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Xie E, Ahmad S, Smyth RP, Sieben C. Advanced fluorescence microscopy in respiratory virus cell biology. Adv Virus Res 2023; 116:123-172. [PMID: 37524480 DOI: 10.1016/bs.aivir.2023.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/02/2023]
Abstract
Respiratory viruses are a major public health burden across all age groups around the globe, and are associated with high morbidity and mortality rates. They can be transmitted by multiple routes, including physical contact or droplets and aerosols, resulting in efficient spreading within the human population. Investigations of the cell biology of virus replication are thus of utmost importance to gain a better understanding of virus-induced pathogenicity and the development of antiviral countermeasures. Light and fluorescence microscopy techniques have revolutionized investigations of the cell biology of virus infection by allowing the study of the localization and dynamics of viral or cellular components directly in infected cells. Advanced microscopy including high- and super-resolution microscopy techniques available today can visualize biological processes at the single-virus and even single-molecule level, thus opening a unique view on virus infection. We will highlight how fluorescence microscopy has supported investigations on virus cell biology by focusing on three major respiratory viruses: respiratory syncytial virus (RSV), Influenza A virus (IAV) and SARS-CoV-2. We will review our current knowledge of virus replication and highlight how fluorescence microscopy has helped to improve our state of understanding. We will start by introducing major imaging and labeling modalities and conclude the chapter with a perspective discussion on remaining challenges and potential opportunities.
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Affiliation(s)
- Enyu Xie
- Nanoscale Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Shazeb Ahmad
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
| | - Redmond P Smyth
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany; Faculty of Medicine, University of Würzburg, Würzburg, Germany
| | - Christian Sieben
- Nanoscale Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany; Institute of Genetics, Technische Universität Braunschweig, Braunschweig, Germany.
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Moreno-Pescador G, Arastoo MR, Ruhoff VT, Chiantia S, Daniels R, Bendix PM. Thermoplasmonic Vesicle Fusion Reveals Membrane Phase Segregation of Influenza Spike Proteins. NANO LETTERS 2023; 23:3377-3384. [PMID: 37040311 PMCID: PMC10141563 DOI: 10.1021/acs.nanolett.3c00371] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Many cellular processes involve the lateral organization of integral and peripheral membrane proteins into nanoscale domains. Despite the biological significance, the mechanisms that facilitate membrane protein clustering into nanoscale lipid domains remain enigmatic. In cells, the analysis of membrane protein phase affinity is complicated by the size and temporal nature of ordered and disordered lipid domains. To overcome these limitations, we developed a method for delivering membrane proteins from transfected cells into phase-separated model membranes that combines optical trapping with thermoplasmonic-mediated membrane fusion and confocal imaging. Using this approach, we observed clear phase partitioning into the liquid disordered phase following the transfer of GFP-tagged influenza hemagglutinin and neuraminidase from transfected cell membranes to giant unilamellar vesicles. The generic platform presented here allows investigation of the phase affinity of any plasma membrane protein which can be labeled or tagged with a fluorescent marker.
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Affiliation(s)
| | - Mohammad Reza Arastoo
- Niels
Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 København Ø, Denmark
| | | | - Salvatore Chiantia
- Institute
of Biochemistry and Biology, University
of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany
| | - Robert Daniels
- Division
of Viral Products, Center for Biologics
Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland 20993, United States
| | - Poul Martin Bendix
- Niels
Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 København Ø, Denmark
- Email
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3
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Roy A, Byrne S, Sarangi NK, Murphy PV, Keyes TE. A cell free biomembrane platform for multimodal study of influenza virus hemagglutinin and for evaluation of entry-inhibitors against hemagglutinin. Front Mol Biosci 2022; 9:1017338. [DOI: 10.3389/fmolb.2022.1017338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 09/07/2022] [Indexed: 11/13/2022] Open
Abstract
Seasonal periodic pandemics and epidemics caused by Influenza A viruses (IAVs) are associated with high morbidity and mortality worldwide. They are frequent and unpredictable in severity so there is a need for biophysical platforms that can be used to provide both mechanistic insights into influenza virulence and its potential treatment by anti-IAV agents. Host membrane viral association through the glycoprotein hemagglutinin (HA) of IAVs is one of the primary steps in infection. HA is thus a potential target for drug discovery and development against influenza. Deconvolution of the multivalent interactions of HA at the interfaces of the host cell membrane can help unravel therapeutic targets. In this contribution, we reported the effect of a multivalent HA glycoprotein association on various glycosphingolipid receptors (GD1a, GM3, GM1) doped asymmetrically into an artificial host membrane spanned across an aqueous filled microcavity array. The extent of HA association and its impact on membrane resistance, capacitance, and diffusivity was measured using highly sensitive electrochemical impedance spectroscopy (EIS) and fluorescence lifetime correlation spectroscopy (FLCS). Furthermore, we investigated the inhibition of the influenza HA glycoprotein association with the host mimetic surface by natural and synthetic sialic acid-based inhibitors (sialic acid, Siaα2,3-GalOMe, FB127, 3-sialyl lactose) using electrochemical impedance spectroscopy and observe that while all inhibit, they do not prevent host binding. Overall, the work demonstrates the platform provides a label-free screening platform for the biophysical evaluation of new inhibitors in the development of potential therapeutics for IAV infection prevention and treatment.
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A Glu-Glu-Tyr Sequence in the Cytoplasmic Tail of the M2 Protein Renders Influenza A Virus Susceptible to Restriction of the Hemagglutinin-M2 Association in Primary Human Macrophages. J Virol 2022; 96:e0071622. [PMID: 36098511 PMCID: PMC9517718 DOI: 10.1128/jvi.00716-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Influenza A virus (IAV) assembly at the plasma membrane is orchestrated by at least five viral components, including hemagglutinin (HA), neuraminidase (NA), matrix (M1), the ion channel M2, and viral ribonucleoprotein (vRNP) complexes, although particle formation is observed with expression of only HA and/or NA. While these five viral components are expressed efficiently in primary human monocyte-derived macrophages (MDMs) upon IAV infection, this cell type does not support efficient HA-M2 association and IAV particle assembly at the plasma membrane. Both defects are specific to MDMs and can be reversed upon disruption of F-actin. However, the relationship between the two defects is unclear. Here, we examined whether M2 contributes to particle assembly in MDMs and if so, which region of M2 determines the susceptibility to the MDM-specific and actin-dependent suppression. An analysis using correlative fluorescence and scanning electron microscopy showed that an M2-deficient virus failed to form budding structures at the cell surface even after F-actin was disrupted, indicating that M2 is essential for virus particle formation at the MDM surface. Notably, proximity ligation analysis revealed that a single amino acid substitution in a Glu-Glu-Tyr sequence (residues 74 to 76) in the M2 cytoplasmic tail allowed the HA-M2 association to occur efficiently even in MDMs with intact actin cytoskeleton. This phenotype did not correlate with known phenotypes of the M2 substitution mutants regarding M1 interaction or vRNP packaging in epithelial cells. Overall, our study identified M2 as a target of MDM-specific restriction of IAV assembly, which requires the Glu-Glu-Tyr sequence in the cytoplasmic tail. IMPORTANCE Human MDMs represent a cell type that is nonpermissive to particle formation of influenza A virus (IAV). We previously showed that close proximity association between viral HA and M2 proteins is blocked in MDMs. However, whether MDMs express a restriction factor against IAV assembly or whether they lack a dependency factor promoting assembly remained unknown. In the current study, we determined that the M2 protein is necessary for particle formation in MDMs but is also a molecular target of the MDM-specific suppression of assembly. Substitutions in the M2 cytoplasmic tail alleviated the block in both the HA-M2 association and particle production in MDMs. These findings suggest that MDMs express dependency factors necessary for assembly but also express a factor(s) that inhibits HA-M2 association and particle formation. High conservation of the M2 sequence rendering the susceptibility to the assembly block highlights the potential for M2 as a target of antiviral strategies.
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ARHGAP1 Transported with Influenza Viral Genome Ensures Integrity of Viral Particle Surface through Efficient Budozone Formation. mBio 2022; 13:e0072122. [PMID: 35475647 PMCID: PMC9239208 DOI: 10.1128/mbio.00721-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Influenza viral particles are assembled at the plasma membrane concomitantly with Rab11a-mediated endocytic transport of viral ribonucleoprotein complexes (vRNPs). The mechanism of spatiotemporal regulation of viral budozone formation and its regulatory molecules on the endocytic vesicles remain unclear. Here, we performed a proximity-based proteomics approach for Rab11a and found that ARHGAP1, a Rho GTPase-activating protein, is transported through the Rab11a-mediated apical transport of vRNP. ARHGAP1 stabilized actin filaments in infected cells for the lateral clustering of hemagglutinin (HA) molecules, a viral surface membrane protein, to the budozone. Disruption of the HA clustering results in the production of virions with low HA content, and such virions were less resistant to protease and had enhanced antigenicity, presumably because reduced clustering of viral membrane proteins exposes hidden surfaces. Collectively, these results demonstrate that Rab11a-mediated endocytic transport of ARHGAP1 with vRNPs stimulates budozone formation to ensure the integrity of virion surface required for viral survival.
