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Abstract
Renewed interest in metabolic research over the last two decades has inspired an explosion of technological developments for studying metabolism. At the forefront of methodological innovation is an approach referred to as "untargeted" or "discovery" metabolomics. The experimental objective of this technique is to comprehensively measure the entire metabolome, which constitutes a largely undefined set of molecules. Given its potential comprehensive coverage, untargeted metabolomics is often the first choice of experiments for investigators pursuing a metabolic research question. It is important to recognize, however, that untargeted metabolomics may not always be the optimal experimental approach. Conventionally, untargeted metabolomics only provides information about relative differences in metabolite pool sizes. Therefore, depending on the specific scientific question at hand, a complementary approach involving stable isotopes (such as metabolic flux analysis) may be better suited to provide biological insights. Unlike untargeted metabolomics, stable-isotope methods can provide information about differences in reaction rates.
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Affiliation(s)
- Nicola Zamboni
- Institute of Molecular Systems Biology, ETH Zurich, 8093 Zurich, Switzerland.
| | - Alan Saghatelian
- Clayton Foundation Laboratories for Peptide Biology, Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
| | - Gary J Patti
- Department of Chemistry and Department of Medicine, Washington University, St. Louis, MO 63130, USA.
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202
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Hill CH, Viuff AH, Spratley SJ, Salamone S, Christensen SH, Read RJ, Moriarty NW, Jensen HH, Deane JE. Azasugar inhibitors as pharmacological chaperones for Krabbe disease. Chem Sci 2015; 6:3075-3086. [PMID: 26029356 PMCID: PMC4445328 DOI: 10.1039/c5sc00754b] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 03/20/2015] [Indexed: 12/21/2022] Open
Abstract
Krabbe disease is a devastating neurodegenerative disorder characterized by rapid demyelination of nerve fibers. This disease is caused by defects in the lysosomal enzyme β-galactocerebrosidase (GALC), which hydrolyzes the terminal galactose from glycosphingolipids. These lipids are essential components of eukaryotic cell membranes: substrates of GALC include galactocerebroside, the primary lipid component of myelin, and psychosine, a cytotoxic metabolite. Mutations of GALC that cause misfolding of the protein may be responsive to pharmacological chaperone therapy (PCT), whereby small molecules are used to stabilize these mutant proteins, thus correcting trafficking defects and increasing residual catabolic activity in cells. Here we describe a new approach for the synthesis of galacto-configured azasugars and the characterization of their interaction with GALC using biophysical, biochemical and crystallographic methods. We identify that the global stabilization of GALC conferred by azasugar derivatives, measured by fluorescence-based thermal shift assays, is directly related to their binding affinity, measured by enzyme inhibition. X-ray crystal structures of these molecules bound in the GALC active site reveal which residues participate in stabilizing interactions, show how potency is achieved and illustrate the penalties of aza/iminosugar ring distortion. The structure-activity relationships described here identify the key physical properties required of pharmacological chaperones for Krabbe disease and highlight the potential of azasugars as stabilizing agents for future enzyme replacement therapies. This work lays the foundation for new drug-based treatments of Krabbe disease.
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Affiliation(s)
- Chris H Hill
- Department of Haematology , Cambridge Institute for Medical Research , University of Cambridge , Cambridge CB2 0XY , UK .
| | - Agnete H Viuff
- Department of Chemistry , Aarhus University , Langelandsgade 140, 8000 Aarhus C. , Denmark .
| | - Samantha J Spratley
- Department of Haematology , Cambridge Institute for Medical Research , University of Cambridge , Cambridge CB2 0XY , UK .
| | - Stéphane Salamone
- Department of Chemistry , Aarhus University , Langelandsgade 140, 8000 Aarhus C. , Denmark .
| | - Stig H Christensen
- Department of Chemistry , Aarhus University , Langelandsgade 140, 8000 Aarhus C. , Denmark .
| | - Randy J Read
- Department of Haematology , Cambridge Institute for Medical Research , University of Cambridge , Cambridge CB2 0XY , UK .
| | - Nigel W Moriarty
- Physical Biosciences Division , Lawrence Berkeley National Laboratory , Berkeley , CA 94720 , USA
| | - Henrik H Jensen
- Department of Chemistry , Aarhus University , Langelandsgade 140, 8000 Aarhus C. , Denmark .
| | - Janet E Deane
- Department of Haematology , Cambridge Institute for Medical Research , University of Cambridge , Cambridge CB2 0XY , UK .
