is mediated by Ca2+-handling proteins. This paper describes the redox-regulated mediators and mechanisms that orchestrate Ca2+ signals from the ER to mitochondria.
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74
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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: 53] [Impact Index Per Article: 6.6] [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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75
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Marchi S, Bittremieux M, Missiroli S, Morganti C, Patergnani S, Sbano L, Rimessi A, Kerkhofs M, Parys JB, Bultynck G, Giorgi C, Pinton P. Endoplasmic Reticulum-Mitochondria Communication Through Ca 2+ Signaling: The Importance of Mitochondria-Associated Membranes (MAMs). ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 997:49-67. [PMID: 28815521 DOI: 10.1007/978-981-10-4567-7_4] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The execution of proper Ca2+ signaling requires close apposition between the endoplasmic reticulum (ER) and mitochondria. Hence, Ca2+ released from the ER is "quasi-synaptically" transferred to mitochondrial matrix, where Ca2+ stimulates mitochondrial ATP synthesis by activating the tricarboxylic acid (TCA) cycle. However, when the Ca2+ transfer is excessive and sustained, mitochondrial Ca2+ overload induces apoptosis by opening the mitochondrial permeability transition pore. A large number of regulatory proteins reside at mitochondria-associated ER membranes (MAMs) to maintain the optimal distance between the organelles and to coordinate the functionality of both ER and mitochondrial Ca2+ transporters or channels. In this chapter, we discuss the different pathways involved in the regulation of ER-mitochondria Ca2+ flux and describe the activities of the various Ca2+ players based on their primary intra-organelle localization.
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Affiliation(s)
- Saverio Marchi
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Mart Bittremieux
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut, KU Leuven, Campus Gasthuisberg O&N-I box 802, Herestraat 49, B-3000, Leuven, Belgium
| | - Sonia Missiroli
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Claudia Morganti
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Simone Patergnani
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Luigi Sbano
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Alessandro Rimessi
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Martijn Kerkhofs
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut, KU Leuven, Campus Gasthuisberg O&N-I box 802, Herestraat 49, B-3000, Leuven, Belgium
| | - Jan B Parys
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut, KU Leuven, Campus Gasthuisberg O&N-I box 802, Herestraat 49, B-3000, Leuven, Belgium
| | - Geert Bultynck
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut, KU Leuven, Campus Gasthuisberg O&N-I box 802, Herestraat 49, B-3000, Leuven, Belgium
| | - Carlotta Giorgi
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy.
| | - Paolo Pinton
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy.
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76
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Kerkhofs M, Giorgi C, Marchi S, Seitaj B, Parys JB, Pinton P, Bultynck G, Bittremieux M. Alterations in Ca 2+ Signalling via ER-Mitochondria Contact Site Remodelling in Cancer. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 997:225-254. [PMID: 28815534 DOI: 10.1007/978-981-10-4567-7_17] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Inter-organellar contact sites establish microdomains for localised Ca2+-signalling events. One of these microdomains is established between the ER and the mitochondria. Importantly, the so-called mitochondria-associated ER membranes (MAMs) contain, besides structural proteins and proteins involved in lipid exchange, several Ca2+-transport systems, mediating efficient Ca2+ transfer from the ER to the mitochondria. These Ca2+ signals critically control several mitochondrial functions, thereby impacting cell metabolism, cell death and survival, proliferation and migration. Hence, the MAMs have emerged as critical signalling hubs in physiology, while their dysregulation is an important factor that drives or at least contributes to oncogenesis and tumour progression. In this book chapter, we will provide an overview of the role of the MAMs in cell function and how alterations in the MAM composition contribute to oncogenic features and behaviours.
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Affiliation(s)
- Martijn Kerkhofs
- Laboratory Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut (LKI), KU Leuven, Campus Gasthuisberg O&N 1 Box 802, Herestraat 49, 3000, Leuven, Belgium
| | - Carlotta Giorgi
- Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, University of Ferrara, Ferrara, Italy
| | - Saverio Marchi
- Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, University of Ferrara, Ferrara, Italy
| | - Bruno Seitaj
- Laboratory Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut (LKI), KU Leuven, Campus Gasthuisberg O&N 1 Box 802, Herestraat 49, 3000, Leuven, Belgium
| | - Jan B Parys
- Laboratory Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut (LKI), KU Leuven, Campus Gasthuisberg O&N 1 Box 802, Herestraat 49, 3000, Leuven, Belgium
| | - Paolo Pinton
- Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, University of Ferrara, Ferrara, Italy
| | - Geert Bultynck
- Laboratory Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut (LKI), KU Leuven, Campus Gasthuisberg O&N 1 Box 802, Herestraat 49, 3000, Leuven, Belgium.
| | - Mart Bittremieux
- Laboratory Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut (LKI), KU Leuven, Campus Gasthuisberg O&N 1 Box 802, Herestraat 49, 3000, Leuven, Belgium
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Organelle Communication at Membrane Contact Sites (MCS): From Curiosity to Center Stage in Cell Biology and Biomedical Research. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 997:1-12. [DOI: 10.1007/978-981-10-4567-7_1] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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78
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Over Six Decades of Discovery and Characterization of the Architecture at Mitochondria-Associated Membranes (MAMs). ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 997:13-31. [PMID: 28815519 DOI: 10.1007/978-981-10-4567-7_2] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The discovery of proteins regulating ER-mitochondria tethering including phosphofurin acidic cluster sorting protein 2 (PACS-2) and mitofusin-2 has pushed contact sites between the endoplasmic reticulum (ER) and mitochondria into the spotlight of cell biology. While the field is developing rapidly and controversies have come and gone multiple times during its history, it is sometimes overlooked that significant research has been done decades ago with the original discovery of these structures in the 1950s and the first characterization of their function (and coining of the term mitochondria-associated membrane, MAM) in 1990. Today, an ever-increasing array of proteins localize to the MAM fraction of the endoplasmic reticulum (ER) to regulate the interaction of this organelle with mitochondria. These mitochondria-ER contacts, sometimes referred to as MERCs, regulate a multitude of biological functions, including lipid metabolism, Ca2+ signaling, bioenergetics, inflammation, autophagy, mitochondrial structure, and apoptosis.
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79
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ER-luminal thiol/selenol-mediated regulation of Ca2+ signalling. Biochem Soc Trans 2016; 44:452-9. [PMID: 27068954 DOI: 10.1042/bst20150233] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Indexed: 01/05/2023]
Abstract
The endoplasmic reticulum (ER) is the main cellular Ca(2+)storage unit. Among other signalling outputs, the ER can release Ca(2+)ions, which can, for instance, communicate the status of ER protein folding to the cytosol and to other organelles, in particular the mitochondria. As a consequence, ER Ca(2+)flux can alter the apposition of the ER with mitochondria, influence mitochondrial ATP production or trigger apoptosis. All aspects of ER Ca(2+)flux have emerged as processes that are intimately controlled by intracellular redox conditions. In this review, we focus on ER-luminal redox-driven regulation of Ca(2+)flux. This involves the direct reduction of disulfides within ER Ca(2+)handling proteins themselves, but also the regulated interaction of ER chaperones and oxidoreductases such as calnexin or ERp57 with them. Well-characterized examples are the activating interactions of Ero1α with inositol 1,4,5-trisphosphate receptors (IP3Rs) or of selenoprotein N (SEPN1) with sarco/endoplasmic reticulum Ca(2+)transport ATPase 2 (SERCA2). The future discovery of novel ER-luminal modulators of Ca(2+)handling proteins is likely. Based on the currently available information, we describe how the variable ER redox conditions govern Ca(2+)flux from the ER.