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Raut P, Weller SR, Obeng B, Soos BL, West BE, Potts CM, Sangroula S, Kinney MS, Burnell JE, King BL, Gosse JA, Hess ST. Cetylpyridinium chloride (CPC) reduces zebrafish mortality from influenza infection: Super-resolution microscopy reveals CPC interference with multiple protein interactions with phosphatidylinositol 4,5-bisphosphate in immune function. Toxicol Appl Pharmacol 2022; 440:115913. [PMID: 35149080 PMCID: PMC8824711 DOI: 10.1016/j.taap.2022.115913] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 01/04/2022] [Accepted: 02/04/2022] [Indexed: 01/12/2023]
Abstract
The COVID-19 pandemic raises significance for a potential influenza therapeutic compound, cetylpyridinium chloride (CPC), which has been extensively used in personal care products as a positively-charged quaternary ammonium antibacterial agent. CPC is currently in clinical trials to assess its effects on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) morbidity. Two published studies have provided mouse and human data indicating that CPC may alleviate influenza infection, and here we show that CPC (0.1 μM, 1 h) reduces zebrafish mortality and viral load following influenza infection. However, CPC mechanisms of action upon viral-host cell interaction are currently unknown. We have utilized super-resolution fluorescence photoactivation localization microscopy to probe the mode of CPC action. Reduction in density of influenza viral protein hemagglutinin (HA) clusters is known to reduce influenza infectivity: here, we show that CPC (at non-cytotoxic doses, 5-10 μM) reduces HA density and number of HA molecules per cluster within the plasma membrane of NIH-3T3 mouse fibroblasts. HA is known to colocalize with the negatively-charged mammalian lipid phosphatidylinositol 4,5-bisphosphate (PIP2); here, we show that nanoscale co-localization of HA with the PIP2-binding Pleckstrin homology (PH) reporter in the plasma membrane is diminished by CPC. CPC also dramatically displaces the PIP2-binding protein myristoylated alanine-rich C-kinase substrate (MARCKS) from the plasma membrane of rat RBL-2H3 mast cells; this disruption of PIP2 is correlated with inhibition of mast cell degranulation. Together, these findings offer a PIP2-focused mechanism underlying CPC disruption of influenza and suggest potential pharmacological use of this drug as an influenza therapeutic to reduce global deaths from viral disease.
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Affiliation(s)
- Prakash Raut
- Department of Physics and Astronomy, University of Maine, Orono, ME, USA
| | - Sasha R Weller
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME, USA
| | - Bright Obeng
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME, USA
| | - Brandy L Soos
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME, USA
| | - Bailey E West
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME, USA
| | - Christian M Potts
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME, USA
| | - Suraj Sangroula
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME, USA
| | - Marissa S Kinney
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME, USA
| | - John E Burnell
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME, USA
| | - Benjamin L King
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME, USA
| | - Julie A Gosse
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME, USA.
| | - Samuel T Hess
- Department of Physics and Astronomy, University of Maine, Orono, ME, USA.
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7
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Mittal A, Chauhan A. Aspects of Biological Replication and Evolution Independent of the Central Dogma: Insights from Protein-Free Vesicular Transformations and Protein-Mediated Membrane Remodeling. J Membr Biol 2022; 255:185-209. [PMID: 35333977 PMCID: PMC8951669 DOI: 10.1007/s00232-022-00230-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Accepted: 03/06/2022] [Indexed: 11/21/2022]
Abstract
Biological membrane remodeling is central to living systems. In spite of serving as “containers” of whole-living systems and functioning as dynamic compartments within living systems, biological membranes still find a “blue collar” treatment compared to the “white collar” nucleic acids and proteins in biology. This may be attributable to the fact that scientific literature on biological membrane remodeling is only 50 years old compared to ~ 150 years of literature on proteins and a little less than 100 years on nucleic acids. However, recently, evidence for symbiotic origins of eukaryotic cells from data only on biological membranes was reported. This, coupled with appreciation of reproducible amphiphilic self-assemblies in aqueous environments (mimicking replication), has already initiated discussions on origins of life beyond nucleic acids and proteins. This work presents a comprehensive compilation and meta-analyses of data on self-assembly and vesicular transformations in biological membranes—starting from model membranes to establishment of Influenza Hemagglutinin-mediated membrane fusion as a prototypical remodeling system to a thorough comparison between enveloped mammalian viruses and cellular vesicles. We show that viral membrane fusion proteins, in addition to obeying “stoichiometry-driven protein folding”, have tighter compositional constraints on their amino acid occurrences than general-structured proteins, regardless of type/class. From the perspective of vesicular assemblies and biological membrane remodeling (with and without proteins) we find that cellular vesicles are quite different from viruses. Finally, we propose that in addition to pre-existing thermodynamic frameworks, kinetic considerations in de novo formation of metastable membrane structures with available “third-party” constituents (including proteins) were not only crucial for origins of life but also continue to offer morphological replication and/or functional mechanisms in modern life forms, independent of the central dogma.
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Affiliation(s)
- Aditya Mittal
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi (IIT Delhi), Hauz Khas, New Delhi, 110016, India. .,Supercomputing Facility for Bioinformatics and Computational Biology (SCFBio), IIT Delhi, Hauz Khas, New Delhi, 110016, India.
| | - Akanksha Chauhan
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi (IIT Delhi), Hauz Khas, New Delhi, 110016, India
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8
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Alazawi MA, Jiang S, Messner SF. Identifying a spatial scale for the analysis of residential burglary: An empirical framework based on point pattern analysis. PLoS One 2022; 17:e0264718. [PMID: 35226707 PMCID: PMC8884495 DOI: 10.1371/journal.pone.0264718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 02/15/2022] [Indexed: 11/18/2022] Open
Abstract
A key issue in the spatial and temporal analysis of residential burglary is the choice of scale: spatial patterns might differ appreciably for different time periods and vary across geographic units of analysis. Based on point pattern analysis of burglary incidents in Columbus, Ohio during a 9-year period, this study develops an empirical framework to identify a useful spatial scale and its dependence on temporal aggregation. Our analysis reveals that residential burglary in Columbus clusters at a characteristic scale of 2.2 km. An ANOVA test shows no significant impact of temporal aggregation on spatial scale of clustering. This study demonstrates the value of point pattern analysis in identifying a scale for the analysis of crime patterns. Furthermore, the characteristic scale of clustering determined using our method has great potential applications: (1) it can reflect the spatial environment of criminogenic processes and thus be used to define the spatial boundary for place-based policing; (2) it can serve as a candidate for the bandwidth (search radius) for hot spot policing; (3) its independence of temporal aggregation implies that police officials need not be concerned about the shifting sizes of risk-areas depending on the time of the year.
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Affiliation(s)
- Mohammed A. Alazawi
- Department of Information Science, University at Albany, State University of New York, Albany, NY, United States of America
| | - Shiguo Jiang
- Department of Geography and Planning, University at Albany, State University of New York, Albany, NY, United States of America
| | - Steven F. Messner
- Department of Sociology, University at Albany, State University of New York, Albany, NY, United States of America
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9
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Pattnaik GP, Chakraborty H. Cholesterol: A key player in membrane fusion that modulates the efficacy of fusion inhibitor peptides. VITAMINS AND HORMONES 2021; 117:133-155. [PMID: 34420578 DOI: 10.1016/bs.vh.2021.06.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The interaction of cholesterol with the neighboring lipids modulates several physical properties of the membrane. Mostly, it affects membrane fluidity, membrane permeability, lateral diffusion of lipids, bilayer thickness, and water penetration into the lipid bilayer. Due to the smaller head group to hydrophobic cross-sectional area of the tail, cholesterol induces intrinsic negative curvature to the membrane. The interaction of cholesterol with sphingolipids forms lipid rafts; generates phase separation in the membrane. The cholesterol-dependent modifications of membrane physical properties modulate viral infections by affecting the fusion between viral and host cell membranes. Cholesterol demonstrates a strong impact on the structure, depth of penetration, conformation, and organization of fusion peptides in membrane milieu. Further, cholesterol has been implicated to modify the fusion inhibitory efficiency of peptide-based membrane fusion inhibitors.
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Affiliation(s)
| | - Hirak Chakraborty
- School of Chemistry, Sambalpur University, Burla, Odisha, India; Centre of Excellence in Natural Products and Therapeutics, Sambalpur University, Burla, Odisha, India.
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10
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Hao M, Hou S, Li W, Li K, Xue L, Hu Q, Zhu L, Chen Y, Sun H, Ju C, Zhang C. Combination of metabolic intervention and T cell therapy enhances solid tumor immunotherapy. Sci Transl Med 2021; 12:12/571/eaaz6667. [PMID: 33239389 DOI: 10.1126/scitranslmed.aaz6667] [Citation(s) in RCA: 77] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Revised: 07/14/2020] [Accepted: 08/21/2020] [Indexed: 12/12/2022]
Abstract
Treatment of solid tumors with T cell therapy has yielded limited therapeutic benefits to date. Although T cell therapy in combination with proinflammatory cytokines or immune checkpoints inhibitors has demonstrated preclinical and clinical successes in a subset of solid tumors, unsatisfactory results and severe toxicities necessitate the development of effective and safe combinatorial strategies. Here, the liposomal avasimibe (a metabolism-modulating drug) was clicked onto the T cell surface by lipid insertion without disturbing the physiological functions of the T cell. Avasimibe could be restrained on the T cell surface during circulation and extravasation and locally released to increase the concentration of cholesterol in the T cell membrane, which induced rapid T cell receptor clustering and sustained T cell activation. Treatment with surface anchor-engineered T cells, including mouse T cell receptor transgenic CD8+ T cells or human chimeric antigen receptor T cells, resulted in superior antitumor efficacy in mouse models of melanoma and glioblastoma. Glioblastoma was completely eradicated in three of the five mice receiving surface anchor-engineered chimeric antigen receptor T cells, whereas mice in other treatment groups survived no more than 64 days. Moreover, the administration of engineered T cells showed no obvious systemic side effects. These cell-surface anchor-engineered T cells hold translational potential because of their simple generation and their safety profile.
