DOCSLIB.ORG

Lipid Raft Association and Subcellular Localization of UNC5 Netrin-1 Receptors

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Lipid Raft Association and Subcellular Localization of UNC5 Netrin-1 Receptors Lipid raft association and subcellular localization of UNC5 Netrin-1 receptors Associació als lípids raft i localització subcelꞏlular de la familia de receptors de la Netrina-1 UNC5 Marc Hernaiz Llorens ADVERTIMENT. La consulta d’aquesta tesi queda condicionada a l’acceptació de les següents condicions d'ús: La difusió d’aquesta tesi per mitjà del servei TDX (www.tdx.cat) i a través del Dipòsit Digital de la UB (diposit.ub.edu) ha estat autoritzada pels titulars dels drets de propietat intelꞏlectual únicament per a usos privats emmarcats en activitats d’investigació i docència. No s’autoritza la seva reproducció amb finalitats de lucre ni la seva difusió i posada a disposició des d’un lloc aliè al servei TDX ni al Dipòsit Digital de la UB. No s’autoritza la presentació del seu contingut en una finestra o marc aliè a TDX o al Dipòsit Digital de la UB (framing). Aquesta reserva de drets afecta tant al resum de presentació de la tesi com als seus continguts. En la utilització o cita de parts de la tesi és obligat indicar el nom de la persona autora. ADVERTENCIA. La consulta de esta tesis queda condicionada a la aceptación de las siguientes condiciones de uso: La difusión de esta tesis por medio del servicio TDR (www.tdx.cat) y a través del Repositorio Digital de la UB (diposit.ub.edu) ha sido autorizada por los titulares de los derechos de propiedad intelectual únicamente para usos privados enmarcados en actividades de investigación y docencia. No se autoriza su reproducción con finalidades de lucro ni su difusión y puesta a disposición desde un sitio ajeno al servicio TDR o al Repositorio Digital de la UB. No se autoriza la presentación de su contenido en una ventana o marco ajeno a TDR o al Repositorio Digital de la UB (framing). Esta reserva de derechos afecta tanto al resumen de presentación de la tesis como a sus contenidos. En la utilización o cita de partes de la tesis es obligado indicar el nombre de la persona autora. WARNING. On having consulted this thesis you’re accepting the following use conditions: Spreading this thesis by the TDX (www.tdx.cat) service and by the UB Digital Repository (diposit.ub.edu) has been authorized by the titular of the intellectual property rights only for private uses placed in investigation and teaching activities. Reproduction with lucrative aims is not authorized nor its spreading and availability from a site foreign to the TDX service or to the UB Digital Repository. Introducing its content in a window or frame foreign to the TDX service or to the UB Digital Repository is not authorized (framing). Those rights affect to the presentation summary of the thesis as well as to its contents. In the using or citation of parts of the thesis it’s obliged to indicate the name of the author. ® Thesis cover illustration: Anna Llorens Christina's World Andrew Wyeth (1917-1989) Tempera on gypsum. 1948 MUSEUM OF MODERN ART (MOMA): NEW YORK This painting shows Christina Olson, an American girl from Cushing, Maine, who suffered from poliomyelitis. Andrew Wyeth was a friend of Christina's parents and stayed at their house on several occasions. There, Wyeth met Christina and witnessed her extraordinary strenght and willpower when it came to getting about, despite that she was unable to walk due to her illness. Wyeth said of her that she was "an admirable woman". With great difficulty, in this painting Christina drags herself across the lawn to reach the house. Andrew Wyeth was born in Chadds Ford, Pennsylvania in 1917. He devoted himself above all to watercolors and tempera on gypsum. His oeuvre is realistic, depicting mainly scenes from rural American day life, in which sentiment dominate each of his paintings. "OBSERVED VULGARITY BECOMES ROMANTIC" ANDREW WYETH To Victor and Anna, ABSTRACT During brain development, UNC5 receptors play a key role in controlling axonal extension through their sensing of the guidance molecule Netrin-1. The correct positioning of receptors into specific cholesterol-enriched membrane raft microdomains is of crucial importance for the efficient transduction of the recognized signal. Whether such microdomains are required for the appropriate axonal guidance mediated by UNC5 receptors remains unknown. Here, we extend the classical biochemical characterization of raft microdomains by performing confocal microscopy, live cell FRAP analysis and sptPALM of fluorescently-tagged UNC5 receptors and we reveal for the first time differences into their membrane mobility properties. Using a combination of pharmacological and genetical approaches in primary neuronal cultures and brain cerebellar explants we further demonstrate that disrupting raft microdomains inhibit the chemorepulsive