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Le T, Ferling I, Qiu L, Nabaile C, Assunção L, Roskelley CD, Grinstein S, Freeman SA. Redistribution of the glycocalyx exposes phagocytic determinants on apoptotic cells. Dev Cell 2024; 59:853-868.e7. [PMID: 38359833 DOI: 10.1016/j.devcel.2024.01.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 11/08/2023] [Accepted: 01/23/2024] [Indexed: 02/17/2024]
Abstract
Phagocytes remove dead and dying cells by engaging "eat-me" ligands such as phosphatidylserine (PtdSer) on the surface of apoptotic targets. However, PtdSer is obscured by the bulky exofacial glycocalyx, which also exposes ligands that activate "don't-eat-me" receptors such as Siglecs. Clearly, unshielding the juxtamembrane "eat-me" ligands is required for the successful engulfment of apoptotic cells, but the mechanisms underlying this process have not been described. Using human and murine cells, we find that apoptosis-induced retraction and weakening of the cytoskeleton that anchors transmembrane proteins cause an inhomogeneous redistribution of the glycocalyx: actin-depleted blebs emerge, lacking the glycocalyx, while the rest of the apoptotic cell body retains sufficient actin to tether the glycocalyx in place. Thus, apoptotic blebs can be engaged by phagocytes and are targeted for engulfment. Therefore, in cells with an elaborate glycocalyx, such as mucinous cancer cells, this "don't-come-close-to-me" barrier must be removed to enable clearance by phagocytosis.
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Affiliation(s)
- Trieu Le
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Iuliia Ferling
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Lanhui Qiu
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Clement Nabaile
- Department of Learning and Research in Biology, Ecole Normale Supérieure Paris-Saclay, Gif-sur-Yvette, France
| | - Leonardo Assunção
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Calvin D Roskelley
- Department of Cellular and Physiological Sciences, the Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Sergio Grinstein
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada; Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Spencer A Freeman
- Program in Cell Biology, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada; Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada.
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2
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Jo S, Fischer BR, Cronin NM, Nurmalasari NPD, Loyd YM, Kerkvliet JG, Bailey EM, Anderson RB, Scott BL, Hoppe AD. Antibody surface mobility amplifies FcγR signaling via Arp2/3 during phagocytosis. Biophys J 2024:S0006-3495(24)00094-8. [PMID: 38321740 DOI: 10.1016/j.bpj.2024.01.036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 11/07/2023] [Accepted: 01/29/2024] [Indexed: 02/08/2024] Open
Abstract
We report herein that the anti-CD20 therapeutic antibody, rituximab, is rearranged into microclusters within the phagocytic synapse by macrophage Fcγ receptors (FcγR) during antibody-dependent cellular phagocytosis. These microclusters were observed to potently recruit Syk and to undergo rearrangements that were limited by the cytoskeleton of the target cell, with depolymerization of target-cell actin filaments leading to modest increases in phagocytic efficiency. Total internal reflection fluorescence analysis revealed that FcγR total phosphorylation, Syk phosphorylation, and Syk recruitment were enhanced when IgG-FcγR microclustering was enabled on fluid bilayers relative to immobile bilayers in a process that required Arp2/3. We conclude that on fluid surfaces, IgG-FcγR microclustering promotes signaling through Syk that is amplified by Arp2/3-driven actin rearrangements. Thus, the surface mobility of antigens bound by IgG shapes the signaling of FcγR with an unrecognized complexity beyond the zipper and trigger models of phagocytosis.
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Affiliation(s)
- Seongwan Jo
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, South Dakota; BioSNTRii, South Dakota State University, Brookings, South Dakota
| | - Brady R Fischer
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, South Dakota; BioSNTRii, South Dakota State University, Brookings, South Dakota
| | - Nicholas M Cronin
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, South Dakota; BioSNTRii, South Dakota State University, Brookings, South Dakota
| | - Ni Putu Dewi Nurmalasari
- Department of Nanoscience & Biomedical Engineering, South Dakota School of Mines and Technology, Rapid City, South Dakota; BioSNTRii, South Dakota School of Mines and Technology, Rapid City, South Dakota
| | - Yoseph M Loyd
- Department of Nanoscience & Biomedical Engineering, South Dakota School of Mines and Technology, Rapid City, South Dakota; BioSNTRii, South Dakota School of Mines and Technology, Rapid City, South Dakota
| | - Jason G Kerkvliet
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, South Dakota; BioSNTRii, South Dakota State University, Brookings, South Dakota
| | - Elizabeth M Bailey
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, South Dakota; BioSNTRii, South Dakota State University, Brookings, South Dakota
| | - Robert B Anderson
- Department of Nanoscience & Biomedical Engineering, South Dakota School of Mines and Technology, Rapid City, South Dakota; BioSNTRii, South Dakota School of Mines and Technology, Rapid City, South Dakota
| | - Brandon L Scott
- Department of Nanoscience & Biomedical Engineering, South Dakota School of Mines and Technology, Rapid City, South Dakota; BioSNTRii, South Dakota School of Mines and Technology, Rapid City, South Dakota
| | - Adam D Hoppe
- Department of Chemistry and Biochemistry, South Dakota State University, Brookings, South Dakota; BioSNTRii, South Dakota State University, Brookings, South Dakota.
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3
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Campos Muñiz C, Fernández Perrino FJ. Evolution of the Concepts of Architecture and Supramolecular Dynamics of the Plasma Membrane. MEMBRANES 2023; 13:547. [PMID: 37367751 DOI: 10.3390/membranes13060547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 05/19/2023] [Accepted: 05/19/2023] [Indexed: 06/28/2023]
Abstract
The plasma membrane (PM) has undergone important conceptual changes during the history of scientific research, although it is undoubtedly a cellular organelle that constitutes the first defining characteristic of cellular life. Throughout history, the contributions of countless scientists have been published, each one of them with an enriching contribution to the knowledge of the structure-location and function of each structural component of this organelle, as well as the interaction between these and other structures. The first published contributions on the plasmatic membrane were the transport through it followed by the description of the structure: lipid bilayer, associated proteins, carbohydrates bound to both macromolecules, association with the cytoskeleton and dynamics of these components.. The data obtained experimentally from each researcher were represented in graphic configurations, as a language that facilitates the understanding of cellular structures and processes. This paper presents a review of some of the concepts and models proposed about the plasma membrane, emphasizing the components, the structure, the interaction between them and the dynamics. The work is illustrated with resignified 3D diagrams to visualize the changes that occurred during the history of the study of this organelle. Schemes were redrawn in 3D from the original articles...
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Affiliation(s)
- Carolina Campos Muñiz
- Department of Health Sciences, Universidad Autónoma Metropolitana Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, Iztapalapa, Mexico City 09340, Mexico
| | - Francisco José Fernández Perrino
- Department of Biotechnology, Universidad Autónoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, Iztapalapa, Mexico City 09340, Mexico
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4
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Vaisey G, Banerjee P, North AJ, Haselwandter CA, MacKinnon R. Piezo1 as a force-through-membrane sensor in red blood cells. eLife 2022; 11:e82621. [PMID: 36515266 PMCID: PMC9750178 DOI: 10.7554/elife.82621] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 12/01/2022] [Indexed: 12/15/2022] Open
Abstract
Piezo1 is the stretch activated Ca2+ channel in red blood cells that mediates homeostatic volume control. Here, we study the organization of Piezo1 in red blood cells using a combination of super-resolution microscopy techniques and electron microscopy. Piezo1 adopts a non-uniform distribution on the red blood cell surface, with a bias toward the biconcave 'dimple'. Trajectories of diffusing Piezo1 molecules, which exhibit confined Brownian diffusion on short timescales and hopping on long timescales, also reflect a bias toward the dimple. This bias can be explained by 'curvature coupling' between the intrinsic curvature of the Piezo dome and the curvature of the red blood cell membrane. Piezo1 does not form clusters with itself, nor does it colocalize with F-actin, Spectrin, or the Gardos channel. Thus, Piezo1 exhibits the properties of a force-through-membrane sensor of curvature and lateral tension in the red blood cell.
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Affiliation(s)
- George Vaisey
- Laboratory of Molecular Neurobiology and Biophysics, Howard Hughes Medical Institute, The Rockefeller UniversityNew YorkUnited States
| | - Priyam Banerjee
- Bio-Imaging Resource Center, The Rockefeller UniversityNew YorkUnited States
| | - Alison J North
- Bio-Imaging Resource Center, The Rockefeller UniversityNew YorkUnited States
| | - Christoph A Haselwandter
- Department of Physics and Astronomy and Department of Quantitative and Computational Biology, University of Southern CaliforniaLos AngelesUnited States
| | - Roderick MacKinnon
- Laboratory of Molecular Neurobiology and Biophysics, Howard Hughes Medical Institute, The Rockefeller UniversityNew YorkUnited States
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5
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Jäger J, Patra P, Sanchez CP, Lanzer M, Schwarz US. A particle-based computational model to analyse remodelling of the red blood cell cytoskeleton during malaria infections. PLoS Comput Biol 2022; 18:e1009509. [PMID: 35394995 PMCID: PMC9020725 DOI: 10.1371/journal.pcbi.1009509] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 04/20/2022] [Accepted: 03/21/2022] [Indexed: 11/18/2022] Open
Abstract
Red blood cells can withstand the harsh mechanical conditions in the vasculature only because the bending rigidity of their plasma membrane is complemented by the shear elasticity of the underlying spectrin-actin network. During an infection by the malaria parasite Plasmodium falciparum, the parasite mines host actin from the junctional complexes and establishes a system of adhesive knobs, whose main structural component is the knob-associated histidine rich protein (KAHRP) secreted by the parasite. Here we aim at a mechanistic understanding of this dramatic transformation process. We have developed a particle-based computational model for the cytoskeleton of red blood cells and simulated it with Brownian dynamics to predict the mechanical changes resulting from actin mining and KAHRP-clustering. Our simulations include the three-dimensional conformations of the semi-flexible spectrin chains, the capping of the actin protofilaments and several established binding sites for KAHRP. For the healthy red blood cell, we find that incorporation of actin protofilaments leads to two regimes in the shear response. Actin mining decreases the shear modulus, but knob formation increases it. We show that dynamical changes in KAHRP binding affinities can explain the experimentally observed relocalization of KAHRP from ankyrin to actin complexes and demonstrate good qualitative agreement with experiments by measuring pair cross-correlations both in the computer simulations and in super-resolution imaging experiments. Malaria is one of the deadliest infectious diseases and its symptoms are related to the blood stage, when the parasite multiplies within red blood cells. In order to avoid clearance by the spleen, the parasite produces specific factors like the adhesion receptor PfEMP1 and the multifunctional protein KAHRP that lead to the formation of adhesive knobs on the surface of the red blood cells and thus increase residence time in the vasculature. We have developed a computational model for the parasite-induced remodelling of the actin-spectrin network to quantitatively predict the dynamical changes in the mechanical properties of the infected red blood cells and the spatial distribution of the different protein components of the membrane skeleton. Our simulations show that KAHRP can relocate to actin junctions due to dynamical changes in binding affinities, in good qualitative agreement with super-resolution imaging experiments. In the future, our simulation framework can be used to gain further mechanistic insight into the way malaria parasites attack the red blood cell cytoskeleton.