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Affiliation(s)
- Meixi Hao
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Drug Discovery for Metabolic Diseases, Center of Advanced Pharmaceuticals and Biomaterials, China Pharmaceutical University, Nanjing 210009, P.R. China
| | - Siyuan Hou
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Drug Discovery for Metabolic Diseases, Center of Advanced Pharmaceuticals and Biomaterials, China Pharmaceutical University, Nanjing 210009, P.R. China
| | - Weishuo Li
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Drug Discovery for Metabolic Diseases, Center of Advanced Pharmaceuticals and Biomaterials, China Pharmaceutical University, Nanjing 210009, P.R. China
| | - Kaiming Li
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Drug Discovery for Metabolic Diseases, Center of Advanced Pharmaceuticals and Biomaterials, China Pharmaceutical University, Nanjing 210009, P.R. China
| | - Lingjing Xue
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Drug Discovery for Metabolic Diseases, Center of Advanced Pharmaceuticals and Biomaterials, China Pharmaceutical University, Nanjing 210009, P.R. China
| | - Qifan Hu
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Drug Discovery for Metabolic Diseases, Center of Advanced Pharmaceuticals and Biomaterials, China Pharmaceutical University, Nanjing 210009, P.R. China
| | - Lulu Zhu
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Drug Discovery for Metabolic Diseases, Center of Advanced Pharmaceuticals and Biomaterials, China Pharmaceutical University, Nanjing 210009, P.R. China
| | - Yue Chen
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Drug Discovery for Metabolic Diseases, Center of Advanced Pharmaceuticals and Biomaterials, China Pharmaceutical University, Nanjing 210009, P.R. China
| | - Hongbin Sun
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Drug Discovery for Metabolic Diseases, Center of Advanced Pharmaceuticals and Biomaterials, China Pharmaceutical University, Nanjing 210009, P.R. China
| | - Caoyun Ju
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Drug Discovery for Metabolic Diseases, Center of Advanced Pharmaceuticals and Biomaterials, China Pharmaceutical University, Nanjing 210009, P.R. China.
| | - Can Zhang
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Drug Discovery for Metabolic Diseases, Center of Advanced Pharmaceuticals and Biomaterials, China Pharmaceutical University, Nanjing 210009, P.R. China.
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11
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Cholesterol Binding to the Transmembrane Region of a Group 2 Hemagglutinin (HA) of Influenza Virus Is Essential for Virus Replication, Affecting both Virus Assembly and HA Fusion Activity. J Virol 2019; 93:JVI.00555-19. [PMID: 31118253 DOI: 10.1128/jvi.00555-19] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 05/14/2019] [Indexed: 12/21/2022] Open
Abstract
Hemagglutinin (HA) of influenza virus is incorporated into cholesterol-enriched nanodomains of the plasma membrane. Phylogenetic group 2 HAs contain the conserved cholesterol consensus motif (CCM) YKLW in the transmembrane region. We previously reported that mutations in the CCM retarded intracellular transport of HA and decreased its nanodomain association. Here, we analyzed whether cholesterol interacts with the CCM. Incorporation of photocholesterol into HA was significantly reduced if the whole CCM is replaced by alanine, both using immunoprecipitated HA and when HA is embedded in the membrane. We next used reverse genetics to investigate the significance of the CCM for virus replication. No virus was rescued if the whole motif is exchanged (YKLW4A); singly (LA) or doubly (YK2A and LW2A) mutated virus showed decreased titers and a comparative fitness disadvantage. In polarized cells, transport of HA mutants to the apical membrane was not disturbed. Reduced amounts of HA and cholesterol were incorporated into the viral membrane. Mutant viruses exhibit a decrease in hemolysis, which is only partially corrected if the membrane is replenished with cholesterol. More specifically, viruses have a defect in hemifusion, as demonstrated by fluorescence dequenching. Cells expressing HA YKLW4A fuse with erythrocytes, but the number of events is reduced. Even after acidification unfused erythrocytes remain cell bound, a phenomenon not observed with wild-type HA. We conclude that cholesterol binding to a group 2 HA is essential for virus replication. It has pleiotropic effects on virus assembly and membrane fusion, mainly on lipid mixing and possibly a preceding step.IMPORTANCE The glycoprotein HA is a major pathogenicity factor of influenza viruses. Whereas the structure and function of HA's ectodomain is known in great detail, similar data for the membrane-anchoring part of the protein are missing. Here, we demonstrate that the transmembrane region of a group 2 HA interacts with cholesterol, the major lipid of the plasma membrane and the defining element of the viral budding site nanodomains of the plasma membrane. The cholesterol binding motif is essential for virus replication. Its partial removal affects various steps of the viral life cycle, such as assembly of new virus particles and their subsequent cell entry via membrane fusion. A cholesterol binding pocket in group 2 HAs might be a promising target for a small lipophilic drug that inactivates the virus.
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12
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Curthoys NM, Mlodzianoski MJ, Parent M, Butler MB, Raut P, Wallace J, Lilieholm J, Mehmood K, Maginnis MS, Waters H, Busse B, Zimmerberg J, Hess ST. Influenza Hemagglutinin Modulates Phosphatidylinositol 4,5-Bisphosphate Membrane Clustering. Biophys J 2019; 116:893-909. [PMID: 30773293 DOI: 10.1016/j.bpj.2019.01.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 01/07/2019] [Accepted: 01/15/2019] [Indexed: 12/13/2022] Open
Abstract
The lipid phosphatidylinositol 4,5-bisphosphate (PIP2) forms nanoscopic clusters in cell plasma membranes; however, the processes determining PIP2 mobility and thus its spatial patterns are not fully understood. Using super-resolution imaging of living cells, we find that PIP2 is tightly colocalized with and modulated by overexpression of the influenza viral protein hemagglutinin (HA). Within and near clusters, HA and PIP2 follow a similar spatial dependence, which can be described by an HA-dependent potential gradient; PIP2 molecules move as if they are attracted to the center of clusters by a radial force of 0.079 ± 0.002 pN in HAb2 cells. The measured clustering and dynamics of PIP2 are inconsistent with the unmodified forms of the raft, tether, and fence models. Rather, we found that the spatial PIP2 distributions and how they change in time are explained via a novel, to our knowledge, dynamic mechanism: a radial gradient of PIP2 binding sites that are themselves mobile. This model may be useful for understanding other biological membrane domains whose distributions display gradients in density while maintaining their mobility.
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Affiliation(s)
- Nikki M Curthoys
- Department of Physics and Astronomy, University of Maine, Orono, Maine
| | | | - Matthew Parent
- Department of Physics and Astronomy, University of Maine, Orono, Maine
| | - Michael B Butler
- Department of Physics and Astronomy, University of Maine, Orono, Maine
| | - Prakash Raut
- Department of Physics and Astronomy, University of Maine, Orono, Maine
| | - Jaqulin Wallace
- Department of Physics and Astronomy, University of Maine, Orono, Maine
| | | | - Kashif Mehmood
- Department of Physics and Astronomy, University of Maine, Orono, Maine; Department of Molecular and Biomedical Sciences, University of Maine, Orono, Maine
| | - Melissa S Maginnis
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, Maine
| | - Hang Waters
- Section on Integrative Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Brad Busse
- Section on Integrative Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Joshua Zimmerberg
- Section on Integrative Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Samuel T Hess
- Department of Physics and Astronomy, University of Maine, Orono, Maine.
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13
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Bedi S, Ono A. Friend or Foe: The Role of the Cytoskeleton in Influenza A Virus Assembly. Viruses 2019; 11:v11010046. [PMID: 30634554 PMCID: PMC6356976 DOI: 10.3390/v11010046] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Revised: 01/02/2019] [Accepted: 01/08/2019] [Indexed: 12/12/2022] Open
Abstract
Influenza A Virus (IAV) is a respiratory virus that causes seasonal outbreaks annually and pandemics occasionally. The main targets of the virus are epithelial cells in the respiratory tract. Like many other viruses, IAV employs the host cell’s machinery to enter cells, synthesize new genomes and viral proteins, and assemble new virus particles. The cytoskeletal system is a major cellular machinery, which IAV exploits for its entry to and exit from the cell. However, in some cases, the cytoskeleton has a negative impact on efficient IAV growth. In this review, we highlight the role of cytoskeletal elements in cellular processes that are utilized by IAV in the host cell. We further provide an in-depth summary of the current literature on the roles the cytoskeleton plays in regulating specific steps during the assembly of progeny IAV particles.
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Affiliation(s)
- Sukhmani Bedi
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109, USA.
| | - Akira Ono
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109, USA.
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14
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Goñi FM. "Rafts": A nickname for putative transient nanodomains. Chem Phys Lipids 2018; 218:34-39. [PMID: 30476484 DOI: 10.1016/j.chemphyslip.2018.11.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 10/29/2018] [Accepted: 11/21/2018] [Indexed: 01/24/2023]
Abstract
The membrane raft hypothesis, proposed in 1997 by Simons and Ikonen, has played a paradoxical role in the history of biomembrane research. While it has generated a large amount of investigations, thus helping to increase our understanding of membranes, the object that gives name to the hypothesis, i.e. the raft itself, has been and still is an object of controversy, in which its very reality is often questioned. In this contribution I review the history of the hypothesis and its reception by membrane biologists, and summarize some of the valuable physico-chemical results that have been obtained while testing the raft hypothesis. To save a useful concept from its many misuses I propose that the expression "(transient) nanodomains" be employed instead of "rafts".
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Affiliation(s)
- Félix M Goñi
- Instituto Biofisika (CSIC, UPV/EHU), Departamento de Bioquímica, Universidad del País Vasco, 48940 Leioa, Spain.
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15
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Abstract
For efficient replication of the influenza virus genome and its post-replicational processes, not only viral factors but also host-derived cellular factors (host factors) are required. The influenza virus genome exists as viral ribonucleoprotein (vRNP) complexes with viral RNA-dependent RNA polymerases and nucleoprotein (NP). Using biochemical and proteomics approaches, we have identified host factors which are required for the vRNP replication and the progeny vRNP transport. We found that MCM complex, a cellular DNA replication licensing factor, is required for successful viral genome replication. In concert with the replication reaction, the nascent RNA chains are encapsidated with NP by cellular splicing factor UAP56. Further, after nuclear export of vRNP, we revealed that vRNP is transported to the plasma membrane using cholesterol-enriched recycling endosomes through cell cycle-independent activation of the centrosome by YB-1, which is a mitotic centrosomal protein. Depletion of YB-1 shows that the cholesterol-enriched endosomes are important for clustering of viral structural proteins at lipid rafts to assemble the virus particles concomitantly with the arrival of vRNP beneath the plasma membrane.