response of growth cones and axons against Netrin-1. Together, our findings indicate that the distribution of all UNC5 receptors into cholesterol-enriched raft microdomains is heterogeneous and that their specific localization have functional consequences for the axonal chemorepulsion against Netrin-1. Alternative splicing is a key mechanism in which a variety of proteins is achieved from "cut and paste" mRNA. The plethora of proteins resulting from alternative splicing processes is crucial for the proper function of certain protein isoforms. In this thesis we have detected alternative splicing in the UNC5A receptor in the nervous system. The resulting product is a UNC5A isoform that lacks the first TSPI repeat, uncovered here, to be important for cell membrane targeting. We have further analyzed the implications of losing the first TSPI repeat. 1 2 TABLE OF CONTENTS ABSTRACT................................................................................................................................. 1 TABLE OF CONTENTS ................................................................................................................ 3 ABREVIATIONS ......................................................................................................................... 7 INTRODUCTION ...................................................................................................................... 11 1. DEVELOPMENT OF THE MAMMAL NERVOUS SYSTEM....................................................................... 11 1. 1. EARLY STAGES OF EMBRYONIC DEVELOPMENT ..................................................................... 11 1. 2. THE NEURAL INDUCTION................................................................................................. 12 1. 3. NEURULATION ............................................................................................................. 13 1. 4. REGIONALIZATION OF THE CENTRAL NERVOUS SYSTEM .......................................................... 14 2. CEREBELLAR DEVELOPMENT ...................................................................................................... 15 2. 1. DEFINING BOUNDARIES (CEREBELLAR PRIMORDIUM) ............................................................ 15 2. 2. CEREBELLAR HISTOGENESIS ............................................................................................. 16 2. 3. CEREBELLAR CYTOARCHITECTURE AND CONNECTIVITY ........................................................... 17 2. 3. 1. Structure of the cerebellum .......................................................................... 17 2. 3. 2. INTRINSIC CONNECTIVITY ..................................................................................... 17 2. 3. 3. AFFERENT PROJECTIONS ...................................................................................... 18 2. 3. 4. EFFERENT PROJECTIONS ...................................................................................... 18 2. 3. 5. GRANULE CELLS ................................................................................................. 19 2. 3. 5. 1. FROM THE RHOMBIC LIP TO THE EXTERNAL GRANULAR LAYER (EGL) ................... 19 2. 3. 5. 2. FROM PROLIFERATION TO DIFFERENTIATION ................................................. 20 2. 3. 5. 3. EXITING THE EXTERNAL GRANULAR LAYER (EGL) ............................................ 20 3. AXON GUIDANCE..................................................................................................................... 22 3. 1. GROWTH CONE ............................................................................................................ 22 3. 2. CYTOSKELETAL DYNAMICS ............................................................................................... 22 3. 3. GUIDANCE CUES ........................................................................................................... 24 3. 3. 1. NETRINS .......................................................................................................... 27 3. 3. 1. 1. NETRIN-1 RECEPTORS .............................................................................. 27 3. 3. 1. 1. 1. DELETED IN COLORECTAL CANCER (DCC) .......................................... 27 3. 3. 1. 1. 2. UNCOORDINATED-5 (UNC5) ......................................................... 28 3. 3. 1. 1. 3. NEOGENIN ................................................................................. 28 3. 3. 1. 1. 4. DOWN SYNDROME CELL ADHESION MOLECULE (DSCAM) ................... 28 3. 2. 1. 2. NETRIN-1 IN NERVOUS SYSTEM DEVELOPMENT .............................................. 30 4. CHOLESTEROL ......................................................................................................................... 30 4. 1. CHOLESTEROL IN THE CENTRAL NERVOUS SYSTEM ...............................................................