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80
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Maurice P, Baud S, Bocharova OV, Bocharov EV, Kuznetsov AS, Kawecki C, Bocquet O, Romier B, Gorisse L, Ghirardi M, Duca L, Blaise S, Martiny L, Dauchez M, Efremov RG, Debelle L. New Insights into Molecular Organization of Human Neuraminidase-1: Transmembrane Topology and Dimerization Ability. Sci Rep 2016; 6:38363. [PMID: 27917893 PMCID: PMC5137157 DOI: 10.1038/srep38363] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 11/09/2016] [Indexed: 11/09/2022] Open
Abstract
Neuraminidase 1 (NEU1) is a lysosomal sialidase catalyzing the removal of terminal sialic acids from sialyloconjugates. A plasma membrane-bound NEU1 modulating a plethora of receptors by desialylation, has been consistently documented from the last ten years. Despite a growing interest of the scientific community to NEU1, its membrane organization is not understood and current structural and biochemical data cannot account for such membrane localization. By combining molecular biology and biochemical analyses with structural biophysics and computational approaches, we identified here two regions in human NEU1 - segments 139-159 (TM1) and 316-333 (TM2) - as potential transmembrane (TM) domains. In membrane mimicking environments, the corresponding peptides form stable α-helices and TM2 is suited for self-association. This was confirmed with full-size NEU1 by co-immunoprecipitations from membrane preparations and split-ubiquitin yeast two hybrids. The TM2 region was shown to be critical for dimerization since introduction of point mutations within TM2 leads to disruption of NEU1 dimerization and decrease of sialidase activity in membrane. In conclusion, these results bring new insights in the molecular organization of membrane-bound NEU1 and demonstrate, for the first time, the presence of two potential TM domains that may anchor NEU1 in the membrane, control its dimerization and sialidase activity.
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Affiliation(s)
- Pascal Maurice
- Laboratoire Signalisation et Récepteurs Matriciels (SiRMa), UMR CNRS 7369 Matrice Extracellulaire et Dynamique Cellulaire (MEDyC), Université de Reims Champagne Ardenne (URCA), UFR Sciences Exactes et Naturelles, Reims, France
| | - Stéphanie Baud
- Laboratoire Signalisation et Récepteurs Matriciels (SiRMa), UMR CNRS 7369 Matrice Extracellulaire et Dynamique Cellulaire (MEDyC), Université de Reims Champagne Ardenne (URCA), UFR Sciences Exactes et Naturelles, Reims, France.,Plateau de Modélisation Moléculaire Multi-échelle, UFR Sciences Exactes et Naturelles, URCA, Reims, France
| | - Olga V Bocharova
- M. M. Shemyakin and Yu. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Eduard V Bocharov
- M. M. Shemyakin and Yu. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Andrey S Kuznetsov
- M. M. Shemyakin and Yu. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Charlotte Kawecki
- Laboratoire Signalisation et Récepteurs Matriciels (SiRMa), UMR CNRS 7369 Matrice Extracellulaire et Dynamique Cellulaire (MEDyC), Université de Reims Champagne Ardenne (URCA), UFR Sciences Exactes et Naturelles, Reims, France
| | - Olivier Bocquet
- Laboratoire Signalisation et Récepteurs Matriciels (SiRMa), UMR CNRS 7369 Matrice Extracellulaire et Dynamique Cellulaire (MEDyC), Université de Reims Champagne Ardenne (URCA), UFR Sciences Exactes et Naturelles, Reims, France
| | - Beatrice Romier
- Laboratoire Signalisation et Récepteurs Matriciels (SiRMa), UMR CNRS 7369 Matrice Extracellulaire et Dynamique Cellulaire (MEDyC), Université de Reims Champagne Ardenne (URCA), UFR Sciences Exactes et Naturelles, Reims, France
| | - Laetitia Gorisse
- Laboratoire Signalisation et Récepteurs Matriciels (SiRMa), UMR CNRS 7369 Matrice Extracellulaire et Dynamique Cellulaire (MEDyC), Université de Reims Champagne Ardenne (URCA), UFR Sciences Exactes et Naturelles, Reims, France
| | - Maxime Ghirardi
- Laboratoire Signalisation et Récepteurs Matriciels (SiRMa), UMR CNRS 7369 Matrice Extracellulaire et Dynamique Cellulaire (MEDyC), Université de Reims Champagne Ardenne (URCA), UFR Sciences Exactes et Naturelles, Reims, France
| | - Laurent Duca
- Laboratoire Signalisation et Récepteurs Matriciels (SiRMa), UMR CNRS 7369 Matrice Extracellulaire et Dynamique Cellulaire (MEDyC), Université de Reims Champagne Ardenne (URCA), UFR Sciences Exactes et Naturelles, Reims, France
| | - Sébastien Blaise
- Laboratoire Signalisation et Récepteurs Matriciels (SiRMa), UMR CNRS 7369 Matrice Extracellulaire et Dynamique Cellulaire (MEDyC), Université de Reims Champagne Ardenne (URCA), UFR Sciences Exactes et Naturelles, Reims, France
| | - Laurent Martiny
- Laboratoire Signalisation et Récepteurs Matriciels (SiRMa), UMR CNRS 7369 Matrice Extracellulaire et Dynamique Cellulaire (MEDyC), Université de Reims Champagne Ardenne (URCA), UFR Sciences Exactes et Naturelles, Reims, France
| | - Manuel Dauchez
- Laboratoire Signalisation et Récepteurs Matriciels (SiRMa), UMR CNRS 7369 Matrice Extracellulaire et Dynamique Cellulaire (MEDyC), Université de Reims Champagne Ardenne (URCA), UFR Sciences Exactes et Naturelles, Reims, France.,Plateau de Modélisation Moléculaire Multi-échelle, UFR Sciences Exactes et Naturelles, URCA, Reims, France
| | - Roman G Efremov
- M. M. Shemyakin and Yu. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia.,Higher School of Economics, Myasnitskaya ul. 20, 101000 Moscow, Russia
| | - Laurent Debelle
- Laboratoire Signalisation et Récepteurs Matriciels (SiRMa), UMR CNRS 7369 Matrice Extracellulaire et Dynamique Cellulaire (MEDyC), Université de Reims Champagne Ardenne (URCA), UFR Sciences Exactes et Naturelles, Reims, France
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81
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To M, Peterson CWH, Roberts MA, Counihan JL, Wu TT, Forster MS, Nomura DK, Olzmann JA. Lipid disequilibrium disrupts ER proteostasis by impairing ERAD substrate glycan trimming and dislocation. Mol Biol Cell 2016; 28:270-284. [PMID: 27881664 PMCID: PMC5231896 DOI: 10.1091/mbc.e16-07-0483] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 11/09/2016] [Accepted: 11/15/2016] [Indexed: 12/12/2022] Open
Abstract
The endoplasmic reticulum (ER) mediates the folding, maturation, and deployment of the secretory proteome. Proteins that fail to achieve their native conformation are retained in the ER and targeted for clearance by ER-associated degradation (ERAD), a sophisticated process that mediates the ubiquitin-dependent delivery of substrates to the 26S proteasome for proteolysis. Recent findings indicate that inhibition of long-chain acyl-CoA synthetases with triacsin C, a fatty acid analogue, impairs lipid droplet (LD) biogenesis and ERAD, suggesting a role for LDs in ERAD. However, whether LDs are involved in the ERAD process remains an outstanding question. Using chemical and genetic approaches to disrupt diacylglycerol acyltransferase (DGAT)-dependent LD biogenesis, we provide evidence that LDs are dispensable for ERAD in mammalian cells. Instead, our results suggest that triacsin C causes global alterations in the cellular lipid landscape that disrupt ER proteostasis by interfering with the glycan trimming and dislocation steps of ERAD. Prolonged triacsin C treatment activates both the IRE1 and PERK branches of the unfolded protein response and ultimately leads to IRE1-dependent cell death. These findings identify an intimate relationship between fatty acid metabolism and ER proteostasis that influences cell viability.