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16
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Lateral Organization of Influenza Virus Proteins in the Budozone Region of the Plasma Membrane. J Virol 2017; 91:JVI.02104-16. [PMID: 28202765 DOI: 10.1128/jvi.02104-16] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 02/12/2017] [Indexed: 12/24/2022] Open
Abstract
Influenza virus assembles and buds at the plasma membrane of virus-infected cells. The viral proteins assemble at the same site on the plasma membrane for budding to occur. This involves a complex web of interactions among viral proteins. Some proteins, like hemagglutinin (HA), NA, and M2, are integral membrane proteins. M1 is peripherally membrane associated, whereas NP associates with viral RNA to form an RNP complex that associates with the cytoplasmic face of the plasma membrane. Furthermore, HA and NP have been shown to be concentrated in cholesterol-rich membrane raft domains, whereas M2, although containing a cholesterol binding motif, is not raft associated. Here we identify viral proteins in planar sheets of plasma membrane using immunogold staining. The distribution of these proteins was examined individually and pairwise by using the Ripley K function, a type of nearest-neighbor analysis. Individually, HA, NA, M1, M2, and NP were shown to self-associate in or on the plasma membrane. HA and M2 are strongly coclustered in the plasma membrane; however, in the case of NA and M2, clustering depends upon the expression system used. Despite both proteins being raft resident, HA and NA occupy distinct but adjacent membrane domains. M2 and M1 strongly cocluster, but the association of M1 with HA or NA is dependent upon the means of expression. The presence of HA and NP at the site of budding depends upon the coexpression of other viral proteins. Similarly, M2 and NP occupy separate compartments, but an association can be bridged by the coexpression of M1.IMPORTANCE The complement of influenza virus proteins necessary for the budding of progeny virions needs to accumulate at budozones. This is complicated by HA and NA residing in lipid raft-like domains, whereas M2, although an integral membrane protein, is not raft associated. Other necessary protein components such as M1 and NP are peripherally associated with the membrane. Our data define spatial relationships between viral proteins in the plasma membrane. Some proteins, such as HA and M2, inherently cocluster within the membrane, although M2 is found mostly at the periphery of regions of HA, consistent with the proposed role of M2 in scission at the end of budding. The association between some pairs of influenza virus proteins, such as M2 and NP, appears to be brokered by additional influenza virus proteins, in this case M1. HA and NA, while raft associated, reside in distinct domains, reflecting their distributions in the viral membrane.
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17
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Kraft ML. Sphingolipid Organization in the Plasma Membrane and the Mechanisms That Influence It. Front Cell Dev Biol 2017; 4:154. [PMID: 28119913 PMCID: PMC5222807 DOI: 10.3389/fcell.2016.00154] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 12/27/2016] [Indexed: 11/13/2022] Open
Abstract
Sphingolipids are structural components in the plasma membranes of eukaryotic cells. Their metabolism produces bioactive signaling molecules that modulate fundamental cellular processes. The segregation of sphingolipids into distinct membrane domains is likely essential for cellular function. This review presents the early studies of sphingolipid distribution in the plasma membranes of mammalian cells that shaped the most popular current model of plasma membrane organization. The results of traditional imaging studies of sphingolipid distribution in stimulated and resting cells are described. These data are compared with recent results obtained with advanced imaging techniques, including super-resolution fluorescence detection and high-resolution secondary ion mass spectrometry (SIMS). Emphasis is placed on the new insight into the sphingolipid organization within the plasma membrane that has resulted from the direct imaging of stable isotope-labeled lipids in actual cell membranes with high-resolution SIMS. Super-resolution fluorescence techniques have recently revealed the biophysical behaviors of sphingolipids and the unhindered diffusion of cholesterol analogs in the membranes of living cells are ultimately in contrast to the prevailing hypothetical model of plasma membrane organization. High-resolution SIMS studies also conflicted with the prevailing hypothesis, showing sphingolipids are concentrated in micrometer-scale membrane domains, but cholesterol is evenly distributed within the plasma membrane. Reductions in cellular cholesterol decreased the number of sphingolipid domains in the plasma membrane, whereas disruption of the cytoskeleton eliminated them. In addition, hemagglutinin, a transmembrane protein that is thought to be a putative raft marker, did not cluster within sphingolipid-enriched regions in the plasma membrane. Thus, sphingolipid distribution in the plasma membrane is dependent on the cytoskeleton, but not on favorable interactions with cholesterol or hemagglutinin. The alternate views of plasma membrane organization suggested by these findings are discussed.
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Affiliation(s)
- Mary L Kraft
- Department of Chemical and Biomolecular Engineering, University of Illinois Urbana, IL, USA
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18
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Kinetic disruption of lipid rafts is a mechanosensor for phospholipase D. Nat Commun 2016; 7:13873. [PMID: 27976674 PMCID: PMC5171650 DOI: 10.1038/ncomms13873] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 11/04/2016] [Indexed: 12/24/2022] Open
Abstract
The sensing of physical force, mechanosensation, underlies two of five human senses—touch and hearing. How transduction of force in a membrane occurs remains unclear. We asked if a biological membrane could employ kinetic energy to transduce a signal absent tension. Here we show that lipid rafts are dynamic compartments that inactivate the signalling enzyme phospholipase D2 (PLD2) by sequestering the enzyme from its substrate. Mechanical disruption of the lipid rafts activates PLD2 by mixing the enzyme with its substrate to produce the signalling lipid phosphatidic acid (PA). We calculate a latency time of <650 μs for PLD activation by mixing. Our results establish a fast, non-tension mechanism for mechanotransduction where disruption of ordered lipids initiates a mechanosensitive signal for cell growth through mechanical mixing.
Mechanosensation by biological membranes can be relayed by mechanical tension to ion channels. Here the authors show that phospholipase D (PLD) is activated by mechanical disruption of lipid rafts which allows PLD to mix with its substrate in the lipid membrane, and propose a kinetic model of force transduction.
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19
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Lee JH, Hsieh CF, Liu HW, Chen CY, Wu SC, Chen TW, Hsu CS, Liao YH, Yang CY, Shyu JF, Fischer WB, Lin CH. Lipid raft-associated stomatin enhances cell fusion. FASEB J 2016; 31:47-59. [PMID: 27663861 DOI: 10.1096/fj.201600643r] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 09/07/2016] [Indexed: 01/25/2023]
Abstract
Membrane fusions that occur during vesicle transport, virus infection, and tissue development, involve receptors that mediate membrane contact and initiate fusion and effectors that execute membrane reorganization and fusion pore formation. Some of these fusogenic receptors/effectors are preferentially recruited to lipid raft membrane microdomains. Therefore, major constituents of lipid rafts, such as stomatin, may be involved in the regulation of cell-cell fusion. Stomatin produced in cells can be released to the extracellular environment, either through protein refolding to pass across lipid bilayer or through exosome trafficking. We report that cells expressing more stomatin or exposed to exogenous stomatin are more prone to undergoing cell fusion. During osteoclastogenesis, depletion of stomatin inhibited cell fusion but had little effect on tartrate-resistant acid phosphatase production. Moreover, in stomatin transgenic mice, increased cell fusion leading to enhanced bone resorption and subsequent osteoporosis were observed. With its unique molecular topology, stomatin forms molecular assembly within lipid rafts or on the appositional plasma membranes, and promotes membrane fusion by modulating fusogenic protein engagement.-Lee, J.-H., Hsieh, C.-F., Liu, H.-W., Chen, C.-Y., Wu, S.-C., Chen, T.-W., Hsu, C.-S., Liao, Y.-H., Yang, C.-Y., Shyu, J.-F., Fischer, W. B., Lin, C.-H. Lipid raft-associated stomatin enhances cell fusion.
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Affiliation(s)
- Jui-Hao Lee
- Taiwan International Graduate Program in Molecular Medicine, National Yang-Ming University and Academia Sinica, Taipei, Taiwan.,Institute of Microbiology and Immunology.,Institute of Biochemistry and Molecular Biology
| | | | - Hong-Wen Liu
- Institute of Microbiology and Immunology.,Chong Hin Loon Memorial Cancer and Biotherapy Research Center, and
| | - Chin-Yau Chen
- Institute of Microbiology and Immunology.,Department of Surgery, I-Lan, Taiwan
| | - Shao-Chin Wu
- Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan
| | - Tung-Wei Chen
- Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan
| | | | - Yu-Hsiu Liao
- Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan
| | - Chih-Yung Yang
- Department of Education and Research, Taipei City Hospital, Taipei, Taiwan; and
| | - Jia-Fwu Shyu
- Department of Biology and Anatomy, National Defense Medical Center, Taipei, Taiwan
| | - Wolfgang B Fischer
- Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan
| | - Chi-Hung Lin
- Taiwan International Graduate Program in Molecular Medicine, National Yang-Ming University and Academia Sinica, Taipei, Taiwan; .,Institute of Microbiology and Immunology.,Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan
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20
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Domanska MK, Dunning RA, Dryden KA, Zawada KE, Yeager M, Kasson PM. Hemagglutinin Spatial Distribution Shifts in Response to Cholesterol in the Influenza Viral Envelope. Biophys J 2016; 109:1917-24. [PMID: 26536268 DOI: 10.1016/j.bpj.2015.09.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 08/29/2015] [Accepted: 09/18/2015] [Indexed: 12/18/2022] Open
Abstract
Influenza virus delivers its genome to the host cytoplasm via a process of membrane fusion mediated by the viral hemagglutinin protein. Optimal fusion likely requires multiple hemagglutinin trimers, so the spatial distribution of hemagglutinin on the viral envelope may influence fusion mechanism. We have previously shown that moderate depletion of cholesterol from the influenza viral envelope accelerates fusion kinetics even though it decreases fusion efficiency, both in a reversible manner. Here, we use electron cryo-microscopy to measure how the hemagglutinin lateral density in the viral envelope changes with cholesterol extraction. We extract this information by measuring the radial distribution function of electron density in >4000 viral images per sample, assigning hemagglutinin density by comparing images with and without anti-HA Fab bound. On average, hemagglutinin trimers move closer together: we estimate that the typical trimer-trimer spacing reduces from 94 to 84 Å when ∼90% of cholesterol is removed from the viral membrane. Upon restoration of viral envelope cholesterol, this spacing once again expands. This finding can qualitatively explain the observed changes to fusion kinetics: contemporary models from single-virus microscopy are that fusion requires the engagement of several hemagglutinin trimers in close proximity. If removing cholesterol increases the lateral density of hemagglutinin, this should result in an increase in the rate of fusion.