Load more

Recommended publications
  • Role of Cholesterol in Lipid Raft Formation: Lessons from Lipid Model Systems
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Biochimica et Biophysica Acta 1610 (2003) 174–183 www.bba-direct.com Review Role of cholesterol in lipid raft formation: lessons from lipid model systems John R. Silvius* Department of Biochemistry, McGill University, Montre´al, Que´bec, Canada H3G 1Y6 Received 21 March 2002; accepted 16 October 2002 Abstract Biochemical and cell-biological experiments have identified cholesterol as an important component of lipid ‘rafts’ and related structures (e.g., caveolae) in mammalian cell membranes, and membrane cholesterol levels as a key factor in determining raft stability and organization. Studies using cholesterol-containing bilayers as model systems have provided important insights into the roles that cholesterol plays in determining lipid raft behavior. This review will discuss recent progress in understanding two aspects of lipid–cholesterol interactions that are particularly relevant to understanding the formation and properties of lipid rafts. First, we will consider evidence that cholesterol interacts differentially with different membrane lipids, associating particularly strongly with saturated, high-melting phospho- and sphingolipids and particularly weakly with highly unsaturated lipid species. Second, we will review recent progress in reconstituting and directly observing segregated raft-like (liquid-ordered) domains in model membranes that mimic the lipid compositions of natural membranes incorporating raft domains. D 2003 Elsevier Science B.V. All rights reserved. Keywords: Sterol; Phospholipid; Sphingolipid; Lipid bilayer; Lipid monolayer; Membrane domain 1. Introduction Two major observations suggest that cholesterol–lipid interactions play an important role in the formation of rafts Cholesterol–lipid interactions have long been recognized in animal cell membranes.
    [Show full text]
  • The Adaptive Remodeling of Endothelial Glycocalyx in Response to Fluid Shear Stress
    City University of New York (CUNY) CUNY Academic Works Publications and Research City College of New York 2014 The Adaptive Remodeling of Endothelial Glycocalyx in Response to Fluid Shear Stress Ye Zeng CUNY City College John M. Tarbell CUNY City College How does access to this work benefit ou?y Let us know! More information about this work at: https://academicworks.cuny.edu/cc_pubs/34 Discover additional works at: https://academicworks.cuny.edu This work is made publicly available by the City University of New York (CUNY). Contact: [email protected] The Adaptive Remodeling of Endothelial Glycocalyx in Response to Fluid Shear Stress Ye Zeng1,2, John M. Tarbell1* 1 Department of Biomedical Engineering, The City College of New York, New York, New York, United States of America, 2 Institute of Biomedical Engineering, School of Preclinical and Forensic Medicine, Sichuan University, Chengdu, China Abstract The endothelial glycocalyx is vital for mechanotransduction and endothelial barrier integrity. We previously demonstrated the early changes in glycocalyx organization during the initial 30 min of shear exposure. In the present study, we tested the hypothesis that long-term shear stress induces further remodeling of the glycocalyx resulting in a robust layer, and explored the responses of membrane rafts and the actin cytoskeleton. After exposure to shear stress for 24 h, the glycocalyx components heparan sulfate, chondroitin sulfate, glypican-1 and syndecan-1, were enhanced on the apical surface, with nearly uniform spatial distributions close to baseline levels that differed greatly from the 30 min distributions. Heparan sulfate and glypican-1 still clustered near the cell boundaries after 24 h of shear, but caveolin-1/caveolae and actin were enhanced and concentrated across the apical aspects of the cell.
    [Show full text]
  • Diffusion of Lipids and GPI-Anchored Proteins in Actin-Free Plasma Membrane Vesicles Measured by STED-FCS Falk Schneidera, Mathias P
    bioRxiv preprint doi: https://doi.org/10.1101/076109; this version posted September 19, 2016. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. Diffusion of lipids and GPI-anchored proteins in actin-free plasma membrane vesicles measured by STED-FCS Falk Schneidera, Mathias P. Clausena,b, Dominic Waithec, Thomas Kollera, Gunes Ozhand,e, Christian Eggelinga,c,*, Erdinc Sezgina,* a MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, OX39DS, Oxford, United Kingdom b MEMPHYS – Center for Biomembrane Physics, Department of Physics, Chemistry, and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark c Wolfson Imaging Centre Oxford, Weatherall Institute of Molecular Medicine, University of Oxford, OX39DS, Oxford, United Kingdom d Izmir International Biomedicine and Genome Institute (iBG-izmir), Dokuz Eylul University, Inciralti- Balcova, 35340 Izmir, Turkey; e Department of Medical Biology and Genetics, Dokuz Eylul University Medical School, Inciralti-Balcova, 35340 Izmir, Turkey. Correspondence: [email protected]; [email protected] Running title: Diffusion in actin-free plasma membrane vesicles Keywords: plasma membrane biophysics, fluorescence correlation spectroscopy, lipid raft, GPI anchored proteins, STED microscopy, STED-FCS, giant plasma membrane vesicles, Abbreviations: giant plasma membrane vesicles (GPMVs), giant unilamellar vesicles (GUVs), Glycophosphatidylinositol anchored protein (GPI-AP), phospholipid (PL), Stimulated emission depletion (STED), fluorescence correlation spectroscopy (FCS) Character count: 19,026 1 bioRxiv preprint doi: https://doi.org/10.1101/076109; this version posted September 19, 2016.