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Affiliation(s)
- Milton To
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA 94720
| | - Clark W H Peterson
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA 94720
| | - Melissa A Roberts
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA 94720
| | - Jessica L Counihan
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA 94720.,Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720.,Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Tiffany T Wu
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA 94720
| | - Mercedes S Forster
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA 94720
| | - Daniel K Nomura
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA 94720.,Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720.,Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - James A Olzmann
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA 94720
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82
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mTORC1 inhibitor rapamycin and ER stressor tunicamycin induce differential patterns of ER-mitochondria coupling. Sci Rep 2016; 6:36394. [PMID: 27808250 PMCID: PMC5093439 DOI: 10.1038/srep36394] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 10/14/2016] [Indexed: 01/01/2023] Open
Abstract
Efficient mitochondrial Ca2+ uptake takes place at contact points between the ER and mitochondria, and represents a key regulator of many cell functions. In a previous study with HeLa cells, we showed that ER-to-mitochondria Ca2+ transfer increases during the early phase of ER stress induced by tunicamycin as an adaptive response to stimulate mitochondrial bioenergetics. It remains unknown whether other types of stress signals trigger similar responses. Here we observed that rapamycin, which inhibits the nutrient-sensing complex mTORC1, increased ER-mitochondria coupling in HeLa cells to a similar extent as did tunicamycin. Interestingly, although global responses to both stressors were comparable, there were notable differences in the spatial distribution of such changes. While tunicamycin increased organelle proximity primarily in the perinuclear region, rapamycin increased organelle contacts throughout the entire cell. These differences were paralleled by dissimilar alterations in the distribution of regulatory proteins of the ER-mitochondria interface, heterogeneities in mitochondrial Ca2+ uptake, and the formation of domains within the mitochondrial network with varying mitochondrial transmembrane potential. Collectively, these data suggest that while increasing ER-mitochondria coupling appears to represent a general response to cell stress, the intracellular distribution of the associated responses needs to be tailored to meet specific cellular requirements.
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83
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Rodríguez-Arribas M, Yakhine-Diop SMS, Pedro JMBS, Gómez-Suaga P, Gómez-Sánchez R, Martínez-Chacón G, Fuentes JM, González-Polo RA, Niso-Santano M. Mitochondria-Associated Membranes (MAMs): Overview and Its Role in Parkinson's Disease. Mol Neurobiol 2016; 54:6287-6303. [PMID: 27714635 DOI: 10.1007/s12035-016-0140-8] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 09/19/2016] [Indexed: 12/21/2022]
Abstract
Mitochondria-associated membranes (MAMs) are structures that regulate physiological functions between endoplasmic reticulum (ER) and mitochondria in order to maintain calcium signaling and mitochondrial biogenesis. Several proteins located in MAMs, including those encoded by PARK genes and some of neurodegeneration-related proteins (huntingtin, presenilin, etc.), ensure this regulation. In this regard, MAM alteration is associated with neurodegenerative diseases such as Parkinson's (PD), Alzheimer's (AD), and Huntington's diseases (HD) and contributes to the appearance of the pathogenesis features, i.e., autophagy dysregulation, mitochondrial dysfunction, oxidative stress, and lately, neuronal death. Moreover,, ER stress and/or damaged mitochondria can be the cause of these disruptions. Therefore, ER-mitochondria contact structure and function are crucial to multiple cellular processes. This review is focused on the molecular interaction between ER and mitochondria indispensable to MAM formation and on MAM alteration-induced etiology of neurodegenerative diseases.
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Affiliation(s)
- M Rodríguez-Arribas
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Universidad de Extremadura, Avda. De la Universidad S/N, C.P, 10003, Cáceres, Cáceres, Spain.,Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, Avda. de la Universidad s/n, C.P, 10003, Cáceres, Cáceres, Spain
| | - S M S Yakhine-Diop
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Universidad de Extremadura, Avda. De la Universidad S/N, C.P, 10003, Cáceres, Cáceres, Spain.,Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, Avda. de la Universidad s/n, C.P, 10003, Cáceres, Cáceres, Spain
| | - J M Bravo-San Pedro
- Equipe 11 labellisée Ligue contre le Cancer, Centre de Recherche des Cordeliers, 75006, Paris, France.,INSERM U1138, 75006, Paris, France.,Université Paris Descartes/Paris V, Sorbonne Paris Cité, 75006, Paris, France.,Université Pierre et Marie Curie/Paris VI, 75006, Paris, France.,Gustave Roussy Comprehensive Cancer Institute, 94805, Villejuif, France
| | - P Gómez-Suaga
- Department Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute Kings College London, London, SE5 9RX, UK
| | - R Gómez-Sánchez
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - G Martínez-Chacón
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Universidad de Extremadura, Avda. De la Universidad S/N, C.P, 10003, Cáceres, Cáceres, Spain.,Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, Avda. de la Universidad s/n, C.P, 10003, Cáceres, Cáceres, Spain
| | - J M Fuentes
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Universidad de Extremadura, Avda. De la Universidad S/N, C.P, 10003, Cáceres, Cáceres, Spain.,Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, Avda. de la Universidad s/n, C.P, 10003, Cáceres, Cáceres, Spain
| | - R A González-Polo
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Universidad de Extremadura, Avda. De la Universidad S/N, C.P, 10003, Cáceres, Cáceres, Spain. .,Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, Avda. de la Universidad s/n, C.P, 10003, Cáceres, Cáceres, Spain.
| | - M Niso-Santano
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Universidad de Extremadura, Avda. De la Universidad S/N, C.P, 10003, Cáceres, Cáceres, Spain. .,Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, Avda. de la Universidad s/n, C.P, 10003, Cáceres, Cáceres, Spain.
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84
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Pagliassotti MJ, Kim PY, Estrada AL, Stewart CM, Gentile CL. Endoplasmic reticulum stress in obesity and obesity-related disorders: An expanded view. Metabolism 2016; 65:1238-46. [PMID: 27506731 PMCID: PMC4980576 DOI: 10.1016/j.metabol.2016.05.002] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 04/01/2016] [Accepted: 05/06/2016] [Indexed: 02/07/2023]
Abstract
The endoplasmic reticulum (ER) is most notable for its central roles in calcium ion storage, lipid biosynthesis, and protein sorting and processing. By virtue of its extensive membrane contact sites that connect the ER to most other organelles and to the plasma membrane, the ER can also regulate diverse cellular processes including inflammatory and insulin signaling, nutrient metabolism, and cell proliferation and death via a signaling pathway called the unfolded protein response (UPR). Chronic UPR activation has been observed in liver and/or adipose tissue of dietary and genetic murine models of obesity, and in human obesity and non-alcoholic fatty liver disease (NAFLD). Activation of the UPR in obesity and obesity-related disorders likely has two origins. One linked to classic ER stress involving the ER lumen and one linked to alterations to the ER membrane environment. This review discusses both of these origins and also considers the role of post-translational protein modifications, such as acetylation and palmitoylation, and ER-mitochondrial interactions to obesity-mediated impairments in the ER and activation of the UPR.
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Affiliation(s)
| | - Paul Y Kim
- Department of Biological Sciences, Grambling State University
| | - Andrea L Estrada
- Department of Food Science and Human Nutrition, Colorado State University
| | - Claire M Stewart
- Department of Food Science and Human Nutrition, Colorado State University
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85
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Raturi A, Gutiérrez T, Ortiz-Sandoval C, Ruangkittisakul A, Herrera-Cruz MS, Rockley JP, Gesson K, Ourdev D, Lou PH, Lucchinetti E, Tahbaz N, Zaugg M, Baksh S, Ballanyi K, Simmen T. TMX1 determines cancer cell metabolism as a thiol-based modulator of ER-mitochondria Ca2+ flux. J Cell Biol 2016; 214:433-44. [PMID: 27502484 PMCID: PMC4987292 DOI: 10.1083/jcb.201512077] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 07/15/2016] [Indexed: 12/31/2022] Open
Abstract
Cancer cells are critically dependent on ER–mitochondria Ca2+ flux that regulates their bioenergetics. Here, Raturi et al. identify the ER oxidoreductase TMX1 as a thiol-dependent regulator of this intracellular signaling mechanism within cancer cells. The flux of Ca2+ from the endoplasmic reticulum (ER) to mitochondria regulates mitochondria metabolism. Within tumor tissue, mitochondria metabolism is frequently repressed, leading to chemotherapy resistance and increased growth of the tumor mass. Therefore, altered ER–mitochondria Ca2+ flux could be a cancer hallmark, but only a few regulatory proteins of this mechanism are currently known. One candidate is the redox-sensitive oxidoreductase TMX1 that is enriched on the mitochondria-associated membrane (MAM), the site of ER–mitochondria Ca2+ flux. Our findings demonstrate that cancer cells with low TMX1 exhibit increased ER Ca2+, accelerated cytosolic Ca2+ clearance, and reduced Ca2+ transfer to mitochondria. Thus, low levels of TMX1 reduce ER–mitochondria contacts, shift bioenergetics away from mitochondria, and accelerate tumor growth. For its role in intracellular ER–mitochondria Ca2+ flux, TMX1 requires its thioredoxin motif and palmitoylation to target to the MAM. As a thiol-based tumor suppressor, TMX1 increases mitochondrial ATP production and apoptosis progression.