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Affiliation(s)
- Julia Jäger
- Institute for Theoretical Physics, Heidelberg University, Heidelberg, Germany
- BioQuant-Center for Quantitative Biology, Heidelberg University, Heidelberg, Germany
| | - Pintu Patra
- Institute for Theoretical Physics, Heidelberg University, Heidelberg, Germany
- BioQuant-Center for Quantitative Biology, Heidelberg University, Heidelberg, Germany
| | - Cecilia P. Sanchez
- Center of Infectious Diseases, Parasitology, University Hospital Heidelberg, Heidelberg, Germany
| | - Michael Lanzer
- Center of Infectious Diseases, Parasitology, University Hospital Heidelberg, Heidelberg, Germany
- * E-mail: (ML); (USS)
| | - Ulrich S. Schwarz
- Institute for Theoretical Physics, Heidelberg University, Heidelberg, Germany
- BioQuant-Center for Quantitative Biology, Heidelberg University, Heidelberg, Germany
- * E-mail: (ML); (USS)
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6
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Iriondo MN, Etxaniz A, Antón Z, Montes LR, Alonso A. Molecular and mesoscopic geometries in autophagosome generation. A review. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183731. [PMID: 34419487 DOI: 10.1016/j.bbamem.2021.183731] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 08/12/2021] [Accepted: 08/15/2021] [Indexed: 01/18/2023]
Abstract
Autophagy is an essential process in cell self-repair and survival. The centre of the autophagic event is the generation of the so-called autophagosome (AP), a vesicle surrounded by a double membrane (two bilayers). The AP delivers its cargo to a lysosome, for degradation and re-use of the hydrolysis products as new building blocks. AP formation is a very complex event, requiring dozens of specific proteins, and involving numerous instances of membrane biogenesis and architecture, including membrane fusion and fission. Many stages of AP generation can be rationalised in terms of curvature, both the molecular geometry of lipids interpreted in terms of 'intrinsic curvature', and the overall mesoscopic curvature of the whole membrane, as observed with microscopy techniques. The present contribution intends to bring together the worlds of biophysics and cell biology of autophagy, in the hope that the resulting cross-pollination will generate abundant fruit.
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Affiliation(s)
- Marina N Iriondo
- Instituto Biofisika (CSIC, UPV/EHU) and Departamento de Bioquímica y Biología Molecular, Universidad del País Vasco, 48940 Leioa, Spain
| | - Asier Etxaniz
- Instituto Biofisika (CSIC, UPV/EHU) and Departamento de Bioquímica y Biología Molecular, Universidad del País Vasco, 48940 Leioa, Spain
| | - Zuriñe Antón
- Instituto Biofisika (CSIC, UPV/EHU) and Departamento de Bioquímica y Biología Molecular, Universidad del País Vasco, 48940 Leioa, Spain
| | - L Ruth Montes
- Instituto Biofisika (CSIC, UPV/EHU) and Departamento de Bioquímica y Biología Molecular, Universidad del País Vasco, 48940 Leioa, Spain
| | - Alicia Alonso
- Instituto Biofisika (CSIC, UPV/EHU) and Departamento de Bioquímica y Biología Molecular, Universidad del País Vasco, 48940 Leioa, Spain.
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7
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Barshtein G, Pajic-Lijakovic I, Gural A. Deformability of Stored Red Blood Cells. Front Physiol 2021; 12:722896. [PMID: 34690797 PMCID: PMC8530101 DOI: 10.3389/fphys.2021.722896] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 08/18/2021] [Indexed: 12/24/2022] Open
Abstract
Red blood cells (RBCs) deformability refers to the cells’ ability to adapt their shape to the dynamically changing flow conditions so as to minimize their resistance to flow. The high red cell deformability enables it to pass through small blood vessels and significantly determines erythrocyte survival. Under normal physiological states, the RBCs are attuned to allow for adequate blood flow. However, rigid erythrocytes can disrupt the perfusion of peripheral tissues and directly block microvessels. Therefore, RBC deformability has been recognized as a sensitive indicator of RBC functionality. The loss of deformability, which a change in the cell shape can cause, modification of cell membrane or a shift in cytosol composition, can occur due to various pathological conditions or as a part of normal RBC aging (in vitro or in vivo). However, despite extensive research, we still do not fully understand the processes leading to increased cell rigidity under cold storage conditions in a blood bank (in vitro aging), In the present review, we discuss publications that examined the effect of RBCs’ cold storage on their deformability and the biological mechanisms governing this change. We first discuss the change in the deformability of cells during their cold storage. After that, we consider storage-related alterations in RBCs features, which can lead to impaired cell deformation. Finally, we attempt to trace a causal relationship between the observed phenomena and offer recommendations for improving the functionality of stored cells.
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Affiliation(s)
- Gregory Barshtein
- Biochemistry Department, The Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | | | - Alexander Gural
- Department of Hematology, Hadassah Hebrew University Medical Center, Jerusalem, Israel
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8
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Jennings ML. Cell Physiology and Molecular Mechanism of Anion Transport by Erythrocyte Band 3/AE1. Am J Physiol Cell Physiol 2021; 321:C1028-C1059. [PMID: 34669510 PMCID: PMC8714990 DOI: 10.1152/ajpcell.00275.2021] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The major transmembrane protein of the red blood cell, known as band 3, AE1, and SLC4A1, has two main functions: 1) catalysis of Cl-/HCO3- exchange, one of the steps in CO2 excretion; 2) anchoring the membrane skeleton. This review summarizes the 150 year history of research on red cell anion transport and band 3 as an experimental system for studying membrane protein structure and ion transport mechanisms. Important early findings were that red cell Cl- transport is a tightly coupled 1:1 exchange and band 3 is labeled by stilbenesulfonate derivatives that inhibit anion transport. Biochemical studies showed that the protein is dimeric or tetrameric (paired dimers) and that there is one stilbenedisulfonate binding site per subunit of the dimer. Transport kinetics and inhibitor characteristics supported the idea that the transporter acts by an alternating access mechanism with intrinsic asymmetry. The sequence of band 3 cDNA provided a framework for detailed study of protein topology and amino acid residues important for transport. The identification of genetic variants produced insights into the roles of band 3 in red cell abnormalities and distal renal tubular acidosis. The publication of the membrane domain crystal structure made it possible to propose concrete molecular models of transport. Future research directions include improving our understanding of the transport mechanism at the molecular level and of the integrative relationships among band 3, hemoglobin, carbonic anhydrase, and gradients (both transmembrane and subcellular) of HCO3-, Cl-, O2, CO2, pH, and NO metabolites during pulmonary and systemic capillary gas exchange.
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Affiliation(s)
- Michael L Jennings
- Department of Physiology and Cell Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States
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9
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Asaro RJ, Cabrales P. Red Blood Cells: Tethering, Vesiculation, and Disease in Micro-Vascular Flow. Diagnostics (Basel) 2021; 11:diagnostics11060971. [PMID: 34072241 PMCID: PMC8228733 DOI: 10.3390/diagnostics11060971] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 05/12/2021] [Accepted: 05/14/2021] [Indexed: 12/14/2022] Open
Abstract
The red blood cell has become implicated in the progression of a range of diseases; mechanisms by which red cells are involved appear to include the transport of inflammatory species via red cell-derived vesicles. We review this role of RBCs in diseases such as diabetes mellitus, sickle cell anemia, polycythemia vera, central retinal vein occlusion, Gaucher disease, atherosclerosis, and myeloproliferative neoplasms. We propose a possibly unifying, and novel, paradigm for the inducement of RBC vesiculation during vascular flow of red cells adhered to the vascular endothelium as well as to the red pulp of the spleen. Indeed, we review the evidence for this hypothesis that links physiological conditions favoring both vesiculation and enhanced RBC adhesion and demonstrate the veracity of this hypothesis by way of a specific example occurring in splenic flow which we argue has various renderings in a wide range of vascular flows, in particular microvascular flows. We provide a mechanistic basis for membrane loss and the formation of lysed red blood cells in the spleen that may mediate their turnover. Our detailed explanation for this example also makes clear what features of red cell deformability are involved in the vesiculation process and hence require quantification and a new form of quantitative indexing.
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Affiliation(s)
- Robert J. Asaro
- Department of Structural Engineering, University of California, San Diego, CA 92093, USA
- Correspondence: ; Tel.: +1-619-890-6888; Fax: +1-858-534-6373
| | - Pedro Cabrales
- Department of Bioengineering, University of California, San Diego, CA 92093, USA;
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10
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Mylvaganam S, Freeman SA, Grinstein S. The cytoskeleton in phagocytosis and macropinocytosis. Curr Biol 2021; 31:R619-R632. [PMID: 34033794 DOI: 10.1016/j.cub.2021.01.036] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Cells of the innate immune system, notably macrophages, neutrophils and dendritic cells, perform essential antimicrobial and homeostatic functions. These functions rely on the dynamic surveillance of the environment supported by the formation of elaborate membrane protrusions. Such protrusions - pseudopodia, lamellipodia and filopodia - facilitate the sampling of the surrounding fluid by macropinocytosis, as well as the engulfment of particulates by phagocytosis. Both processes entail extreme plasma membrane deformations that require the coordinated rearrangement of cytoskeletal polymers, which exert protrusive force and drive membrane coalescence and scission. The resulting vacuolar compartments undergo pronounced remodeling and ultimate resolution by mechanisms that also involve the cytoskeleton. Here, we describe the regulation and functions of cytoskeletal assembly and remodeling during macropinocytosis and phagocytosis.
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Affiliation(s)
- Sivakami Mylvaganam
- Program in Cell Biology, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada; Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Spencer A Freeman
- Program in Cell Biology, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada; Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada.
| | - Sergio Grinstein
- Program in Cell Biology, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada; Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada.
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11
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Mylvaganam S, Riedl M, Vega A, Collins RF, Jaqaman K, Grinstein S, Freeman SA. Stabilization of Endothelial Receptor Arrays by a Polarized Spectrin Cytoskeleton Facilitates Rolling and Adhesion of Leukocytes. Cell Rep 2021; 31:107798. [PMID: 32579925 PMCID: PMC7548125 DOI: 10.1016/j.celrep.2020.107798] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 04/15/2020] [Accepted: 06/01/2020] [Indexed: 12/15/2022] Open
Abstract
Multivalent complexes of endothelial adhesion receptors (e.g., selectins) engage leukocytes to orchestrate their migration to inflamed tissues. Proper anchorage and sufficient density (clustering) of endothelial receptors are required for efficient leukocyte capture and rolling. We demonstrate that a polarized spectrin network dictates the stability of the endothelial cytoskeleton, which is attached to the apical membrane, at least in part, by the abundant transmembrane protein CD44. Single-particle tracking revealed that CD44 undergoes prolonged periods of immobilization as it tethers to the cytoskeleton. The CD44-spectrin "picket fence" alters the behavior of bystander molecules-notably, selectins-curtailing their mobility, inducing their apical accumulation, and favoring their clustering within caveolae. Accordingly, depletion of either spectrin or CD44 virtually eliminated leukocyte rolling and adhesion to the endothelium. Our results indicate that a unique spectrin-based apical cytoskeleton tethered to transmembrane pickets-notably, CD44-is essential for proper extravasation of leukocytes in response to inflammation.
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Affiliation(s)
- Sivakami Mylvaganam
- Program in Cell Biology, Peter Gilgan Centre for Research and Learning, Hospital for Sick Children, 686 Bay Street, 19-9800, Toronto, ON M5G 0A4, Canada; Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Magdalena Riedl
- Program in Cell Biology, Peter Gilgan Centre for Research and Learning, Hospital for Sick Children, 686 Bay Street, 19-9800, Toronto, ON M5G 0A4, Canada
| | - Anthony Vega
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Richard F Collins
- Program in Cell Biology, Peter Gilgan Centre for Research and Learning, Hospital for Sick Children, 686 Bay Street, 19-9800, Toronto, ON M5G 0A4, Canada
| | - Khuloud Jaqaman
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Sergio Grinstein
- Program in Cell Biology, Peter Gilgan Centre for Research and Learning, Hospital for Sick Children, 686 Bay Street, 19-9800, Toronto, ON M5G 0A4, Canada; Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada; Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON M5B 1W8, Canada.
| | - Spencer A Freeman
- Program in Cell Biology, Peter Gilgan Centre for Research and Learning, Hospital for Sick Children, 686 Bay Street, 19-9800, Toronto, ON M5G 0A4, Canada; Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada.