    [Show full text]
  • Lipid Rafts Facilitate LPS Responses 2605
    Research Article 2603 Mediators of innate immune recognition of bacteria concentrate in lipid rafts and facilitate lipopolysaccharide-induced cell activation Martha Triantafilou1, Kensuke Miyake2, Douglas T. Golenbock3,* and Kathy Triantafilou1,‡ 1University of Portsmouth, School of Biological Sciences, King Henry Building, King Henry I Street, Portsmouth, PO1 2DY, UK 2Department of Immunology, Saga Medical School, Nabeshima, Japan 3Boston University School of Medicine, Boston Medical Center, The Maxwell Finland Laboratory for Infectious Diseases, Boston, Massachusetts 02118, USA *Present address: Department of Medicine, Division of Infectious Diseases, University of Massachusetts Medical School, Worcester, MA 01665, USA ‡Author for correspondence (e-mail: [email protected]) Accepted 19 March 2002 Journal of Cell Science 115, 2603-2611 (2002) © The Company of Biologists Ltd Summary The plasma membrane of cells is composed of lateral present in microdomains following LPS stimulation. Lipid heterogeneities, patches and microdomains. These raft integrity is essential for LPS-cellular activation, since membrane microdomains or lipid rafts are enriched raft-disrupting drugs, such as nystatin or MCD, inhibit in glycosphingolipids and cholesterol and have been LPS-induced TNF-α secretion. Our results suggest that the implicated in cellular processes such as membrane sorting entire bacterial recognition system is based around the and signal transduction. In this study we investigated the ligation of CD14 by bacterial components and the importance of lipid raft formation in the innate immune recruitment of multiple signalling molecules, such as hsp70, recognition of bacteria using biochemical and fluorescence hsp90, CXCR4, GDF5 and TLR4, at the site of CD14-LPS imaging techniques. We found that receptor molecules ligation, within the lipid rafts.
    [Show full text]
  • The Importance of Lipid Raft Proteins for Sepsis: Could Raftlin-2 Be a New Biomarker?
    DOI: 10.14744/ejmi.2018.69875 EJMI 2018;2(2):95–100 Research Article The Importance of Lipid Raft Proteins for Sepsis: Could Raftlin-2 be a New Biomarker? Hilmi Erdem Sumbul,1 Emre Karakoc,2 Murat Erdogan,2 Ozlem Ozkan Kuscu,2 Filiz Kibar,3 Salih Cetiner,4 Tugba Korkmaz,2 Merve Yahsi,2 Firat Kocabas2 1Department of Internal Medicine, Health Science University, Adana City Training and Research Hospital, Adana, Turkey 2Department of Internal Medicine, Cukurova University, Adana, Turkey 3Department of Microbiology, Cukurova University, Adana, Turkey 4Department of Biochemistry, Cukurova University, Adana, Turkey Abstract Objectives: Bacterial infections and sepsis are common problems in patients receiving intensive care unit treatment. Raftlin-2 is a protein with an important role in lipid rafts, and the aim of this study was to compare raftlin-2 micro pro- tein blood levels in a healthy control group with a patient group with septicemia. Methods: A prospective, controlled study was conducted in the intensive care unit (ICU) of a university hospital and a control group was selected from healthy individuals. There were 64 ICU patients and 74 individuals in the control group. Blood samples were taken from the study group before the start of antibiotic therapy. The C-reactive protein, procalci- tonin, lactate, biochemistry, and raftlin-2 levels of the patient and control groups were compared. Results: There was a statistically significant difference between the lactate levels in the healthy group and the patient group with septicemia, but not in the raftlin-2 protein level. The p-values were calculated at 0.350 for raftlin-2 and 0.007 for lactate.
