1
|
Matsuura H, Akahane S, Kaido T, Kamijo T, Sakamoto K, Yamauchi K. Apolipoprotein E isoforms and their Cys-thiol modifications impact LRP1-mediated metabolism of triglyceride-rich lipoproteins. FEBS Lett 2024; 598:347-362. [PMID: 38279679 DOI: 10.1002/1873-3468.14803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 11/14/2023] [Accepted: 12/15/2023] [Indexed: 01/28/2024]
Abstract
The low-density lipoprotein (LDL) receptor-related protein (LRP)1 participates in the metabolism of apolipoprotein (apo) E-containing lipoproteins (apoE-LP). We investigated the effects of modifications of cysteine (Cys)-thiol of apoE on LRP1-mediated metabolism. Among the three isoforms, apoE2-LP exhibited the lowest affinity for LRP1 but was significantly catabolized, whereas apoE4-LP was sufficiently bound to LRP1 but showed the lowest catabolic capability. The reduction enhanced the binding and suppressed the catabolism of apoE3-LP, but had no effect on apoE2-LP. The formation of disulfide-linked complexes with apoAII suppressed binding, but enhanced the catabolism of apoE2-LP. Redox modifications of apoE-Cys-thiol may modulate the LRP1-mediated metabolism of apoE2- or apoE3-LP, but not apoE4-LP. The failure of this function may be involved in the pathophysiology of dyslipidemia.
Collapse
Affiliation(s)
- Hiroto Matsuura
- Department of Clinical Laboratory Investigation, Graduate School of Medicine, Shinshu University, Matsumoto, Japan
| | - Shogo Akahane
- Department of Clinical Laboratory Investigation, Graduate School of Medicine, Shinshu University, Matsumoto, Japan
| | - Takahiro Kaido
- Department of Clinical Laboratory Investigation, Graduate School of Medicine, Shinshu University, Matsumoto, Japan
- Department of Laboratory Medicine, Shinshu University Hospital, Matsumoto, Japan
| | - Tomu Kamijo
- Department of Clinical Laboratory Investigation, Graduate School of Medicine, Shinshu University, Matsumoto, Japan
- Department of Laboratory Medicine, Shinshu University Hospital, Matsumoto, Japan
| | - Kenta Sakamoto
- Department of Laboratory Medicine, University of Yamanashi Hospital, Japan
| | - Kazuyoshi Yamauchi
- Department of Clinical Laboratory Investigation, Graduate School of Medicine, Shinshu University, Matsumoto, Japan
- Department of Biomedical Laboratory Sciences, School of Health Sciences, Shinshu University, Matsumoto, Japan
| |
Collapse
|
2
|
Lira RB, Hammond JCF, Cavalcanti RRM, Rous M, Riske KA, Roos WH. The underlying mechanical properties of membranes tune their ability to fuse. J Biol Chem 2023; 299:105430. [PMID: 37926280 PMCID: PMC10716014 DOI: 10.1016/j.jbc.2023.105430] [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: 08/10/2023] [Revised: 10/16/2023] [Accepted: 10/23/2023] [Indexed: 11/07/2023] Open
Abstract
Membrane fusion is a ubiquitous process associated with a multitude of biological events. Although it has long been appreciated that membrane mechanics plays an important role in membrane fusion, the molecular interplay between mechanics and fusion has remained elusive. For example, although different lipids modulate membrane mechanics differently, depending on their composition, molar ratio, and complex interactions, differing lipid compositions may lead to similar mechanical properties. This raises the question of whether (i) the specific lipid composition or (ii) the average mesoscale mechanics of membranes acts as the determining factor for cellular function. Furthermore, little is known about the potential consequences of fusion on membrane disruption. Here, we use a combination of confocal microscopy, time-resolved imaging, and electroporation to shed light onto the underlying mechanical properties of membranes that regulate membrane fusion. Fusion efficiency follows a nearly universal behavior that depends on membrane fluidity parameters, such as membrane viscosity and bending rigidity, rather than on specific lipid composition. This helps explaining why the charged and fluid membranes of the inner leaflet of the plasma membrane are more fusogenic than their outer counterparts. Importantly, we show that physiological levels of cholesterol, a key component of biological membranes, has a mild effect on fusion but significantly enhances membrane mechanical stability against pore formation, suggesting that its high cellular levels buffer the membrane against disruption. The ability of membranes to efficiently fuse while preserving their integrity may have given evolutionary advantages to cells by enabling their function while preserving membrane stability.
Collapse
Affiliation(s)
- Rafael B Lira
- Moleculaire Biofysica, Zernike Instituut, Rijksuniversiteit Groningen, Groningen, Netherlands.
| | - Jayna C F Hammond
- Moleculaire Biofysica, Zernike Instituut, Rijksuniversiteit Groningen, Groningen, Netherlands
| | | | - Madelief Rous
- Moleculaire Biofysica, Zernike Instituut, Rijksuniversiteit Groningen, Groningen, Netherlands
| | - Karin A Riske
- Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Wouter H Roos
- Moleculaire Biofysica, Zernike Instituut, Rijksuniversiteit Groningen, Groningen, Netherlands.
| |
Collapse
|
3
|
Mandal T, Gupta S, Soni J. Simulation study of membrane bending by protein crowding: a case study with the epsin N-terminal homology domain. SOFT MATTER 2023. [PMID: 37376999 DOI: 10.1039/d3sm00280b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/29/2023]
Abstract
The mechanisms by which peripheral membrane proteins generate curvature is currently an active area of research. One of the proposed mechanisms is amphipathic insertion or the 'wedge' mechanism in which the protein shallowly inserts an amphipathic helix inside the membrane to drive the curvature. However, recent experimental studies have challenged the efficiency of the 'wedge' mechanism as it requires unusual protein densities. These studies proposed an alternative mechanism, namely 'protein-crowding', in which the lateral pressure generated by the random collisions among the membrane bound proteins drives the bending. In this study, we employ atomistic and coarse-grained molecular dynamics simulations to investigate the effects of amphipathic insertion and protein crowding on the membrane surface. Considering epsin N-terminal homology (ENTH) domain as a model protein, we show that amphipathic insertion is not essential for membrane bending. Our results suggest that ENTH domains can aggregate on the membrane surface by employing another structured region (H3 helix). And this protein crowding decreases the cohesive energy of the lipid tails which causes a significant decrease in the membrane bending rigidity. The ENTH domain can generate a similar degree of membrane curvature irrespective of the activity of its H0 helix. Our results are consistent with the recent experimental results.
Collapse
Affiliation(s)
- Taraknath Mandal
- Department of Physics, Indian Institute of Technology Kanpur, Kanpur-208016, India.
| | - Shivam Gupta
- Department of Physics, Indian Institute of Technology Kanpur, Kanpur-208016, India.
| | - Jatin Soni
- Department of Physics, Indian Institute of Technology Kanpur, Kanpur-208016, India.
| |
Collapse
|
4
|
Canepa E, Bochicchio D, Brosio G, Silva PHJ, Stellacci F, Dante S, Rossi G, Relini A. Cholesterol-Containing Liposomes Decorated With Au Nanoparticles as Minimal Tunable Fusion Machinery. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2207125. [PMID: 36899445 DOI: 10.1002/smll.202207125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 01/30/2023] [Indexed: 06/08/2023]
Abstract
Membrane fusion is essential for the basal functionality of eukaryotic cells. In physiological conditions, fusion events are regulated by a wide range of specialized proteins, operating with finely tuned local lipid composition and ionic environment. Fusogenic proteins, assisted by membrane cholesterol and calcium ions, provide the mechanical energy necessary to achieve vesicle fusion in neuromediator release. Similar cooperative effects must be explored when considering synthetic approaches for controlled membrane fusion. We show that liposomes decorated with amphiphilic Au nanoparticles (AuLips) can act as minimal tunable fusion machinery. AuLips fusion is triggered by divalent ions, while the number of fusion events dramatically changes with, and can be finely tuned by, the liposome cholesterol content. We combine quartz-crystal-microbalance with dissipation monitoring (QCM-D), fluorescence assays, and small-angle X-ray scattering (SAXS) with molecular dynamics (MD) at coarse-grained (CG) resolution, revealing new mechanistic details on the fusogenic activity of amphiphilic Au nanoparticles (AuNPs) and demonstrating the ability of these synthetic nanomaterials to induce fusion regardless of the divalent ion used (Ca2+ or Mg2+ ). The results provide a novel contribution to developing new artificial fusogenic agents for next-generation biomedical applications that require tight control of the rate of fusion events (e.g., targeted drug delivery).
Collapse
Affiliation(s)
- Ester Canepa
- Department of Physics, University of Genoa, Genoa, 16146, Italy
- Institute of Materials Science & Engineering, EPFL, Lausanne, 1015, Switzerland
| | | | - Giorgia Brosio
- Department of Physics, University of Genoa, Genoa, 16146, Italy
| | | | - Francesco Stellacci
- Materials Characterization Facility, Istituto Italiano di Tecnologia, Genoa, 16163, Italy
| | - Silvia Dante
- Institute of Materials Science & Engineering, EPFL, Lausanne, 1015, Switzerland
| | - Giulia Rossi
- Department of Physics, University of Genoa, Genoa, 16146, Italy
| | - Annalisa Relini
- Department of Physics, University of Genoa, Genoa, 16146, Italy
| |
Collapse
|
5
|
Milogrodzka I, Nguyen Pham DT, Sama GR, Samadian H, Zhai J, de Campo L, Kirby NM, Scott TF, Banaszak Holl MM, van 't Hag L. Effect of Cholesterol on Biomimetic Membrane Curvature and Coronavirus Fusion Peptide Encapsulation. ACS NANO 2023; 17:8598-8612. [PMID: 37078604 DOI: 10.1021/acsnano.3c01095] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Biomimetic cubic phases can be used for protein encapsulation in a variety of applications such as biosensors and drug delivery. Cubic phases with a high concentration of cholesterol and phospholipids were obtained herein. It is shown that the cubic phase structure can be maintained with a higher concentration of biomimetic membrane additives than has been reported previously. Opposing effects on the curvature of the membrane were observed upon the addition of phospholipids and cholesterol. Furthermore, the coronavirus fusion peptide significantly increased the negative curvature of the biomimetic membrane with cholesterol. We show that the viral fusion peptide can undergo structural changes leading to the formation of hydrophobic α-helices that insert into the lipid bilayer. This is of high importance, as a fusion peptide that induces increased negative curvature as shown by the formation of inverse hexagonal phases allows for greater contact area between two membranes, which is required for viral fusion to occur. The cytotoxicity assay showed that the toxicity toward HeLa cells was dramatically decreased when the cholesterol or peptide level in the nanoparticles increased. This suggests that the addition of cholesterol can improve the biocompatibility of the cubic phase nanoparticles, making them safer for use in biomedical applications. As the results, this work improves the potential for the biomedical end-use applications of the nonlamellar lipid nanoparticles and shows the need of systematic formulation studies due to the complex interplay of all components.