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12
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Asaro RJ, Zhu Q, MacDonald IC. Tethering, evagination, and vesiculation via cell-cell interactions in microvascular flow. Biomech Model Mechanobiol 2020; 20:31-53. [PMID: 32656697 DOI: 10.1007/s10237-020-01366-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 06/25/2020] [Indexed: 12/13/2022]
Abstract
Vesiculation is a ubiquitous process undergone by most cell types and serves a variety of vital cell functions; vesiculation from erythrocytes, in particular, is a well-known example and constitutes a self-protection mechanism against premature clearance, inter alia. Herein, we explore a paradigm that red blood cell derived vesicles may form within the microvascular, in intense shear flow, where cells become adhered to either other cells or the extracellular matrix, by forming tethers or an evagination. Adherence may be enhanced, or caused, by diseased states or chemical anomalies as are discussed herein. The mechanisms for such processes are detailed via numerical simulations that are patterned directly from video-recorded cell microflow within the splenic venous sinus (MacDonald et al. 1987), as included, e.g., as Supplementary Material. The mechanisms uncovered highlight the necessity of accounting for remodeling of the erythrocyte's membrane skeleton and, specifically, for the time scales associated with that process that is an integral part of cell deformation. In this way, the analysis provides pointed, and vital, insights into the notion of what the, often used phrase, cell deformability actually entails in a more holistic manner. The analysis also details what data are required to make further quantitative descriptions possible and suggests experimental pathways for acquiring such.
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Affiliation(s)
- Robert J Asaro
- Department of Structural Engineering, University of California, San Diego, CA, USA.
| | - Qiang Zhu
- Department of Structural Engineering, University of California, San Diego, CA, USA
| | - Ian C MacDonald
- Department of Medical Biophysics, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
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13
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Svetina S. Theoretical Bases for the Role of Red Blood Cell Shape in the Regulation of Its Volume. Front Physiol 2020; 11:544. [PMID: 32581839 PMCID: PMC7297144 DOI: 10.3389/fphys.2020.00544] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 04/30/2020] [Indexed: 12/21/2022] Open
Abstract
The red blood cell (RBC) membrane contains a mechanosensitive cation channel Piezo1 that is involved in RBC volume homeostasis. In a recent model of the mechanism of its action it was proposed that Piezo1 cation permeability responds to changes of the RBC shape. The aim here is to review in a descriptive manner different previous studies of RBC behavior that formed the basis for this proposal. These studies include the interpretation of RBC and vesicle shapes based on the minimization of membrane bending energy, the analyses of various consequences of compositional and structural features of RBC membrane, in particular of its membrane skeleton and its integral membrane proteins, and the modeling of the establishment of RBC volume. The proposed model of Piezo1 action is critically evaluated, and a perspective presented for solving some remaining experimental and theoretical problems. Part of the discussion is devoted to the usefulness of theoretical modeling in studies of the behavior of cell systems in general.
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Affiliation(s)
- Saša Svetina
- Institute of Biophysics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.,Jožef Stefan Institute, Ljubljana, Slovenia
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14
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Morise J, Suzuki KGN, Kitagawa A, Wakazono Y, Takamiya K, Tsunoyama TA, Nemoto YL, Takematsu H, Kusumi A, Oka S. AMPA receptors in the synapse turnover by monomer diffusion. Nat Commun 2019; 10:5245. [PMID: 31748519 PMCID: PMC6868016 DOI: 10.1038/s41467-019-13229-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 10/28/2019] [Indexed: 12/27/2022] Open
Abstract
The number and subunit compositions of AMPA receptors (AMPARs), hetero- or homotetramers composed of four subunits GluA1–4, in the synapse is carefully tuned to sustain basic synaptic activity. This enables stimulation-induced synaptic plasticity, which is central to learning and memory. The AMPAR tetramers have been widely believed to be stable from their formation in the endoplasmic reticulum until their proteolytic decomposition. However, by observing GluA1 and GluA2 at the level of single molecules, we find that the homo- and heterotetramers are metastable, instantaneously falling apart into monomers, dimers, or trimers (in 100 and 200 ms, respectively), which readily form tetramers again. In the dendritic plasma membrane, GluA1 and GluA2 monomers and dimers are far more mobile than tetramers and enter and exit from the synaptic regions. We conclude that AMPAR turnover by lateral diffusion, essential for sustaining synaptic function, is largely done by monomers of AMPAR subunits, rather than preformed tetramers. The mechanisms regulating the turnover of the AMPARs in the synapse, which is critically important to sustain basic synaptic activity, remains unclear. In this study, authors used single-molecule imaging techniques to demonstrate that AMPAR tetramers are not stable entities and readily fall apart to dimers and monomers that could reform to tetramers at the synapse, and that rapidly diffusing monomers in the plasma membrane are primarily responsible for the AMPAR turnover in the synapse.
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Affiliation(s)
- Jyoji Morise
- Department of Biological Chemistry, Division of Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, Japan
| | - Kenichi G N Suzuki
- Center for Highly Advanced Integration of Nano and Life Sciences (G-CHAIN), Gifu University, Gifu, 501-1193, Japan. .,Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyoto, 606-8507, Japan.
| | - Ayaka Kitagawa
- Department of Biological Chemistry, Division of Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, Japan
| | - Yoshihiko Wakazono
- Department of Integrative Physiology, Faculty of Medicine, University of Miyazaki, Miyazaki, 889-1692, Japan
| | - Kogo Takamiya
- Department of Integrative Physiology, Faculty of Medicine, University of Miyazaki, Miyazaki, 889-1692, Japan
| | - Taka A Tsunoyama
- Membrane Cooperativity Unit, Okinawa Institute of Science and Technology Graduate University (OIST), Onna-son, Okinawa, 904-0495, Japan
| | - Yuri L Nemoto
- Membrane Cooperativity Unit, Okinawa Institute of Science and Technology Graduate University (OIST), Onna-son, Okinawa, 904-0495, Japan
| | - Hiromu Takematsu
- Department of Biological Chemistry, Division of Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, Japan.,Department of Molecular Cell Biology, Faculty of Medical Technology, Graduate School of Health Sciences, Fujita Health University, Aichi, 470-1192, Japan
| | - Akihiro Kusumi
- Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyoto, 606-8507, Japan. .,Membrane Cooperativity Unit, Okinawa Institute of Science and Technology Graduate University (OIST), Onna-son, Okinawa, 904-0495, Japan.
| | - Shogo Oka
- Department of Biological Chemistry, Division of Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, Japan.
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15
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Zhang Y, Tzingounis AV, Lykotrafitis G. Modeling of the axon plasma membrane structure and its effects on protein diffusion. PLoS Comput Biol 2019; 15:e1007003. [PMID: 31048841 PMCID: PMC6497228 DOI: 10.1371/journal.pcbi.1007003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 04/03/2019] [Indexed: 11/30/2022] Open
Abstract
The axon plasma membrane consists of the membrane skeleton, which comprises ring-like actin filaments connected to each other by spectrin tetramers, and the lipid bilayer, which is tethered to the skeleton via, at least, ankyrin. Currently it is unknown whether this unique axon plasma membrane skeleton (APMS) sets the diffusion rules of lipids and proteins in the axon. To answer this question, we developed a coarse-grain molecular dynamics model for the axon that includes the APMS, the phospholipid bilayer, transmembrane proteins (TMPs), and integral monotopic proteins (IMPs) in both the inner and outer lipid layers. We first showed that actin rings limit the longitudinal diffusion of TMPs and the IMPs of the inner leaflet but not of the IMPs of the outer leaflet. To reconcile the experimental observations, which show restricted diffusion of IMPs of the outer leaflet, with our simulations, we conjectured the existence of actin-anchored proteins that form a fence which restricts the longitudinal diffusion of IMPs of the outer leaflet. We also showed that spectrin filaments could modify transverse diffusion of TMPs and IMPs of the inner leaflet, depending on the strength of the association between lipids and spectrin. For instance, in areas where spectrin binds to the lipid bilayer, spectrin filaments would restrict diffusion of proteins within the skeleton corrals. In contrast, in areas where spectrin and lipids are not associated, spectrin modifies the diffusion of TMPs and IMPs of the inner leaflet from normal to confined-hop diffusion. Overall, we showed that diffusion of axon plasma membrane proteins is deeply anisotropic, as longitudinal diffusion is of different type than transverse diffusion. Finally, we investigated how accumulation of TMPs affects diffusion of TMPs and IMPs of both the inner and outer leaflets by changing the density of TMPs. We showed that the APMS structure acts as a fence that restricts the diffusion of TMPs and IMPs of the inner leaflet within the membrane skeleton corrals. Our findings provide insight into how the axon skeleton acts as diffusion barrier and maintains neuronal polarity. The axon plasma membrane skeleton consists of repeated periodic actin ring-like structures along its length connected via spectrin tetramers and anchored to the lipid bilayer at least via ankyrin. However, it is currently unclear whether this structure controls diffusion of lipids and proteins in the axon. Here, we developed a coarse-grain molecular dynamics computational model for the axon plasma membrane that comprises minimal representations for the APMS and the lipid bilayer. In a departure from current models, we found that actin rings limit diffusion of proteins only in the inner membrane leaflet. Then, we showed that actin anchored proteins likely act as “fences” confining diffusion of proteins in the outer leaflet. Our simulations, unexpectedly, also revealed that spectrin filaments could impede transverse diffusion in the inner leaflet of the axon and in some conditions modify diffusion from normal to abnormal. We predicted that diffusion of axon plasma membrane proteins is anisotropic as longitudinal diffusion is of different type than transverse (azimuthal) diffusion. We conclude that the periodic structure of the axon plays a critical role in controlling diffusion of proteins and lipids in the axon plasma membrane.
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Affiliation(s)
- Yihao Zhang
- Department of Mechanical Engineering, University of Connecticut, Storrs, CT, United States of America
| | - Anastasios V. Tzingounis
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, United States of America
| | - George Lykotrafitis
- Department of Mechanical Engineering, University of Connecticut, Storrs, CT, United States of America
- Department of Biomedical Engineering, University of Connecticut, Storrs, CT, United States of America
- * E-mail:
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16
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Evidence for three populations of the glucose transporter in the human erythrocyte membrane. Blood Cells Mol Dis 2019; 77:61-66. [PMID: 30974390 DOI: 10.1016/j.bcmd.2019.03.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 03/22/2019] [Accepted: 03/23/2019] [Indexed: 11/23/2022]
Abstract
Glucose transporter 1 (GLUT1) is one of 13 members of the human equilibrative glucose transport protein family and the only glucose transporter thought to be expressed in human erythrocyte membranes. Although GLUT1 has been shown to be anchored to adducin at the junctional spectrin-actin complex of the membrane through interactions with multiple proteins, whether other populations of GLUT1 also exist in the human erythrocyte membrane has not been examined. Because GLUT1 plays such a critical role in erythrocyte biology and since it comprises 10% of the total membrane protein, we undertook to evaluate the subpopulations of erythrocyte GLUT1 using single particle tracking. By monitoring the diffusion of individual AlexaFluor 488-labeled GLUT1 molecules on the surfaces of intact erythrocytes, we are able to identify three distinct subpopulations of GLUT1. While the mobility of the major subpopulation is similar to that of the anion transporter, band 3, both a more mobile and more anchored subpopulation also exist. From these studies, we conclude that ~65% of GLUT1 resides in similar or perhaps the same protein complex as band 3, while the remaining 1/3rd are either freely diffusing or interacting with other cytoskeletally anchored membrane protein complexes.