    [Show full text]
  • Shedding and Uptake of Gangliosides and Glycosylphosphatidylinositol-Anchored Proteins ⁎ Gordan Lauc A,B, , Marija Heffer-Lauc C
    Biochimica et Biophysica Acta 1760 (2006) 584–602 http://www.elsevier.com/locate/bba Review Shedding and uptake of gangliosides and glycosylphosphatidylinositol-anchored proteins ⁎ Gordan Lauc a,b, , Marija Heffer-Lauc c a Department of Chemistry and Biochemistry, University of Osijek School of Medicine, J. Huttlera 4, 31000 Osijek, Croatia b Department of Biochemistry and Molecular Biology, Faculty of Pharmacy and Biochemistry, University of Zagreb, A. Kovačića 1, 10000 Zagreb, Croatia c Department of Biology, University of Osijek School of Medicine, J. Huttlera 4, 31000 Osijek, Croatia Received 30 September 2005; received in revised form 22 November 2005; accepted 23 November 2005 Available online 20 December 2005 Abstract Gangliosides and glycosylphosphatidylinositol (GPI)-anchored proteins have very different biosynthetic origin, but they have one thing in common: they are both comprised of a relatively large hydrophilic moiety tethered to a membrane by a relatively small lipid tail. Both gangliosides and GPI-anchored proteins can be actively shed from the membrane of one cell and taken up by other cells by insertion of their lipid anchors into the cell membrane. The process of shedding and uptake of gangliosides and GPI-anchored proteins has been independently discovered in several disciplines during the last few decades, but these discoveries were largely ignored by people working in other areas of science. By bringing together results from these, sometimes very distant disciplines, in this review, we give an overview of current knowledge about shedding and uptake of gangliosides and GPI-anchored proteins. Tumor cells and some pathogens apparently misuse this process for their own advantage, but its real physiological functions remain to be discovered.
    [Show full text]
  • 1529.Full.Pdf
    Intracellular Lipid Flux and Membrane Microdomains as Organizing Principles in Inflammatory Cell Signaling This information is current as Michael B. Fessler and John S. Parks of September 24, 2021. J Immunol 2011; 187:1529-1535; ; doi: 10.4049/jimmunol.1100253 http://www.jimmunol.org/content/187/4/1529 Downloaded from References This article cites 92 articles, 48 of which you can access for free at: http://www.jimmunol.org/content/187/4/1529.full#ref-list-1 Why The JI? Submit online. http://www.jimmunol.org/ • Rapid Reviews! 30 days* from submission to initial decision • No Triage! Every submission reviewed by practicing scientists • Fast Publication! 4 weeks from acceptance to publication *average by guest on September 24, 2021 Subscription Information about subscribing to The Journal of Immunology is online at: http://jimmunol.org/subscription Permissions Submit copyright permission requests at: http://www.aai.org/About/Publications/JI/copyright.html Email Alerts Receive free email-alerts when new articles cite this article. Sign up at: http://jimmunol.org/alerts The Journal of Immunology is published twice each month by The American Association of Immunologists, Inc., 1451 Rockville Pike, Suite 650, Rockville, MD 20852 All rights reserved. Print ISSN: 0022-1767 Online ISSN: 1550-6606. Intracellular Lipid Flux and Membrane Microdomains as Organizing Principles in Inflammatory Cell Signaling Michael B. Fessler* and John S. Parks† Lipid rafts and caveolae play a pivotal role in organiza- remodeling of raft lipid is not only necessary in many sig- tion of signaling by TLR4 and several other immune naling cascades, but that primary perturbations of raft lipid receptors.
    [Show full text]
  • Lipid Rafts in Health and Disease
    Biol. Cell (2007) 99, 129–140 (Printed in Great Britain) doi:10.1042/BC20060051 Review Lipid rafts in health and disease Vera Michel and Marica Bakovic1 Department of Human Health and Nutritional Sciences, Animal Science and Nutrition Building, Room 346, University of Guelph, Guelph, Ontario, Canada N1G 2W1 Lipid rafts are sphingolipid- and cholesterol-rich domains of the plasma membrane which contain a variety of signalling and transport proteins. Different subtypes of lipid rafts can be distinguished according to their protein and lipid composition. Caveolae are types of rafts that are rich in proteins of the caveolin family (caveolin-1, -2 and -3) which present a distinct signalling platform. The importance of lipid raft signalling in the pathogenesis of a variety of conditions, such as Alzheimer’s, Parkinson’s, cardiovascular and prion diseases, systemic lupus erythematosus and HIV, has been elucidated over recent years and makes these specific membrane domains an interesting target for pharmacological approaches in the cure and prevention of these diseases. This Review analyses the importance of lipid raft proteins and lipids in health and disease, with a focus on the current state of knowledge. Introduction the first time by discovering a similar sorting path- The traditional model of the plasma membrane as a way for fluorescently labelled GPI-linked proteins. homogeneous fluid lipid bilayer, as demonstrated by These early discoveries were evident by localiza- Singer and Nicholson (1972), has been extended in tion of GPI-linked proteins to distinct cholesterol- recent years, as it has become clear that the plasma and sphingolipid-rich microdomains in the plasma membrane consists of thousands of different lipids membrane (Zurzolo et al., 1994; Varma and Mayor, and is a much more complex structure than previously 1998) and the development of a method to isolate thought.