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Affiliation(s)
- Marta K Domanska
- Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia
| | - Rebecca A Dunning
- Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia
| | - Kelly A Dryden
- Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia
| | - Katarzyna E Zawada
- Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia
| | - Mark Yeager
- Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia
| | - Peter M Kasson
- Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia.
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21
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Makino A, Abe M, Ishitsuka R, Murate M, Kishimoto T, Sakai S, Hullin-Matsuda F, Shimada Y, Inaba T, Miyatake H, Tanaka H, Kurahashi A, Pack CG, Kasai RS, Kubo S, Schieber NL, Dohmae N, Tochio N, Hagiwara K, Sasaki Y, Aida Y, Fujimori F, Kigawa T, Nishibori K, Parton RG, Kusumi A, Sako Y, Anderluh G, Yamashita M, Kobayashi T, Greimel P, Kobayashi T. A novel sphingomyelin/cholesterol domain-specific probe reveals the dynamics of the membrane domains during virus release and in Niemann-Pick type C. FASEB J 2016; 31:1301-1322. [PMID: 27492925 DOI: 10.1096/fj.201500075r] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 07/18/2016] [Indexed: 01/07/2023]
Abstract
We identified a novel, nontoxic mushroom protein that specifically binds to a complex of sphingomyelin (SM), a major sphingolipid in mammalian cells, and cholesterol (Chol). The purified protein, termed nakanori, labeled cell surface domains in an SM- and Chol-dependent manner and decorated specific lipid domains that colocalized with inner leaflet small GTPase H-Ras, but not K-Ras. The use of nakanori as a lipid-domain-specific probe revealed altered distribution and dynamics of SM/Chol on the cell surface of Niemann-Pick type C fibroblasts, possibly explaining some of the disease phenotype. In addition, that nakanori treatment of epithelial cells after influenza virus infection potently inhibited virus release demonstrates the therapeutic value of targeting specific lipid domains for anti-viral treatment.-Makino, A., Abe, M., Ishitsuka, R., Murate, M., Kishimoto, T., Sakai, S., Hullin-Matsuda, F., Shimada, Y., Inaba, T., Miyatake, H., Tanaka, H., Kurahashi, A., Pack, C.-G., Kasai, R. S., Kubo, S., Schieber, N. L., Dohmae, N., Tochio, N., Hagiwara, K., Sasaki, Y., Aida, Y., Fujimori, F., Kigawa, T., Nishibori, K., Parton, R. G., Kusumi, A., Sako, Y., Anderluh, G., Yamashita, M., Kobayashi, T., Greimel, P., Kobayashi, T. A novel sphingomyelin/cholesterol domain-specific probe reveals the dynamics of the membrane domains during virus release and in Niemann-Pick type C.
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Affiliation(s)
| | | | | | | | | | | | - Françoise Hullin-Matsuda
- Rikagaku Kenkyūsho (RIKEN), Saitama, Japan.,Université Lyon 1, INSERM, Unité 1060, Villeurbanne, France
| | | | | | | | - Hideko Tanaka
- Faculty of Core Research, Natural Science Division, Ochanomizu University, Tokyo, Japan
| | | | | | - Rinshi S Kasai
- Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan
| | - Shuku Kubo
- Daiichi Sankyo Co., Limited, Tokyo, Japan
| | - Nicole L Schieber
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Queensland, Australia
| | | | | | | | | | - Yoko Aida
- Rikagaku Kenkyūsho (RIKEN), Saitama, Japan
| | - Fumihiro Fujimori
- Graduate School of Humanities and Life Sciences, Tokyo Kasei University, Tokyo, Japan
| | | | | | - Robert G Parton
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Queensland, Australia.,Centre for Microscopy and Microanalysis, The University of Queensland, St. Lucia, Queensland, Australia
| | - Akihiro Kusumi
- Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan.,Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyoto, Japan
| | | | - Gregor Anderluh
- National Institute of Chemistry, Ljubljana, Slovenia.,Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia; and
| | | | - Tetsuyuki Kobayashi
- Faculty of Core Research, Natural Science Division, Ochanomizu University, Tokyo, Japan
| | | | - Toshihide Kobayashi
- Rikagaku Kenkyūsho (RIKEN), Saitama, Japan; .,Unité Mixte de Recherche 7213, Centre National de la Recherche Scientifique, Université de Strasbourg, Illkirch, France
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22
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Influenza viral membrane fusion is sensitive to sterol concentration but surprisingly robust to sterol chemical identity. Sci Rep 2016; 6:29842. [PMID: 27431907 PMCID: PMC4949436 DOI: 10.1038/srep29842] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 06/24/2016] [Indexed: 12/20/2022] Open
Abstract
Influenza virions are enriched in cholesterol relative to the plasma membrane from which they bud. Previous work has shown that fusion between influenza virus and synthetic liposomes is sensitive to the amount of cholesterol in either the virus or the target membrane. Here, we test the chemical properties of cholesterol required to promote influenza fusion by replacing cholesterol with other sterols and assaying viral fusion kinetics. We find that influenza fusion with liposomes is surprisingly robust to sterol chemical identity, showing no significant dependence on sterol identity in target membranes for any of the sterols tested. In the viral membrane, lanosterol slowed fusion somewhat, while polar sterols produced a more pronounced slowing and inhibition of fusion. No other sterols tested showed a significant perturbation in fusion rates, including ones previously shown to alter membrane bending moduli or phase behavior. Although fusion rates depend on viral cholesterol, they thus do not require cholesterol’s ability to support liquid-liquid phase coexistence. Using electron cryo-microscopy, we further find that sterol-dependent changes to hemagglutinin spatial patterning in the viral membrane do not require liquid-liquid phase coexistence. We therefore speculate that local sterol-hemagglutinin interactions in the viral envelope may control the rate-limiting step of fusion.
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23
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Abstract
Influenza A viruses (IAVs) harbor a segmented RNA genome that is organized into eight distinct viral ribonucleoprotein (vRNP) complexes. Although a segmented genome may be a major advantage to adapt to new host environments, it comes at the cost of a highly sophisticated genome packaging mechanism. Newly synthesized vRNPs conquer the cellular endosomal recycling machinery to access the viral budding site at the plasma membrane. Genome packaging sequences unique to each RNA genome segment are thought to be key determinants ensuring the assembly and incorporation of eight distinct vRNPs into progeny viral particles. Recent studies using advanced fluorescence microscopy techniques suggest the formation of vRNP sub-bundles (comprising less than eight vRNPs) during their transport on recycling endosomes. The formation of such sub-bundles might be required for efficient packaging of a bundle of eight different genomes segments at the budding site, further highlighting the complexity of IAV genome packaging.
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24
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Wilson RL, Frisz JF, Klitzing HA, Zimmerberg J, Weber PK, Kraft ML. Hemagglutinin clusters in the plasma membrane are not enriched with cholesterol and sphingolipids. Biophys J 2016; 108:1652-1659. [PMID: 25863057 DOI: 10.1016/j.bpj.2015.02.026] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 02/11/2015] [Accepted: 02/18/2015] [Indexed: 01/28/2023] Open
Abstract
The clusters of the influenza envelope protein, hemagglutinin, within the plasma membrane are hypothesized to be enriched with cholesterol and sphingolipids. Here, we directly tested this hypothesis by using high-resolution secondary ion mass spectrometry to image the distributions of antibody-labeled hemagglutinin and isotope-labeled cholesterol and sphingolipids in the plasma membranes of fibroblast cells that stably express hemagglutinin. We found that the hemagglutinin clusters were neither enriched with cholesterol nor colocalized with sphingolipid domains. Thus, hemagglutinin clustering and localization in the plasma membrane is not controlled by cohesive interactions between hemagglutinin and liquid-ordered domains enriched with cholesterol and sphingolipids, or from specific binding interactions between hemagglutinin, cholesterol, and/or the majority of sphingolipid species in the plasma membrane.
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Affiliation(s)
- Robert L Wilson
- Department of Chemistry, University of Illinois, Urbana, Illinois
| | - Jessica F Frisz
- Department of Chemistry, University of Illinois, Urbana, Illinois
| | - Haley A Klitzing
- Department of Chemistry, University of Illinois, Urbana, Illinois
| | - Joshua Zimmerberg
- Section on Cellular and Membrane Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Peter K Weber
- Glenn T. Seaborg Institute, Lawrence Livermore National Laboratory, Livermore, California
| | - Mary L Kraft
- Department of Chemistry, University of Illinois, Urbana, Illinois; Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana, Illnois.