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203
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C8-glycosphingolipids preferentially insert into tumor cell membranes and promote chemotherapeutic drug uptake. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:1656-70. [PMID: 25917957 DOI: 10.1016/j.bbamem.2015.04.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 04/15/2015] [Accepted: 04/19/2015] [Indexed: 02/06/2023]
Abstract
Insufficient drug delivery into tumor cells limits the therapeutic efficacy of chemotherapy. Co-delivery of liposome-encapsulated drug and synthetic short-chain glycosphingolipids (SC-GSLs) significantly improved drug bioavailability by enhancing intracellular drug uptake. Investigating the mechanisms underlying this SC-GSL-mediated drug uptake enhancement is the aim of this study. Fluorescence microscopy was used to visualize the cell membrane lipid transfer intracellular fate of fluorescently labeled C6-NBD-GalCer incorporated in liposomes in tumor and non-tumor cells. Additionally click chemistry was applied to image and quantify native SC-GSLs in tumor and non-tumor cell membranes. SC-GSL-mediated flip-flop was investigated in model membranes to confirm membrane-incorporation of SC-GSL and its effect on membrane remodeling. SC-GSL enriched liposomes containing doxorubicin (Dox) were incubated at 4°C and 37°C and intracellular drug uptake was studied in comparison to standard liposomes and free Dox. SC-GSL transfer to the cell membrane was independent of liposomal uptake and the majority of the transferred lipid remained in the plasma membrane. The transfer of SC-GSL was tumor cell-specific and induced membrane rearrangement as evidenced by a transbilayer flip-flop of pyrene-SM. However, pore formation was measured, as leakage of hydrophilic fluorescent probes was not observed. Moreover, drug uptake appeared to be mediated by SC-GSLs. SC-GSLs enhanced the interaction of doxorubicin (Dox) with the outer leaflet of the plasma membrane of tumor cells at 4°C. Our results demonstrate that SC-GSLs preferentially insert into tumor cell plasma membranes enhancing cell intrinsic capacity to translocate amphiphilic drugs such as Dox across the membrane via a biophysical process.
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204
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Levental KR, Levental I. Giant plasma membrane vesicles: models for understanding membrane organization. CURRENT TOPICS IN MEMBRANES 2015; 75:25-57. [PMID: 26015280 DOI: 10.1016/bs.ctm.2015.03.009] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The organization of eukaryotic membranes into functional domains continues to fascinate and puzzle cell biologists and biophysicists. The lipid raft hypothesis proposes that collective lipid interactions compartmentalize the membrane into coexisting liquid domains that are central to membrane physiology. This hypothesis has proven controversial because such structures cannot be directly visualized in live cells by light microscopy. The recent observations of liquid-liquid phase separation in biological membranes are an important validation of the raft hypothesis and enable application of the experimental toolbox of membrane physics to a biologically complex phase-separated membrane. This review addresses the role of giant plasma membrane vesicles (GPMVs) in refining the raft hypothesis and expands on the application of GPMVs as an experimental model to answer some of key outstanding problems in membrane biology.
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Affiliation(s)
- Kandice R Levental
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston - Medical School, Houston, TX, USA
| | - Ilya Levental
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston - Medical School, Houston, TX, USA
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205
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Trimble WS, Grinstein S. Barriers to the free diffusion of proteins and lipids in the plasma membrane. ACTA ACUST UNITED AC 2015; 208:259-71. [PMID: 25646084 PMCID: PMC4315255 DOI: 10.1083/jcb.201410071] [Citation(s) in RCA: 131] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Biological membranes segregate into specialized functional domains of distinct composition, which can persist for the entire life of the cell. How separation of their lipid and (glyco)protein components is generated and maintained is not well understood, but the existence of diffusional barriers has been proposed. Remarkably, the physical nature of such barriers and the manner whereby they impede the free diffusion of molecules in the plane of the membrane has rarely been studied in depth. Moreover, alternative mechanisms capable of generating membrane inhomogeneity are often disregarded. Here we describe prototypical biological systems where membrane segregation has been amply documented and discuss the role of diffusional barriers and other processes in the generation and maintenance of their structural and functional compartmentalization.
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Affiliation(s)
- William S Trimble
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Sergio Grinstein
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada Keenan Research Centre of the Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario M5C 1N8, Canada
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206
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Tofoleanu F, Brooks BR, Buchete NV. Modulation of Alzheimer's Aβ protofilament-membrane interactions by lipid headgroups. ACS Chem Neurosci 2015; 6:446-55. [PMID: 25581460 DOI: 10.1021/cn500277f] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The molecular pathogenesis of Alzheimer's disease (AD) is complex and sparsely understood. The relationship between AD's amyloid β (Aβ) peptides and neuronal membranes is central to Aβ's cytotoxicity and is directly modulated by the composition of the lipid headgroups. Molecular studies of the insertion of model Aβ40 protofilaments in lipid bilayers revealed strong interactions that affect the structural integrity of both the membranes and the ordered amyloid aggregates. In particular, electrostatics plays a crucial role in the interaction between Aβ protofilaments and palmytoil-oleoyl-phosphatidylethanolamine (POPE) lipids, a common component of neuronal plasma membranes. Here, we use all-atom molecular dynamics and steered molecular dynamics simulations to systematically compare the effects that POPE and palmytoil-oleoyl-phosphatidylcholine (POPC) headgroups have on the Aβ-lipid interactions. We find that Aβ protofilaments exhibit weaker electrostatic interactions with POPC headgroups and establish significantly shorter-lived contacts with the POPC bilayer. This illustrates the crucial yet complex role of electrostatic and hydrogen bonding interactions in modulating the anchoring and insertion of Aβ peptides into lipid bilayers. Our study reveals the atomistic details behind the barrier created by the lipid headgroup region in impeding solution-aggregated fibrillar oligomers to spontaneously insert into POPC bilayers, in contrast to the POPE case. While the biological reality is notoriously more complex (e.g., including other factors such as cholesterol), our results evidence a simple experimentally and computationally testable case for probing the factors that control the insertion of Aβ oligomeric aggregates in neuronal cell membranes--a process central to their neurotoxicity.