    [Show full text]
  • One Raft to Guide Them All, and in Axon Regeneration Inhibit Them
    International Journal of Molecular Sciences Review One Raft to Guide Them All, and in Axon Regeneration Inhibit Them Marc Hernaiz-Llorens 1,* , Ramón Martínez-Mármol 2,* , Cristina Roselló-Busquets 1 and Eduardo Soriano 1,3 1 Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, University of Barcelona, 08028 Barcelona, Spain; [email protected] (C.R.-B.); [email protected] (E.S.) 2 Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia Campus, Brisbane, QLD 4072, Australia 3 Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, 28031 Madrid, Spain * Correspondence: [email protected] (M.H.-L.); [email protected] (R.M.-M.) Abstract: Central nervous system damage caused by traumatic injuries, iatrogenicity due to surgical interventions, stroke and neurodegenerative diseases is one of the most prevalent reasons for physical disability worldwide. During development, axons must elongate from the neuronal cell body to contact their precise target cell and establish functional connections. However, the capacity of the adult nervous system to restore its functionality after injury is limited. Given the inefficacy of the nervous system to heal and regenerate after damage, new therapies are under investigation to enhance axonal regeneration. Axon guidance cues and receptors, as well as the molecular machinery activated after nervous system damage, are organized into lipid raft microdomains, a term typically used to describe nanoscale membrane domains enriched in cholesterol and glycosphingolipids that act as signaling platforms for certain transmembrane proteins. Here, we systematically review the most recent findings that link the stability of lipid rafts and their composition with the capacity of Citation: Hernaiz-Llorens, M.; axons to regenerate and rebuild functional neural circuits after damage.
    [Show full text]
  • Lipid Rafts in Anticancer Therapy: Theory and Practice (Review)
    167-172 12/2/08 11:40 Page 167 MOLECULAR MEDICINE REPORTS 1: 167-172, 2008 167 Lipid rafts in anticancer therapy: Theory and practice (Review) BEATA PAJAK1, URSZULA WOJEWÓDZKA1, BARBARA GAJKOWSKA1 and ARKADIUSZ ORZECHOWSKI1,2 1Department of Cell Ultrastructure, Medical Research Center, Polish Academy of Sciences, Pawinskiego 5, 02-106 Warsaw; 2Department of Physiological Sciences, Faculty of Veterinary Medicine, Warsaw University of Life Sciences (SGGW), Nowoursynowska 159, 02-776 Warsaw, Poland Received November 26, 2007; Accepted December 18, 2007 Abstract. To enlarge and stabilize transient raft patterns, 4. TNFR superfamily and lipid rafts proteins interact with membrane lipids. By lateral movements, 5. Lipid rafts in cell transformation these small lipid rafts (LRs) may coalesce into large platforms 6. Lipid rafts as targets in anticancer therapy (raft clusters), allowing the alignment of transmembrane 7. Conclusions and perspectives proteins that easily crosslink. The formation of raft clusters permits TNFR superfamily membrane receptors of the Lo phase to subsequently cooperate with transducer and adaptor 1. Introduction proteins to create receptosomes and/or signalosomes, even without external ligand binding. Chemical agents that disrupt According to the fluid mosaic model proposed by Singer and actin and/or the microtubular network were also found to Nicholson (1), the cell membrane is a phospholipid bilayer facilitate the death signal through the known death cascades. with peripheral, integral and transmembrane proteins. Over a Hence, death machinery is triggered to initiate, transmit and decade ago, extensive research provided evidence that the execute the apoptosis (extrinsic and/or intrinsic) of tumor cells. plasma membrane is not entirely neutral liquid disordered (Ld) Certain anticancer drugs such as edelfosine and aplidin convey fluid, but is rather compartmentalized into functional micro- these death signals, suggesting a disregard for the necessity domains: cholesterol-rich liquid ordered (Lo, with intermediate of ligand-receptor communication.