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17
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Clarkson CG, Johnson A, Leggett GJ, Geoghegan M. Slow polymer diffusion on brush-patterned surfaces in aqueous solution. NANOSCALE 2019; 11:6052-6061. [PMID: 30869707 DOI: 10.1039/c9nr00341j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A model system for the investigation of diffusional transport in compartmentalized nanosystems is described. Arrays of "corrals" enclosed within poly[oligo(ethylene glycol)methyl ether methacrylate] (POEGMA) "walls" were fabricated using double-exposure interferometric lithography to deprotect aminosilane films protected by a nitrophenyl group. In exposed regions, removal of the nitrophenyl group enabled attachment of an initiator for the atom-transfer radical polymerization of end-grafted POEGMA (brushes). Diffusion coefficients for poly(ethylene glycol) in these corrals were obtained by fluorescence correlation spectroscopy. Two modes of surface diffusion were observed: one which is similar to diffusion on the unpatterned surface and a very slow mode of surface diffusion that becomes increasingly important as confinement increases. Diffusion within the POEGMA brushes does not significantly contribute to the results.
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18
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Li H, Papageorgiou DP, Chang HY, Lu L, Yang J, Deng Y. Synergistic Integration of Laboratory and Numerical Approaches in Studies of the Biomechanics of Diseased Red Blood Cells. BIOSENSORS 2018; 8:E76. [PMID: 30103419 PMCID: PMC6164935 DOI: 10.3390/bios8030076] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 07/31/2018] [Accepted: 08/06/2018] [Indexed: 12/25/2022]
Abstract
In red blood cell (RBC) disorders, such as sickle cell disease, hereditary spherocytosis, and diabetes, alterations to the size and shape of RBCs due to either mutations of RBC proteins or changes to the extracellular environment, lead to compromised cell deformability, impaired cell stability, and increased propensity to aggregate. Numerous laboratory approaches have been implemented to elucidate the pathogenesis of RBC disorders. Concurrently, computational RBC models have been developed to simulate the dynamics of RBCs under physiological and pathological conditions. In this work, we review recent laboratory and computational studies of disordered RBCs. Distinguished from previous reviews, we emphasize how experimental techniques and computational modeling can be synergically integrated to improve the understanding of the pathophysiology of hematological disorders.
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Affiliation(s)
- He Li
- Division of Applied Mathematics, Brown University, Providence, RI 02912, USA.
| | - Dimitrios P Papageorgiou
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
| | - Hung-Yu Chang
- Division of Applied Mathematics, Brown University, Providence, RI 02912, USA.
| | - Lu Lu
- Division of Applied Mathematics, Brown University, Providence, RI 02912, USA.
| | - Jun Yang
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
| | - Yixiang Deng
- Division of Applied Mathematics, Brown University, Providence, RI 02912, USA.
- School of Engineering, Brown University, Providence, RI 02912, USA.
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19
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Mourão LC, Baptista RDP, de Almeida ZB, Grynberg P, Pucci MM, Castro-Gomes T, Fontes CJF, Rathore S, Sharma YD, da Silva-Pereira RA, Bemquerer MP, Braga ÉM. Anti-band 3 and anti-spectrin antibodies are increased in Plasmodium vivax infection and are associated with anemia. Sci Rep 2018; 8:8762. [PMID: 29884876 PMCID: PMC5993813 DOI: 10.1038/s41598-018-27109-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 05/18/2018] [Indexed: 11/09/2022] Open
Abstract
Clearance of non-infected red blood cells (nRBCs) is one of the main components of anemia associated with Plasmodium vivax malaria. Recently, we have shown that anemic patients with P. vivax infection had elevated levels of anti-RBCs antibodies, which could enhance in vitro phagocytosis of nRBCs and decrease their deformability. Using immunoproteomics, here we characterized erythrocytic antigens that are differentially recognized by autoantibodies from anemic and non-anemic patients with acute vivax malaria. Protein spots exclusively recognized by anemic P. vivax-infected patients were identified by mass spectrometry revealing band 3 and spectrin as the main targets. To confirm this finding, antibody responses against these specific proteins were assessed by ELISA. In addition, an inverse association between hemoglobin and anti-band 3 or anti-spectrin antibodies levels was found. Anemic patients had higher levels of IgG against both band 3 and spectrin than the non-anemic ones. To determine if these autoantibodies were elicited because of molecular mimicry, we used in silico analysis and identified P. vivax proteins that share homology with human RBC proteins such as spectrin, suggesting that infection drives autoimmune responses. These findings suggest that band 3 and spectrin are potential targets of autoantibodies that may be relevant for P. vivax malaria-associated anemia.
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Affiliation(s)
- Luiza Carvalho Mourão
- Departamento de Parasitologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | | | | | | | - Maíra Mazzoni Pucci
- Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, MG, Brazil
| | - Thiago Castro-Gomes
- Departamento de Parasitologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | | | - Sumit Rathore
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
| | - Yagya D Sharma
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
| | | | | | - Érika Martins Braga
- Departamento de Parasitologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
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20
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Unsain N, Stefani FD, Cáceres A. The Actin/Spectrin Membrane-Associated Periodic Skeleton in Neurons. Front Synaptic Neurosci 2018; 10:10. [PMID: 29875650 PMCID: PMC5974029 DOI: 10.3389/fnsyn.2018.00010] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 05/04/2018] [Indexed: 11/28/2022] Open
Abstract
Neurons are the most asymmetric cell types, with their axons commonly extending over lengths that are thousand times longer than the diameter of the cell soma. Fluorescence nanoscopy has recently unveiled that actin, spectrin and accompanying proteins form a membrane-associated periodic skeleton (MPS) that is ubiquitously present in mature axons from all neuronal types evaluated so far. The MPS is a regular supramolecular protein structure consisting of actin “rings” separated by spectrin tetramer “spacers”. Although the MPS is best organized in axons, it is also present in dendrites, dendritic spine necks and thin cellular extensions of non-neuronal cells such as oligodendrocytes and microglia. The unique organization of the actin/spectrin skeleton has raised the hypothesis that it might serve to support the extreme physical and structural conditions that axons must resist during the lifespan of an organism. Another plausible function of the MPS consists of membrane compartmentalization and subsequent organization of protein domains. This review focuses on what we know so far about the structure of the MPS in different neuronal subdomains, its dynamics and the emerging evidence of its impact in axonal biology.
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Affiliation(s)
- Nicolas Unsain
- Instituto de Investigación Médica Mercedes y Martín Ferreyra (INIMEC), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina.,Universidad Nacional de Córdoba, Córdoba, Argentina.,Instituto Universitario Ciencias Biomédicas de Córdoba (IUCBC), Córdoba, Argentina
| | - Fernando D Stefani
- Centro de Investigaciones en Bionanociencias (CIBION), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.,Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Alfredo Cáceres
- Instituto de Investigación Médica Mercedes y Martín Ferreyra (INIMEC), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina.,Universidad Nacional de Córdoba, Córdoba, Argentina.,Instituto Universitario Ciencias Biomédicas de Córdoba (IUCBC), Córdoba, Argentina
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21
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Sumi T, Okumoto A, Goto H, Sekino H. Numerical calculation on a two-step subdiffusion behavior of lateral protein movement in plasma membranes. Phys Rev E 2018; 96:042410. [PMID: 29347488 DOI: 10.1103/physreve.96.042410] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Indexed: 11/06/2022]
Abstract
A two-step subdiffusion behavior of lateral movement of transmembrane proteins in plasma membranes has been observed by using single-molecule experiments. A nested double-compartment model where large compartments are divided into several smaller ones has been proposed in order to explain this observation. These compartments are considered to be delimited by membrane-skeleton "fences" and membrane-protein "pickets" bound to the fences. We perform numerical simulations of a master equation using a simple two-dimensional lattice model to investigate the heterogeneous diffusion dynamics behavior of transmembrane proteins within plasma membranes. We show that the experimentally observed two-step subdiffusion process can be described using fence and picket models combined with decreased local diffusivity of transmembrane proteins in the vicinity of the pickets. This allows us to explain the two-step subdiffusion behavior without explicitly introducing nested double compartments.
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Affiliation(s)
- Tomonari Sumi
- Research Institute for Interdisciplinary Science and Department of Chemistry, Faculty of Science, Okayama University, 3-1-1 Tsushima-Naka, Kita-ku, Okayama 700-8530, Japan
| | - Atsushi Okumoto
- Department of Computer Science and Engineering, Graduate School of Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi 441-8580, Japan
| | - Hitoshi Goto
- Department of Computer Science and Engineering, Graduate School of Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi 441-8580, Japan
| | - Hideo Sekino
- Department of Computer Science and Engineering, Graduate School of Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi 441-8580, Japan.,Institute for Advanced Computational Science, Stony Brook University, Stony Brook, New York 11794, USA
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22
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Abstract
PURPOSE OF REVIEW Reception and transmission of signals across the plasma membrane has been a function generally attributed to transmembrane proteins. In the last 3 years, however, a growing number of reports have further acknowledged important contributions played by membrane lipids in the process of signal transduction. RECENT FINDINGS In particular, the constituency of membrane lipids can regulate how proteins with SH2 domains and molecules like K-Ras expose their catalytic domains to the cytosol and interact with effectors and second messengers. Recent reports have also shown that the degree of saturation of phospholipids can reduce the activation of certain G-protein-coupled receptors, and signaling downstream to Toll-like receptor 4 with consequences to nuclear factor kappa B activation and inflammation. Levels of specific gangliosides in the membrane were reported to activate integrins in a cell-autonomous manner affecting tumor cell migration. Furthermore, high resolution of the association of cholesterol with the smoothened receptor has clarified its participation in sonic hedgehog signaling. These are some of the key advancements that have further propelled our understanding of the broad versatile contributions of membrane lipids in signal transduction. SUMMARY As we gain definitive detail regarding the impact of lipid-protein interactions and their consequences to cell function, the options for therapeutic targeting expand with the possibility of greater specificity.
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Affiliation(s)
- Hannah Sunshine
- Molecular, Cellular and Integrative Physiology Graduate Program, UCLA
| | - M. Luisa Iruela-Arispe
- Departments of Molecular, Cell and Developmental Biology, UCLA, Los Angeles, California 90095
- Molecular Biology Institute, University of California, Los Angeles, California 90095, USA
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23
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Abstract
Phagocytes recognize and eliminate pathogens, alert other tissues of impending threats, and provide a link between innate and adaptive immunity. They also maintain tissue homeostasis, consuming dead cells without causing alarm. The receptor engagement, signal transduction, and cytoskeletal rearrangements underlying phagocytosis are paradigmatic of other immune responses and bear similarities to macropinocytosis and cell migration. We discuss how the glycocalyx restricts access to phagocytic receptors, the processes that enable receptor engagement and clustering, and the remodeling of the actin cytoskeleton that controls the mobility of membrane proteins and lipids and provides the mechanical force propelling the phagocyte membrane toward and around the phagocytic prey.