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Affiliation(s)
- Florentina Tofoleanu
- Laboratory
of Computational Biology, Biochemistry and Biophysics Center, National
Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Bernard R. Brooks
- Laboratory
of Computational Biology, Biochemistry and Biophysics Center, National
Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Nicolae-Viorel Buchete
- School of Physics & Complex and Adaptive Systems Laboratory, University College Dublin, Belfield, Dublin 4, Ireland
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207
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Abstract
Cell division ends with the physical separation of the two daughter cells, a process known as cytokinesis. This final event ensures that nuclear and cytoplasmic contents are accurately partitioned between the two nascent cells. Cytokinesis is one of the most dramatic changes in cell shape and requires an extensive reorganization of the cell's cytoskeleton. Here, we describe the cytoskeletal structures, factors, and signaling pathways that orchestrate this robust and yet highly dynamic process in animal cells. Finally, we discuss possible future directions in this growing area of cell division research and its implications in human diseases, including cancer.
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Affiliation(s)
- Pier Paolo D'Avino
- Department of Pathology, University of Cambridge, Cambridge CB2 1QP, United Kingdom
| | - Maria Grazia Giansanti
- Istituto di Biologia e Patologia Molecolari c/o Dipartimento di Biologia e Biotecnologie, Università Sapienza di Roma, 00185 Roma, Italy
| | - Mark Petronczki
- Cell Division and Aneuploidy Laboratory, Cancer Research UK-London Research Institute, Clare Hall Laboratories, South Mimms, Hertfordshire EN6 3LD, United Kingdom
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208
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Muro E, Atilla-Gokcumen GE, Eggert US. Lipids in cell biology: how can we understand them better? Mol Biol Cell 2015; 25:1819-23. [PMID: 24925915 PMCID: PMC4055261 DOI: 10.1091/mbc.e13-09-0516] [Citation(s) in RCA: 129] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Lipids are a major class of biological molecules and play many key roles in different processes. The diversity of lipids is on the same order of magnitude as that of proteins: cells express tens of thousands of different lipids and hundreds of proteins to regulate their metabolism and transport. Despite their clear importance and essential functions, lipids have not been as well studied as proteins. We discuss here some of the reasons why it has been challenging to study lipids and outline technological developments that are allowing us to begin lifting lipids out of their “Cinderella” status. We focus on recent advances in lipid identification, visualization, and investigation of their biophysics and perturbations and suggest that the field has sufficiently advanced to encourage broader investigation into these intriguing molecules.
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Affiliation(s)
- Eleonora Muro
- Department of Chemistry and Randall Division of Cell and Molecular Biophysics, King's College London, London SE1 1UL, United Kingdom
| | - G Ekin Atilla-Gokcumen
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY 14260
| | - Ulrike S Eggert
- Department of Chemistry and Randall Division of Cell and Molecular Biophysics, King's College London, London SE1 1UL, United Kingdom
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209
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Wu SH, Bi JF, Cloughesy T, Cavenee WK, Mischel PS. Emerging function of mTORC2 as a core regulator in glioblastoma: metabolic reprogramming and drug resistance. Cancer Biol Med 2015; 11:255-63. [PMID: 25610711 PMCID: PMC4296088 DOI: 10.7497/j.issn.2095-3941.2014.04.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 10/08/2014] [Indexed: 12/29/2022] Open
Abstract
Glioblastoma (GBM) is one of the most lethal human cancers. Genomic analyses define the molecular architecture of GBM and highlight a central function for mechanistic target of rapamycin (mTOR) signaling. mTOR kinase exists in two multi-protein complexes, namely, mTORC1 and mTORC2. These complexes differ in terms of function, regulation and rapamycin sensitivity. mTORC1 is well established as a cancer drug target, whereas the functions of mTORC2 in cancer, including GBM, remains poorly understood. This study reviews the recent findings that demonstrate a central function of mTORC2 in regulating tumor growth, metabolic reprogramming, and targeted therapy resistance in GBM, which makes mTORC2 as a critical GBM drug target.