Collapse
Affiliation(s)
- Izabela Milogrodzka
- Department of Chemical and Biological Engineering, Monash University, Clayton, VIC 3800, Australia
| | - Duy Tue Nguyen Pham
- Department of Chemical and Biological Engineering, Monash University, Clayton, VIC 3800, Australia
| | - Gopal R Sama
- Department of Chemical and Biological Engineering, Monash University, Clayton, VIC 3800, Australia
| | - Hajar Samadian
- Department of Chemical and Biological Engineering, Monash University, Clayton, VIC 3800, Australia
| | - Jiali Zhai
- School of Science, STEM College, RMIT University, Melbourne, VIC 3000, Australia
| | - Liliana de Campo
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Kirrawee, NSW 2234, Australia
| | - Nigel M Kirby
- Australian Synchrotron, 800 Blackburn Road, Clayton, VIC 3168, Australia
| | - Timothy F Scott
- Department of Chemical and Biological Engineering, Monash University, Clayton, VIC 3800, Australia
- Department of Materials Science and Engineering, Monash University, Clayton, VIC 3800, Australia
| | - Mark M Banaszak Holl
- Department of Chemical and Biological Engineering, Monash University, Clayton, VIC 3800, Australia
- Department of Mechanical and Materials Engineering, University of Alabama at Birmingham, Birmingham, Alabama 35294, United States
| | - Leonie van 't Hag
- Department of Chemical and Biological Engineering, Monash University, Clayton, VIC 3800, Australia
| |
Collapse
|
6
|
Juvekar V, Lee HW, Lee DJ, Kim HM. Two-photon fluorescent probes for quantitative bio-imaging analysis in live tissues. Trends Analyt Chem 2022. [DOI: 10.1016/j.trac.2022.116787] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
7
|
Kalutsky MA, Galimzyanov TR, Molotkovsky RJ. A Model of Lipid Monolayer-Bilayer Fusion of Lipid Droplets and Peroxisomes. MEMBRANES 2022; 12:membranes12100992. [PMID: 36295751 PMCID: PMC9612070 DOI: 10.3390/membranes12100992] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 10/06/2022] [Accepted: 10/10/2022] [Indexed: 06/01/2023]
Abstract
Lipid droplets are unique organelles that store neutral lipids encapsulated by the lipid monolayer. In some processes of cellular metabolism, lipid droplets interact with peroxisomes resulting in the fusion of their envelopes and the formation of protrusions of the peroxisome monolayer, called pexopodia. The formation of pexopodia is facilitated by free fatty acids generated during lipolysis within lipid droplets. In this work, we studied the fusion of monolayer and bilayer membranes during the interaction between lipid droplets and peroxisomes. To this end, we built the energy trajectory of this process using the continuum elasticity theory and investigated the molecular details of the fusion structures utilizing molecular dynamics. We divided the fusion process into two stages: formation of a stalk and its consequent expansion into pexopodia. We found that in the considered system, the stalk was energetically more stable and had a lower energy barrier of formation compared to the case of bilayer fusion. The further evolution of the stalk depended on the value of the spontaneous curvature of the membrane in a threshold manner. We attributed the possible expansion of the stalk to the incorporation of free fatty acids into the stalk region. The developed model allowed describing quantitatively the process of monolayer-bilayer fusion.
Collapse
Affiliation(s)
- Maksim A. Kalutsky
- A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/5 Leninskiy Prospekt, 119071 Moscow, Russia
- Department of Theoretical Physics and Quantum Technologies, National University of Science and Technology “MISiS”, 4 Leninskiy Prospekt, 119049 Moscow, Russia
| | - Timur R. Galimzyanov
- A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/5 Leninskiy Prospekt, 119071 Moscow, Russia
| | - Rodion J. Molotkovsky
- A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/5 Leninskiy Prospekt, 119071 Moscow, Russia
| |
Collapse
|
8
|
Fifty Years of the Fluid–Mosaic Model of Biomembrane Structure and Organization and Its Importance in Biomedicine with Particular Emphasis on Membrane Lipid Replacement. Biomedicines 2022; 10:biomedicines10071711. [PMID: 35885016 PMCID: PMC9313417 DOI: 10.3390/biomedicines10071711] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 07/06/2022] [Accepted: 07/10/2022] [Indexed: 12/29/2022] Open
Abstract
The Fluid–Mosaic Model has been the accepted general or basic model for biomembrane structure and organization for the last 50 years. In order to establish a basic model for biomembranes, some general principles had to be established, such as thermodynamic assumptions, various molecular interactions, component dynamics, macromolecular organization and other features. Previous researchers placed most membrane proteins on the exterior and interior surfaces of lipid bilayers to form trimolecular structures or as lipoprotein units arranged as modular sheets. Such membrane models were structurally and thermodynamically unsound and did not allow independent lipid and protein lateral movements. The Fluid–Mosaic Membrane Model was the only model that accounted for these and other characteristics, such as membrane asymmetry, variable lateral movements of membrane components, cis- and transmembrane linkages and dynamic associations of membrane components into multimolecular complexes. The original version of the Fluid–Mosaic Membrane Model was never proposed as the ultimate molecular description of all biomembranes, but it did provide a basic framework for nanometer-scale biomembrane organization and dynamics. Because this model was based on available 1960s-era data, it could not explain all of the properties of various biomembranes discovered in subsequent years. However, the fundamental organizational and dynamic aspects of this model remain relevant to this day. After the first generation of this model was published, additional data on various structures associated with membranes were included, resulting in the addition of membrane-associated cytoskeletal, extracellular matrix and other structures, specialized lipid–lipid and lipid–protein domains, and other configurations that can affect membrane dynamics. The presence of such specialized membrane domains has significantly reduced the extent of the fluid lipid membrane matrix as first proposed, and biomembranes are now considered to be less fluid and more mosaic with some fluid areas, rather than a fluid matrix with predominantly mobile components. However, the fluid–lipid matrix regions remain very important in biomembranes, especially those involved in the binding and release of membrane lipid vesicles and the uptake of various nutrients. Membrane phospholipids can associate spontaneously to form lipid structures and vesicles that can fuse with various cellular membranes to transport lipids and other nutrients into cells and organelles and expel damaged lipids and toxic hydrophobic molecules from cells and tissues. This process and the clinical use of membrane phospholipid supplements has important implications for chronic illnesses and the support of healthy mitochondria, plasma membranes and other cellular membrane structures.
Collapse
|
9
|
Wu Z, Xiao M, Lai W, Sun Y, Li L, Hu Z, Pei H. Nucleic Acid-Based Cell Surface Engineering Strategies and Their Applications. ACS APPLIED BIO MATERIALS 2022; 5:1901-1915. [DOI: 10.1021/acsabm.1c01126] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Zhongdong Wu
- Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Mingshu Xiao
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
| | - Wei Lai
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
| | - Yueyang Sun
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
| | - Li Li
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
| | - Zongqian Hu
- Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Hao Pei
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
| |
Collapse
|
10
|
Zhang KS, Nadkarni AV, Paul R, Martin AM, Tang SKY. Microfluidic Surgery in Single Cells and Multicellular Systems. Chem Rev 2022; 122:7097-7141. [PMID: 35049287 DOI: 10.1021/acs.chemrev.1c00616] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Microscale surgery on single cells and small organisms has enabled major advances in fundamental biology and in engineering biological systems. Examples of applications range from wound healing and regeneration studies to the generation of hybridoma to produce monoclonal antibodies. Even today, these surgical operations are often performed manually, but they are labor intensive and lack reproducibility. Microfluidics has emerged as a powerful technology to control and manipulate cells and multicellular systems at the micro- and nanoscale with high precision. Here, we review the physical and chemical mechanisms of microscale surgery and the corresponding design principles, applications, and implementations in microfluidic systems. We consider four types of surgical operations: (1) sectioning, which splits a biological entity into multiple parts, (2) ablation, which destroys part of an entity, (3) biopsy, which extracts materials from within a living cell, and (4) fusion, which joins multiple entities into one. For each type of surgery, we summarize the motivating applications and the microfluidic devices developed. Throughout this review, we highlight existing challenges and opportunities. We hope that this review will inspire scientists and engineers to continue to explore and improve microfluidic surgical methods.
Collapse
Affiliation(s)
- Kevin S Zhang
- Department of Mechanical Engineering, Stanford University, Stanford, California 94305, United States
| | - Ambika V Nadkarni
- Department of Mechanical Engineering, Stanford University, Stanford, California 94305, United States.,Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California 94158, United States
| | - Rajorshi Paul
- Department of Mechanical Engineering, Stanford University, Stanford, California 94305, United States
| | - Adrian M Martin
- Department of Mechanical Engineering, Stanford University, Stanford, California 94305, United States
| | - Sindy K Y Tang
- Department of Mechanical Engineering, Stanford University, Stanford, California 94305, United States
| |
Collapse
|
11
|
Batishchev OV. Physico-Chemical Mechanisms of the Functioning of Membrane-Active Proteins of Enveloped Viruses. BIOCHEMISTRY (MOSCOW) SUPPLEMENT. SERIES A, MEMBRANE AND CELL BIOLOGY 2022; 16:247-260. [PMCID: PMC9734521 DOI: 10.1134/s1990747822050038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 06/01/2022] [Accepted: 06/02/2022] [Indexed: 12/14/2022]
Abstract
Over the past few years, the attention of the whole world has been riveted to the emergence of new dangerous strains of viruses, among which a special place is occupied by coronaviruses that have overcome the interspecies barrier in the past 20 years: SARS viruses (SARS), Middle East respiratory syndrome (MERS), as well as a new coronavirus infection (SARS-CoV-2), which caused the largest pandemic since the Spanish flu in 1918. Coronaviruses are members of a class of enveloped viruses that have a lipoprotein envelope. This class also includes such serious pathogens as human immunodeficiency virus (HIV), hepatitis, Ebola virus, influenza, etc. Despite significant differences in the clinical picture of the course of disease caused by enveloped viruses, they themselves have a number of characteristic features, which determine their commonality. Regardless of the way of penetration into the cell—by endocytosis or direct fusion with the cell membrane—enveloped viruses are characterized by the following stages of interaction with the target cell: binding to receptors on the cell surface, interaction of the surface glycoproteins of the virus with the membrane structures of the infected cell, fusion of the lipid envelope of the virion with plasma or endosomal membrane, destruction of the protein capsid and its dissociation from the viral nucleoprotein. Subsequently, within the infected cell, the newly synthesized viral proteins must self-assemble on various membrane structures to form a progeny virion. Thus, both the initial stages of viral infection and the assembly and release of new viral particles are associated with the activity of viral proteins in relation to the cell membrane and its organelles. This review is devoted to the analysis of physicochemical mechanisms of functioning of the main structural proteins of a number of enveloped viruses in order to identify possible strategies for the membrane activity of such proteins at various stages of viral infection of the cell.