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Affiliation(s)
- Arun Raturi
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada
| | - Tomás Gutiérrez
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada
| | - Carolina Ortiz-Sandoval
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada
| | - Araya Ruangkittisakul
- Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada
| | - Maria Sol Herrera-Cruz
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada
| | - Jeremy P Rockley
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada
| | - Kevin Gesson
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada
| | - Dimitar Ourdev
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada
| | - Phing-How Lou
- Department of Anesthesiology and Pain Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada
| | - Eliana Lucchinetti
- Department of Anesthesiology and Pain Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada
| | - Nasser Tahbaz
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada
| | - Michael Zaugg
- Department of Anesthesiology and Pain Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada
| | - Shairaz Baksh
- Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada Department of Biochemistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada Alberta Inflammatory Bowel Disease Consortium, University of Alberta, Edmonton, Alberta T6G2H7, Canada
| | - Klaus Ballanyi
- Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada
| | - Thomas Simmen
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G2H7, Canada
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86
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Suzuki J, Kanemaru K, Iino M. Genetically Encoded Fluorescent Indicators for Organellar Calcium Imaging. Biophys J 2016; 111:1119-1131. [PMID: 27477268 DOI: 10.1016/j.bpj.2016.04.054] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 03/30/2016] [Accepted: 04/01/2016] [Indexed: 12/14/2022] Open
Abstract
Optical Ca(2+) indicators are powerful tools for investigating intracellular Ca(2+) signals in living cells. Although a variety of Ca(2+) indicators have been developed, deciphering the physiological functions and spatiotemporal dynamics of Ca(2+) in intracellular organelles remains challenging. Genetically encoded Ca(2+) indicators (GECIs) using fluorescent proteins are promising tools for organellar Ca(2+) imaging, and much effort has been devoted to their development. In this review, we first discuss the key points of organellar Ca(2+) imaging and summarize the requirements for optimal organellar Ca(2+) indicators. Then, we highlight some of the recent advances in the engineering of fluorescent GECIs targeted to specific organelles. Finally, we discuss the limitations of currently available GECIs and the requirements for advancing the research on intraorganellar Ca(2+) signaling.
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Affiliation(s)
- Junji Suzuki
- Department of Pharmacology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; Department of Physiology, University of California San Francisco, San Francisco, California
| | - Kazunori Kanemaru
- Department of Pharmacology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Masamitsu Iino
- Department of Pharmacology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; Department of Cellular and Molecular Pharmacology, Nihon University School of Medicine, Tokyo, Japan.
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Hunegnaw R, Vassylyeva M, Dubrovsky L, Pushkarsky T, Sviridov D, Anashkina AA, Üren A, Brichacek B, Vassylyev DG, Adzhubei AA, Bukrinsky M. Interaction Between HIV-1 Nef and Calnexin: From Modeling to Small Molecule Inhibitors Reversing HIV-Induced Lipid Accumulation. Arterioscler Thromb Vasc Biol 2016; 36:1758-71. [PMID: 27470515 DOI: 10.1161/atvbaha.116.307997] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 07/13/2016] [Indexed: 01/22/2023]
Abstract
OBJECTIVE HIV-infected patients are at an increased risk of developing atherosclerosis, in part because of downmodulation and functional impairment of ATP-binding cassette A1 (ABCA1) cholesterol transporter by the HIV-1 protein Nef. The mechanism of this effect involves Nef interacting with an ER chaperone calnexin and disrupting calnexin binding to ABCA1, leading to ABCA1 retention in ER, its degradation and resulting suppression of cholesterol efflux. However, molecular details of Nef-calnexin interaction remained unknown, limiting the translational impact of this finding. APPROACH AND RESULTS Here, we used molecular modeling and mutagenesis to characterize Nef-calnexin interaction and to identify small molecule compounds that could block it. We demonstrated that the interaction between Nef and calnexin is direct and can be reconstituted using recombinant proteins in vitro with a binding affinity of 89.1 nmol/L measured by surface plasmon resonance. The cytoplasmic tail of calnexin is essential and sufficient for interaction with Nef, and binds Nef with an affinity of 9.4 nmol/L. Replacing lysine residues in positions 4 and 7 of Nef with alanines abrogates Nef-calnexin interaction, prevents ABCA1 downregulation by Nef, and preserves cholesterol efflux from HIV-infected cells. Through virtual screening of the National Cancer Institute library of compounds, we identified a compound, 1[(7-oxo-7H-benz[de]anthracene-3-yl)amino]anthraquinone, which blocked Nef-calnexin interaction, partially restored ABCA1 activity in HIV-infected cells, and reduced foam cell formation in a culture of HIV-infected macrophages. CONCLUSION This study identifies potential targets that can be exploited to block the pathogenic effect of HIV infection on cholesterol metabolism and prevent atherosclerosis in HIV-infected subjects.
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Affiliation(s)
- Ruth Hunegnaw
- From the George Washington University School of Medicine and Health Sciences, Washington, DC (R.H., L.D., T.P., B.B., A.A.A., M.B.); University of Alabama School of Medicine and Dentistry, Birmingham, (M.V., D.V.); Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (D.S.); Engelhardt Institute of Molecular Biology RAS, Moscow, Russia (A.A. Anashkina, A.A. Adzhubei); and Georgetown University Medical Center, Lombardi Comprehensive Cancer Center, Washington, DC (A.Ü)
| | - Marina Vassylyeva
- From the George Washington University School of Medicine and Health Sciences, Washington, DC (R.H., L.D., T.P., B.B., A.A.A., M.B.); University of Alabama School of Medicine and Dentistry, Birmingham, (M.V., D.V.); Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (D.S.); Engelhardt Institute of Molecular Biology RAS, Moscow, Russia (A.A. Anashkina, A.A. Adzhubei); and Georgetown University Medical Center, Lombardi Comprehensive Cancer Center, Washington, DC (A.Ü)
| | - Larisa Dubrovsky
- From the George Washington University School of Medicine and Health Sciences, Washington, DC (R.H., L.D., T.P., B.B., A.A.A., M.B.); University of Alabama School of Medicine and Dentistry, Birmingham, (M.V., D.V.); Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (D.S.); Engelhardt Institute of Molecular Biology RAS, Moscow, Russia (A.A. Anashkina, A.A. Adzhubei); and Georgetown University Medical Center, Lombardi Comprehensive Cancer Center, Washington, DC (A.Ü)
| | - Tatiana Pushkarsky
- From the George Washington University School of Medicine and Health Sciences, Washington, DC (R.H., L.D., T.P., B.B., A.A.A., M.B.); University of Alabama School of Medicine and Dentistry, Birmingham, (M.V., D.V.); Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (D.S.); Engelhardt Institute of Molecular Biology RAS, Moscow, Russia (A.A. Anashkina, A.A. Adzhubei); and Georgetown University Medical Center, Lombardi Comprehensive Cancer Center, Washington, DC (A.Ü)
| | - Dmitri Sviridov
- From the George Washington University School of Medicine and Health Sciences, Washington, DC (R.H., L.D., T.P., B.B., A.A.A., M.B.); University of Alabama School of Medicine and Dentistry, Birmingham, (M.V., D.V.); Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (D.S.); Engelhardt Institute of Molecular Biology RAS, Moscow, Russia (A.A. Anashkina, A.A. Adzhubei); and Georgetown University Medical Center, Lombardi Comprehensive Cancer Center, Washington, DC (A.Ü)
| | - Anastasia A Anashkina
- From the George Washington University School of Medicine and Health Sciences, Washington, DC (R.H., L.D., T.P., B.B., A.A.A., M.B.); University of Alabama School of Medicine and Dentistry, Birmingham, (M.V., D.V.); Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (D.S.); Engelhardt Institute of Molecular Biology RAS, Moscow, Russia (A.A. Anashkina, A.A. Adzhubei); and Georgetown University Medical Center, Lombardi Comprehensive Cancer Center, Washington, DC (A.Ü)