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Affiliation(s)
- Si-Han Wu
- 1 Ludwig Institute for Cancer Research, University of California, San Diego, La Jolla, CA 92093, USA ; 2 Neuro-Oncology Program, University of California, Los Angeles, CA 90095, USA
| | - Jun-Feng Bi
- 1 Ludwig Institute for Cancer Research, University of California, San Diego, La Jolla, CA 92093, USA ; 2 Neuro-Oncology Program, University of California, Los Angeles, CA 90095, USA
| | - Timothy Cloughesy
- 1 Ludwig Institute for Cancer Research, University of California, San Diego, La Jolla, CA 92093, USA ; 2 Neuro-Oncology Program, University of California, Los Angeles, CA 90095, USA
| | - Webster K Cavenee
- 1 Ludwig Institute for Cancer Research, University of California, San Diego, La Jolla, CA 92093, USA ; 2 Neuro-Oncology Program, University of California, Los Angeles, CA 90095, USA
| | - Paul S Mischel
- 1 Ludwig Institute for Cancer Research, University of California, San Diego, La Jolla, CA 92093, USA ; 2 Neuro-Oncology Program, University of California, Los Angeles, CA 90095, USA
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210
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Rodriguez-Cuenca S, Barbarroja N, Vidal-Puig A. Dihydroceramide desaturase 1, the gatekeeper of ceramide induced lipotoxicity. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1851:40-50. [DOI: 10.1016/j.bbalip.2014.09.021] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 09/24/2014] [Accepted: 09/25/2014] [Indexed: 12/25/2022]
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211
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Kalucka J, Missiaen R, Georgiadou M, Schoors S, Lange C, De Bock K, Dewerchin M, Carmeliet P. Metabolic control of the cell cycle. Cell Cycle 2015; 14:3379-88. [PMID: 26431254 PMCID: PMC4825590 DOI: 10.1080/15384101.2015.1090068] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 08/29/2015] [Indexed: 12/14/2022] Open
Abstract
Cell division is a metabolically demanding process, requiring the production of large amounts of energy and biomass. Not surprisingly therefore, a cell's decision to initiate division is co-determined by its metabolic status and the availability of nutrients. Emerging evidence reveals that metabolism is not only undergoing substantial changes during the cell cycle, but it is becoming equally clear that metabolism regulates cell cycle progression. Here, we overview the emerging role of those metabolic pathways that have been best characterized to change during or influence cell cycle progression. We then studied how Notch signaling, a key angiogenic pathway that inhibits endothelial cell (EC) proliferation, controls EC metabolism (glycolysis) during the cell cycle.
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Affiliation(s)
- Joanna Kalucka
- Laboratory of Angiogenesis and Neurovascular link; Department of Oncology; KU Leuven; Leuven, Belgium
- Laboratory of Angiogenesis and Neurovascular link; Vesalius Research Center; VIB, Leuven, Belgium
| | - Rindert Missiaen
- Laboratory of Angiogenesis and Neurovascular link; Department of Oncology; KU Leuven; Leuven, Belgium
- Laboratory of Angiogenesis and Neurovascular link; Vesalius Research Center; VIB, Leuven, Belgium
| | - Maria Georgiadou
- Laboratory of Angiogenesis and Neurovascular link; Department of Oncology; KU Leuven; Leuven, Belgium
- Laboratory of Angiogenesis and Neurovascular link; Vesalius Research Center; VIB, Leuven, Belgium
- Present address: Turku Centre for Biotechnology; Turku, Finland
| | - Sandra Schoors
- Laboratory of Angiogenesis and Neurovascular link; Department of Oncology; KU Leuven; Leuven, Belgium
- Laboratory of Angiogenesis and Neurovascular link; Vesalius Research Center; VIB, Leuven, Belgium
| | - Christian Lange
- Laboratory of Angiogenesis and Neurovascular link; Department of Oncology; KU Leuven; Leuven, Belgium
- Laboratory of Angiogenesis and Neurovascular link; Vesalius Research Center; VIB, Leuven, Belgium
| | - Katrien De Bock
- Laboratory of Angiogenesis and Neurovascular link; Department of Oncology; KU Leuven; Leuven, Belgium
- Laboratory of Angiogenesis and Neurovascular link; Vesalius Research Center; VIB, Leuven, Belgium
- Present address: Exercise Physiology Research Group; Department of Kinesiology; KU Leuven; Leuven, Belgium
| | - Mieke Dewerchin
- Laboratory of Angiogenesis and Neurovascular link; Department of Oncology; KU Leuven; Leuven, Belgium
- Laboratory of Angiogenesis and Neurovascular link; Vesalius Research Center; VIB, Leuven, Belgium
| | - Peter Carmeliet
- Laboratory of Angiogenesis and Neurovascular link; Department of Oncology; KU Leuven; Leuven, Belgium
- Laboratory of Angiogenesis and Neurovascular link; Vesalius Research Center; VIB, Leuven, Belgium
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212
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Kennedy EJ. EMBO conference series: Chemical Biology 2014. Chembiochem 2014; 15:2783-7. [PMID: 25318996 DOI: 10.1002/cbic.201402527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Indexed: 11/07/2022]
Abstract
Around 300 people from 18 countries took part in the fourth biennial Chemical Biology conference at The European Molecular Biology Laboratory (EMBL) in Heidelberg, from August 20 to 23, 2014. Many advances in the field of chemical biology were presented in talks and poster sessions. Picture: Petra Riedinger (EMBL).
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Affiliation(s)
- Eileen J Kennedy
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, 240 W. Green Street, Athens, GA 30602 (USA).