Collapse
Affiliation(s)
- O. V. Batishchev
- Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 119071 Moscow, Russia
| |
Collapse
|
12
|
Nicolson GL, Ferreira de Mattos G. A Brief Introduction to Some Aspects of the Fluid-Mosaic Model of Cell Membrane Structure and Its Importance in Membrane Lipid Replacement. MEMBRANES 2021; 11:947. [PMID: 34940448 PMCID: PMC8708848 DOI: 10.3390/membranes11120947] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 11/18/2021] [Accepted: 11/22/2021] [Indexed: 12/15/2022]
Abstract
Early cell membrane models placed most proteins external to lipid bilayers in trimolecular structures or as modular lipoprotein units. These thermodynamically untenable structures did not allow lipid lateral movements independent of membrane proteins. The Fluid-Mosaic Membrane Model accounted for these and other properties, such as membrane asymmetry, variable lateral mobilities of membrane components and their associations with dynamic complexes. Integral membrane proteins can transform into globular structures that are intercalated to various degrees into a heterogeneous lipid bilayer matrix. This simplified version of cell membrane structure was never proposed as the ultimate biomembrane description, but it provided a basic nanometer scale framework for membrane organization. Subsequently, the structures associated with membranes were considered, including peripheral membrane proteins, and cytoskeletal and extracellular matrix components that restricted lateral mobility. In addition, lipid-lipid and lipid-protein membrane domains, essential for cellular signaling, were proposed and eventually discovered. The presence of specialized membrane domains significantly reduced the extent of the fluid lipid matrix, so membranes have become more mosaic with some fluid areas over time. However, the fluid regions of membranes are very important in lipid transport and exchange. Various lipid globules, droplets, vesicles and other membranes can fuse to incorporate new lipids or expel damaged lipids from membranes, or they can be internalized in endosomes that eventually fuse with other internal vesicles and membranes. They can also be externalized in a reverse process and released as extracellular vesicles and exosomes. In this Special Issue, the use of membrane phospholipids to modify cellular membranes in order to modulate clinically relevant host properties is considered.
Collapse
Affiliation(s)
- Garth L. Nicolson
- Department of Molecular Pathology, The Institute for Molecular Medicine, Huntington Beach, CA 92647, USA
| | - Gonzalo Ferreira de Mattos
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Department of Biophysics, Facultad de Medicina, Universidad de la República, Montevideo 11600, Uruguay;
| |
Collapse
|
13
|
Lozada C, Barlow TMA, Gonzalez S, Lubin-Germain N, Ballet S. Identification and Characteristics of Fusion Peptides Derived From Enveloped Viruses. Front Chem 2021; 9:689006. [PMID: 34497798 PMCID: PMC8419435 DOI: 10.3389/fchem.2021.689006] [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: 03/31/2021] [Accepted: 08/10/2021] [Indexed: 01/28/2023] Open
Abstract
Membrane fusion events allow enveloped viruses to enter and infect cells. The study of these processes has led to the identification of a number of proteins that mediate this process. These proteins are classified according to their structure, which vary according to the viral genealogy. To date, three classes of fusion proteins have been defined, but current evidence points to the existence of additional classes. Despite their structural differences, viral fusion processes follow a common mechanism through which they exert their actions. Additional studies of the viral fusion proteins have demonstrated the key role of specific proteinogenic subsequences within these proteins, termed fusion peptides. Such peptides are able to interact and insert into membranes for which they hold interest from a pharmacological or therapeutic viewpoint. Here, the different characteristics of fusion peptides derived from viral fusion proteins are described. These criteria are useful to identify new fusion peptides. Moreover, this review describes the requirements of synthetic fusion peptides derived from fusion proteins to induce fusion by themselves. Several sequences of the viral glycoproteins E1 and E2 of HCV were, for example, identified to be able to induce fusion, which are reviewed here.
Collapse
Affiliation(s)
- Camille Lozada
- BioCIS, CNRS, CY Cergy-Paris Université, Cergy-Pontoise, France
- Research Group of Organic Chemistry, Vrije Universiteit Brussel, Brussels, Belgium
| | - Thomas M. A. Barlow
- Research Group of Organic Chemistry, Vrije Universiteit Brussel, Brussels, Belgium
| | - Simon Gonzalez
- BioCIS, CNRS, CY Cergy-Paris Université, Cergy-Pontoise, France
| | | | - Steven Ballet
- Research Group of Organic Chemistry, Vrije Universiteit Brussel, Brussels, Belgium
| |
Collapse
|
14
|
Abstract
During multicellular organism development, complex structures are sculpted to form organs and tissues, which are maintained throughout adulthood. Many of these processes require cells to fuse with one another, or with themselves. These plasma membrane fusions merge endoplasmic cellular content across external, exoplasmic, space. In the nematode Caenorhabditis elegans, such cell fusions serve as a unique sculpting force, involved in the embryonic morphogenesis of the skin-like multinuclear hypodermal cells, but also in refining delicate structures, such as valve openings and the tip of the tail. During post-embryonic development, plasma membrane fusions continue to shape complex neuron structures and organs such as the vulva, while during adulthood fusion participates in cell and tissue repair. These processes rely on two fusion proteins (fusogens): EFF-1 and AFF-1, which are part of a broader family of structurally related membrane fusion proteins, encompassing sexual reproduction, viral infection, and tissue remodeling. The established capabilities of these exoplasmic fusogens are further expanded by new findings involving EFF-1 and AFF-1 in endocytic vesicle fission and phagosome sealing. Tight regulation by cell-autonomous and non-cell autonomous mechanisms orchestrates these diverse cell fusions at the correct place and time-these processes and their significance are discussed in this review.
Collapse
|
15
|
Zhou J, Wu Z, Hu J, Yang D, Chen X, Wang Q, Liu J, Dou M, Peng W, Wu Y, Wang W, Xie C, Wang M, Song Y, Zeng H, Bai C. High-throughput single-EV liquid biopsy: Rapid, simultaneous, and multiplexed detection of nucleic acids, proteins, and their combinations. SCIENCE ADVANCES 2020; 6:6/47/eabc1204. [PMID: 33219024 PMCID: PMC7679165 DOI: 10.1126/sciadv.abc1204] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 09/30/2020] [Indexed: 05/03/2023]
Abstract
MicroRNAs (miRNAs), mRNA, and proteins in/on extracellular vesicles (EVs) represent potential cancer biomarkers. Concurrent detection of multiple biomarkers at a single-EV level would greatly improve prognosis and/or diagnosis and understanding of EV phenotypes, biogenesis, and functions. Here, we introduced a High-throughput Nano-bio Chip Integrated System for Liquid Biopsy (HNCIB) system for simultaneous detection of proteins and mRNA/miRNA in a single EV. Validated through systematic control experiments, HNCIB showed high reliability, sensitivity, and specificity. In a panel of 34 patients with lung adenocarcinoma (LUAD) and 35 healthy donors, HNCIB detected an up-regulated expression of programmed death-ligand 1 mRNA and protein and miR-21 in EVs derived from patients with LUAD compared to those from healthy donors. HNCIB has low sample requirement (~90 μl), fast assay time (~6 hours), and high throughput (up to 384 samples per assay) and would have great potential in the study of EVs and their clinical applications.
Collapse
Affiliation(s)
- Jian Zhou
- Department of Pulmonary Medicine, Shanghai Respiratory Research Institute, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Zuoren Wu
- Hangzhou Dixiang Co. Ltd., Hangzhou, China
| | - Jie Hu
- Department of Pulmonary Medicine, Shanghai Respiratory Research Institute, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Dawei Yang
- Department of Pulmonary Medicine, Shanghai Respiratory Research Institute, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Xiaoyan Chen
- Department of Pulmonary Medicine, Shanghai Respiratory Research Institute, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Qin Wang
- Department of Pulmonary Medicine, Shanghai Respiratory Research Institute, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Jie Liu
- Department of Pulmonary Medicine, Shanghai Respiratory Research Institute, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Maosen Dou
- Department of Pulmonary Medicine, Shanghai Respiratory Research Institute, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Wenjun Peng
- Department of Pulmonary Medicine, Shanghai Respiratory Research Institute, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yuanyuan Wu
- Department of Pulmonary Medicine, Shanghai Respiratory Research Institute, Zhongshan Hospital, Fudan University, Shanghai, China
| | | | | | - Ming Wang
- Hangzhou Dixiang Co. Ltd., Hangzhou, China
| | - Yuanlin Song
- Department of Pulmonary Medicine, Shanghai Respiratory Research Institute, Zhongshan Hospital, Fudan University, Shanghai, China
| | | | - Chunxue Bai
- Department of Pulmonary Medicine, Shanghai Respiratory Research Institute, Zhongshan Hospital, Fudan University, Shanghai, China.
| |
Collapse
|
16
|
Akimov SA, Kondrashov OV, Zimmerberg J, Batishchev OV. Ectodomain Pulling Combines with Fusion Peptide Inserting to Provide Cooperative Fusion for Influenza Virus and HIV. Int J Mol Sci 2020; 21:ijms21155411. [PMID: 32751407 PMCID: PMC7432320 DOI: 10.3390/ijms21155411] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 07/24/2020] [Accepted: 07/28/2020] [Indexed: 12/18/2022] Open
Abstract
Enveloped viruses include the most dangerous human and animal pathogens, in particular coronavirus, influenza virus, and human immunodeficiency virus (HIV). For these viruses, receptor binding and entry are accomplished by a single viral envelope protein (termed the fusion protein), the structural changes of which trigger the remodeling and merger of the viral and target cellular membranes. The number of fusion proteins required for fusion activity is still under debate, and several studies report this value to range from 1 to 9 for type I fusion proteins. Here, we consider the earliest stage of viral fusion based on the continuum theory of membrane elasticity. We demonstrate that membrane deformations induced by the oblique insertion of amphipathic fusion peptides mediate the lateral interaction of these peptides and drive them to form into a symmetric fusion rosette. The pulling force produced by the structural rearrangements of the fusion protein ectodomains gives additional torque, which deforms the membrane and additionally stabilizes the symmetric fusion rosette, thus allowing a reduction in the number of fusion peptides needed for fusion. These findings can resolve the large range of published cooperativity indices for HIV, influenza, and other type I fusion proteins.