| | - Aykut Üren
- From the George Washington University School of Medicine and Health Sciences, Washington, DC (R.H., L.D., T.P., B.B., A.A.A., M.B.); University of Alabama School of Medicine and Dentistry, Birmingham, (M.V., D.V.); Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (D.S.); Engelhardt Institute of Molecular Biology RAS, Moscow, Russia (A.A. Anashkina, A.A. Adzhubei); and Georgetown University Medical Center, Lombardi Comprehensive Cancer Center, Washington, DC (A.Ü)
| | - Beda Brichacek
- From the George Washington University School of Medicine and Health Sciences, Washington, DC (R.H., L.D., T.P., B.B., A.A.A., M.B.); University of Alabama School of Medicine and Dentistry, Birmingham, (M.V., D.V.); Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (D.S.); Engelhardt Institute of Molecular Biology RAS, Moscow, Russia (A.A. Anashkina, A.A. Adzhubei); and Georgetown University Medical Center, Lombardi Comprehensive Cancer Center, Washington, DC (A.Ü)
| | - Dmitry G Vassylyev
- From the George Washington University School of Medicine and Health Sciences, Washington, DC (R.H., L.D., T.P., B.B., A.A.A., M.B.); University of Alabama School of Medicine and Dentistry, Birmingham, (M.V., D.V.); Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (D.S.); Engelhardt Institute of Molecular Biology RAS, Moscow, Russia (A.A. Anashkina, A.A. Adzhubei); and Georgetown University Medical Center, Lombardi Comprehensive Cancer Center, Washington, DC (A.Ü)
| | - Alexei A Adzhubei
- From the George Washington University School of Medicine and Health Sciences, Washington, DC (R.H., L.D., T.P., B.B., A.A.A., M.B.); University of Alabama School of Medicine and Dentistry, Birmingham, (M.V., D.V.); Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (D.S.); Engelhardt Institute of Molecular Biology RAS, Moscow, Russia (A.A. Anashkina, A.A. Adzhubei); and Georgetown University Medical Center, Lombardi Comprehensive Cancer Center, Washington, DC (A.Ü).
| | - Michael Bukrinsky
- From the George Washington University School of Medicine and Health Sciences, Washington, DC (R.H., L.D., T.P., B.B., A.A.A., M.B.); University of Alabama School of Medicine and Dentistry, Birmingham, (M.V., D.V.); Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (D.S.); Engelhardt Institute of Molecular Biology RAS, Moscow, Russia (A.A. Anashkina, A.A. Adzhubei); and Georgetown University Medical Center, Lombardi Comprehensive Cancer Center, Washington, DC (A.Ü).
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88
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Baumann J, Wong J, Sun Y, Conklin DS. Palmitate-induced ER stress increases trastuzumab sensitivity in HER2/neu-positive breast cancer cells. BMC Cancer 2016; 16:551. [PMID: 27464732 PMCID: PMC4964104 DOI: 10.1186/s12885-016-2611-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 07/25/2016] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND HER2/neu-positive breast cancer cells have recently been shown to use a unique Warburg-like metabolism for survival and aggressive behavior. These cells exhibit increased fatty acid synthesis and storage compared to normal breast cells or other tumor cells. Disruption of this synthetic process results in apoptosis. Since the addition of physiological doses of exogenous palmitate induces cell death in HER2/neu-positive breast cancer cells, the pathway is likely operating at its limits in these cells. We have studied the response of HER2/neu-positive breast cancer cells to physiological concentrations of exogenous palmitate to identify lipotoxicity-associated consequences of this physiology. Since epidemiological data show that a diet rich in saturated fatty acids is negatively associated with the development of HER2/neu-positive cancer, this cellular physiology may be relevant to the etiology and treatment of the disease. We sought to identify signaling pathways that are regulated by physiological concentrations of exogenous palmitate specifically in HER2/neu-positive breast cancer cells and gain insights into the molecular mechanism and its relevance to disease prevention and treatment. METHODS Transcriptional profiling was performed to assess programs that are regulated in HER2-normal MCF7 and HER2/neu-positive SKBR3 breast cancer cells in response to exogenous palmitate. Computational analyses were used to define and predict functional relationships and identify networks that are differentially regulated in the two cell lines. These predictions were tested using reporter assays, fluorescence-based high content microscopy, flow cytometry and immunoblotting. Physiological effects were confirmed in HER2/neu-positive BT474 and HCC1569 breast cancer cell lines. RESULTS Exogenous palmitate induces functionally distinct transcriptional programs in HER2/neu-positive breast cancer cells. In the lipogenic HER2/neu-positive SKBR3 cell line, palmitate induces a G2 phase cell cycle delay and CHOP-dependent apoptosis as well as a partial activation of the ER stress response network via XBP1 and ATF6. This response appears to be a general feature of HER2/neu-positive breast cancer cells but not cells that overexpress only HER2/neu. Exogenous palmitate reduces HER2 and HER3 protein levels without changes in phosphorylation and sensitizes HER2/neu-positive breast cancer cells to treatment with the HER2-targeted therapy trastuzumab. CONCLUSIONS Several studies have shown that HER2, FASN and fatty acid synthesis are functionally linked. Exogenous palmitate exerts its toxic effects in part through inducing ER stress, reducing HER2 expression and thereby sensitizing cells to trastuzumab. These data provide further evidence that HER2 signaling and fatty acid metabolism are highly integrated processes that may be important for disease development and progression.
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Affiliation(s)
- Jan Baumann
- Department of Biomedical Sciences, Cancer Research Center, State University of New York, University at Albany, Rensselaer, NY, 12144, USA
| | - Jason Wong
- Department of Biomedical Sciences, Cancer Research Center, State University of New York, University at Albany, Rensselaer, NY, 12144, USA
| | - Yan Sun
- Department of Biomedical Sciences, Cancer Research Center, State University of New York, University at Albany, Rensselaer, NY, 12144, USA
| | - Douglas S Conklin
- Department of Biomedical Sciences, Cancer Research Center, State University of New York, University at Albany, Rensselaer, NY, 12144, USA.
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89
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McFie PJ, Izzard S, Vu H, Jin Y, Beauchamp E, Berthiaume LG, Stone SJ. Membrane topology of human monoacylglycerol acyltransferase-2 and identification of regions important for its localization to the endoplasmic reticulum. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1192-1204. [PMID: 27373844 DOI: 10.1016/j.bbalip.2016.06.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 06/27/2016] [Accepted: 06/30/2016] [Indexed: 11/16/2022]
Abstract
Acyl CoA:2-monoacylglycerol acyltransferase (MGAT)-2 has an important role in dietary fat absorption in the intestine. MGAT2 resides in the endoplasmic reticulum and catalyzes the synthesis of diacylglycerol which is then utilized as a substrate for triacylglycerol synthesis. This triacylglycerol is then incorporated into chylomicrons which are released into the circulation. In this study, we determined the membrane topology of human MGAT2. Protease protection experiments showed that the C-terminus is exposed to the cytosol, while the N-terminus is partially buried in the ER membrane. MGAT2, like murine DGAT2, was found to have two transmembrane domains. We also identified a region of MGAT2 associated with the ER membrane that contains the histidine-proline-histidine-glycine sequence present in all DGAT2 family members that is thought to comprise the active site. Proteolysis experiments demonstrated that digestion of total cellular membranes from cells expressing MGAT2 with trypsin abolished MGAT activity, indicating that domains that are important for catalysis face the cytosol. We also explored the role that the five cysteines residues present in MGAT2 have in catalysis. MGAT activity was sensitive to two thiol modifiers, N-ethylmaleimide and 5,5'-dithiobis-(2-nitrobenzoic acid). Furthermore, mutation of four cysteines resulted in a reduction in MGAT activity. However, when the C-terminal cysteine (C334) was mutated, MGAT activity was actually higher than that of wild-type FL-MGAT2. Lastly, we determined that both transmembrane domains of MGAT2 are important for its ER localization, and that MGAT2 is present in mitochondrial-associated membranes.