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213
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Frescatada-Rosa M, Stanislas T, Backues SK, Reichardt I, Men S, Boutté Y, Jürgens G, Moritz T, Bednarek SY, Grebe M. High lipid order of Arabidopsis cell-plate membranes mediated by sterol and DYNAMIN-RELATED PROTEIN1A function. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 80:745-57. [PMID: 25234576 PMCID: PMC4280860 DOI: 10.1111/tpj.12674] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2014] [Revised: 08/21/2014] [Accepted: 09/04/2014] [Indexed: 05/22/2023]
Abstract
Membranes of eukaryotic cells contain high lipid-order sterol-rich domains that are thought to mediate temporal and spatial organization of cellular processes. Sterols are crucial for execution of cytokinesis, the last stage of cell division, in diverse eukaryotes. The cell plate of higher-plant cells is the membrane structure that separates daughter cells during somatic cytokinesis. Cell-plate formation in Arabidopsis relies on sterol- and DYNAMIN-RELATED PROTEIN1A (DRP1A)-dependent endocytosis. However, functional relationships between lipid membrane order or lipid packing and endocytic machinery components during eukaryotic cytokinesis have not been elucidated. Using ratiometric live imaging of lipid order-sensitive fluorescent probes, we show that the cell plate of Arabidopsis thaliana represents a dynamic, high lipid-order membrane domain. The cell-plate lipid order was found to be sensitive to pharmacological and genetic alterations of sterol composition. Sterols co-localize with DRP1A at the cell plate, and DRP1A accumulates in detergent-resistant membrane fractions. Modifications of sterol concentration or composition reduce cell-plate membrane order and affect DRP1A localization. Strikingly, DRP1A function itself is essential for high lipid order at the cell plate. Our findings provide evidence that the cell plate represents a high lipid-order domain, and pave the way to explore potential feedback between lipid order and function of dynamin-related proteins during cytokinesis.
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Affiliation(s)
- Márcia Frescatada-Rosa
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå UniversitySE-90187, Umeå, Sweden
| | - Thomas Stanislas
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå UniversitySE-90187, Umeå, Sweden
| | - Steven K Backues
- Department of Biochemistry, University of Wisconsin-MadisonMadison, WI, 53706, USA
- ‡Present address: 6036 Life Sciences Institute, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, MI, 48109-2216, USA
| | - Ilka Reichardt
- Department of Developmental Genetics, Centre for Plant Molecular Biology, University of TübingenAuf der Morgenstelle 3, D-72076, Tübingen, Germany
- §Present address: Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Dr Bohr Gasse 3, A-1030, Vienna, Austria
| | - Shuzhen Men
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå UniversitySE-90187, Umeå, Sweden
- ¶Present address: College of Life Sciences, Nankai University, 94 Weijin Road, Nankai District, Tianjin, 300071, China
| | - Yohann Boutté
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå UniversitySE-90187, Umeå, Sweden
- **Present address: Membrane Biogenesis Laboratory, UMR 5200 CNRS, Université Bordeaux Segalen Bâtiment A3, INRA Bordeaux Aquitaine BP81, 71 Avenue Edouard Bourlaux, 33883, F-Villenave d'Ornon, France
| | - Gerd Jürgens
- Department of Developmental Genetics, Centre for Plant Molecular Biology, University of TübingenAuf der Morgenstelle 3, D-72076, Tübingen, Germany
| | - Thomas Moritz
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural SciencesSE-90183, Umeå, Sweden
| | - Sebastian Y Bednarek
- Department of Biochemistry, University of Wisconsin-MadisonMadison, WI, 53706, USA
| | - Markus Grebe
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå UniversitySE-90187, Umeå, Sweden
- Institute for Biochemistry and Biology, Plant Physiology, University of PotsdamKarl Liebknecht Straße 24-25, Building 20, D-14476, Potsdam-Golm, Germany
- *For correspondence (e-mail )
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214
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Phosphoinositides: Lipids with informative heads and mastermind functions in cell division. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1851:832-43. [PMID: 25449648 DOI: 10.1016/j.bbalip.2014.10.013] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 10/21/2014] [Accepted: 10/28/2014] [Indexed: 01/22/2023]
Abstract
Phosphoinositides are low abundant but essential phospholipids in eukaryotic cells and refer to phosphatidylinositol and its seven polyphospho-derivatives. In this review, we summarize our current knowledge on phosphoinositides in multiple aspects of cell division in animal cells, including mitotic cell rounding, longitudinal cell elongation, cytokinesis furrow ingression, intercellular bridge abscission and post-cytokinesis events. PtdIns(4,5)P₂production plays critical roles in spindle orientation, mitotic cell shape and bridge stability after furrow ingression by recruiting force generator complexes and numerous cytoskeleton binding proteins. Later, PtdIns(4,5)P₂hydrolysis and PtdIns3P production are essential for normal cytokinesis abscission. Finally, emerging functions of PtdIns3P and likely PtdIns(4,5)P₂have recently been reported for midbody remnant clearance after abscission. We describe how the multiple functions of phosphoinositides in cell division reflect their distinct roles in local recruitment of protein complexes, membrane traffic and cytoskeleton remodeling. This article is part of a Special Issue entitled Phosphoinositides.