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Affiliation(s)
- Philip P Ostrowski
- Program in Cell Biology, Peter Gilgan Centre for Research & Learning, Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada; Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Sergio Grinstein
- Program in Cell Biology, Peter Gilgan Centre for Research & Learning, Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada; Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada; Keenan Research Centre of the Li Ka Shing Knowledge Institute, St. Michael's Hospital, 290 Victoria Street, Toronto, ON M5C 1N8, Canada.
| | - Spencer A Freeman
- Program in Cell Biology, Peter Gilgan Centre for Research & Learning, Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada
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24
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Zhang Y, Abiraman K, Li H, Pierce DM, Tzingounis AV, Lykotrafitis G. Modeling of the axon membrane skeleton structure and implications for its mechanical properties. PLoS Comput Biol 2017; 13:e1005407. [PMID: 28241082 PMCID: PMC5348042 DOI: 10.1371/journal.pcbi.1005407] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 03/13/2017] [Accepted: 02/14/2017] [Indexed: 01/12/2023] Open
Abstract
Super-resolution microscopy recently revealed that, unlike the soma and dendrites, the axon membrane skeleton is structured as a series of actin rings connected by spectrin filaments that are held under tension. Currently, the structure-function relationship of the axonal structure is unclear. Here, we used atomic force microscopy (AFM) to show that the stiffness of the axon plasma membrane is significantly higher than the stiffnesses of dendrites and somata. To examine whether the structure of the axon plasma membrane determines its overall stiffness, we introduced a coarse-grain molecular dynamics model of the axon membrane skeleton that reproduces the structure identified by super-resolution microscopy. Our proposed computational model accurately simulates the median value of the Young’s modulus of the axon plasma membrane determined by atomic force microscopy. It also predicts that because the spectrin filaments are under entropic tension, the thermal random motion of the voltage-gated sodium channels (Nav), which are bound to ankyrin particles, a critical axonal protein, is reduced compared to the thermal motion when spectrin filaments are held at equilibrium. Lastly, our model predicts that because spectrin filaments are under tension, any axonal injuries that lacerate spectrin filaments will likely lead to a permanent disruption of the membrane skeleton due to the inability of spectrin filaments to spontaneously form their initial under-tension configuration. Super-resolution microscopy has suggested that the actin cytoskeleton structure differ between various neuronal subcompartments. To determine the possible implication of the differing actin cytoskeleton structure, we determined the stiffness of the plasma membrane of neuronal subcompartments using atomic force microscopy (AFM). We found that axons are almost ~6 fold stiffer than the soma and ~2 fold stiffer than dendrites. By using a particle-based model for the surface membrane skeleton of the axon that comprises actin rings connected with spring filaments to represent the axonal structure, we show that regions neighboring actin rings are stiffer than areas between these rings. In these in between sub-regions, the spectrin filaments determine stiffness. Our modeling also shows that because the spectrin filaments are under tension, the thermal jitter of the actin-associated ankyrin particles, connected to the middle area of spectrin filaments, is minimal. As a result, we propose that the sodium channels bound to ankyrin particles will maintain an ordered distribution along the axon. We also predict that laceration of the spectrin filaments due to injury will cause a permanent damage to the axon since spontaneous repair of the spectrin network is not possible as spectrin filaments are under entropic tension.
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Affiliation(s)
- Yihao Zhang
- Department of Mechanical Engineering, University of Connecticut, Storrs, Connecticut, United States of America
| | - Krithika Abiraman
- Department of Biomedical Engineering, University of Connecticut, Storrs, Connecticut, United States of America
| | - He Li
- Division of Applied Mathematics, Brown University, Providence, Rhode Island, United States of America
| | - David M. Pierce
- Department of Mechanical Engineering, University of Connecticut, Storrs, Connecticut, United States of America
- Department of Biomedical Engineering, University of Connecticut, Storrs, Connecticut, United States of America
- Department of Mathematics, University of Connecticut, Storrs, Connecticut, United States of America
| | - Anastasios V. Tzingounis
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, United States of America
| | - George Lykotrafitis
- Department of Mechanical Engineering, University of Connecticut, Storrs, Connecticut, United States of America
- Department of Biomedical Engineering, University of Connecticut, Storrs, Connecticut, United States of America
- * E-mail:
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25
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Spector J, Kodippili GC, Ritchie K, Low PS. Single Molecule Studies of the Diffusion of Band 3 in Sickle Cell Erythrocytes. PLoS One 2016; 11:e0162514. [PMID: 27598991 PMCID: PMC5012561 DOI: 10.1371/journal.pone.0162514] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 08/24/2016] [Indexed: 01/29/2023] Open
Abstract
Sickle cell disease (SCD) is caused by an inherited mutation in hemoglobin that leads to sickle hemoglobin (HbS) polymerization and premature HbS denaturation. Previous publications have shown that HbS denaturation is followed by binding of denatured HbS (a.k.a. hemichromes) to band 3, the consequent clustering of band 3 in the plane of the erythrocyte membrane that in turn promotes binding of autologous antibodies to the clustered band 3, and removal of the antibody-coated erythrocytes from circulation. Although each step of the above process has been individually demonstrated, the fraction of band 3 that is altered by association with denatured HbS has never been determined. For this purpose, we evaluated the lateral diffusion of band 3 in normal cells, reversibly sickled cells (RSC), irreversibly sickled cells (ISC), and hemoglobin SC erythrocytes (HbSC) in order to estimate the fraction of band 3 that was diffusing more slowly due to hemichrome-induced clustering. We labeled fewer than ten band 3 molecules per intact erythrocyte with a quantum dot to avoid perturbing membrane structure and we then monitored band 3 lateral diffusion by single particle tracking. We report here that the size of the slowly diffusing population of band 3 increases in the sequence: normal cells<HbSC<RSC<ISC. We also demonstrate that the size of the compartment in which band 3 is free to diffuse decreases roughly in the same order, with band 3 diffusing in two compartments of sizes 35 and 71 nm in normal cells, but only a single compartment in HbSC cells (58 nm), RSC (45 nm) and ISC (36 nm). These data suggest that the mobility of band 3 is increasingly constrained during SCD progression, suggesting a global impact of the mutated hemoglobin on erythrocyte membrane properties.
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MESH Headings
- Anemia, Sickle Cell/blood
- Anemia, Sickle Cell/pathology
- Anion Exchange Protein 1, Erythrocyte/chemistry
- Anion Exchange Protein 1, Erythrocyte/metabolism
- Cells, Cultured
- Diffusion
- Erythrocyte Membrane/chemistry
- Erythrocyte Membrane/metabolism
- Erythrocyte Membrane/ultrastructure
- Erythrocytes, Abnormal/chemistry
- Erythrocytes, Abnormal/metabolism
- Erythrocytes, Abnormal/ultrastructure
- Hemeproteins/chemistry
- Hemeproteins/metabolism
- Hemoglobin, Sickle/chemistry
- Hemoglobin, Sickle/metabolism
- Humans
- Molecular Probes/chemistry
- Quantum Dots/chemistry
- Single Molecule Imaging/methods
- Staining and Labeling/methods
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Affiliation(s)
- Jeff Spector
- Department of Physics, Purdue University, West Lafayette, IN, 47907, United States of America
| | - Gayani C. Kodippili
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907, United States of America
| | - Ken Ritchie
- Department of Physics, Purdue University, West Lafayette, IN, 47907, United States of America
| | - Philip S. Low
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907, United States of America
- * E-mail:
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Li H, Zhang Y, Ha V, Lykotrafitis G. Modeling of band-3 protein diffusion in the normal and defective red blood cell membrane. SOFT MATTER 2016; 12:3643-3653. [PMID: 26977476 DOI: 10.1039/c4sm02201g] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We employ a two-component red blood cell (RBC) membrane model to simulate lateral diffusion of band-3 proteins in the normal RBC and in the RBC with defective membrane proteins. The defects reduce the connectivity between the lipid bilayer and the membrane skeleton (vertical connectivity), or the connectivity of the membrane skeleton itself (horizontal connectivity), and are associated with the blood disorders of hereditary spherocytosis (HS) and hereditary elliptocytosis (HE) respectively. Initially, we demonstrate that the cytoskeleton limits band-3 lateral mobility by measuring the band-3 macroscopic diffusion coefficients in the normal RBC membrane and in a lipid bilayer without the cytoskeleton. Then, we study band-3 diffusion in the defective RBC membrane and quantify the relation between band-3 diffusion coefficients and percentage of protein defects in HE RBCs. In addition, we illustrate that at low spectrin network connectivity (horizontal connectivity) band-3 subdiffusion can be approximated as anomalous diffusion, while at high horizontal connectivity band-3 diffusion is characterized as confined diffusion. Our simulations show that the band-3 anomalous diffusion exponent depends on the percentage of protein defects in the membrane cytoskeleton. We also confirm that the introduction of attraction between the lipid bilayer and the spectrin network reduces band-3 diffusion, but we show that this reduction is lower than predicted by the percolation theory. Furthermore, we predict that the attractive force between the spectrin filament and the lipid bilayer is at least 20 times smaller than the binding forces at band-3 and glycophorin C, the two major membrane binding sites. Finally, we explore diffusion of band-3 particles in the RBC membrane with defects related to vertical connectivity. We demonstrate that in this case band-3 diffusion can be approximated as confined diffusion for all attraction levels between the spectrin network and the lipid bilayer. By comparing the diffusion coefficients measured in horizontal vs. vertical defects, we conclude that band-3 mobility is primarily controlled by the horizontal connectivity.
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Affiliation(s)
- He Li
- Division of Applied Mathematics, Brown University, Providence, RI 02912, USA
| | - Yihao Zhang
- Department of Mechanical Engineering, University of Connecticut, 191 Auditorium Road, Unit 3139, Storrs, CT 06269-3139, USA.
| | - Vi Ha
- Department of Mechanical Engineering, University of Connecticut, 191 Auditorium Road, Unit 3139, Storrs, CT 06269-3139, USA.
| | - George Lykotrafitis
- Department of Mechanical Engineering, University of Connecticut, 191 Auditorium Road, Unit 3139, Storrs, CT 06269-3139, USA. and Department of Biomedical Engineering, University of Connecticut, Storrs, CT 06269, USA
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27
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Fujiwara TK, Iwasawa K, Kalay Z, Tsunoyama TA, Watanabe Y, Umemura YM, Murakoshi H, Suzuki KGN, Nemoto YL, Morone N, Kusumi A. Confined diffusion of transmembrane proteins and lipids induced by the same actin meshwork lining the plasma membrane. Mol Biol Cell 2016; 27:1101-19. [PMID: 26864625 PMCID: PMC4814218 DOI: 10.1091/mbc.e15-04-0186] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 02/02/2016] [Indexed: 11/11/2022] Open
Abstract
Ultraspeed single-molecule tracking with <25-μs resolution and electron tomography show that transmembrane proteins and phospholipids in the plasma membrane hop among submicrometer compartments of the same size, probably delimited by the anchored-transmembrane-protein pickets lining the actin-based membrane-skeleton fence, once every 1–58 ms. The mechanisms by which the diffusion rate in the plasma membrane (PM) is regulated remain unresolved, despite their importance in spatially regulating the reaction rates in the PM. Proposed models include entrapment in nanoscale noncontiguous domains found in PtK2 cells, slow diffusion due to crowding, and actin-induced compartmentalization. Here, by applying single-particle tracking at high time resolutions, mainly to the PtK2-cell PM, we found confined diffusion plus hop movements (termed “hop diffusion”) for both a nonraft phospholipid and a transmembrane protein, transferrin receptor, and equal compartment sizes for these two molecules in all five of the cell lines used here (actual sizes were cell dependent), even after treatment with actin-modulating drugs. The cross-section size and the cytoplasmic domain size both affected the hop frequency. Electron tomography identified the actin-based membrane skeleton (MSK) located within 8.8 nm from the PM cytoplasmic surface of PtK2 cells and demonstrated that the MSK mesh size was the same as the compartment size for PM molecular diffusion. The extracellular matrix and extracellular domains of membrane proteins were not involved in hop diffusion. These results support a model of anchored TM-protein pickets lining actin-based MSK as a major mechanism for regulating diffusion.