Collapse
Affiliation(s)
- Sergey A. Akimov
- Laboratory of Bioelectrochemistry, A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/4 Leninskiy Prospekt, 119071 Moscow, Russia; (O.V.K.); (O.V.B.)
- Correspondence: ; Tel.: +7-495-955-4776
| | - Oleg V. Kondrashov
- Laboratory of Bioelectrochemistry, A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/4 Leninskiy Prospekt, 119071 Moscow, Russia; (O.V.K.); (O.V.B.)
| | - Joshua Zimmerberg
- Section on Integrative Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA;
| | - Oleg V. Batishchev
- Laboratory of Bioelectrochemistry, A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/4 Leninskiy Prospekt, 119071 Moscow, Russia; (O.V.K.); (O.V.B.)
| |
Collapse
|
17
|
Akimov SA, Molotkovsky RJ, Kuzmin PI, Galimzyanov TR, Batishchev OV. Continuum Models of Membrane Fusion: Evolution of the Theory. Int J Mol Sci 2020; 21:E3875. [PMID: 32485905 PMCID: PMC7312925 DOI: 10.3390/ijms21113875] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/24/2020] [Accepted: 05/27/2020] [Indexed: 12/18/2022] Open
Abstract
Starting from fertilization, through tissue growth, hormone secretion, synaptic transmission, and sometimes morbid events of carcinogenesis and viral infections, membrane fusion regulates the whole life of high organisms. Despite that, a lot of fusion processes still lack well-established models and even a list of main actors. A merger of membranes requires their topological rearrangements controlled by elastic properties of a lipid bilayer. That is why continuum models based on theories of membrane elasticity are actively applied for the construction of physical models of membrane fusion. Started from the view on the membrane as a structureless film with postulated geometry of fusion intermediates, they developed along with experimental and computational techniques to a powerful tool for prediction of the whole process with molecular accuracy. In the present review, focusing on fusion processes occurring in eukaryotic cells, we scrutinize the history of these models, their evolution and complication, as well as open questions and remaining theoretical problems. We show that modern approaches in this field allow continuum models of membrane fusion to stand shoulder to shoulder with molecular dynamics simulations, and provide the deepest understanding of this process in multiple biological systems.
Collapse
Affiliation(s)
- Sergey A. Akimov
- Laboratory of Bioelectrochemistry, A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/4 Leninskiy Prospekt, 119071 Moscow, Russia; (R.J.M.); (P.I.K.); (T.R.G.); (O.V.B.)
| | | | | | | | | |
Collapse
|
18
|
Huang Y, Yu L, Ren J, Gu B, Longstaff C, Hughes AD, Thom SA, Xu XY, Chen R. An activated-platelet-sensitive nanocarrier enables targeted delivery of tissue plasminogen activator for effective thrombolytic therapy. J Control Release 2019; 300:1-12. [PMID: 30807804 DOI: 10.1016/j.jconrel.2019.02.033] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 02/17/2019] [Accepted: 02/21/2019] [Indexed: 11/28/2022]
Abstract
It remains a major challenge to develop a selective and effective fibrinolytic system for thrombolysis with minimal undesirable side effects. Herein, we report a multifunctional liposomal system (164.6 ± 5.3 nm in diameter) which can address this challenge through targeted delivery and controlled release of tissue plasminogen activator (tPA) at the thrombus site. The tPA-loaded liposomes were PEGylated to improve their stability, and surface coated with a conformationally-constrained, cyclic arginine-glycine-aspartic acid (cRGD) to enable highly selective binding to activated platelets. The in vitro drug release profiles at 37 °C showed that over 90% of tPA was released through liposomal membrane destabilization involving membrane fusion upon incubation with activated platelets within 1 h, whereas passive release of the encapsulated tPA in pH 7.4 PBS buffer was 10% after 6 h. The release of tPA could be readily manipulated by changing the concentration of activated platelets. The presence of activated platelets enabled the tPA-loaded, cRGD-coated, PEGylated liposomes to induce efficient fibrin clot lysis in a fibrin-agar plate model and the encapsulated tPA retained 97.4 ± 1.7% of fibrinolytic activity as compared with that of native tPA. Furthermore, almost complete blood clot lysis was achieved in 75 min, showing considerably higher and quicker thrombolytic activity compared to the tPA-loaded liposomes without cRGD labelling. These results suggest that the nano-sized, activated-platelet-sensitive, multifunctional liposomes could facilitate selective delivery and effective release of tPA at the site of thrombus, thus achieving efficient clot dissolution whilst minimising undesirable side effects.
Collapse
Affiliation(s)
- Yu Huang
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, United Kingdom
| | - Li Yu
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, United Kingdom
| | - Jie Ren
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, United Kingdom
| | - Boram Gu
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, United Kingdom
| | - Colin Longstaff
- Biotherapeutics Section, National Institute for Biological Standards and Control, South Mimms, Herts, United Kingdom
| | - Alun D Hughes
- Institute of Cardiovascular Science, University College London, London, United Kingdom; MRC Unit for Lifelong Health and Ageing at University College London, London, United Kingdom
| | - Simon A Thom
- National Heart & Lung Institute, Imperial College London, Hammersmith Campus, London, United Kingdom
| | - Xiao Yun Xu
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, United Kingdom
| | - Rongjun Chen
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, United Kingdom.
| |
Collapse
|
19
|
Wild P, Leisinger S, de Oliveira AP, Doehner J, Schraner EM, Fraevel C, Ackermann M, Kaech A. Nuclear envelope impairment is facilitated by the herpes simplex virus 1 Us3 kinase. F1000Res 2019; 8:198. [PMID: 31249678 PMCID: PMC6584977 DOI: 10.12688/f1000research.17802.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/11/2019] [Indexed: 12/22/2022] Open
Abstract
Background: Capsids of herpes simplex virus 1 (HSV-1) are assembled in the nucleus, translocated either to the perinuclear space by budding at the inner nuclear membrane acquiring tegument and envelope, or released to the cytosol in a "naked" state via impaired nuclear pores that finally results in impairment of the nuclear envelope. The Us3 gene encodes a protein acting as a kinase, which is responsible for phosphorylation of numerous viral and cellular substrates. The Us3 kinase plays a crucial role in nucleus to cytoplasm capsid translocation. We thus investigate the nuclear surface in order to evaluate the significance of Us3 in maintenance of the nuclear envelope during HSV-1 infection. Methods: To address alterations of the nuclear envelope and capsid nucleus to cytoplasm translocation related to the function of the Us3 kinase we investigated cells infected with wild type HSV-1 or the Us3 deletion mutant R7041(∆Us3) by transmission electron microscopy, focused ion-beam electron scanning microscopy, cryo-field emission scanning electron microscopy, confocal super resolution light microscopy, and polyacrylamide gel electrophoresis. Results: Confocal super resolution microscopy and cryo-field emission scanning electron microscopy revealed decrement in pore numbers in infected cells. Number and degree of pore impairment was significantly reduced after infection with R7041(∆Us3) compared to infection with wild type HSV-1. The nuclear surface was significantly enlarged in cells infected with any of the viruses. Morphometric analysis revealed that additional nuclear membranes were produced forming multiple folds and caveolae, in which virions accumulated as documented by three-dimensional reconstruction after ion-beam scanning electron microscopy. Finally, significantly more R7041(∆Us3) capsids were retained in the nucleus than wild-type capsids whereas the number of R7041(∆Us3) capsids in the cytosol was significantly lower. Conclusions: The data indicate that Us3 kinase is involved in facilitation of nuclear pore impairment and, concomitantly, in capsid release through impaired nuclear envelope.
Collapse
Affiliation(s)
- Peter Wild
- Department of Veterinary Anatomy, University of Zuerich, Zürich, CH-8057, Switzerland
| | - Sabine Leisinger
- Department of Veterinary Anatomy, University of Zuerich, Zürich, CH-8057, Switzerland
| | | | - Jana Doehner
- Center for Microcopy and Image Analysis, Universit of Zürich, Zürich, CH-8057, Switzerland
| | - Elisabeth M. Schraner
- Department of Veterinary Anatomy, University of Zuerich, Zürich, CH-8057, Switzerland
- Instute of Virology, University of Zürich, Zürich, ZH-8057, Switzerland
| | - Cornel Fraevel
- Instute of Virology, University of Zürich, Zürich, ZH-8057, Switzerland
| | - Mathias Ackermann
- Instute of Virology, University of Zürich, Zürich, ZH-8057, Switzerland
| | - Andres Kaech
- Center for Microcopy and Image Analysis, Universit of Zürich, Zürich, CH-8057, Switzerland
| |
Collapse
|
20
|
Jun YW, Wang T, Hwang S, Kim D, Ma D, Kim KH, Kim S, Jung J, Ahn KH. A Ratiometric Two-Photon Fluorescent Probe for Tracking Lysosomal ATP: Direct In Cellulo Observation of Lysosomal Membrane Fusion Processes. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201804743] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Yong Woong Jun
- Department of Chemistry; Pohang University of Science and Technology (POSTECH); 77 Cheongam-Ro, Nam-Gu Pohang 37673 Rep. of Korea
| | - Taejun Wang
- Division of Integrative Biosciences and Biotechnology; Pohang University of Science and Technology (POSTECH); 77 Cheongam-Ro, Nam-Gu Pohang 37673 Rep. of Korea
| | - Sekyu Hwang
- Department of Chemistry; Pohang University of Science and Technology (POSTECH); 77 Cheongam-Ro, Nam-Gu Pohang 37673 Rep. of Korea
| | - Dokyoung Kim
- Department of Anatomy and Neurobiology; College of Medicine; Kyung Hee University; 26 Kyungheedae-Ro, Dongdaemun-Gu Seoul 02447 Rep. of Korea
- Center for Converging Humanities; College of Medicine; Kyung Hee University; 26 Kyungheedae-Ro, Dongdaemun-Gu Seoul 02447 Rep. of Korea
| | - Donghee Ma
- Department of Chemistry; Pohang University of Science and Technology (POSTECH); 77 Cheongam-Ro, Nam-Gu Pohang 37673 Rep. of Korea
| | - Ki Hean Kim
- Division of Integrative Biosciences and Biotechnology; Pohang University of Science and Technology (POSTECH); 77 Cheongam-Ro, Nam-Gu Pohang 37673 Rep. of Korea
| | - Sungjee Kim
- Department of Chemistry; Pohang University of Science and Technology (POSTECH); 77 Cheongam-Ro, Nam-Gu Pohang 37673 Rep. of Korea
| | - Junyang Jung
- Department of Anatomy and Neurobiology; College of Medicine; Kyung Hee University; 26 Kyungheedae-Ro, Dongdaemun-Gu Seoul 02447 Rep. of Korea
| | - Kyo Han Ahn
- Department of Chemistry; Pohang University of Science and Technology (POSTECH); 77 Cheongam-Ro, Nam-Gu Pohang 37673 Rep. of Korea
| |
Collapse
|
21
|
Jun YW, Wang T, Hwang S, Kim D, Ma D, Kim KH, Kim S, Jung J, Ahn KH. A Ratiometric Two-Photon Fluorescent Probe for Tracking Lysosomal ATP: Direct In Cellulo Observation of Lysosomal Membrane Fusion Processes. Angew Chem Int Ed Engl 2018; 57:10142-10147. [PMID: 29873167 DOI: 10.1002/anie.201804743] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Indexed: 11/10/2022]
Abstract
Vesicles exchange their contents through membrane fusion processes, kiss-and-run and full-collapse fusion. Indirect observation of these fusion processes using artificial vesicles enhanced our understanding on the molecular mechanisms involved. Direct observation of the fusion processes in a real biological system, however, remains a challenge owing to many technical obstacles. We report a ratiometric two-photon probe offering real-time tracking of lysosomal ATP with quantitative information for the first time. By applying the probe to two-photon live-cell imaging, the lysosomal membrane fusion process in cells has been directly observed and the concentration of its content, lysosomal ATP, has been measured. Results show that the kiss-and-run process between lysosomes proceeds through repeated transient interactions with gradual content mixing, whereas the full-fusion process occurs at once. Furthermore, it is confirmed that both the fusion processes proceed with conservation of the content. Such a small-molecule probe exerts minimal disturbance and hence has potential for studying various biological processes associated with lysosomal ATP.