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215
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Baum DA, Baum B. An inside-out origin for the eukaryotic cell. BMC Biol 2014; 12:76. [PMID: 25350791 PMCID: PMC4210606 DOI: 10.1186/s12915-014-0076-2] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 09/17/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Although the origin of the eukaryotic cell has long been recognized as the single most profound change in cellular organization during the evolution of life on earth, this transition remains poorly understood. Models have always assumed that the nucleus and endomembrane system evolved within the cytoplasm of a prokaryotic cell. RESULTS Drawing on diverse aspects of cell biology and phylogenetic data, we invert the traditional interpretation of eukaryotic cell evolution. We propose that an ancestral prokaryotic cell, homologous to the modern-day nucleus, extruded membrane-bound blebs beyond its cell wall. These blebs functioned to facilitate material exchange with ectosymbiotic proto-mitochondria. The cytoplasm was then formed through the expansion of blebs around proto-mitochondria, with continuous spaces between the blebs giving rise to the endoplasmic reticulum, which later evolved into the eukaryotic secretory system. Further bleb-fusion steps yielded a continuous plasma membrane, which served to isolate the endoplasmic reticulum from the environment. CONCLUSIONS The inside-out theory is consistent with diverse kinds of data and provides an alternative framework by which to explore and understand the dynamic organization of modern eukaryotic cells. It also helps to explain a number of previously enigmatic features of cell biology, including the autonomy of nuclei in syncytia and the subcellular localization of protein N-glycosylation, and makes many predictions, including a novel mechanism of interphase nuclear pore insertion.
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216
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Zíková M, Konířová J, Ditrychová K, Corlett A, Kolář M, Bartůněk P. DISP3 promotes proliferation and delays differentiation of neural progenitor cells. FEBS Lett 2014; 588:4071-7. [PMID: 25281927 DOI: 10.1016/j.febslet.2014.09.036] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 09/04/2014] [Accepted: 09/25/2014] [Indexed: 12/20/2022]
Abstract
DISP3 (PTCHD2), a sterol-sensing domain-containing protein, is highly expressed in neural tissue but its role in neural differentiation is unknown. In the present study we used a multipotent cerebellar progenitor cell line, C17.2, to investigate the impact of DISP3 on the proliferation and differentiation of neural precursors. We found that ectopically expressed DISP3 promotes cell proliferation and alters expression of genes that are involved in tumorigenesis. Finally, the differentiation profile of DISP3-expressing cells was altered, as evidenced by delayed expression of neural specific markers and a reduced capacity to undergo neural differentiation.
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Affiliation(s)
- Martina Zíková
- Institute of Molecular Genetics AS CR v.v.i., Vídeňská 1083, 142 20 Prague 4, Czech Republic
| | - Jana Konířová
- Institute of Molecular Genetics AS CR v.v.i., Vídeňská 1083, 142 20 Prague 4, Czech Republic
| | - Karolína Ditrychová
- Institute of Molecular Genetics AS CR v.v.i., Vídeňská 1083, 142 20 Prague 4, Czech Republic
| | - Alicia Corlett
- Institute of Molecular Genetics AS CR v.v.i., Vídeňská 1083, 142 20 Prague 4, Czech Republic
| | - Michal Kolář
- Institute of Molecular Genetics AS CR v.v.i., Vídeňská 1083, 142 20 Prague 4, Czech Republic
| | - Petr Bartůněk
- Institute of Molecular Genetics AS CR v.v.i., Vídeňská 1083, 142 20 Prague 4, Czech Republic.
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217
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Zhu H, Han M. Exploring developmental and physiological functions of fatty acid and lipid variants through worm and fly genetics. Annu Rev Genet 2014; 48:119-48. [PMID: 25195508 DOI: 10.1146/annurev-genet-041814-095928] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Lipids are more than biomolecules for energy storage and membrane structure. With ample structural variation, lipids critically participate in nearly all aspects of cellular function. Lipid homeostasis and metabolism are closely related to major human diseases and health problems. However, lipid functional studies have been significantly underdeveloped, partly because of the difficulty in applying genetics and common molecular approaches to tackle the complexity associated with lipid biosynthesis, metabolism, and function. In the past decade, a number of laboratories began to analyze the roles of lipid metabolism in development and other physiological functions using animal models and combining genetics, genomics, and biochemical approaches. These pioneering efforts have not only provided valuable insights regarding lipid functions in vivo but have also established feasible methodology for future studies. Here, we review a subset of these studies using Caenorhabditis elegans and Drosophila melanogaster.