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Affiliation(s)
- Pamela J McFie
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Sabrina Izzard
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Huyen Vu
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Youzhi Jin
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Erwan Beauchamp
- Department of Cell Biology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Luc G Berthiaume
- Department of Cell Biology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Scot J Stone
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada.
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90
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Giacomello M, Pellegrini L. The coming of age of the mitochondria-ER contact: a matter of thickness. Cell Death Differ 2016; 23:1417-27. [PMID: 27341186 DOI: 10.1038/cdd.2016.52] [Citation(s) in RCA: 337] [Impact Index Per Article: 37.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 05/02/2016] [Accepted: 05/05/2016] [Indexed: 12/12/2022] Open
Abstract
The sites of near-contact between the mitochondrion and the endoplasmic reticulum (ER) have earned a lot of attention due to their key role in the maintenance of lipid and calcium (Ca(2+)) homeostasis, in the initiation of autophagy and mitochondrial division, and in sensing metabolic shifts. At these sites, typically called MAMs (mitochondria-associated ER membranes) or MERCs (mitochondria-ER contacts), the organelles juxtapose at a distance that can range from ~10 to ~50 nm. The multifunctional role of this subcellular compartment is puzzling; further, recent studies have shown that mitochondria-ER contacts are highly plastic structures that remodel upon metabolic transitions and that their activity in controlling lipid homeostasis could be involved in Alzheimer's disease pathogenesis. This review aims at integrating the functions of this subcellular compartment to its most characterizing and unexplored structural parameter, their 'thickness': that is, the width of the cleft that separates the cytosolic face of the outer mitochondrial membrane from that of the ER. We describe and discuss the reasons why the thickness of a MERC should be considered a regulated structural parameter of the cell that defines and controls its function. Further, we propose a MERC classification that will help organize the expanding field of MERCs biology and of their role in cell physiology and human disease.
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Affiliation(s)
- M Giacomello
- Department of Biology, Università di Padova, Padua, Italy.,Venetian Institute of Molecular Medicine, Padua, Italy
| | - L Pellegrini
- Department of Molecular Biology, Medical Biochemistry and Pathology, Faculty of Medicine, Universitè Laval, Quebec, Québec, Canada.,Mitochondria Biology Laboratory, CRIUSMQ, Quebec, Québec, Canada
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91
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Heaton NS, Moshkina N, Fenouil R, Gardner TJ, Aguirre S, Shah PS, Zhao N, Manganaro L, Hultquist JF, Noel J, Sachs D, Hamilton J, Leon PE, Chawdury A, Tripathi S, Melegari C, Campisi L, Hai R, Metreveli G, Gamarnik AV, García-Sastre A, Greenbaum B, Simon V, Fernandez-Sesma A, Krogan NJ, Mulder LCF, van Bakel H, Tortorella D, Taunton J, Palese P, Marazzi I. Targeting Viral Proteostasis Limits Influenza Virus, HIV, and Dengue Virus Infection. Immunity 2016; 44:46-58. [PMID: 26789921 DOI: 10.1016/j.immuni.2015.12.017] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 10/26/2015] [Accepted: 10/28/2015] [Indexed: 12/22/2022]
Abstract
Viruses are obligate parasites and thus require the machinery of the host cell to replicate. Inhibition of host factors co-opted during active infection is a strategy hosts use to suppress viral replication and a potential pan-antiviral therapy. To define the cellular proteins and processes required for a virus during infection is thus crucial to understanding the mechanisms of virally induced disease. In this report, we generated fully infectious tagged influenza viruses and used infection-based proteomics to identify pivotal arms of cellular signaling required for influenza virus growth and infectivity. Using mathematical modeling and genetic and pharmacologic approaches, we revealed that modulation of Sec61-mediated cotranslational translocation selectively impaired glycoprotein proteostasis of influenza as well as HIV and dengue viruses and led to inhibition of viral growth and infectivity. Thus, by studying virus-human protein-protein interactions in the context of active replication, we have identified targetable host factors for broad-spectrum antiviral therapies.
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Affiliation(s)
- Nicholas S Heaton
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Natasha Moshkina
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Romain Fenouil
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Thomas J Gardner
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Sebastian Aguirre
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Priya S Shah
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158-2140, USA
| | - Nan Zhao
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Lara Manganaro
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Judd F Hultquist
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158-2140, USA
| | - Justine Noel
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - David Sachs
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Jennifer Hamilton
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Paul E Leon
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Amit Chawdury
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Division of Hematology and Oncology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Shashank Tripathi
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Camilla Melegari
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Laura Campisi
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Rong Hai
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Giorgi Metreveli
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Andrea V Gamarnik
- Fundación Instituto Leloir-CONICET, Avenida Patricias Argentinas 435, Buenos Aires 1405, Argentina
| | - Adolfo García-Sastre
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Benjamin Greenbaum
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Division of Hematology and Oncology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Viviana Simon
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Ana Fernandez-Sesma
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Nevan J Krogan
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158-2140, USA
| | - Lubbertus C F Mulder
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Harm van Bakel
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Domenico Tortorella
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Jack Taunton
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158-2140, USA
| | - Peter Palese
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Ivan Marazzi
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA.
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92
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Garofalo T, Matarrese P, Manganelli V, Marconi M, Tinari A, Gambardella L, Faggioni A, Misasi R, Sorice M, Malorni W. Evidence for the involvement of lipid rafts localized at the ER-mitochondria associated membranes in autophagosome formation. Autophagy 2016; 12:917-35. [PMID: 27123544 DOI: 10.1080/15548627.2016.1160971] [Citation(s) in RCA: 130] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Mitochondria-associated membranes (MAMs) are subdomains of the endoplasmic reticulum (ER) that interact with mitochondria. This membrane scrambling between ER and mitochondria appears to play a critical role in the earliest steps of autophagy. Recently, lipid microdomains, i.e. lipid rafts, have been identified as further actors of the autophagic process. In the present work, a series of biochemical and molecular analyses has been carried out in human fibroblasts with the specific aim of characterizing lipid rafts in MAMs and to decipher their possible implication in the autophagosome formation. In fact, the presence of lipid microdomains in MAMs has been detected and, in these structures, a molecular interaction of the ganglioside GD3, a paradigmatic "brick" of lipid rafts, with core-initiator proteins of autophagy, such as AMBRA1 and WIPI1, was revealed. This association seems thus to take place in the early phases of autophagic process in which MAMs have been hypothesized to play a key role. The functional activity of GD3 was suggested by the experiments carried out by knocking down ST8SIA1 gene expression, i.e., the synthase that leads to the ganglioside formation. This experimental condition results in fact in the impairment of the ER-mitochondria crosstalk and the subsequent hindering of autophagosome nucleation. We thus hypothesize that MAM raft-like microdomains could be pivotal in the initial organelle scrambling activity that finally leads to the formation of autophagosome.