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25
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Alginate Biosynthesis Factories in Pseudomonas fluorescens: Localization and Correlation with Alginate Production Level. Appl Environ Microbiol 2015; 82:1227-1236. [PMID: 26655760 DOI: 10.1128/aem.03114-15] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 12/03/2015] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas fluorescens is able to produce the medically and industrially important exopolysaccharide alginate. The proteins involved in alginate biosynthesis and secretion form a multiprotein complex spanning the inner and outer membranes. In the present study, we developed a method by which the porin AlgE was detected by immunogold labeling and transmission electron microscopy. Localization of the AlgE protein was found to depend on the presence of other proteins in the multiprotein complex. No correlation was found between the number of alginate factories and the alginate production level, nor were the numbers of these factories affected in an algC mutant that is unable to produce the precursor needed for alginate biosynthesis. Precursor availability and growth phase thus seem to be the main determinants for the alginate production rate in our strain. Clustering analysis demonstrated that the alginate multiprotein complexes were not distributed randomly over the entire outer cell membrane surface.
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26
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Kawaguchi A, Hirohama M, Harada Y, Osari S, Nagata K. Influenza Virus Induces Cholesterol-Enriched Endocytic Recycling Compartments for Budozone Formation via Cell Cycle-Independent Centrosome Maturation. PLoS Pathog 2015; 11:e1005284. [PMID: 26575487 PMCID: PMC4648529 DOI: 10.1371/journal.ppat.1005284] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 10/27/2015] [Indexed: 01/05/2023] Open
Abstract
Influenza virus particles are assembled at the plasma membrane in concert with incorporation of the virus genome, but the details of its spatio-temporal regulation are not understood. Here we showed that influenza virus infection induces the assembly of pericentrosomal endocytic recycling compartment (ERC) through the activation of Rab11a GTPase and cell cycle-independent maturation of centrosome by YB-1, a multifunctional protein that is involved in mitotic division, RNA metabolism and tumorigenesis. YB-1 is recruited to the centrosome in infected cells and is required for anchoring microtubules to the centrosome. We also found that viral infection accumulates cholesterol in ERC and is dependent on YB-1. Depletion of YB-1 shows reduced cholesterol-enriched ERC and prevented budozone formation at the plasma membrane. These results suggest that cholesterol in recycling endosomes, which are emanated from ERC, may trigger the virus assembly concomitantly with the packaging of the virus genome. We propose that the virus genome is transported to the plasma membrane by cholesterol-enriched recycling endosomes through cell cycle-independent activation of the centrosome by YB-1. Influenza virus particles are assembled at the plasma membrane in concert with incorporation of the virus genome, but the details of its spatiotemporal regulation are unknown. We found that the virus genome is transported to the plasma membrane using cholesterol-enriched recycling endosomes through cell cycle-independent activation of the centrosome by recruiting YB-1, which is a mitotic centrosomal protein. We also revealed that the cholesterol-enriched endosomes are important for clustering of viral structural proteins at lipid rafts to assemble the virus particles. These results suggest that local accumulation of cholesterol, via fusion of endosomes to the plasma membrane, is one of the triggers for the virus assembly concomitantly with arrival of the virus genome beneath the plasma membrane.
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Affiliation(s)
- Atsushi Kawaguchi
- Department of Infection Biology, Faculty of Medicine, University of Tsukuba, Tennodai, Tsukuba, Japan
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennodai, Tsukuba, Japan
- * E-mail:
| | - Mikako Hirohama
- Department of Infection Biology, Faculty of Medicine, University of Tsukuba, Tennodai, Tsukuba, Japan
| | - Yoshimi Harada
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennodai, Tsukuba, Japan
| | - Suguru Osari
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennodai, Tsukuba, Japan
| | - Kyosuke Nagata
- Department of Infection Biology, Faculty of Medicine, University of Tsukuba, Tennodai, Tsukuba, Japan
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27
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Curthoys NM, Parent M, Mlodzianoski M, Nelson AJ, Lilieholm J, Butler MB, Valles M, Hess ST. Dances with Membranes: Breakthroughs from Super-resolution Imaging. CURRENT TOPICS IN MEMBRANES 2015; 75:59-123. [PMID: 26015281 PMCID: PMC5584789 DOI: 10.1016/bs.ctm.2015.03.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Biological membrane organization mediates numerous cellular functions and has also been connected with an immense number of human diseases. However, until recently, experimental methodologies have been unable to directly visualize the nanoscale details of biological membranes, particularly in intact living cells. Numerous models explaining membrane organization have been proposed, but testing those models has required indirect methods; the desire to directly image proteins and lipids in living cell membranes is a strong motivation for the advancement of technology. The development of super-resolution microscopy has provided powerful tools for quantification of membrane organization at the level of individual proteins and lipids, and many of these tools are compatible with living cells. Previously inaccessible questions are now being addressed, and the field of membrane biology is developing rapidly. This chapter discusses how the development of super-resolution microscopy has led to fundamental advances in the field of biological membrane organization. We summarize the history and some models explaining how proteins are organized in cell membranes, and give an overview of various super-resolution techniques and methods of quantifying super-resolution data. We discuss the application of super-resolution techniques to membrane biology in general, and also with specific reference to the fields of actin and actin-binding proteins, virus infection, mitochondria, immune cell biology, and phosphoinositide signaling. Finally, we present our hopes and expectations for the future of super-resolution microscopy in the field of membrane biology.
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Affiliation(s)
- Nikki M. Curthoys
- Department of Physics and Astronomy, University of Maine, Orono, ME, USA
| | - Matthew Parent
- Department of Physics and Astronomy, University of Maine, Orono, ME, USA
| | | | - Andrew J. Nelson
- Department of Physics and Astronomy, University of Maine, Orono, ME, USA
| | - Jennifer Lilieholm
- Department of Physics and Astronomy, University of Maine, Orono, ME, USA
| | - Michael B. Butler
- Department of Physics and Astronomy, University of Maine, Orono, ME, USA
| | - Matthew Valles
- Department of Physics and Astronomy, University of Maine, Orono, ME, USA
| | - Samuel T. Hess
- Department of Physics and Astronomy, University of Maine, Orono, ME, USA
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A cholesterol consensus motif is required for efficient intracellular transport and raft association of a group 2 HA from influenza virus. Biochem J 2015; 465:305-14. [DOI: 10.1042/bj20141114] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The external part of the transmembrane region of HA (haemagglutinin) of influenza virus contains a cholesterol consensus motif originally identified in G-protein-coupled receptors. Various mutations in this motif retard transport of HA through the Golgi and reduce raft association.
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Abstract
UNLABELLED In the extracellular environment, cell-free virions seek out naive host cells over long distances and between organisms. This is the primary mechanism of spread for most viruses. Here we provide evidence for an alternative pathway previously undescribed for orthomyxoviruses, whereby the spread of influenza A virus (IAV) infectious cores to neighboring cells can occur within intercellular connections. The formation of these connections requires actin dynamics and is enhanced by viral infection. Connected cells have contiguous membranes, and the core infectious viral machinery (RNP and polymerase) was present inside the intercellular connections. A live-cell movie of green fluorescent protein (GFP)-tagged NS1 of IAV shows viral protein moving from one cell to another through an intercellular connection. The movement of tagged protein was saltatory but overall traveled only in one direction. Infectious virus cores can move from one cell to another without budding and release of cell-free virions, as evidenced by the finding that whereas a neuraminidase inhibitor alone did not inhibit the development of IAV microplaques, the presence of a neuraminidase inhibitor together with drugs inhibiting actin dynamics or the microtubule stabilizer paclitaxel (originally named taxol) precluded microplaque formation. Similar results were also observed with parainfluenza virus 5 (PIV5), a paramyxovirus, when neutralizing antibody was used to block spread by cell-free virions. Intercellular spread of infectious core particles was unaffected or enhanced in the presence of nocodazole for IAV but inhibited for PIV5. The intercellular connections have a core of filamentous actin, which hints toward transport of virus particles through the use of a myosin motor. IMPORTANCE Here we describe a new method by which influenza A virus (IAV) spreads from cell to cell: IAV uses intracellular connections. The formation of these connections requires actin dynamics and is enhanced by viral infection and the absence of microtubules. Connected cells appeared to have contiguous membranes, and the core infectious viral machinery (RNP and polymerase) was present inside the intercellular connections. Infectious virus cores can move from one cell to another without budding and release of cell-free virions. Similar results were also observed with parainfluenza virus 5 (PIV5).
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Lee DW, Thapar V, Clancy P, Daniel S. Stochastic fusion simulations and experiments suggest passive and active roles of hemagglutinin during membrane fusion. Biophys J 2014; 106:843-54. [PMID: 24559987 DOI: 10.1016/j.bpj.2013.12.048] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 11/23/2013] [Accepted: 12/06/2013] [Indexed: 10/25/2022] Open
Abstract
Influenza enters the host cell cytoplasm by fusing the viral and host membrane together. Fusion is mediated by hemagglutinin (HA) trimers that undergo conformational change when acidified in the endosome. It is currently debated how many HA trimers, w, and how many conformationally changed HA trimers, q, are minimally required for fusion. Conclusions vary because there are three common approaches for determining w and q from fusion data. One approach correlates the fusion rate with the fraction of fusogenic HA trimers and leads to the conclusion that one HA trimer is required for fusion. A second approach correlates the fusion rate with the total concentration of fusogenic HA trimers and indicates that more than one HA trimer is required. A third approach applies statistical models to fusion rate data obtained at a single HA density to establish w or q and suggests that more than one HA trimer is required. In this work, all three approaches are investigated through stochastic fusion simulations and experiments to elucidate the roles of HA and its ability to bend the target membrane during fusion. We find that the apparent discrepancies among the results from the various approaches may be resolved if nonfusogenic HA participates in fusion through interactions with a fusogenic HA. Our results, based on H3 and H1 serotypes, suggest that three adjacent HA trimers and one conformationally changed HA trimer are minimally required to induce membrane fusion (w = 3 and q = 1).
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Affiliation(s)
- Donald W Lee
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York
| | - Vikram Thapar
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York
| | - Paulette Clancy
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York
| | - Susan Daniel
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York.