Collapse
Affiliation(s)
- Yong Woong Jun
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, 37673, Rep. of Korea
| | - Taejun Wang
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, 37673, Rep. of Korea
| | - Sekyu Hwang
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, 37673, Rep. of Korea
| | - Dokyoung Kim
- Department of Anatomy and Neurobiology, College of Medicine, Kyung Hee University, 26 Kyungheedae-Ro, Dongdaemun-Gu, Seoul, 02447, Rep. of Korea.,Center for Converging Humanities, College of Medicine, Kyung Hee University, 26 Kyungheedae-Ro, Dongdaemun-Gu, Seoul, 02447, Rep. of Korea
| | - Donghee Ma
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, 37673, Rep. of Korea
| | - Ki Hean Kim
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, 37673, Rep. of Korea
| | - Sungjee Kim
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, 37673, Rep. of Korea
| | - Junyang Jung
- Department of Anatomy and Neurobiology, College of Medicine, Kyung Hee University, 26 Kyungheedae-Ro, Dongdaemun-Gu, Seoul, 02447, Rep. of Korea
| | - Kyo Han Ahn
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, 37673, Rep. of Korea
| |
Collapse
|
22
|
Vesicular stomatitis virus G protein transmembrane region is crucial for the hemi-fusion to full fusion transition. Sci Rep 2018; 8:10669. [PMID: 30006542 PMCID: PMC6045571 DOI: 10.1038/s41598-018-28868-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 06/29/2018] [Indexed: 11/30/2022] Open
Abstract
Viral fusion proteins are essential for enveloped virus infection. These proteins mediate fusion between the virus envelope and host cellular membrane to release the viral genome into cells. Vesicular stomatitis virus G (VSV G) protein is a typical type III viral fusion protein. To study the mechanism of VSV G protein mediated membrane fusion, we set up a cell-cell fusion system in which cells are marked by different fluorescent proteins. Taking advantage of this system, we performed real-time recording and quantitative analysis of the cell fusion mediated by VSV G. We found that the time scale required for VSV G mediated cell-cell fusion was approximately 1–2 minutes. Next, we specifically examined the function of the transmembrane (TM) region of VSV G protein in membrane fusion by replacing the TM region with those of other fusion proteins. The TM region replacements dramatically impaired VSV G protein function in the cell-cell fusion assay and diminished VSV G mediated lentivirus and recombinant VSV infection efficiency. Further experiments implied that the TM region played a role in the transition from hemi-fusion to full fusion. Several residues within the TM region were identified as important for membrane fusion. Overall, our findings unraveled the important function of the TM region in VSV G mediated viral fusion.
Collapse
|
23
|
Fusogenic properties of the Ectodomain of HCV E2 envelope protein. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:728-736. [DOI: 10.1016/j.bbamem.2017.12.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 12/05/2017] [Accepted: 12/18/2017] [Indexed: 01/04/2023]
|
24
|
de Oliveira GA, Silva JL. The push-and-pull hypothesis in protein unfolding, misfolding and aggregation. Biophys Chem 2017; 231:20-26. [DOI: 10.1016/j.bpc.2017.03.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Revised: 03/25/2017] [Accepted: 03/27/2017] [Indexed: 01/17/2023]
|
25
|
Wild P, Kaech A, Schraner EM, Walser L, Ackermann M. Endoplasmic reticulum-to-Golgi transitions upon herpes virus infection. F1000Res 2017; 6:1804. [PMID: 30135710 PMCID: PMC6080407 DOI: 10.12688/f1000research.12252.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/29/2017] [Indexed: 09/29/2023] Open
Abstract
Background: Herpesvirus capsids are assembled in the nucleus before they are translocated to the perinuclear space by budding, acquiring tegument and envelope, or releasing to the cytoplasm in a "naked" state via impaired nuclear envelope. One model proposes that envelopment, "de-envelopment" and "re-envelopment" are essential steps for production of infectious virus. Glycoproteins gB/gH were reported to be essential for de-envelopment, by fusion of the "primary" envelope with the outer nuclear membrane. Yet, a high proportion of enveloped virions generated from genomes with deleted gB/gH were found in the cytoplasm and extracellular space, suggesting the existence of an alternative exit route. Methods: We investigated the relatedness between the nuclear envelope and membranes of the endoplasmic reticulum and Golgi complex, in cells infected with either herpes simplex virus 1 (HSV-1) or a Us3 deletion mutant thereof, or with bovine herpesvirus 1 (BoHV-1) by transmission and scanning electron microscopy, employing freezing technique protocols that lead to improved spatial and temporal resolution. Results: Scanning electron microscopy showed the Golgi complex as a compact entity in a juxtanuclear position covered by a membrane on the cis face. Transmission electron microscopy revealed that Golgi membranes merge with membranes of the endoplasmic reticulum forming an entity with the perinuclear space. All compartments contained enveloped virions. After treatment with brefeldin A, HSV-1 virions aggregated in the perinuclear space and endoplasmic reticulum, while infectious progeny virus was still produced. Conclusions: The data strongly suggest that virions are intraluminally transported from the perinuclear space via Golgi complex-endoplasmic reticulum transitions into Golgi cisternae for packaging into transport vacuoles. Furthermore, virions derived by budding at nuclear membranes are infective as has been shown for HSV-1 Us3 deletion mutants, which almost entirely accumulate in the perinuclear space. Therefore, de-envelopment followed by re-envelopment is not essential for production of infective progeny virus.
Collapse
Affiliation(s)
- Peter Wild
- Institute of Veterinary Anatomy, Zürich, Switzerland
- Institute of Virology, Zürich, Switzerland
| | - Andres Kaech
- Center for Microscopy and Image Analysis, Zürich, Switzerland
| | - Elisabeth M. Schraner
- Institute of Veterinary Anatomy, Zürich, Switzerland
- Institute of Virology, Zürich, Switzerland
| | - Ladina Walser
- Institute of Veterinary Anatomy, Zürich, Switzerland
| | | |
Collapse
|
26
|
Wild P, Kaech A, Schraner EM, Walser L, Ackermann M. Endoplasmic reticulum-to-Golgi transitions upon herpes virus infection. F1000Res 2017; 6:1804. [PMID: 30135710 PMCID: PMC6080407 DOI: 10.12688/f1000research.12252.2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/19/2018] [Indexed: 11/23/2022] Open
Abstract
Background: Herpesvirus capsids are assembled in the nucleus, translocated to the perinuclear space by budding, acquiring tegument and envelope, or released to the cytoplasm via impaired nuclear envelope. One model proposes that envelopment, "de-envelopment" and "re-envelopment" is essential for production of infectious virus. Glycoproteins gB/gH were reported to be essential for de-envelopment, by fusion of the "primary" envelope with the outer nuclear membrane. Yet, a high proportion of enveloped virions generated from genomes with deleted gB/gH were found in the cytoplasm and extracellular space, suggesting the existence of alternative exit routes. Methods: We investigated the relatedness between the nuclear envelope and membranes of the endoplasmic reticulum and Golgi complex, in cells infected with either herpes simplex virus 1 (HSV-1) or a Us3 deletion mutant thereof, or with bovine herpesvirus 1 (BoHV-1) by transmission and scanning electron microscopy, employing freezing technique protocols. Results: The Golgi complex is a compact entity in a juxtanuclear position covered by a membrane on the cis face. Golgi membranes merge with membranes of the endoplasmic reticulum forming an entity with the perinuclear space. All compartments contained enveloped virions. After treatment with brefeldin A, HSV-1 virions aggregated in the perinuclear space and endoplasmic reticulum, while infectious progeny virus was still produced. Conclusions: The data suggest that virions derived by budding at nuclear membranes are intraluminally transported from the perinuclear space via Golgi -endoplasmic reticulum transitions into Golgi cisternae for packaging. Virions derived by budding at nuclear membranes are infective like Us3 deletion mutants, which accumulate in the perinuclear space. Therefore, i) de-envelopment followed by re-envelopment is not essential for production of infective progeny virus, ii) the process taking place at the outer nuclear membrane is budding not fusion, and iii) naked capsids gain access to the cytoplasmic matrix via impaired nuclear envelope as reported earlier.
Collapse
Affiliation(s)
- Peter Wild
- Institute of Veterinary Anatomy, Zürich, Switzerland
- Institute of Virology, Zürich, Switzerland
| | - Andres Kaech
- Center for Microscopy and Image Analysis, Zürich, Switzerland
| | - Elisabeth M. Schraner
- Institute of Veterinary Anatomy, Zürich, Switzerland
- Institute of Virology, Zürich, Switzerland
| | - Ladina Walser
- Institute of Veterinary Anatomy, Zürich, Switzerland
| | | |
Collapse
|
27
|
Abstract
Micro-organisms and higher organisms have evolved together and interact in complex ways. Only a small percentage of microbes are inherently pathogenic. Pathogenicity, the ability of infectious agents to cause disease, must be interpreted in the context of the properties of both transmissible agent and host. Understanding this interplay is important to developing methods to prevent infection and reduce the severity of disease. The initial step in infection is usually adherence, mediated by the interaction of surface structures on the pathogen with host cell membrane proteins or carbohydrates. This often presents excellent targets for immunity. Intracellular pathogens have evolved methods to neutralize the cellular defenses that can destroy invaders.