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Affiliation(s)
- Huanhu Zhu
- Howard Hughes Medical Institute and Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309;
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218
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Airola MV, Tumolo JM, Snider J, Hannun YA. Identification and biochemical characterization of an acid sphingomyelinase-like protein from the bacterial plant pathogen Ralstonia solanacearum that hydrolyzes ATP to AMP but not sphingomyelin to ceramide. PLoS One 2014; 9:e105830. [PMID: 25144372 PMCID: PMC4140839 DOI: 10.1371/journal.pone.0105830] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 07/25/2014] [Indexed: 11/18/2022] Open
Abstract
Acid sphingomyelinase (aSMase) is a human enzyme that catalyzes the hydrolysis of sphingomyelin to generate the bioactive lipid ceramide and phosphocholine. ASMase deficiency is the underlying cause of the genetic diseases Niemann-Pick Type A and B and has been implicated in the onset and progression of a number of other human diseases including cancer, depression, liver, and cardiovascular disease. ASMase is the founding member of the aSMase protein superfamily, which is a subset of the metallophosphatase (MPP) superfamily. To date, MPPs that share sequence homology with aSMase, termed aSMase-like proteins, have been annotated and presumed to function as aSMases. However, none of these aSMase-like proteins have been biochemically characterized to verify this. Here we identify RsASML, previously annotated as RSp1609: acid sphingomyelinase-like phosphodiesterase, as the first bacterial aSMase-like protein from the deadly plant pathogen Ralstonia solanacearum based on sequence homology with the catalytic and C-terminal domains of human aSMase. A biochemical characterization of RsASML does not support a role in sphingomyelin hydrolysis but rather finds RsASML capable of acting as an ATP diphosphohydrolase, catalyzing the hydrolysis of ATP and ADP to AMP. In addition, RsASML displays a neutral, not acidic, pH optimum and prefers Ni2+ or Mn2+, not Zn2+, for catalysis. This alters the expectation that all aSMase-like proteins function as acid SMases and expands the substrate possibilities of this protein superfamily to include nucleotides. Overall, we conclude that sequence homology with human aSMase is not sufficient to predict substrate specificity, pH optimum for catalysis, or metal dependence. This may have implications to the biochemically uncharacterized human aSMase paralogs, aSMase-like 3a (aSML3a) and aSML3b, which have been implicated in cancer and kidney disease, respectively, and assumed to function as aSMases.
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Affiliation(s)
- Michael V. Airola
- Department of Medicine and the Stony Brook University Cancer Center, Stony Brook University, Stony Brook, New York, United States of America
| | - Jessica M. Tumolo
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Justin Snider
- Department of Medicine and the Stony Brook University Cancer Center, Stony Brook University, Stony Brook, New York, United States of America
| | - Yusuf A. Hannun
- Department of Medicine and the Stony Brook University Cancer Center, Stony Brook University, Stony Brook, New York, United States of America
- * E-mail:
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219
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Furse S. The physical influence of inositides-a disproportionate effect? J Chem Biol 2014; 8:1-3. [PMID: 25584076 DOI: 10.1007/s12154-014-0117-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2014] [Accepted: 07/07/2014] [Indexed: 12/16/2022] Open
Abstract
After the initial observation that lipids form a considerable part of biological membranes, the details of the physical role of lipids in biological systems have emerged gradually. There have been few 'Eureka' moments in which a class or individual lipid has appeared as a game-changing physical player. However, evidence collected in the last five years suggests that that notion may be about to change. In chemical biology studies, inositides are increasingly showing themselves to be lipids that have a physical influence on membrane systems that is as strong as their biological (signalling) one. Additionally, recent evidence has shown that the concentration of at least one inositide changes during important stages of the cell cycle, and not in a manner consistent with its traditional signalling roles. The balance between these data is explored and a forward-looking view is proposed.
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Affiliation(s)
- Samuel Furse
- Membrane Biochemistry and Biophysics, Universiteit Utrecht, Kruytgebouw, Padualaan 8, Utrecht, 3584 CH The Netherlands
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220
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Zavala E, Marquez-Lago TT. The long and viscous road: uncovering nuclear diffusion barriers in closed mitosis. PLoS Comput Biol 2014; 10:e1003725. [PMID: 25032937 PMCID: PMC4102450 DOI: 10.1371/journal.pcbi.1003725] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Accepted: 06/02/2014] [Indexed: 11/18/2022] Open
Abstract
Diffusion barriers are effective means for constraining protein lateral exchange in cellular membranes. In Saccharomyces cerevisiae, they have been shown to sustain parental identity through asymmetric segregation of ageing factors during closed mitosis. Even though barriers have been extensively studied in the plasma membrane, their identity and organization within the nucleus remains poorly understood. Based on different lines of experimental evidence, we present a model of the composition and structural organization of a nuclear diffusion barrier during anaphase. By means of spatial stochastic simulations, we propose how specialised lipid domains, protein rings, and morphological changes of the nucleus may coordinate to restrict protein exchange between mother and daughter nuclear lobes. We explore distinct, plausible configurations of these diffusion barriers and offer testable predictions regarding their protein exclusion properties and the diffusion regimes they generate. Our model predicts that, while a specialised lipid domain and an immobile protein ring at the bud neck can compartmentalize the nucleus during early anaphase; a specialised lipid domain spanning the elongated bridge between lobes would be entirely sufficient during late anaphase. Our work shows how complex nuclear diffusion barriers in closed mitosis may arise from simple nanoscale biophysical interactions. Spatial segregation of molecular contents is often necessary for an accurate, timely accomplishment of cellular functions, such as signal transduction and cell-fate decisions. For instance, budding yeast division requires the asymmetric segregation of proteins to distinguish a newborn cell from its parent. However, the strategies to achieve this parental identity are poorly understood. This holds especially true for key proteins and molecular complexes involved in mitosis that diffuse within the nuclear envelope. In fact, segregation within the nuclear envelope has been experimentally verified, but both the nature and configuration of any plausible diffusion barrier remain unknown. In this work, we built virtual models of the nucleus and carried out simulations testing the plausibility of specialised lipid domains and protein rings constituting the diffusion barrier. Moreover, we explored distinct barrier configurations in early and late stages of cell division, and verified our simulation results match experimental observations. Our work shows that the biophysical properties of these molecules, coordinated with morphological changes in the nucleus, make them suitable components of the nuclear diffusion barrier. Importantly, our research approach offers a novel avenue to study diffusion barriers in other biological membranes.