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31
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Lü J, Yang J, Dong M, Sahin O. Nanomechanical spectroscopy of synthetic and biological membranes. NANOSCALE 2014; 6:7604-8. [PMID: 24895687 DOI: 10.1039/c3nr02643d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
We report that atomic force microscopy based high-speed nanomechanical analysis can identify components of complex heterogeneous synthetic and biological membranes from the measured spectrum of nanomechanical properties. We have investigated phase separated ternary lipid bilayers and purple membranes of Halobacterium salinarum. The nanomechanical spectra recorded on these samples identify all membrane components, some of which are difficult to resolve in conventional phase images. This non-destructive approach can aid the design of synthetic lipid bilayers and studies lateral organization of complex heterogeneous cellular membranes.
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Affiliation(s)
- Junhong Lü
- The Rowland Institute at Harvard, Harvard University, Cambridge, MA, USA
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32
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Thaa B, Siche S, Herrmann A, Veit M. Acylation and cholesterol binding are not required for targeting of influenza A virus M2 protein to the hemagglutinin-defined budozone. FEBS Lett 2014; 588:1031-6. [PMID: 24561202 DOI: 10.1016/j.febslet.2014.02.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2013] [Revised: 01/30/2014] [Accepted: 02/04/2014] [Indexed: 12/20/2022]
Abstract
Influenza virus assembles in the budozone, a cholesterol-/sphingolipid-enriched ("raft") domain at the apical plasma membrane, organized by hemagglutinin (HA). The viral protein M2 localizes to the budozone edge for virus particle scission. This was proposed to depend on acylation and cholesterol binding. We show that M2-GFP without these motifs is still transported apically in polarized cells. Employing FRET, we determined that clustering between HA and M2 is reduced upon disruption of HA's raft-association features (acylation, transmembranous VIL motif), but remains unchanged with M2 lacking acylation and/or cholesterol-binding sites. The motifs are thus irrelevant for M2 targeting in cells.
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Affiliation(s)
- Bastian Thaa
- Freie Universität Berlin, Fachbereich Veterinärmedizin, Institut für Virologie, Zentrum für Infektionsmedizin - Robert-von-Ostertag-Haus, Robert-von-Ostertag-Straße 7-13, 14163 Berlin, Germany
| | - Stefanie Siche
- Freie Universität Berlin, Fachbereich Veterinärmedizin, Institut für Virologie, Zentrum für Infektionsmedizin - Robert-von-Ostertag-Haus, Robert-von-Ostertag-Straße 7-13, 14163 Berlin, Germany
| | - Andreas Herrmann
- Humboldt-Universität zu Berlin, Institute of Biology, Molecular Biophysics, Invalidenstraße 42, 10115 Berlin, Germany
| | - Michael Veit
- Freie Universität Berlin, Fachbereich Veterinärmedizin, Institut für Virologie, Zentrum für Infektionsmedizin - Robert-von-Ostertag-Haus, Robert-von-Ostertag-Straße 7-13, 14163 Berlin, Germany.
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33
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Truong-Quang BA, Lenne PF. Membrane microdomains: from seeing to understanding. FRONTIERS IN PLANT SCIENCE 2014; 5:18. [PMID: 24600455 PMCID: PMC3927121 DOI: 10.3389/fpls.2014.00018] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 01/15/2014] [Indexed: 05/08/2023]
Abstract
The plasma membrane is a composite material, which forms a semi-permeable barrier and an interface for communication between the intracellular and extracellular environments. While the existence of membrane microdomains with nanoscale organization has been proved by the application of numerous biochemical and physical methods, direct observation of these heterogeneities using optical microscopy has remained challenging for decades, partly due to the optical diffraction limit, which restricts the resolution to ~200 nm. During the past years, new optical methods which circumvent this fundamental limit have emerged. Not only do these techniques allow direct visualization, but also quantitative characterization of nanoscopic structures. We discuss how these emerging optical methods have refined our knowledge of membrane microdomains and how they may shed light on the basic principles of the mesoscopic membrane organization.
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Affiliation(s)
| | - Pierre-François Lenne
- *Correspondence: Pierre-François Lenne, Developmental Biology Institute of Marseilles, UMR 7288 CNRS, Aix-Marseille Université, 13288 Marseille Cedex 9, France e-mail:
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34
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Gudheti MV, Curthoys NM, Gould TJ, Kim D, Gunewardene MS, Gabor KA, Gosse JA, Kim CH, Zimmerberg J, Hess ST. Actin mediates the nanoscale membrane organization of the clustered membrane protein influenza hemagglutinin. Biophys J 2013; 104:2182-92. [PMID: 23708358 DOI: 10.1016/j.bpj.2013.03.054] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Revised: 03/15/2013] [Accepted: 03/20/2013] [Indexed: 12/22/2022] Open
Abstract
The influenza viral membrane protein hemagglutinin (HA) is required at high concentrations on virion and host-cell membranes for infectivity. Because the role of actin in membrane organization is not completely understood, we quantified the relationship between HA and host-cell actin at the nanoscale. Results obtained using superresolution fluorescence photoactivation localization microscopy (FPALM) in nonpolarized cells show that HA clusters colocalize with actin-rich membrane regions (ARMRs). Individual molecular trajectories in live cells indicate restricted HA mobility in ARMRs, and actin disruption caused specific changes to HA clustering. Surprisingly, the actin-binding protein cofilin was excluded from some regions within several hundred nanometers of HA clusters, suggesting that HA clusters or adjacent proteins within the same clusters influence local actin structure. Thus, with the use of imaging, we demonstrate a dynamic relationship between glycoprotein membrane organization and the actin cytoskeleton at the nanoscale.
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Affiliation(s)
- Manasa V Gudheti
- Department of Physics and Astronomy, University of Maine, Orono, ME, USA
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35
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The amphipathic helix of influenza A virus M2 protein is required for filamentous bud formation and scission of filamentous and spherical particles. J Virol 2013; 87:9973-82. [PMID: 23843641 DOI: 10.1128/jvi.01363-13] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Influenza virus assembles and buds at the infected-cell plasma membrane. This involves extrusion of the plasma membrane followed by scission of the bud, resulting in severing the nascent virion from its former host. The influenza virus M2 ion channel protein contains in its cytoplasmic tail a membrane-proximal amphipathic helix that facilitates the scission process and is also required for filamentous particle formation. Mutation of five conserved hydrophobic residues to alanines within the amphipathic helix (M2 five-point mutant, or 5PM) reduced scission and also filament formation, whereas single mutations had no apparent phenotype. Here, we show that any two of these five residues mutated together to alanines result in virus debilitated for growth and filament formation in a manner similar to 5PM. Growth kinetics of the M2 mutants are approximately 2 logs lower than the wild-type level, and plaque diameter was significantly reduced. When the 5PM and a representative double mutant (I51A-Y52A) were introduced into A/WSN/33 M2, a strain that produces spherical particles, similar debilitation in viral growth occurred. Electron microscopy showed that with the 5PM and the I51A-Y52A A/Udorn/72 and WSN viruses, scission failed, and emerging virus particles exhibited a "beads-on-a-string" morphology. The major spike glycoprotein hemagglutinin is localized within lipid rafts in virus-infected cells, whereas M2 is associated at the periphery of rafts. Mutant M2s were more widely dispersed, and their abundance at the raft periphery was reduced, suggesting that the M2 amphipathic helix is required for proper localization in the host membrane and that this has implications for budding and scission.
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36
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Frisz JF, Klitzing HA, Lou K, Hutcheon ID, Weber PK, Zimmerberg J, Kraft ML. Sphingolipid domains in the plasma membranes of fibroblasts are not enriched with cholesterol. J Biol Chem 2013; 288:16855-16861. [PMID: 23609440 PMCID: PMC3675618 DOI: 10.1074/jbc.m113.473207] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The plasma membranes of mammalian cells are widely expected to contain domains that are enriched with cholesterol and sphingolipids. In this work, we have used high-resolution secondary ion mass spectrometry to directly map the distributions of isotope-labeled cholesterol and sphingolipids in the plasma membranes of intact fibroblast cells. Although acute cholesterol depletion reduced sphingolipid domain abundance, cholesterol was evenly distributed throughout the plasma membrane and was not enriched within the sphingolipid domains. Thus, we rule out favorable cholesterol-sphingolipid interactions as dictating plasma membrane organization in fibroblast cells. Because the sphingolipid domains are disrupted by drugs that depolymerize the cells actin cytoskeleton, cholesterol must instead affect the sphingolipid organization via an indirect mechanism that involves the cytoskeleton.
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Affiliation(s)
| | | | - Kaiyan Lou
- Chemical and Biomolecular Engineering, University of Illinois, Urbana, Illinois 61801
| | - Ian D Hutcheon
- Glenn T. Seaborg Institute, Lawrence Livermore National Laboratory, Livermore, California 94551
| | - Peter K Weber
- Glenn T. Seaborg Institute, Lawrence Livermore National Laboratory, Livermore, California 94551
| | - Joshua Zimmerberg
- Program in Physical Biology, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, Maryland 20892
| | - Mary L Kraft
- Departments of Chemistry, Urbana, Illinois 61801; Chemical and Biomolecular Engineering, University of Illinois, Urbana, Illinois 61801.