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Affiliation(s)
- Takahiro K Fujiwara
- Center for Meso-Bio Single-Molecule Imaging, Institute for Integrated Cell-Material Sciences, Kyoto 606-8501, Japan
| | - Kokoro Iwasawa
- Institute for Frontier Medical Sciences, Kyoto University, Kyoto 606-8507, Japan
| | - Ziya Kalay
- Institute for Integrated Cell-Material Sciences, Kyoto 606-8507, Japan
| | - Taka A Tsunoyama
- Institute for Integrated Cell-Material Sciences, Kyoto 606-8507, Japan
| | - Yusuke Watanabe
- Institute for Integrated Cell-Material Sciences, Kyoto 606-8507, Japan
| | - Yasuhiro M Umemura
- Department of Physiology and Systems Bioscience, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Hideji Murakoshi
- National Institute for Physiological Sciences, Okazaki 444-8585, Japan
| | - Kenichi G N Suzuki
- Institute for Integrated Cell-Material Sciences, Kyoto 606-8507, Japan Institute for Stem Cell Biology and Regenerative Medicine and National Centre for Biological Sciences, Bangalore 650056, India
| | - Yuri L Nemoto
- Institute for Integrated Cell-Material Sciences, Kyoto 606-8507, Japan
| | - Nobuhiro Morone
- MRC Toxicology Unit, University of Leicester, Leicester LE1 9HN, United Kingdom
| | - Akihiro Kusumi
- Institute for Frontier Medical Sciences, Kyoto University, Kyoto 606-8507, Japan Institute for Integrated Cell-Material Sciences, Kyoto 606-8507, Japan Membrane Cooperativity Unit, Okinawa Institute of Science and Technology, Onna-son, Okinawa 904-0412, Japan
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28
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Lin LCL, Brown FLH. Simulating Membrane Dynamics in Nonhomogeneous Hydrodynamic Environments. J Chem Theory Comput 2015; 2:472-83. [PMID: 26626658 DOI: 10.1021/ct050293s] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Two previously introduced simulation algorithms for the dynamics of elastic membrane sheets embedded in a fluid medium are extended to account for inhomogeneous hydrodynamic environments. We calculate the height autocorrelation function for a lipid bilayer randomly pinned to a flat substrate and the influence of fluid confinement by the spectrin cytoskeleton on short wavelength membrane undulations of the human red blood cell. Altering the hydrodynamic environment of the membrane leads to significant changes in dynamics, and we discuss these effects in the context of recent experiments.
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Affiliation(s)
- Lawrence C-L Lin
- Department of Physics, University of California, Santa Barbara, California 93106-9530, and Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106-9510
| | - Frank L H Brown
- Department of Physics, University of California, Santa Barbara, California 93106-9530, and Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106-9510
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29
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Role of band 3 in the erythrocyte membrane structural changes under thermal fluctuations –multi scale modeling considerations. J Bioenerg Biomembr 2015; 47:507-18. [DOI: 10.1007/s10863-015-9633-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 10/27/2015] [Indexed: 10/22/2022]
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Erythrocyte membrane model with explicit description of the lipid bilayer and the spectrin network. Biophys J 2015; 107:642-653. [PMID: 25099803 DOI: 10.1016/j.bpj.2014.06.031] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 05/23/2014] [Accepted: 06/18/2014] [Indexed: 11/22/2022] Open
Abstract
The membrane of the red blood cell (RBC) consists of spectrin tetramers connected at actin junctional complexes, forming a two-dimensional (2D) sixfold triangular network anchored to the lipid bilayer. Better understanding of the erythrocyte mechanics in hereditary blood disorders such as spherocytosis, elliptocytosis, and especially, sickle cell disease requires the development of a detailed membrane model. In this study, we introduce a mesoscale implicit-solvent coarse-grained molecular dynamics (CGMD) model of the erythrocyte membrane that explicitly describes the phospholipid bilayer and the cytoskeleton, by extending a previously developed two-component RBC membrane model. We show that the proposed model represents RBC membrane with the appropriate bending stiffness and shear modulus. The timescale and self-consistency of the model are established by comparing our results with experimentally measured viscosity and thermal fluctuations of the RBC membrane. Furthermore, we measure the pressure exerted by the cytoskeleton on the lipid bilayer. We find that defects at the anchoring points of the cytoskeleton to the lipid bilayer (as in spherocytes) cause a reduction in the pressure compared with an intact membrane, whereas defects in the dimer-dimer association of a spectrin filament (as in elliptocytes) cause an even larger decrease in the pressure. We conjecture that this finding may explain why the experimentally measured diffusion coefficients of band-3 proteins are higher in elliptocytes than in spherocytes, and higher than in normal RBCs. Finally, we study the effects that possible attractive forces between the spectrin filaments and the lipid bilayer have on the pressure applied on the lipid bilayer by the filaments. We discover that the attractive forces cause an increase in the pressure as they diminish the effect of membrane protein defects. As this finding contradicts with experimental results, we conclude that the attractive forces are moderate and do not impose a complete attachment of the filaments to the lipid bilayer.
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31
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Choi W, Yi J, Kim YW. Fluctuations of red blood cell membranes: The role of the cytoskeleton. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:012717. [PMID: 26274212 DOI: 10.1103/physreve.92.012717] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Indexed: 06/04/2023]
Abstract
We theoretically investigate the membrane fluctuations of red blood cells with focus laid on the role of the cytoskeleton, viewing the system as a membrane coupled to a sparse spring network. This model is exactly solvable and enables us to examine the coupling strength dependence of the membrane undulation. We find that the coupling modifies the fluctuation spectrum at wavelengths longer than the mesh size of the network, while leaving the fluid-like behavior of the membrane intact at shorter wavelengths. The fluctuation spectra can be markedly different, depending on not only the relative amplitude of the bilayer bending energy with respect to the cytoskeleton deformation energy but also the bilayer-cytoskelton coupling strength.
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Affiliation(s)
- Wonjune Choi
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea
| | - Juyeon Yi
- Department of Physics, Pusan National University, Busan 609-735, Korea
| | - Yong Woon Kim
- Graduate School of Nanoscience and Technology, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea
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32
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Shimo H, Arjunan SNV, Machiyama H, Nishino T, Suematsu M, Fujita H, Tomita M, Takahashi K. Particle Simulation of Oxidation Induced Band 3 Clustering in Human Erythrocytes. PLoS Comput Biol 2015; 11:e1004210. [PMID: 26046580 PMCID: PMC4457884 DOI: 10.1371/journal.pcbi.1004210] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 02/24/2015] [Indexed: 01/06/2023] Open
Abstract
Oxidative stress mediated clustering of membrane protein band 3 plays an essential role in the clearance of damaged and aged red blood cells (RBCs) from the circulation. While a number of previous experimental studies have observed changes in band 3 distribution after oxidative treatment, the details of how these clusters are formed and how their properties change under different conditions have remained poorly understood. To address these issues, a framework that enables the simultaneous monitoring of the temporal and spatial changes following oxidation is needed. In this study, we established a novel simulation strategy that incorporates deterministic and stochastic reactions with particle reaction-diffusion processes, to model band 3 cluster formation at single molecule resolution. By integrating a kinetic model of RBC antioxidant metabolism with a model of band 3 diffusion, we developed a model that reproduces the time-dependent changes of glutathione and clustered band 3 levels, as well as band 3 distribution during oxidative treatment, observed in prior studies. We predicted that cluster formation is largely dependent on fast reverse reaction rates, strong affinity between clustering molecules, and irreversible hemichrome binding. We further predicted that under repeated oxidative perturbations, clusters tended to progressively grow and shift towards an irreversible state. Application of our model to simulate oxidation in RBCs with cytoskeletal deficiency also suggested that oxidation leads to more enhanced clustering compared to healthy RBCs. Taken together, our model enables the prediction of band 3 spatio-temporal profiles under various situations, thus providing valuable insights to potentially aid understanding mechanisms for removing senescent and premature RBCs. In order to maintain a steady internal environment, our bodies must be able to specifically recognize old and damaged red blood cells (RBCs), and remove them from the circulation in a timely manner. Clusters of membrane protein band 3, which form in response to elevated oxidative damage, serve as essential molecular markers that initiate this cell removal process. However, little is known about the details of how these clusters are formed and how their properties change under different conditions. To understand these mechanisms in detail, we developed a computational model that enables the prediction of the time course profiles of metabolic intermediates, as well as the visualization of the resulting band 3 distribution during oxidative treatment. Our model predictions were in good agreement with previous published experimental data, and provided predictive insights on the key factors of cluster formation. Furthermore, simulation experiments of the effects of multiple oxidative pulses and cytoskeletal defect using the model also suggested that clustering is enhanced under such conditions. Analyses using our model can provide hypotheses and suggest experiments to aid the understanding of the physiology of anemia-associated RBC disorders, and optimization of quality control of RBCs in stored blood.
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Affiliation(s)
- Hanae Shimo
- Laboratory for Biochemical Simulation, RIKEN Quantitative Biology Center, Osaka, Japan
- Department of Biochemistry, School of Medicine, Keio University, Shinjuku, Tokyo, Japan
| | | | - Hiroaki Machiyama
- Laboratory for Biochemical Simulation, RIKEN Quantitative Biology Center, Osaka, Japan
- Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | - Taiko Nishino
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, Japan
| | - Makoto Suematsu
- Department of Biochemistry, School of Medicine, Keio University, Shinjuku, Tokyo, Japan
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, Japan
| | - Hideaki Fujita
- Laboratory for Biochemical Simulation, RIKEN Quantitative Biology Center, Osaka, Japan
- Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | - Masaru Tomita
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, Japan
- Department of Environment and Information Studies, Keio University, Fujisawa, Kanagawa, Japan
| | - Koichi Takahashi
- Laboratory for Biochemical Simulation, RIKEN Quantitative Biology Center, Osaka, Japan
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, Japan
- * E-mail:
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33
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Arraud N, Gounou C, Turpin D, Brisson AR. Fluorescence triggering: A general strategy for enumerating and phenotyping extracellular vesicles by flow cytometry. Cytometry A 2015; 89:184-95. [DOI: 10.1002/cyto.a.22669] [Citation(s) in RCA: 116] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 03/01/2015] [Accepted: 03/12/2015] [Indexed: 12/18/2022]
Affiliation(s)
- Nicolas Arraud
- Molecular Imaging and NanoBioTechnology, UMR-5248-CBMN CNRS-University of Bordeaux-IPB; Allée Geoffroy Saint-Hilaire Pessac F-33600 France
| | - Céline Gounou
- Molecular Imaging and NanoBioTechnology, UMR-5248-CBMN CNRS-University of Bordeaux-IPB; Allée Geoffroy Saint-Hilaire Pessac F-33600 France
| | - Delphine Turpin
- Molecular Imaging and NanoBioTechnology, UMR-5248-CBMN CNRS-University of Bordeaux-IPB; Allée Geoffroy Saint-Hilaire Pessac F-33600 France
| | - Alain R. Brisson
- Molecular Imaging and NanoBioTechnology, UMR-5248-CBMN CNRS-University of Bordeaux-IPB; Allée Geoffroy Saint-Hilaire Pessac F-33600 France
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Katoch P, Mitra S, Ray A, Kelsey L, Roberts BJ, Wahl JK, Johnson KR, Mehta PP. The carboxyl tail of connexin32 regulates gap junction assembly in human prostate and pancreatic cancer cells. J Biol Chem 2015; 290:4647-4662. [PMID: 25548281 PMCID: PMC4335205 DOI: 10.1074/jbc.m114.586057] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 12/23/2014] [Indexed: 12/20/2022] Open
Abstract
Connexins, the constituent proteins of gap junctions, are transmembrane proteins. A connexin (Cx) traverses the membrane four times and has one intracellular and two extracellular loops with the amino and carboxyl termini facing the cytoplasm. The transmembrane and the extracellular loop domains are highly conserved among different Cxs, whereas the carboxyl termini, often called the cytoplasmic tails, are highly divergent. We have explored the role of the cytoplasmic tail of Cx32, a Cx expressed in polarized and differentiated cells, in regulating gap junction assembly. Our results demonstrate that compared with the full-length Cx32, the cytoplasmic tail-deleted Cx32 is assembled into small gap junctions in human pancreatic and prostatic cancer cells. Our results further document that the expression of the full-length Cx32 in cells, which express the tail-deleted Cx32, increases the size of gap junctions, whereas the expression of the tail-deleted Cx32 in cells, which express the full-length Cx32, has the opposite effect. Moreover, we show that the tail is required for the clustering of cell-cell channels and that in cells expressing the tail-deleted Cx32, the expression of cell surface-targeted cytoplasmic tail alone is sufficient to enhance the size of gap junctions. Our live-cell imaging data further demonstrate that gap junctions formed of the tail-deleted Cx32 are highly mobile compared with those formed of full-length Cx32. Our results suggest that the cytoplasmic tail of Cx32 is not required to initiate the assembly of gap junctions but for their subsequent growth and stability. Our findings suggest that the cytoplasmic tail of Cx32 may be involved in regulating the permeability of gap junctions by regulating their size.