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Affiliation(s)
- Eder Zavala
- Integrative Systems Biology Unit, Okinawa Institute of Science and Technology, Okinawa, Japan
| | - Tatiana T. Marquez-Lago
- Integrative Systems Biology Unit, Okinawa Institute of Science and Technology, Okinawa, Japan
- * E-mail:
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221
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Crowell EF, Gaffuri AL, Gayraud-Morel B, Tajbakhsh S, Echard A. Engulfment of the midbody remnant after cytokinesis in mammalian cells. J Cell Sci 2014; 127:3840-51. [PMID: 25002399 DOI: 10.1242/jcs.154732] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The midbody remnant (MBR) that is generated after cytokinetic abscission has recently attracted a lot of attention, because it might have crucial consequences for cell differentiation and tumorigenesis in mammalian cells. In these cells, it has been reported that the MBR is either released into the extracellular medium or retracted into one of the two daughter cells where it can be degraded by autophagy. Here, we describe a major alternative pathway in a variety of human and mouse immortalized cells, cancer cells and primary stem cells. Using correlative light and scanning electron microscopy and quantitative assays, we found that sequential abscissions on both sides of the midbody generate free MBRs, which are tightly associated with the cell surface through a Ca(2+)/Mg(2+)-dependent receptor. Surprisingly, MBRs move over the cell surface for several hours, before being eventually engulfed by an actin-dependent phagocytosis-like mechanism. Mathematical modeling combined with experimentation further demonstrates that lysosomal activities fully account for the clearance of MBRs after engulfment. This study changes our understanding of how MBRs are inherited and degraded in mammalian cells and suggests a mechanism by which MBRs might signal over long distances between cells.
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Affiliation(s)
- Elizabeth Faris Crowell
- Institut Pasteur, Membrane Traffic and Cell Division Lab, Department of Cell Biology and Infection, 25 Rue du Dr Roux, 75015 Paris, France CNRS URA 2582, F-75015 Paris, France
| | - Anne-Lise Gaffuri
- Institut Pasteur, Membrane Traffic and Cell Division Lab, Department of Cell Biology and Infection, 25 Rue du Dr Roux, 75015 Paris, France CNRS URA 2582, F-75015 Paris, France
| | - Barbara Gayraud-Morel
- Institut Pasteur, Stem Cells and Development, Department of Developmental & Stem Cell Biology, CNRS URA 2578, 25 Rue du Dr Roux, F-75015 Paris, France
| | - Shahragim Tajbakhsh
- Institut Pasteur, Stem Cells and Development, Department of Developmental & Stem Cell Biology, CNRS URA 2578, 25 Rue du Dr Roux, F-75015 Paris, France
| | - Arnaud Echard
- Institut Pasteur, Membrane Traffic and Cell Division Lab, Department of Cell Biology and Infection, 25 Rue du Dr Roux, 75015 Paris, France CNRS URA 2582, F-75015 Paris, France
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222
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Affiliation(s)
- J Mark Brown
- Department of Cellular and Molecular Medicine, Cleveland Clinic Lerner Research Institute, Cleveland, OH
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223
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Changing lipids. Nat Rev Mol Cell Biol 2014. [DOI: 10.1038/nrm3764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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224
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225
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Divalent Metal Cations in DNA–Phospholipid Binding. ACTA ACUST UNITED AC 2014. [DOI: 10.1016/b978-0-12-418698-9.00004-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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226
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Le Bras S, Le Borgne R. Epithelial cell division – multiplying without losing touch. J Cell Sci 2014; 127:5127-37. [DOI: 10.1242/jcs.151472] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Epithelia are compact tissues comprising juxtaposed cells that function as mechanical and chemical barriers between the body and the environment. This barrier relies, in part, on adhesive contacts within adherens junctions, which are formed and stabilized by E-cadherin and catenin proteins linked to the actomyosin cytoskeleton. During development and throughout adult life, epithelia are continuously growing or regenerating, largely as a result of cell division. Although persistence of adherens junctions is needed for epithelial integrity, these junctions are continually remodelled during cell division. In this Commentary, we will focus on cytokinesis, the final step of mitosis, a multiparty phenomenon in which the adherens junction belt plays an essential role and during which a new cell–cell interface is generated between daughter cells. This new interface is the site of intense remodelling, where new adhesive contacts are assembled and cell polarity is transmitted from mother to daughter cells, ultimately becoming the site of cell signalling.
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