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Affiliation(s)
- Tina Garofalo
- a Department of Experimental Medicine , Sapienza University , Rome , Italy
| | - Paola Matarrese
- b Section of Cell Aging and Degeneration, Department of Drug Research and Evaluation, Istituto Superiore di Sanita' , Rome , Italy.,c Center of Metabolomics , Rome , Italy
| | - Valeria Manganelli
- a Department of Experimental Medicine , Sapienza University , Rome , Italy
| | - Matteo Marconi
- b Section of Cell Aging and Degeneration, Department of Drug Research and Evaluation, Istituto Superiore di Sanita' , Rome , Italy
| | - Antonella Tinari
- d Department of Technology and Health , Istituto Superiore di Sanita' , Rome , Italy
| | - Lucrezia Gambardella
- b Section of Cell Aging and Degeneration, Department of Drug Research and Evaluation, Istituto Superiore di Sanita' , Rome , Italy
| | - Alberto Faggioni
- a Department of Experimental Medicine , Sapienza University , Rome , Italy
| | - Roberta Misasi
- a Department of Experimental Medicine , Sapienza University , Rome , Italy
| | - Maurizio Sorice
- a Department of Experimental Medicine , Sapienza University , Rome , Italy
| | - Walter Malorni
- b Section of Cell Aging and Degeneration, Department of Drug Research and Evaluation, Istituto Superiore di Sanita' , Rome , Italy.,e Istituto San Raffaele Pisana , Rome , Italy
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93
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Ellgaard L, McCaul N, Chatsisvili A, Braakman I. Co- and Post-Translational Protein Folding in the ER. Traffic 2016; 17:615-38. [PMID: 26947578 DOI: 10.1111/tra.12392] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Revised: 02/26/2016] [Accepted: 03/03/2016] [Indexed: 12/19/2022]
Abstract
The biophysical rules that govern folding of small, single-domain proteins in dilute solutions are now quite well understood. The mechanisms underlying co-translational folding of multidomain and membrane-spanning proteins in complex cellular environments are often less clear. The endoplasmic reticulum (ER) produces a plethora of membrane and secretory proteins, which must fold and assemble correctly before ER exit - if these processes fail, misfolded species accumulate in the ER or are degraded. The ER differs from other cellular organelles in terms of the physicochemical environment and the variety of ER-specific protein modifications. Here, we review chaperone-assisted co- and post-translational folding and assembly in the ER and underline the influence of protein modifications on these processes. We emphasize how method development has helped advance the field by allowing researchers to monitor the progression of folding as it occurs inside living cells, while at the same time probing the intricate relationship between protein modifications during folding.
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Affiliation(s)
- Lars Ellgaard
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Nicholas McCaul
- Cellular Protein Chemistry, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Anna Chatsisvili
- Cellular Protein Chemistry, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Ineke Braakman
- Cellular Protein Chemistry, Faculty of Science, Utrecht University, Utrecht, The Netherlands
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94
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Model-Driven Understanding of Palmitoylation Dynamics: Regulated Acylation of the Endoplasmic Reticulum Chaperone Calnexin. PLoS Comput Biol 2016; 12:e1004774. [PMID: 26900856 PMCID: PMC4765739 DOI: 10.1371/journal.pcbi.1004774] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 01/25/2016] [Indexed: 11/29/2022] Open
Abstract
Cellular functions are largely regulated by reversible post-translational modifications of proteins which act as switches. Amongst these, S-palmitoylation is unique in that it confers hydrophobicity. Due to technical difficulties, the understanding of this modification has lagged behind. To investigate principles underlying dynamics and regulation of palmitoylation, we have here studied a key cellular protein, the ER chaperone calnexin, which requires dual palmitoylation for function. Apprehending the complex inter-conversion between single-, double- and non- palmitoylated species required combining experimental determination of kinetic parameters with extensive mathematical modelling. We found that calnexin, due to the presence of two cooperative sites, becomes stably acylated, which not only confers function but also a remarkable increase in stability. Unexpectedly, stochastic simulations revealed that palmitoylation does not occur soon after synthesis, but many hours later. This prediction guided us to find that phosphorylation actively delays calnexin palmitoylation in resting cells. Altogether this study reveals that cells synthesize 5 times more calnexin than needed under resting condition, most of which is degraded. This unused pool can be mobilized by preventing phosphorylation or increasing the activity of the palmitoyltransferase DHHC6. The endoplasmic reticulum (ER) is the largest intracellular organelle of mammalian cells. It is responsible for many fundamental cellular functions, such as folding, quality control of membrane and secreted protein, lipid biosynthesis, control of apoptosis and calcium storage. Recent studies have shown that many ER membrane proteins are lipid modified. We therefore hypothesized that palmitoyltransferases, the enzymes responsible for this modifications, act as a regulator of the mammalian ER, controlling the function of a network of key proteins through reversible acylation. In this work we combine computational methods with experimental determination of parameters to study the mechanisms and properties of ER palmitoylation, using as a model the palmitoylation of the ER protein calnexin. The systematic analysis of the mathematical model, built and calibrated with the help of experimental data, shows that Calnexin palmitoylation leads to a 9-fold increase in half-life and that a long delay separates synthesis from palmitoylation in unstimulated cells. Surprisingly during this delay, 75% of synthesized calnexin is degraded before being palmitoylated. We hypothesize that this unexpected apparent inefficiency is a design principle that provides the cell with a means to post-translationally tune the calnexin content.
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95
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Lamriben L, Graham JB, Adams BM, Hebert DN. N-Glycan-based ER Molecular Chaperone and Protein Quality Control System: The Calnexin Binding Cycle. Traffic 2016; 17:308-26. [PMID: 26676362 DOI: 10.1111/tra.12358] [Citation(s) in RCA: 125] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 12/14/2015] [Accepted: 12/14/2015] [Indexed: 12/17/2022]
Abstract
Helenius and colleagues proposed over 20-years ago a paradigm-shifting model for how chaperone binding in the endoplasmic reticulum was mediated and controlled for a new type of molecular chaperone- the carbohydrate-binding chaperones, calnexin and calreticulin. While the originally established basics for this lectin chaperone binding cycle holds true today, there has been a number of important advances that have expanded our understanding of its mechanisms of action, role in protein homeostasis, and its connection to disease states that are highlighted in this review.
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Affiliation(s)
- Lydia Lamriben
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA, 01003, USA
| | - Jill B Graham
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA, 01003, USA
| | - Benjamin M Adams
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA, 01003, USA
| | - Daniel N Hebert
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA, 01003, USA
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96
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Garofalo T, Manganelli V, Grasso M, Mattei V, Ferri A, Misasi R, Sorice M. Role of mitochondrial raft-like microdomains in the regulation of cell apoptosis. Apoptosis 2015; 20:621-34. [PMID: 25652700 DOI: 10.1007/s10495-015-1100-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Lipid rafts are envisaged as lateral assemblies of specific lipids and proteins that dissociate and associate rapidly and form functional clusters in cell membranes. These structural platforms are not confined to the plasma membrane; indeed lipid microdomains are similarly formed at subcellular organelles, which include endoplasmic reticulum, Golgi and mitochondria, named raft-like microdomains. In addition, some components of raft-like microdomains are present within ER-mitochondria associated membranes. This review is focused on the role of mitochondrial raft-like microdomains in the regulation of cell apoptosis, since these microdomains may represent preferential sites where key reactions take place, regulating mitochondria hyperpolarization, fission-associated changes, megapore formation and release of apoptogenic factors. These structural platforms appear to modulate cytoplasmic pathways switching cell fate towards cell survival or death. Main insights on this issue derive from some pathological conditions in which alterations of microdomains structure or function can lead to severe alterations of cell activity and life span. In the light of the role played by raft-like microdomains to integrate apoptotic signals and in regulating mitochondrial dynamics, it is conceivable that these membrane structures may play a role in the mitochondrial alterations observed in some of the most common human neurodegenerative diseases, such as Amyotrophic lateral sclerosis, Huntington's chorea and prion-related diseases. These findings introduce an additional task for identifying new molecular target(s) of pharmacological agents in these pathologies.