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Affiliation(s)
- Parul Katoch
- From the Department of Biochemistry and Molecular Biology, Department of Oral Biology, Eppley Institute for Research in Cancer and Allied Diseases, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | - Shalini Mitra
- From the Department of Biochemistry and Molecular Biology, Department of Oral Biology, Eppley Institute for Research in Cancer and Allied Diseases, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | - Anuttoma Ray
- From the Department of Biochemistry and Molecular Biology, Department of Oral Biology, Eppley Institute for Research in Cancer and Allied Diseases, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | - Linda Kelsey
- From the Department of Biochemistry and Molecular Biology, Department of Oral Biology, Eppley Institute for Research in Cancer and Allied Diseases, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | - Brett J Roberts
- From the Department of Biochemistry and Molecular Biology, Department of Oral Biology, Eppley Institute for Research in Cancer and Allied Diseases, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | - James K Wahl
- From the Department of Biochemistry and Molecular Biology, Department of Oral Biology, Eppley Institute for Research in Cancer and Allied Diseases, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | - Keith R Johnson
- From the Department of Biochemistry and Molecular Biology, Department of Oral Biology, Eppley Institute for Research in Cancer and Allied Diseases, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | - Parmender P Mehta
- From the Department of Biochemistry and Molecular Biology, Department of Oral Biology, Eppley Institute for Research in Cancer and Allied Diseases, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198.
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Suzuki KG. New Insights into the Organization of Plasma Membrane and Its Role in Signal Transduction. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 317:67-96. [DOI: 10.1016/bs.ircmb.2015.02.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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36
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Pajic-Lijakovic I. Erythrocytes under osmotic stress – modeling considerations. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2015; 117:113-24. [DOI: 10.1016/j.pbiomolbio.2014.11.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 10/10/2014] [Accepted: 11/19/2014] [Indexed: 10/24/2022]
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37
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Kwiatek JM, Hinde E, Gaus K. Microscopy approaches to investigate protein dynamics and lipid organization. Mol Membr Biol 2014; 31:141-51. [DOI: 10.3109/09687688.2014.937469] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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38
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Cambi A, Lakadamyali M, Lidke DS, Garcia-Parajo MF. Meeting report--Visualizing signaling nanoplatforms at a higher spatiotemporal resolution. J Cell Sci 2014; 126:3817-21. [PMID: 23995382 DOI: 10.1242/jcs.137901] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The International Symposium entitled ‘Visualizing signaling nanoplatforms at a higher spatiotemporal resolution’ sponsored by the Institució Catalana de Recerca i Estudis Avançats (ICREA) was held on 29–31 May 2013 at the ICFO-Institute of Photonic Sciences, in Barcelona, Spain. The meeting brought together a multidisciplinary group of international leaders in the fields of super-resolution imaging (nanoscopy) and cell membrane biology, and served as a forum to further our understanding of the fundamental mechanisms that govern nanostructures and protein–function relationships at the cell membrane.
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Affiliation(s)
- Alessandra Cambi
- Department of Tumor Immunology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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39
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Hiramoto-Yamaki N, Tanaka KAK, Suzuki KGN, Hirosawa KM, Miyahara MSH, Kalay Z, Tanaka K, Kasai RS, Kusumi A, Fujiwara TK. Ultrafast diffusion of a fluorescent cholesterol analog in compartmentalized plasma membranes. Traffic 2014; 15:583-612. [PMID: 24506328 PMCID: PMC4265843 DOI: 10.1111/tra.12163] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Revised: 02/05/2014] [Accepted: 02/07/2014] [Indexed: 01/20/2023]
Abstract
Cholesterol distribution and dynamics in the plasma membrane (PM) are poorly understood. The recent development of Bodipy488-conjugated cholesterol molecule (Bdp-Chol) allowed us to study cholesterol behavior in the PM, using single fluorescent-molecule imaging. Surprisingly, in the intact PM, Bdp-Chol diffused at the fastest rate ever found for any molecules in the PM, with a median diffusion coefficient (D) of 3.4 µm2/second, which was ∼10 times greater than that of non-raft phospholipid molecules (0.33 µm2/second), despite Bdp-Chol's probable association with raft domains. Furthermore, Bdp-Chol exhibited no sign of entrapment in time scales longer than 0.5 milliseconds. In the blebbed PM, where actin filaments were largely depleted, Bdp-Chol and Cy3-conjugated dioleoylphosphatidylethanolamine (Cy3-DOPE) diffused at comparable Ds (medians = 5.8 and 6.2 µm2/second, respectively), indicating that the actin-based membrane skeleton reduces the D of Bdp-Chol only by a factor of ∼2 from that in the blebbed PM, whereas it reduces the D of Cy3-DOPE by a factor of ∼20. These results are consistent with the previously proposed model, in which the PM is compartmentalized by the actin-based membrane-skeleton fence and its associated transmembrane picket proteins for the macroscopic diffusion of all of the membrane molecules, and suggest that the probability of Bdp-Chol passing through the compartment boundaries, once it enters the boundary, is ∼10× greater than that of Cy3-DOPE. Since the compartment sizes are greater than those of the putative raft domains, we conclude that raft domains coexist with membrane-skeleton-induced compartments and are contained within them.
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Affiliation(s)
- Nao Hiramoto-Yamaki
- Institute for Integrated Cell-Material Sciences (WPI-iCeMS) and Institute for Frontier Medical Sciences, Kyoto University, Kyoto, 606-8507, Japan
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Goñi FM. The basic structure and dynamics of cell membranes: an update of the Singer-Nicolson model. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:1467-76. [PMID: 24440423 DOI: 10.1016/j.bbamem.2014.01.006] [Citation(s) in RCA: 210] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2013] [Revised: 12/30/2013] [Accepted: 01/08/2014] [Indexed: 01/03/2023]
Abstract
The fluid mosaic model of Singer and Nicolson (1972) is a commonly used representation of the cell membrane structure and dynamics. However a number of features, the result of four decades of research, must be incorporated to obtain a valid, contemporary version of the model. Among the novel aspects to be considered are: (i) the high density of proteins in the bilayer, that makes the bilayer a molecularly "crowded" space, with important physiological consequences; (ii) the proteins that bind the membranes on a temporary basis, thus establishing a continuum between the purely soluble proteins, never in contact with membranes, and those who cannot exist unless bilayer-bound; (iii) the progress in our knowledge of lipid phases, the putative presence of non-lamellar intermediates in membranes, and the role of membrane curvature and its relation to lipid geometry, (iv) the existence of lateral heterogeneity (domain formation) in cell membranes, including the transient microdomains known as rafts, and (v) the possibility of transient and localized transbilayer (flip-flop) lipid motion. This article is part of a Special Issue entitled: Membrane Structure and Function: Relevance in the Cell's Physiology, Pathology and Therapy.
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Affiliation(s)
- Félix M Goñi
- Unidad de Biofísica (CSIC, UPV/EHU), Universidad del País Vasco, P.O. Box 644, 48080 Bilbao, Spain; Departamento de Bioquímica, Universidad del País Vasco, P.O. Box 644, 48080 Bilbao, Spain.
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41
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Höfling F, Franosch T. Anomalous transport in the crowded world of biological cells. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2013; 76:046602. [PMID: 23481518 DOI: 10.1088/0034-4885/76/4/046602] [Citation(s) in RCA: 579] [Impact Index Per Article: 52.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
A ubiquitous observation in cell biology is that the diffusive motion of macromolecules and organelles is anomalous, and a description simply based on the conventional diffusion equation with diffusion constants measured in dilute solution fails. This is commonly attributed to macromolecular crowding in the interior of cells and in cellular membranes, summarizing their densely packed and heterogeneous structures. The most familiar phenomenon is a sublinear, power-law increase of the mean-square displacement (MSD) as a function of the lag time, but there are other manifestations like strongly reduced and time-dependent diffusion coefficients, persistent correlations in time, non-Gaussian distributions of spatial displacements, heterogeneous diffusion and a fraction of immobile particles. After a general introduction to the statistical description of slow, anomalous transport, we summarize some widely used theoretical models: Gaussian models like fractional Brownian motion and Langevin equations for visco-elastic media, the continuous-time random walk model, and the Lorentz model describing obstructed transport in a heterogeneous environment. Particular emphasis is put on the spatio-temporal properties of the transport in terms of two-point correlation functions, dynamic scaling behaviour, and how the models are distinguished by their propagators even if the MSDs are identical. Then, we review the theory underlying commonly applied experimental techniques in the presence of anomalous transport like single-particle tracking, fluorescence correlation spectroscopy (FCS) and fluorescence recovery after photobleaching (FRAP). We report on the large body of recent experimental evidence for anomalous transport in crowded biological media: in cyto- and nucleoplasm as well as in cellular membranes, complemented by in vitro experiments where a variety of model systems mimic physiological crowding conditions. Finally, computer simulations are discussed which play an important role in testing the theoretical models and corroborating the experimental findings. The review is completed by a synthesis of the theoretical and experimental progress identifying open questions for future investigation.
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Affiliation(s)
- Felix Höfling
- Max-Planck-Institut für Intelligente Systeme, Heisenbergstraße 3, 70569 Stuttgart, and Institut für Theoretische Physik IV, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
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Yamagishi M, Shirasaki Y, Funatsu T. Single-molecule tracking of mRNA in living cells. Methods Mol Biol 2013; 950:153-67. [PMID: 23086875 DOI: 10.1007/978-1-62703-137-0_10] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Some mRNAs localize to specific regions within eukaryotic cells to express their functions. The movement and localization of mRNA molecules provides valuable information about how they concentrate to particular regions. Recent technical advances in optical microscopy and image analysis algorithms enable real-time tracking of single mRNA molecules in living cells. This chapter presents the methods to visualize and track single β-actin mRNA molecules that localize at the leading edge of chicken embryo fibroblasts. Furthermore, this chapter presents an analysis approach for single-molecule tracking data to extract quantitative information about the microenvironments of the mRNA molecules.