Collapse
|
28
|
Zahariev TK, Tadjer AV, Ivanova AN. Transfer of non-ionic surfactants across the water-oil interface: A molecular dynamics study. Colloids Surf A Physicochem Eng Asp 2016. [DOI: 10.1016/j.colsurfa.2016.06.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
29
|
Ibarguren M, Bomans PHH, Ruiz-Mirazo K, Frederik PM, Alonso A, Goñi FM. Thermally-induced aggregation and fusion of protein-free lipid vesicles. Colloids Surf B Biointerfaces 2015; 136:545-52. [PMID: 26454544 DOI: 10.1016/j.colsurfb.2015.09.047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 08/21/2015] [Accepted: 09/24/2015] [Indexed: 12/11/2022]
Abstract
Membrane fusion is an important phenomenon in cell biology and pathology. This phenomenon can be modeled using vesicles of defined size and lipid composition. Up to now fusion models typically required the use of chemical (polyethyleneglycol, cations) or enzymatic catalysts (phospholipases). We present here a model of lipid vesicle fusion induced by heat. Large unilamellar vesicles consisting of a phospholipid (dioleoylphosphatidylcholine), cholesterol and diacylglycerol in a 43:57:3 mol ratio were employed. In this simple system, fusion was the result of thermal fluctuations, above 60 °C. A similar system containing phospholipid and cholesterol but no diacylglycerol was observed to aggregate at and above 60 °C, in the absence of fusion. Vesicle fusion occurred under our experimental conditions only when (31)P NMR and cryo-transmission electron microscopy of the lipid mixtures used in vesicle preparation showed non-lamellar lipid phase formation (hexagonal and cubic). Non-lamellar structures are probably the result of lipid reassembly of the products of individual fusion events, or of fusion intermediates. A temperature-triggered mechanism of lipid reassembly might have occurred at various stages of protocellular evolution.
Collapse
Affiliation(s)
- Maitane Ibarguren
- Unidad de Biofísica (Centro Mixto CSIC, UPV/EHU), and Departamento de Bioquímica, Universidad del País Vasco, Apto. 644, 48080 Bilbao, Spain.
| | - Paul H H Bomans
- Soft Matter CryoTEM Research Unit, Laboratory for Materials and Interface Chemistry, P.O. Box 513, 5600MB Eindhoven, The Netherlands.
| | - Kepa Ruiz-Mirazo
- Unidad de Biofísica (Centro Mixto CSIC, UPV/EHU), and Departamento de Bioquímica, Universidad del País Vasco, Apto. 644, 48080 Bilbao, Spain; Logic and Philosophy of Science Department, University of the Basque Country, Spain.
| | - Peter M Frederik
- Soft Matter CryoTEM Research Unit, Laboratory for Materials and Interface Chemistry, P.O. Box 513, 5600MB Eindhoven, The Netherlands.
| | - Alicia Alonso
- Unidad de Biofísica (Centro Mixto CSIC, UPV/EHU), and Departamento de Bioquímica, Universidad del País Vasco, Apto. 644, 48080 Bilbao, Spain.
| | - Félix M Goñi
- Unidad de Biofísica (Centro Mixto CSIC, UPV/EHU), and Departamento de Bioquímica, Universidad del País Vasco, Apto. 644, 48080 Bilbao, Spain.
| |
Collapse
|
30
|
Intracellular trafficking of bio-nanocapsule-liposome complex: Identification of fusogenic activity in the pre-S1 region of hepatitis B virus surface antigen L protein. J Control Release 2015; 212:10-8. [PMID: 26074149 DOI: 10.1016/j.jconrel.2015.06.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Revised: 05/07/2015] [Accepted: 06/09/2015] [Indexed: 12/18/2022]
Abstract
Bio-nanocapsules (BNCs) are a hollow nanoparticle consisting of about 100-nm liposome (LP) embedding about 110 molecules of hepatitis B virus (HBV) surface antigen (HBsAg) L protein as a transmembrane protein. Owing to the human hepatocyte-recognizing domains on the N-terminal region (pre-S1 region), BNCs have recently been shown to attach and enter into human hepatic cells using the early infection mechanism of HBV. Since BNCs could form a complex with an LP containing various drugs and genes, BNC-LP complexes have been used as a human hepatic cell-specific drug and gene-delivery system in vitro and in vivo. However, the role of BNCs in cell entry and intracellular trafficking of payloads in BNC-LP complexes has not been fully elucidated. In this study, we demonstrate that low pH-dependent fusogenic activity resides in the N-terminal part of pre-S1 region (NPLGFFPDHQLDPAFG), of which the first FF residues are essential for the activity, and which facilitates membrane fusion between LPs in vitro. Moreover, BNC-LP complexes can bind human hepatic cells specifically, enter into the cells via clathrin-mediated endocytosis, and release their payloads mostly into the cytoplasm. Taken together, the BNC portion of BNC-LP complexes can induce membrane fusion between LPs and endosomal membranes under low pH conditions, and thereby facilitate the endosomal escape of payloads. Furthermore, the fusogenic domain of the pre-S1 region of HBsAg L protein may play a pivotal role in the intracellular trafficking of not only BNC-LP complexes but also of HBV.
Collapse
|
31
|
Pastén K, Bastian Y, Roa-Espitia AL, Maldonado-García D, Mendoza-Hernández G, Ortiz-García CI, Mújica A, Hernández-González EO. ADAM15 participates in fertilization through a physical interaction with acrogranin. Reproduction 2014; 148:623-34. [DOI: 10.1530/rep-14-0179] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Mammalian fertilization is completed by direct interaction between sperm and egg. This process is primarily mediated by both adhesion and membrane-fusion proteins found on the gamete surface. ADAM1, 2, and 3 are members of the ADAMs protein family, and have been involved in sperm–egg binding. In this study, we demonstrate the proteolytic processing of ADAM15 during epididymal maturation of guinea pig spermatozoa to produce a mature form a size of 45 kDa. We find that the size of the mature ADAM15, 45 kDa, in cauda epididymal spermatozoa indicates that the pro-domain and metalloprotease domain are absent. In addition, using indirect immunofluorescence, ADAM15 was found throughout the acrosome, at the equatorial region and along the flagellum of guinea pig spermatozoa. After acrosome reaction, ADAM15 is lost from the acrosomal region and retained in the equatorial region and flagellum. In this study, we also report the first evidence of a complex between ADAM15 and acrogranin. By immunoprecipitation, we detected a protein band of 65 kDa which co-immunoprecipated together ADAM15. Analysis of the N-terminal sequence of this 65 kDa protein has revealed its identity as acrogranin. In addition, using cell-surface labeling, ADAM15 was found to be present on the cell surface. Assays of heterologous fertilization showed that the antibody against acrogranin inhibited the sperm–egg adhesion. Interestingly, ADAM15 and acrogranin were also found associated in two breast cancer cell lines. In conclusion, our results demonstrated that ADAM15 and acrogranin are present on and associated with the surface of guinea pig spermatozoa; besides both proteins may play a role during sperm–egg binding.
Collapse
|
32
|
Kawamoto S, Shinoda W. Free energy analysis along the stalk mechanism of membrane fusion. SOFT MATTER 2014; 10:3048-3054. [PMID: 24695575 DOI: 10.1039/c3sm52344f] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The free energy profile of the stalk model of membrane fusion has been calculated using coarse-grained molecular dynamics simulations. The proposed method guides the lipid configuration using a guiding wall potential to make the transition from two apposed membranes to a stalk and a fusion pore. The free energy profile is obtained with a thermodynamic integration scheme using the mean force working on the guiding wall as a response of the system. We applied the method to two apposed flat bilayers composed of dioleoyl phosphatidylethanolamine/dioleoyl phosphatidylcholine expanding over the simulation box under the periodic boundary conditions. The two transition states are identified as pre-stalk and pre-pore states. The free energy barrier for the latter is confirmed to be in good agreement with that estimated by the pulling method. The present method provides a practical way to calculate the free energy profile along the stalk mechanism.
Collapse
Affiliation(s)
- Shuhei Kawamoto
- Health Research Institute, National Institute of Advanced Industrial Science & Technology (AIST), 1-8-31, Midorigaoka, Ikeda, Osaka 563-8577, Japan.
| | | |
Collapse
|
33
|
Brice AR, Lazaridis T. Structure and dynamics of a fusion peptide helical hairpin on the membrane surface: comparison of molecular simulations and NMR. J Phys Chem B 2014; 118:4461-70. [PMID: 24712538 PMCID: PMC4010296 DOI: 10.1021/jp409412g] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The conserved N-terminal residues of the HA2 subunit of influenza hemagglutinin (fusion peptide) are essential for membrane fusion and viral entry. Recent NMR studies showed that the 23-residue fusion peptide forms a helical hairpin that undergoes rocking motion relative to the membrane surface on a nanosecond time scale. To compare with NMR and to obtain a detailed molecular picture of the peptide-membrane interaction, we performed molecular dynamics simulations of the fusion peptide in explicit dimyristoylphosphatidylcholine and with the IMM1 implicit membrane model. To account for low and neutral pH conditions, simulations were performed with acidic groups (E11 and D19) protonated and unprotonated, respectively. The hairpin structure was stable in the simulations, with the N-terminal helix buried more deeply into the hydrophobic membrane interior than the C-terminal helix. Interactions between the tryptophans in the fusion peptide and phospholipid residues contribute to peptide orientation. Higher flexibility of the hairpin was observed in the implicit membrane simulations. Internal correlation functions of backbone N-H vectors were fit to the extended Lipari-Szabo model-free approach to obtain order parameters and correlation times. Good agreement with the NMR results was obtained for orientational fluctuations around the hairpin axis (rotation), but those around the perpendicular axis (tilting) were more limited in the simulations than inferred from the NMR experiments.
Collapse
Affiliation(s)
- Allyn R Brice
- Department of Chemistry, City College of New York , 160 Convent Avenue, New York, New York 10031, United States
| | | |
Collapse
|
34
|
Apellániz B, Huarte N, Largo E, Nieva JL. The three lives of viral fusion peptides. Chem Phys Lipids 2014; 181:40-55. [PMID: 24704587 PMCID: PMC4061400 DOI: 10.1016/j.chemphyslip.2014.03.003] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 03/19/2014] [Accepted: 03/20/2014] [Indexed: 02/07/2023]
Abstract
The presence of a fusion peptide (FP) is a hallmark of viral fusion glycoproteins. Structure–function relationships underlying FP conservation remain greatly unknown. FPs establish interactions satisfying their folding within pre-fusion glycoproteins. Upon fusion activation FPs insert into and restructure target membranes. FPs can finally combine with transmembrane domains to form integral membrane bundles.