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Affiliation(s)
- Tina Garofalo
- Department of Experimental Medicine, Sapienza University of Rome, Viale Regina Elena 324, 00161, Rome, Italy
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97
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Human Mitochondrial DNA-Protein Complexes Attach to a Cholesterol-Rich Membrane Structure. Sci Rep 2015; 5:15292. [PMID: 26478270 PMCID: PMC4609938 DOI: 10.1038/srep15292] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 09/22/2015] [Indexed: 01/05/2023] Open
Abstract
The helicase Twinkle is indispensable for mtDNA replication in nucleoids. Previously, we showed that Twinkle is tightly membrane-associated even in the absence of mtDNA, which suggests that Twinkle is part of a membrane-attached replication platform. Here we show that this platform is a cholesterol-rich membrane structure. We fractionated mitochondrial membrane preparations on flotation gradients and show that membrane-associated nucleoids accumulate at the top of the gradient. This fraction was shown to be highly enriched in cholesterol, a lipid that is otherwise low abundant in mitochondria. In contrast, more common mitochondrial lipids, and abundant inner-membrane associated proteins concentrated in the bottom-half of these gradients. Gene silencing of ATAD3, a protein with proposed functions related to nucleoid and mitochondrial cholesterol homeostasis, modified the distribution of cholesterol and nucleoids in the gradient in an identical fashion. Both cholesterol and ATAD3 were previously shown to be enriched in ER-mitochondrial junctions, and we detect nucleoid components in biochemical isolates of these structures. Our data suggest an uncommon membrane composition that accommodates platforms for replicating mtDNA, and reconcile apparently disparate functions of ATAD3. We suggest that mtDNA replication platforms are organized in connection with ER-mitochondrial junctions, facilitated by a specialized membrane architecture involving mitochondrial cholesterol.
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98
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Abstract
The endoplasmic reticulum (ER) supports many cellular processes and performs diverse functions, including protein synthesis, translocation across the membrane, integration into the membrane, folding, and posttranslational modifications including N-linked glycosylation; and regulation of Ca2+ homeostasis. In mammalian systems, the majority of proteins synthesized by the rough ER have N-linked glycans critical for protein maturation. The N-linked glycan is used as a quality control signal in the secretory protein pathway. A series of chaperones, folding enzymes, glucosidases, and carbohydrate transferases support glycoprotein synthesis and processing. Perturbation of ER-associated functions such as disturbed ER glycoprotein quality control, protein glycosylation and protein folding results in activation of an ER stress coping response. Collectively this ER stress coping response is termed the unfolded protein response (UPR), and occurs through the activation of complex cytoplasmic and nuclear signaling pathways. Cellular and ER homeostasis depends on balanced activity of the ER protein folding, quality control, and degradation pathways; as well as management of the ER stress coping response.
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99
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Caramelo JJ, Parodi AJ. A sweet code for glycoprotein folding. FEBS Lett 2015; 589:3379-87. [PMID: 26226420 DOI: 10.1016/j.febslet.2015.07.021] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 07/15/2015] [Accepted: 07/15/2015] [Indexed: 12/11/2022]
Abstract
Glycoprotein synthesis is initiated in the endoplasmic reticulum (ER) lumen upon transfer of a glycan (Glc3Man9GlcNAc2) from a lipid derivative to Asn residues (N-glycosylation). N-Glycan-dependent quality control of glycoprotein folding in the ER prevents exit to Golgi of folding intermediates, irreparably misfolded glycoproteins and incompletely assembled multimeric complexes. It also enhances folding efficiency by preventing aggregation and facilitating formation of proper disulfide bonds. The control mechanism essentially involves four components, resident lectin-chaperones (calnexin and calreticulin) that recognize monoglucosylated polymannose protein-linked glycans, lectin-associated oxidoreductase acting on monoglucosylated glycoproteins (ERp57), a glucosyltransferase that creates monoglucosylated epitopes in protein-linked glycans (UGGT) and a glucosidase (GII) that removes the glucose units added by UGGT. This last enzyme is the only mechanism component sensing glycoprotein conformations as it creates monoglucosylated glycans exclusively in not properly folded glycoproteins or in not completely assembled multimeric glycoprotein complexes. Glycoproteins that fail to properly fold are eventually driven to proteasomal degradation in the cytosol following the ER-associated degradation pathway, in which the extent of N-glycan demannosylation by ER mannosidases play a relevant role in the identification of irreparably misfolded glycoproteins.
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Affiliation(s)
- Julio J Caramelo
- Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA-CONICET), Avda. Patricias Argentinas 435, Buenos Aires C1405BWE, Argentina.
| | - Armando J Parodi
- Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA-CONICET), Avda. Patricias Argentinas 435, Buenos Aires C1405BWE, Argentina.
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100
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López-Crisosto C, Bravo-Sagua R, Rodriguez-Peña M, Mera C, Castro PF, Quest AFG, Rothermel BA, Cifuentes M, Lavandero S. ER-to-mitochondria miscommunication and metabolic diseases. Biochim Biophys Acta Mol Basis Dis 2015; 1852:2096-105. [PMID: 26171812 DOI: 10.1016/j.bbadis.2015.07.011] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Revised: 07/09/2015] [Accepted: 07/10/2015] [Indexed: 12/17/2022]
Abstract
Eukaryotic cells contain a variety of subcellular organelles, each of which performs unique tasks. Thus follows that in order to coordinate these different intracellular functions, a highly dynamic system of communication must exist between the various compartments. Direct endoplasmic reticulum (ER)-mitochondria communication is facilitated by the physical interaction of their membranes in dedicated structural domains known as mitochondria-associated membranes (MAMs), which facilitate calcium (Ca(2+)) and lipid transfer between organelles and also act as platforms for signaling. Numerous studies have demonstrated the importance of MAM in ensuring correct function of both organelles, and recently MAMs have been implicated in the genesis of various human diseases. Here, we review the salient structural features of interorganellar communication via MAM and discuss the most common experimental techniques employed to assess functionality of these domains. Finally, we will highlight the contribution of MAM to a variety of cellular functions and consider the potential role of MAM in the genesis of metabolic diseases. In doing so, the importance for cell functions of maintaining appropriate communication between ER and mitochondria will be emphasized.
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Affiliation(s)
- Camila López-Crisosto
- Advanced Center for Chronic Diseases (ACCDiS), Center for Molecular Studies of the Cell (CEMC), Faculty of Chemical & Pharmaceutical Sciences, Faculty of Medicine, University of Chile, Santiago 8380492, Chile
| | - Roberto Bravo-Sagua
- Advanced Center for Chronic Diseases (ACCDiS), Center for Molecular Studies of the Cell (CEMC), Faculty of Chemical & Pharmaceutical Sciences, Faculty of Medicine, University of Chile, Santiago 8380492, Chile
| | - Marcelo Rodriguez-Peña
- Advanced Center for Chronic Diseases (ACCDiS), Center for Molecular Studies of the Cell (CEMC), Faculty of Chemical & Pharmaceutical Sciences, Faculty of Medicine, University of Chile, Santiago 8380492, Chile
| | - Claudia Mera
- Advanced Center for Chronic Diseases (ACCDiS), Center for Molecular Studies of the Cell (CEMC), Faculty of Chemical & Pharmaceutical Sciences, Faculty of Medicine, University of Chile, Santiago 8380492, Chile
| | - Pablo F Castro
- Advanced Center for Chronic Diseases (ACCDiS), Faculty of Medicine, Pontifical Catholic University of Chile, Santiago 8380492, Chile
| | - Andrew F G Quest
- Advanced Center for Chronic Diseases (ACCDiS), Center for Molecular Studies of the Cell (CEMC), Faculty of Chemical & Pharmaceutical Sciences, Faculty of Medicine, University of Chile, Santiago 8380492, Chile
| | - Beverly A Rothermel
- Department of Internal Medicine (Cardiology), University of Texas Southwestern Medical Center, Dallas, TX 75235, USA; Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75235, USA
| | - Mariana Cifuentes
- Institute of Nutrition and Food Technology (INTA), University of Chile, Santiago 7830490, Chile
| | - Sergio Lavandero
- Advanced Center for Chronic Diseases (ACCDiS), Center for Molecular Studies of the Cell (CEMC), Faculty of Chemical & Pharmaceutical Sciences, Faculty of Medicine, University of Chile, Santiago 8380492, Chile; Department of Internal Medicine (Cardiology), University of Texas Southwestern Medical Center, Dallas, TX 75235, USA; Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75235, USA.
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