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Affiliation(s)
- Mai Yamagishi
- Laboratory for Immunogenomics, RIKEN Research Center for Allergy and Immunology, Kanagawa, Japan
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ABCA1 dimer-monomer interconversion during HDL generation revealed by single-molecule imaging. Proc Natl Acad Sci U S A 2013; 110:5034-9. [PMID: 23479619 DOI: 10.1073/pnas.1220703110] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The generation of high-density lipoprotein (HDL), one of the most critical events for preventing atherosclerosis, is mediated by ATP-binding cassette protein A1 (ABCA1). ABCA1 is known to transfer cellular cholesterol and phospholipids to apolipoprotein A-I (apoA-I) for generating discoidal HDL (dHDL) particles, composed of 100-200 lipid molecules surrounded by two apoA-I molecules; however, the regulatory mechanisms are still poorly understood. Here we observed ABCA1-GFP and apoA-I at the level of single molecules on the plasma membrane via a total internal reflection fluorescence microscope. We found that about 70% of total ABCA1-GFP spots are immobilized on the plasma membrane and estimated that about 89% of immobile ABCA1 molecules are in dimers. Furthermore, an ATPase-deficient ABCA1 mutant failed to be immobilized or form a dimer. We found that the lipid acceptor apoA-I interacts with the ABCA1 dimer to generate dHDL and is followed by ABCA1 dimer-monomer interconversion. This indicates that the formation of the ABCA1 dimer is the key for apoA-I binding and nascent HDL generation. Our findings suggest the physiological significance of conversion of the ABCA1 monomer to a dimer: The dimer serves as a receptor for two apoA-I molecules for dHDL particle generation.
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Martinière A, Runions J. Protein diffusion in plant cell plasma membranes: the cell-wall corral. FRONTIERS IN PLANT SCIENCE 2013; 4:515. [PMID: 24381579 PMCID: PMC3865442 DOI: 10.3389/fpls.2013.00515] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 12/01/2013] [Indexed: 05/08/2023]
Abstract
Studying protein diffusion informs us about how proteins interact with their environment. Work on protein diffusion over the last several decades has illustrated the complex nature of biological lipid bilayers. The plasma membrane contains an array of membrane-spanning proteins or proteins with peripheral membrane associations. Maintenance of plasma membrane microstructure can be via physical features that provide intrinsic ordering such as lipid microdomains, or from membrane-associated structures such as the cytoskeleton. Recent evidence indicates, that in the case of plant cells, the cell wall seems to be a major player in maintaining plasma membrane microstructure. This interconnection / interaction between cell-wall and plasma membrane proteins most likely plays an important role in signal transduction, cell growth, and cell physiological responses to the environment.
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Affiliation(s)
- Alexandre Martinière
- Biochimie et Physiologie Moléculaire des Plantes, Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique, Université Montpellier 2Montpellier, France
- *Correspondence: Alexandre Martinière, Biochimie et Physiologie Moléculaire des Plantes, Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique, Université Montpellier 2, SupAgro. Bat 7, 2 place Viala, 34060 Montpellier Cedex 1, France e-mail: ;
| | - John Runions
- Department of Biological and Medical Sciences, Oxford Brookes UniversityOxford, UK
- John Runions, Department of Biological and Medical Sciences, Oxford Brookes University, Gipsy Lane, Oxford OX30BP, UK e-mail:
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Alenghat FJ, Golan DE. Membrane protein dynamics and functional implications in mammalian cells. CURRENT TOPICS IN MEMBRANES 2013; 72:89-120. [PMID: 24210428 PMCID: PMC4193470 DOI: 10.1016/b978-0-12-417027-8.00003-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The organization of the plasma membrane is both highly complex and highly dynamic. One manifestation of this dynamic complexity is the lateral mobility of proteins within the plane of the membrane, which is often an important determinant of intermolecular protein-binding interactions, downstream signal transduction, and local membrane mechanics. The mode of membrane protein mobility can range from random Brownian motion to immobility and from confined or restricted motion to actively directed motion. Several methods can be used to distinguish among the various modes of protein mobility, including fluorescence recovery after photobleaching, single-particle tracking, fluorescence correlation spectroscopy, and variations of these techniques. Here, we present both a brief overview of these methods and examples of their use to elucidate the dynamics of membrane proteins in mammalian cells-first in erythrocytes, then in erythroblasts and other cells in the hematopoietic lineage, and finally in non-hematopoietic cells. This multisystem analysis shows that the cytoskeleton frequently governs modes of membrane protein motion by stably anchoring the proteins through direct-binding interactions, by restricting protein diffusion through steric interactions, or by facilitating directed protein motion. Together, these studies have begun to delineate mechanisms by which membrane protein dynamics influence signaling sequelae and membrane mechanical properties, which, in turn, govern cell function.
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Affiliation(s)
- Francis J. Alenghat
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA
| | - David E. Golan
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA
- Hematology Division, Brigham and Women’s Hospital, Boston, Massachusetts, USA
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Kusumi A, Fujiwara TK, Chadda R, Xie M, Tsunoyama TA, Kalay Z, Kasai RS, Suzuki KGN. Dynamic organizing principles of the plasma membrane that regulate signal transduction: commemorating the fortieth anniversary of Singer and Nicolson's fluid-mosaic model. Annu Rev Cell Dev Biol 2012; 28:215-50. [PMID: 22905956 DOI: 10.1146/annurev-cellbio-100809-151736] [Citation(s) in RCA: 284] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The recent rapid accumulation of knowledge on the dynamics and structure of the plasma membrane has prompted major modifications of the textbook fluid-mosaic model. However, because the new data have been obtained in a variety of research contexts using various biological paradigms, the impact of the critical conceptual modifications on biomedical research and development has been limited. In this review, we try to synthesize our current biological, chemical, and physical knowledge about the plasma membrane to provide new fundamental organizing principles of this structure that underlie every molecular mechanism that realizes its functions. Special attention is paid to signal transduction function and the dynamic aspect of the organizing principles. We propose that the cooperative action of the hierarchical three-tiered mesoscale (2-300 nm) domains--actin-membrane-skeleton induced compartments (40-300 nm), raft domains (2-20 nm), and dynamic protein complex domains (3-10 nm)--is critical for membrane function and distinguishes the plasma membrane from a classical Singer-Nicolson-type model.
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Affiliation(s)
- Akihiro Kusumi
- Institute for Integrated Cell-Material Sciences, Kyoto University, Kyoto 606-8507, Japan.
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Lill Y, Kaserer WA, Newton SM, Lill M, Klebba PE, Ritchie K. Single-molecule study of molecular mobility in the cytoplasm of Escherichia coli. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 86:021907. [PMID: 23005785 DOI: 10.1103/physreve.86.021907] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Indexed: 06/01/2023]
Abstract
The cytoplasm of bacterial cells is filled with individual molecules and molecular complexes that rely on diffusion to bring them together for interaction. The mobility of molecules in the cytoplasm has been characterized by several techniques mainly using fluorescent probes and ensemble methods. In order to probe the microenvrionment inside the cytoplasm as viewed by an individual molecule, we have studied single green fluorescent proteins (GFPs) diffusing in the cytoplasm of Escherichia coli cells at observation at rates ranging from 60 to 1000 Hz. Over long times the diffusion shows confinement due to the geometry of the cells themselves. A simulation in model cells using the actual distribution of cell sizes found in the experiments describes accurately the experimental results as well as reveals a short time diffusion coefficient that agrees well with that determined by ensemble methods. Higher short time diffusion coefficients can be obtained by filling the simulated cell with small spheres modeling cytoplasmic molecules and, depending on the density of particles included in the modeled cytoplasm, can approach the diffusion coefficient of GFPs found in water. Thus, single-molecule tracking combined with analysis using simple simulation of Brownian motion is able to reveal the main contributors to the GFP mobility in the cytoplasm of E. coli.
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Affiliation(s)
- Yoriko Lill
- Department of Physics, Purdue University, West Lafayette, Indiana 47907, USA
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Dreaden EC, Alkilany AM, Huang X, Murphy CJ, El-Sayed MA. The golden age: gold nanoparticles for biomedicine. Chem Soc Rev 2012; 41:2740-79. [PMID: 22109657 PMCID: PMC5876014 DOI: 10.1039/c1cs15237h] [Citation(s) in RCA: 1991] [Impact Index Per Article: 165.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Gold nanoparticles have been used in biomedical applications since their first colloidal syntheses more than three centuries ago. However, over the past two decades, their beautiful colors and unique electronic properties have also attracted tremendous attention due to their historical applications in art and ancient medicine and current applications in enhanced optoelectronics and photovoltaics. In spite of their modest alchemical beginnings, gold nanoparticles exhibit physical properties that are truly different from both small molecules and bulk materials, as well as from other nanoscale particles. Their unique combination of properties is just beginning to be fully realized in range of medical diagnostic and therapeutic applications. This critical review will provide insights into the design, synthesis, functionalization, and applications of these artificial molecules in biomedicine and discuss their tailored interactions with biological systems to achieve improved patient health. Further, we provide a survey of the rapidly expanding body of literature on this topic and argue that gold nanotechnology-enabled biomedicine is not simply an act of 'gilding the (nanomedicinal) lily', but that a new 'Golden Age' of biomedical nanotechnology is truly upon us. Moving forward, the most challenging nanoscience ahead of us will be to find new chemical and physical methods of functionalizing gold nanoparticles with compounds that can promote efficient binding, clearance, and biocompatibility and to assess their safety to other biological systems and their long-term term effects on human health and reproduction (472 references).
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Affiliation(s)
- Erik C. Dreaden
- Laser Dynamics Laboratory, Department of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332-0400, USA
| | - Alaaldin M. Alkilany
- Department of Pharmacology and Toxicology, Georgia Health Sciences University, 1459 Laney Walker Blvd., Augusta, GA 30912, USA
| | - Xiaohua Huang
- Department of Chemistry, University of Memphis, 213 Smith Chemistry Bldg, Memphis, TN 38152-3550, USA
| | - Catherine J. Murphy
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL 61801, USA. E-mail: ; Fax: +1 217 244 3186; Tel: +1 217 333 7680
| | - Mostafa A. El-Sayed
- Laser Dynamics Laboratory, Department of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332-0400, USA
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Ayling LJ, Briddon SJ, Halls ML, Hammond GRV, Vaca L, Pacheco J, Hill SJ, Cooper DMF. Adenylyl cyclase AC8 directly controls its micro-environment by recruiting the actin cytoskeleton in a cholesterol-rich milieu. J Cell Sci 2012; 125:869-86. [PMID: 22399809 DOI: 10.1242/jcs.091090] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The central and pervasive influence of cAMP on cellular functions underscores the value of stringent control of the organization of adenylyl cyclases (ACs) in the plasma membrane. Biochemical data suggest that ACs reside in membrane rafts and could compartmentalize intermediary scaffolding proteins and associated regulatory elements. However, little is known about the organization or regulation of the dynamic behaviour of ACs in a cellular context. The present study examines these issues, using confocal image analysis of various AC8 constructs, combined with fluorescence recovery after photobleaching and fluorescence correlation spectroscopy. These studies reveal that AC8, through its N-terminus, enhances the cortical actin signal at the plasma membrane; an interaction that was confirmed by GST pull-down and immunoprecipitation experiments. AC8 also associates dynamically with lipid rafts; the direct association of AC8 with sterols was confirmed in Förster resonance energy transfer experiments. Disruption of the actin cytoskeleton and lipid rafts indicates that AC8 tracks along the cytoskeleton in a cholesterol-enriched domain, and the cAMP that it produces contributes to sculpting the actin cytoskeleton. Thus, an adenylyl cyclase is shown not just to act as a scaffold, but also to actively orchestrate its own micro-environment, by associating with the cytoskeleton and controlling the association by producing cAMP, to yield a highly organized signalling hub.
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Affiliation(s)
- Laura J Ayling
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, UK
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Ziółkowska NE, Christiano R, Walther TC. Organized living: formation mechanisms and functions of plasma membrane domains in yeast. Trends Cell Biol 2012; 22:151-8. [DOI: 10.1016/j.tcb.2011.12.002] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Revised: 12/09/2011] [Accepted: 12/12/2011] [Indexed: 11/25/2022]
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