Fusion peptides comprise conserved hydrophobic domains absolutely required for the fusogenic activity of glycoproteins from divergent virus families. After 30 years of intensive research efforts, the structures and functions underlying their high degree of sequence conservation are not fully elucidated. The long-hydrophobic viral fusion peptide (VFP) sequences are structurally constrained to access three successive states after biogenesis. Firstly, the VFP sequence must fulfill the set of native interactions required for (meta) stable folding within the globular ectodomains of glycoprotein complexes. Secondly, at the onset of the fusion process, they get transferred into the target cell membrane and adopt specific conformations therein. According to commonly accepted mechanistic models, membrane-bound states of the VFP might promote the lipid bilayer remodeling required for virus-cell membrane merger. Finally, at least in some instances, several VFPs co-assemble with transmembrane anchors into membrane integral helical bundles, following a locking movement hypothetically coupled to fusion-pore expansion. Here we review different aspects of the three major states of the VFPs, including the functional assistance by other membrane-transferring glycoprotein regions, and discuss briefly their potential as targets for clinical intervention.
Collapse
Affiliation(s)
- Beatriz Apellániz
- Biophysics Unit (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain
| | - Nerea Huarte
- Biophysics Unit (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain
| | - Eneko Largo
- Biophysics Unit (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain
| | - José L Nieva
- Biophysics Unit (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain.
| |
Collapse
|
35
|
Marchi-Artzner V, Gulik-Krzywicki T, Guedeau-Boudeville MA, Gosse C, Sanderson JM, Dedieu JC, Lehn JM. Selective adhesion, lipid exchange and membrane-fusion processes between vesicles of various sizes bearing complementary molecular recognition groups. Chemphyschem 2014; 2:367-76. [PMID: 23686958 DOI: 10.1002/1439-7641(20010618)2:6<367::aid-cphc367>3.0.co;2-#] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2000] [Revised: 01/12/2001] [Indexed: 11/10/2022]
Abstract
Equimolar mixtures of large unilamellar vesicles (LUVs) obtained from mixtures of egg lecithin and lipids containing complementary hydrogen bonding head groups (barbituric acid (BAR) and 2,4,6-triaminopyrimidine (TAP)) were shown to aggregate and fuse. These events have been studied in detail using electron microscopy and dynamic light scattering, and by fluorimetry using membrane or water-soluble fluorescence probes. It was shown that aggregation was followed by two competitive processes: a) lipid mixing leading to redispersion of the vesicles; b) fusion events generating much larger vesicles. In order to better understand the nature of the interaction, the effects of ionic strength and surface concentration of recognition lipids on the aggregation process were investigated by dynamic light scattering. Additionally, it was possible to inhibit the aggregation kinetics through addition of a soluble barbituric acid competitor. The study was extended to giant unilamellar vesicles (GUVs) to investigate the size effect and visualise the phenomena in situ. The interactions between complementary LUVs and GUVs or GUVs and GUVs were studied by optical microscopy using dual fluorescent labelling of both vesicle populations. A selective adhesion of LUVs onto GUVs was observed by electron and optical microscopies, whereas no aggregation took place in case of a GUV/GUV mixture. Furthermore, a fusion assay of GUV and LUV using the difference of size between GUV and LUV and calceine self-quenching showed that no mixing between the aqueous pools occured.
Collapse
Affiliation(s)
- V Marchi-Artzner
- Laboratoire de Chimie des Interactions Moléculaires, UPR 285, Collège de France, Paris, France
| | | | | | | | | | | | | |
Collapse
|
36
|
Ting CL, Frischknecht AL. Activated pathways for the directed insertion of patterned nanoparticles into polymer membranes. SOFT MATTER 2013; 9:9615-9623. [PMID: 26029770 DOI: 10.1039/c3sm51734a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We combine the string method with self-consistent field theory to compute the most probable transition pathway, i.e. the minimum free energy path, for the insertion of Janus and protein-like nanoparticles into a polymer membrane bilayer. The method makes no assumptions in the reaction coordinate and overcomes the long timescales challenge associated with simulating rare events. Our study suggests that one approach to building functional polymer–nanoparticle composite membranes with oriented nanoparticles is through electrostatic interactions. In particular, hydrophobic Janus nanoparticles with an asymmetric charge distribution can be made to directionally insert into charged membranes. This process is kinetically driven, and involves overcoming a thermally surmountable activation barrier, which requires favorable interactions between the nanoparticle and the hydrophilic block of the membrane. In contrast, the insertion of protein-like nanoparticles with alternating hydrophilic–hydrophobic–hydrophilic domains into polymer membranes does not occur as a thermally activated event.
Collapse
Affiliation(s)
- Christina L Ting
- Sandia National Laboratories, Albuquerque, NM 87185, USA. E-mail:
| | | |
Collapse
|
37
|
Qiu J, Ashkenazi A, Liu S, Shai Y. Structural and functional properties of the membranotropic HIV-1 glycoprotein gp41 loop region are modulated by its intrinsic hydrophobic core. J Biol Chem 2013; 288:29143-50. [PMID: 23960077 DOI: 10.1074/jbc.m113.496646] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The gp41 disulfide loop region switches from a soluble state to a membrane-bound state during the human immunodeficiency virus type 1 (HIV-1) envelope-mediated membrane fusion process. The loop possesses a hydrophobic core at the center of the region with an unusual basic residue (Lys-601). Furthermore, two loop core mutations, K601A and L602A, are found to inhibit HIV-1 infectivity while keeping wild type-like levels of the envelope, implying that they exert an inhibitory effect on gp41 during the membrane fusion event. Here, we investigated the mode of action of these mutations on the loop region. We show that the K601A mutation, but not the L602A mutation, abolished the binding of a loop-specific monoclonal antibody to a loop domain peptide. Additionally, the K601A, but not the L602A, impaired disulfide bond formation in the peptides. This was correlated with changes in the circular dichroism spectrum imposed by the K601A mutation. In the membrane, however, the L602A, but not the K601A, reduced the lipid mixing ability of the loop peptides, which was correlated with decreased α-helical content of the L602A mutant. The results suggest that the Lys-601 residue provides a moderate hydrophobicity level within the gp41 loop core that contributes to the proper structure and function of the loop inside and outside the membrane. Because basic residues are found between the loop Cys residues of several lentiviral fusion proteins, the findings may contribute to understanding the fusion mechanism of other viruses as well.
Collapse
Affiliation(s)
- Jiayin Qiu
- From the Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, 76100 Israel and
| | | | | | | |
Collapse
|
38
|
Abstract
Shape changes and topological remodeling of membranes are essential for the identity of organelles and membrane trafficking. Although all cellular membranes have common features, membranes of different organelles create unique environments that support specialized biological functions. The endoplasmic reticulum (ER) is a prime example of this specialization, as its lipid bilayer forms an interconnected system of cisternae, vesicles, and tubules, providing a highly compartmentalized structure for a multitude of biochemical processes. A variety of peripheral and integral membrane proteins that facilitate membrane curvature generation, fission, and/or fusion have been identified over the past two decades. Among these, the dynamin-related proteins (DRPs) have emerged as key players. Here, we review recent advances in our functional and molecular understanding of fusion DRPs, exemplified by atlastin, an ER-resident DRP that controls ER structure, function, and signaling.
Collapse
Affiliation(s)
- James A McNew
- Department of Biochemistry and Cell Biology, Rice University, Houston, Texas 77005;
| | | | | | | | | |
Collapse
|
39
|
Wang J, Cheng H, Ratia K, Varhegyi E, Hendrickson WG, Li J, Rong L. A comparative high-throughput screening protocol to identify entry inhibitors of enveloped viruses. ACTA ACUST UNITED AC 2013; 19:100-7. [PMID: 23821643 DOI: 10.1177/1087057113494405] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Emerging and reemerging human viral pathogens pose great public health concerns since therapeutics against these viruses are limited. Thus, there is an urgent need to develop novel drugs that can block infection of either a specific virus or a number of viruses. Viral entry is thought to be an ideal target for potential therapeutic prevention. One of the challenges of developing antivirals is that most of these viruses are highly pathogenic and therefore require high biosafety-level containment. In this study, we have adopted a comparative high-throughput screening protocol to identify entry inhibitors for three enveloped viruses (Marburg virus, influenza virus H5N1, and Lassa virus) using a human immunodeficiency virus-based pseudotyping platform. We demonstrate the utility of this approach by screening a small compound library and identifying putative entry inhibitors for these viruses. One major advantage of this protocol is to reduce the number of false positives in hit selection, and we believe that the protocol is useful for inhibitor screening for many enveloped viruses.
Collapse
Affiliation(s)
- Juan Wang
- 1Department of Microbiology and Immunology, College of Medicine, University of Illinois at Chicago, IL, USA
| | | | | | | | | | | | | |
Collapse
|
40
|
Functional complementation of a model target to study Vpu sensitivity. PLoS One 2013; 8:e68507. [PMID: 23840857 PMCID: PMC3695915 DOI: 10.1371/journal.pone.0068507] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 06/03/2013] [Indexed: 11/25/2022] Open
Abstract
HIV-1 forms infectious particles with Murine Leukemia virus (MLV) Env, but not with the closely related Gibbon ape Leukemia Virus (GaLV) Env. We have determined that the incompatibility between HIV-1 and GaLV Env is primarily caused by the HIV-1 accessory protein Vpu, which prevents GaLV Env from being incorporated into particles. We have characterized the ‘Vpu sensitivity sequence’ in the cytoplasmic tail domain (CTD) of GaLV Env using a chimeric MLV Env with the GaLV Env CTD (MLV/GaLV Env). Vpu sensitivity is dependent on an alpha helix with a positively charged face containing at least one Lysine. In the present study, we utilized functional complementation to address whether all the three helices in the CTD of an Env trimer have to contain the Vpu sensitivity motif for the trimer to be modulated by Vpu. Taking advantage of the functional complementation of the binding defective (D84K) and fusion defective (L493V) MLV and MLV/GaLV Env mutants, we were able to assay the activity of mixed trimers containing both MLV and GaLV CTDs. Mixed trimers containing both MLV and GaLV CTDs were functionally active and remained sensitive to Vpu. However, trimers containing an Env with the GaLV CTD and an Env with no CTD remained functional but were resistant to Vpu. Together these data suggest that the presence of at least one GaLV CTD is sufficient to make an Env trimer sensitive to Vpu, but only if it is part of a trimeric CTD complex.