    [Show full text]
  • Dynasore - Not Just a Dynamin Inhibitor Giulio Preta, James G Cronin and I Martin Sheldon*
    Preta et al. Cell Communication and Signaling (2015) 13:24 DOI 10.1186/s12964-015-0102-1 REVIEW Open Access Dynasore - not just a dynamin inhibitor Giulio Preta, James G Cronin and I Martin Sheldon* Abstract Dynamin is a GTPase protein that is essential for membrane fission during clathrin-mediated endocytosis in eukaryotic cells. Dynasore is a GTPase inhibitor that rapidly and reversibly inhibits dynamin activity, which prevents endocytosis. However, comparison between cells treated with dynasore and RNA interference of genes encoding dynamin, reveals evidence that dynasore reduces labile cholesterol in the plasma membrane, and disrupts lipid raft organization, in a dynamin-independent manner. To explore the role of dynamin it is important to use multiple dynamin inhibitors, alongside the use of dynamin mutants and RNA interference targeting genes encoding dynamin. On the other hand, dynasore provides an interesting tool to explore the regulation of cholesterol in plasma membranes. Keywords: Dynasore, GTPase, Dynamin, Endocytosis, Cholesterol, Lipid rafts Introduction addition to the GTPase domain, dynamin also contains a Dynamin is an intracellular protein with essential roles pleckstrin homology domain implicated in membrane in membrane remodelling and fission of clathrin-coated binding, a GTPase effector domain essential for self- vesicles formed during endocytosis, and vesicles that assembly, and a C-terminal proline-rich domain, which bud from the trans-Golgi network [1]. In particular, contains several SH3-binding sites [1]. Dynamin partners endocytosis is dependent on dynamin for the invagin- bind to the proline-rich domain, stimulating dynamin’s ation of plasma membrane to form clathrin-coated pits, GTPase activity and targeting dynamin to the plasma and dynamin polymerizes to form a helix around the membrane [11].
    [Show full text]
  • Mitochondrial Targeting Involving Cholesterol-Rich Lipid Rafts in the Mechanism of Action of the Antitumor Ether Lipid and Alkylphospholipid Analog Edelfosine
    pharmaceutics Review Mitochondrial Targeting Involving Cholesterol-Rich Lipid Rafts in the Mechanism of Action of the Antitumor Ether Lipid and Alkylphospholipid Analog Edelfosine Faustino Mollinedo * and Consuelo Gajate Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas (CSIC), Laboratory of Cell Death and Cancer Therapy, Department of Molecular Biomedicine, C/Ramiro de Maeztu 9, E-28040 Madrid, Spain; [email protected] * Correspondence: [email protected] Abstract: The ether lipid edelfosine induces apoptosis selectively in tumor cells and is the prototypic molecule of a family of synthetic antitumor compounds collectively known as alkylphospholipid analogs. Cumulative evidence shows that edelfosine interacts with cholesterol-rich lipid rafts, endo- plasmic reticulum (ER) and mitochondria. Edelfosine induces apoptosis in a number of hematological cancer cells by recruiting death receptors and downstream apoptotic signaling into lipid rafts, whereas it promotes apoptosis in solid tumor cells through an ER stress response. Edelfosine-induced apop- tosis, mediated by lipid rafts and/or ER, requires the involvement of a mitochondrial-dependent step to eventually elicit cell death, leading to the loss of mitochondrial membrane potential, cy- tochrome c release and the triggering of cell death. The overexpression of Bcl-2 or Bcl-xL blocks edelfosine-induced apoptosis. Edelfosine induces the redistribution of lipid rafts from the plasma Citation: Mollinedo, F.; Gajate, C. membrane to the mitochondria. The pro-apoptotic action of edelfosine on cancer cells is associated Mitochondrial Targeting Involving with the recruitment of F1FO–ATP synthase into cholesterol-rich lipid rafts. Specific inhibition of the Cholesterol-Rich Lipid Rafts in the F sector of the F F –ATP synthase, which contains the membrane-embedded c-subunit ring that Mechanism of Action of the O 1 O Antitumor Ether Lipid and constitutes the mitochondrial permeability transcription pore, hinders edelfosine-induced cell death.
    [Show full text]