Collapse
|
41
|
Kabaso D, Jorgačevski J, Calejo AI, Flašker A, Guček A, Kreft M, Zorec R. Comparison of unitary exocytic events in pituitary lactotrophs and in astrocytes: modeling the discrete open fusion-pore states. Front Cell Neurosci 2013; 7:33. [PMID: 23576951 PMCID: PMC3616249 DOI: 10.3389/fncel.2013.00033] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Accepted: 03/14/2013] [Indexed: 11/13/2022] Open
Abstract
In regulated exocytosis the merger between the vesicle and the plasma membranes leads to the formation of an aqueous channel (a fusion-pore), through which vesicular secretions exit into the extracellular space. A fusion pore was thought to be a short-lived intermediate preceding full-fusion of the vesicle and the plasma membranes (full-fusion exocytosis). However, transient exocytic events were also observed, where the fusion-pore opens and closes, repetitively. Here we asked whether there are different discrete states of the open fusion-pore. Unitary exocytic events were recorded by the high-resolution cell-attached patch-clamp method in pituitary lactotrophs and brain astrocytes. We monitored reversible unitary exocytic events, characterized by an on-step, which is followed by an off-step in membrane capacitance (Cm), a parameter linearly related to the membrane area. The results revealed three categories of reversible exocytic events (transient fusion-pore openings), which do not end with the complete integration of the vesicle membrane into the plasma membrane. These were categorized according to the observed differences in the amplitude and sign of the change in the real (Re) parts of the admittance signals: in case I events (Re ≈ 0) fusion pores are relatively wide; in case II (Re > 0) and case III (Re < 0) events fusion pores are relatively narrow. We show that case III events are more likely to occur for small vesicles, whereas, case II events are more likely to occur for larger vesicles. Case III events were considerably more frequent in astrocytes than in lactotrophs.
Collapse
Affiliation(s)
- Doron Kabaso
- Laboratory of Biophysics, Faculty of Electrical Engineering, University of Ljubljana Ljubljana, Slovenia ; Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana Ljubljana, Slovenia
| | | | | | | | | | | | | |
Collapse
|
42
|
Khan AA, Jabeen M, Khan AA, Owais M. Anticancer efficacy of a novel propofol-linoleic acid-loaded escheriosomal formulation against murine hepatocellular carcinoma. Nanomedicine (Lond) 2013; 8:1281-94. [PMID: 23311988 DOI: 10.2217/nnm.12.166] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
AIM The preparation and characterization of a novel escheriosomal nanoparticle formulation of a potent anticancer conjugate, 2,6-diisopropylphenol-linoleic acid (2,6P-LA), and evaluation of its anticancer efficacy against diethyl nitrosamine-induced hepatocellular carcinoma (HCC) in BALB/c mice. MATERIALS & METHODS Escheriosomized 2,6P-LA nanoparticles were characterized for size, zeta-potential, entrapment efficiency, release kinetics and in vivo toxicity. Their anticancer potential was evaluated on the basis of survival, DNA fragmentation, caspase-3 activation, western blot analysis of apoptotic factors and histopathological changes in hepatocytes of treated animals. RESULTS The escheriosomized 2,6P-LA nanoparticles exhibited low toxicity, biocompatibility and bioavailability. As revealed by apoptosis induction, survival rate, expression profiles of Bax, Bcl-2 and caspase-9, escheriosomized 2,6P-LA nanoparticles were more effective in the treatment of HCC than the free form of 2,6P-LA in experimental animals. CONCLUSION 2,6P-LA-bearing escheriosome nanoparticles are effective in suppressing HCC in mice. Original submitted 17 January 2012; Revised submitted 27 August 2012; Published online 14 January 2013.
Collapse
Affiliation(s)
- Azmat Ali Khan
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh 202002, India.
| | | | | | | |
Collapse
|
43
|
Zheng T, Voskuhl J, Versluis F, Zope HR, Tomatsu I, Marsden HR, Kros A. Controlling the rate of coiled coil driven membrane fusion. Chem Commun (Camb) 2013; 49:3649-51. [DOI: 10.1039/c3cc38926j] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
44
|
Ashkenazi A, Merklinger E, Shai Y. Intramolecular interactions within the human immunodeficiency virus-1 gp41 loop region and their involvement in lipid merging. Biochemistry 2012; 51:6981-9. [PMID: 22894130 DOI: 10.1021/bi300868f] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The human immunodeficiency virus utilizes its gp41 fusion protein to mediate virus-cell membrane fusion. The conserved disulfide loop region in the gp41 hairpin conformation reverses the protein chain, such that the N-terminal heptad repeat and the C-terminal heptad repeat regions interact to form the six-helix bundle. Hence, it is conceivable that the sequential folded N- and C-terminal parts of the loop region also interact. We show that the N- and C-terminal parts of the loop preferably form disulfide-bonded heterodimers with slow oxidation kinetics. Furthermore, when the two parts were linked to a single polypeptide to form the full-length loop, only an intramolecular disulfide-bonded loop was formed. Fluorescence studies revealed that an interaction takes place between the N- and C-terminal parts of the loop in solution, which was sustained in membranes. Functionally, only a combination of the N- and C-loop parts induced lipid mixing of model liposomes, the level of which increased 8-fold when they were connected to a single polypeptide chain. In both cases, the activity was independent of the oxidation state of the cysteines. Overall, the data (i) provide evidence of a specific interaction between the N- and C-terminal parts of the loop, which can further stabilize gp41 hairpin conformation, and (ii) suggest that the interaction between the N- and C-terminal parts of the loop is sufficient to induce lipid merging without forming a disulfide bond.
Collapse
Affiliation(s)
- Avraham Ashkenazi
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, 76100 Israel
| | | | | |
Collapse
|
45
|
Faingold O, Cohen T, Shai Y. A GxxxG-like motif within HIV-1 fusion peptide is critical to its immunosuppressant activity, structure, and interaction with the transmembrane domain of the T-cell receptor. J Biol Chem 2012; 287:33503-11. [PMID: 22872636 DOI: 10.1074/jbc.m112.370817] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To thrive in the human body, HIV fuses to its target cell and evades the immune response via several mechanisms. The fusion cascade is initiated by the fusion peptide (FP), which is located at the N-terminal of gp41, the transmembrane protein of HIV. Recently, it has been shown that the HIV-1 FP, particularly its 5-13 amino acid region (FP(5-13)), suppresses T-cell activation and interacts with the transmembrane domain (TMD) of the T-cell receptor (TCR) complex. Specific amino acid motifs often contribute to such interactions in TMDs of membrane proteins. Using bioinformatics and experimental studies, we report on a GxxxG-like motif (AxxxG), which is conserved in the FP throughout different clades and strains of HIV-1. Biological activity studies and FTIR spectroscopy revealed that HIV FP(5-13)-derived peptides, in which the motif was altered either by randomization or by a single amino acid shift, lost their immunosuppressive activity concomitant with a loss of the β-sheet structure in a membranous environment. Furthermore, fluorescence studies revealed that the inactive mutants lost their ability to interact with their target site, namely, the TMD of TCRα, designated CP. Importantly, lipotechoic acid activated macrophages (lacking TCR) were not affected by FP, further demonstrating the specificity of the immunosuppressant activity of CP. Finally, although the AxxxG WT and the GxxxG analog both associated with the CP and immunosuppressed T-cells, the AxxxG WT but not the GxxxG analog induced lipid mixing. Overall, the data support an important role for the AxxxG motif in the function of FP and might explain the natural selection of the AxxxG motif rather than the classical GxxxG motif in FP.
Collapse
Affiliation(s)
- Omri Faingold
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
| | | | | |
Collapse
|
46
|
Suzuki K, Aboshi R, Kurihara K, Sugawara T. Adhesion and Fusion of Two Kinds of Phospholipid Hybrid Vesicles Controlled by Surface Charges of Vesicular Membranes. CHEM LETT 2012. [DOI: 10.1246/cl.2012.789] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Kentaro Suzuki
- Research Center of Life Science as Complex Systems, The University of Tokyo
| | - Ryo Aboshi
- Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo
| | - Kensuke Kurihara
- Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo
| | - Tadashi Sugawara
- Research Center of Life Science as Complex Systems, The University of Tokyo
| |
Collapse
|
47
|
Komatsu T, Kido N, Sugiyama T, Yokochi T. Antiviral activity of acidic polysaccharides fromCoccomyxa gloeobotrydiformi, a green alga, against anin vitrohuman influenza A virus infection. Immunopharmacol Immunotoxicol 2012; 35:1-7. [DOI: 10.3109/08923973.2012.710636] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
|
48
|
Yao W, Qian H, Zhang J, Wu W, Jiang X. Multifusion-induced wall-super-thick giant multilamellar vesicles. Chem Commun (Camb) 2012; 48:7079-81. [PMID: 22684038 DOI: 10.1039/c2cc32387g] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A polymeric multivesicular system was created by hydrating a film. This system underwent multifusion events and eventually evolved into giant multilamellar vesicles with extremely thick walls. The semi-permeable wall and large size make these vesicles suitable for encapsulating living cells.
Collapse
Affiliation(s)
- Wei Yao
- Laboratory of Mesoscopic Chemistry and Department of Polymer Science and Engineering, College of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China
| | | | | | | | | |
Collapse
|
49
|
Abstract
Membrane fusion is one of the most important cellular processes by which two initially distinct lipid bilayers merge their hydrophobic cores, resulting in one interconnected structure. Proteins, called SNARE (soluble N-ethylmaleimide-sensitive factor-attachment protein receptor), play a central role in the fusion process that is also regulated by several accessory proteins. In order to study the SNARE-mediated membrane fusion, the in vitro protein reconstitution assay involving ensemble FRET (fluorescence resonance energy transfer) has been used over a decade. In this mini-review, we describe several single-molecule-based FRET approaches that have been applied to this field to overcome the shortage of the bulk assay in terms of protein and fusion dynamics.
Collapse
Affiliation(s)
- Jiajie Diao
- Department of Physics and Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Yuji Ishitsuka
- Department of Physics and Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Howard Hughes Medical Institute, University of Illinois at Urbana–Champaign, Urbana, IL 61801, USA
| | - Woo-Ri Bae
- Department of Physics, KAIST, Daejeon 305-701, Republic of Korea
| |
Collapse
|
50
|
Ashkenazi A, Wexler-Cohen Y, Shai Y. Multifaceted action of Fuzeon as virus–cell membrane fusion inhibitor. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:2352-8. [DOI: 10.1016/j.bbamem.2011.06.020] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Revised: 06/24/2011] [Accepted: 06/27/2011] [Indexed: 12/30/2022]
|