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37
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Formation of raft-like assemblies within clusters of influenza hemagglutinin observed by MD simulations. PLoS Comput Biol 2013; 9:e1003034. [PMID: 23592976 PMCID: PMC3623702 DOI: 10.1371/journal.pcbi.1003034] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Accepted: 03/03/2013] [Indexed: 11/19/2022] Open
Abstract
The association of hemagglutinin (HA) with lipid rafts in the plasma membrane is an important feature of the assembly process of influenza virus A. Lipid rafts are thought to be small, fluctuating patches of membrane enriched in saturated phospholipids, sphingolipids, cholesterol and certain types of protein. However, raft-associating transmembrane (TM) proteins generally partition into Ld domains in model membranes, which are enriched in unsaturated lipids and depleted in saturated lipids and cholesterol. The reason for this apparent disparity in behavior is unclear, but model membranes differ from the plasma membrane in a number of ways. In particular, the higher protein concentration in the plasma membrane may influence the partitioning of membrane proteins for rafts. To investigate the effect of high local protein concentration, we have conducted coarse-grained molecular dynamics (CG MD) simulations of HA clusters in domain-forming bilayers. During the simulations, we observed a continuous increase in the proportion of raft-type lipids (saturated phospholipids and cholesterol) within the area of membrane spanned by the protein cluster. Lateral diffusion of unsaturated lipids was significantly attenuated within the cluster, while saturated lipids were relatively unaffected. On this basis, we suggest a possible explanation for the change in lipid distribution, namely that steric crowding by the slow-diffusing proteins increases the chemical potential for unsaturated lipids within the cluster region. We therefore suggest that a local aggregation of HA can be sufficient to drive association of the protein with raft-type lipids. This may also represent a general mechanism for the targeting of TM proteins to rafts in the plasma membrane, which is of functional importance in a wide range of cellular processes. The cell membrane is composed of a wide variety of lipids and proteins. Until recently, these were thought to be mixed evenly, but we now have evidence of the existence of “lipid rafts” — small, slow-moving areas of membrane in which certain types of lipid and protein accumulate. Rafts have many important biological functions in healthy cells, but also play a role in the assembly of influenza virus. For example, after the viral protein hemagglutinin is made inside the host cell, it accumulates in rafts. Exiting virus particles then take these portions of cell membrane with them as they leave the host cell. However, the mechanism by which proteins associate with lipid rafts is unclear. Here, we have used computers to simulate lipid membranes containing hemagglutinin. The simulations allow us to look in detail at the motions and interactions of individual proteins and lipids. We found that clusters of proteins altered the properties of nearby lipids, leading to accumulation of raft-type lipids. It therefore appears that aggregation of hemagglutinin may be enough to drive its association with rafts. This helps us to better understand both the influenza assembly process and the properties of lipid rafts.
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Lizunov VA, Stenkula K, Troy A, Cushman SW, Zimmerberg J. Insulin regulates Glut4 confinement in plasma membrane clusters in adipose cells. PLoS One 2013; 8:e57559. [PMID: 23520472 PMCID: PMC3592853 DOI: 10.1371/journal.pone.0057559] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 01/22/2013] [Indexed: 01/12/2023] Open
Abstract
Insulin-stimulated delivery of glucose transporter-4 (GLUT4) to the plasma membrane (PM) is the hallmark of glucose metabolism. In this study we examined insulin’s effects on GLUT4 organization in PM of adipose cells by direct microscopic observation of single monomers tagged with photoswitchable fluorescent protein. In the basal state, after exocytotic delivery only a fraction of GLUT4 is dispersed into the PM as monomers, while most of the GLUT4 stays at the site of fusion and forms elongated clusters (60–240 nm). GLUT4 monomers outside clusters diffuse freely and do not aggregate with other monomers. In contrast, GLUT4 molecule collision with an existing cluster can lead to immediate confinement and association with that cluster. Insulin has three effects: it shifts the fraction of dispersed GLUT4 upon delivery, it augments the dissociation of GLUT4 monomers from clusters ∼3-fold and it decreases the rate of endocytic uptake. All together these three effects of insulin shift most of the PM GLUT4 from clustered to dispersed states. GLUT4 confinement in clusters represents a novel kinetic mechanism for insulin regulation of glucose homeostasis.
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Affiliation(s)
- Vladimir A. Lizunov
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Karin Stenkula
- Experimental Diabetes, Metabolism, and Nutrition Section, Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Aaron Troy
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Samuel W. Cushman
- Experimental Diabetes, Metabolism, and Nutrition Section, Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Joshua Zimmerberg
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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39
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Direct chemical evidence for sphingolipid domains in the plasma membranes of fibroblasts. Proc Natl Acad Sci U S A 2013; 110:E613-22. [PMID: 23359681 DOI: 10.1073/pnas.1216585110] [Citation(s) in RCA: 159] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Sphingolipids play important roles in plasma membrane structure and cell signaling. However, their lateral distribution in the plasma membrane is poorly understood. Here we quantitatively analyzed the sphingolipid organization on the entire dorsal surface of intact cells by mapping the distribution of (15)N-enriched ions from metabolically labeled (15)N-sphingolipids in the plasma membrane, using high-resolution imaging mass spectrometry. Many types of control experiments (internal, positive, negative, and fixation temperature), along with parallel experiments involving the imaging of fluorescent sphingolipids--both in living cells and during fixation of living cells--exclude potential artifacts. Micrometer-scale sphingolipid patches consisting of numerous (15)N-sphingolipid microdomains with mean diameters of ∼200 nm are always present in the plasma membrane. Depletion of 30% of the cellular cholesterol did not eliminate the sphingolipid domains, but did reduce their abundance and long-range organization in the plasma membrane. In contrast, disruption of the cytoskeleton eliminated the sphingolipid domains. These results indicate that these sphingolipid assemblages are not lipid rafts and are instead a distinctly different type of sphingolipid-enriched plasma membrane domain that depends upon cortical actin.
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40
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Veit M, Engel S, Thaa B, Scolari S, Herrmann A. Lipid domain association of influenza virus proteins detected by dynamic fluorescence microscopy techniques. Cell Microbiol 2012; 15:179-89. [PMID: 23057766 DOI: 10.1111/cmi.12045] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 09/16/2012] [Accepted: 09/17/2012] [Indexed: 01/31/2023]
Abstract
Influenza virus is thought to assemble in raft domains of the plasma membrane, but many of the conclusions were based on (controversial) Triton extraction experiments. Here we review how sophisticated methods of fluorescence microscopy, such as FPALM, FRET and FRAP, contributed to our understanding of lipid domain association of the viral proteins HA and M2. The results are summarized in light of the current model for virus assembly and lipid domain organization. Finally, it is described how the signals that govern domain association in transfected cells affect replication of influenza virus.
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Affiliation(s)
- Michael Veit
- Institute of Immunology, Free University Berlin, Philippstr. 13, 10115 Berlin, Germany.
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41
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Embar A, Dolbow J, Fried E. Microdomain evolution on giant unilamellar vesicles. Biomech Model Mechanobiol 2012; 12:597-615. [PMID: 22907599 DOI: 10.1007/s10237-012-0428-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 08/02/2012] [Indexed: 11/28/2022]
Abstract
A chemo-mechanical model is used to capture the formation and evolution of microdomains on the deforming surface of giant unilamellar vesicles. The model is intended for the regime of vesicle dynamics characterized by a distinct difference in time scales between shape change and species transport. This is achieved by ensuring that shape equilibrium holds away from chemical equilibrium. Conventional descriptions are used to define the curvature and chemical contributions to the vesicle energetics. Both contributions are consistently non-dimensionalized. The phase-field framework is used to cast the coupled model in a diffuse-interface form. The resulting fourth-order nonlinear system of equations is discretized using the finite- element method with a uniform cubic spline basis, which satisfies global higher-order continuity. Two-dimensional and axisymmetric numerical examples of domain evolution coupled to vesicle shape deformation are presented. Curvature-dependent domain sorting and shape deformation dominated by line tension are also considered.
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Affiliation(s)
- Anand Embar
- Department of Civil Engineering, Duke University, Durham, NC 27708, USA
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42
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Abstract
Recent advances in far-field microscopy have demonstrated that fluorescence imaging is possible at resolutions well below the long-standing diffraction limit. By exploiting photophysical properties of fluorescent probe molecules, this new class of methods yields a resolving power that is fundamentally diffraction unlimited. Although these methods are becoming more widely used in biological imaging, they must be complemented by suitable data analysis approaches if their potential is to be fully realized. Here we review the basic principles of diffraction-unlimited microscopy and how these principles influence the selection of available algorithms for data analysis. Furthermore, we provide an overview of existing analysis strategies and discuss their application.
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Affiliation(s)
- Travis J Gould
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06510, USA.
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43
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Abstract
The polarized distribution of proteins and lipids at the surface membrane of epithelial cells results in the formation of an apical and a basolateral domain, which are separated by tight junctions. The generation and maintenance of epithelial polarity require elaborate mechanisms that guarantee correct sorting and vectorial delivery of cargo molecules. This dynamic process involves the interaction of sorting signals with sorting machineries and the formation of transport carriers. Here we review the recent advances in the field of polarized sorting in epithelial cells. We especially highlight the role of lipid rafts in apical sorting.
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Itano MS, Steinhauer C, Schmied JJ, Forthmann C, Liu P, Neumann AK, Thompson NL, Tinnefeld P, Jacobson K. Super-resolution imaging of C-type lectin and influenza hemagglutinin nanodomains on plasma membranes using blink microscopy. Biophys J 2012; 102:1534-42. [PMID: 22500753 DOI: 10.1016/j.bpj.2012.02.022] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Revised: 01/30/2012] [Accepted: 02/13/2012] [Indexed: 11/28/2022] Open
Abstract
Dendritic cells express DC-SIGN, a C-type lectin (CTL) that binds a variety of pathogens and facilitates their uptake for subsequent antigen presentation. DC-SIGN forms remarkably stable microdomains on the plasma membrane. However, inner leaflet lipid markers are able to diffuse through these microdomains suggesting that, rather than being densely packed with DC-SIGN proteins, an elemental substructure exists. Therefore, a super-resolution imaging technique, Blink Microscopy (Blink), was applied to further investigate the lateral distribution of DC-SIGN. Blink indicates that DC-SIGN, another CTL (CD206), and influenza hemagglutinin (HA) are all localized in small (∼80 nm in diameter) nanodomains. DC-SIGN and CD206 nanodomains are randomly distributed on the plasma membrane, whereas HA nanodomains cluster on length scales up to several microns. We estimate, as a lower limit, that DC-SIGN and HA nanodomains contain on average two tetramers or two trimers, respectively, whereas CD206 is often nonoligomerized. Two-color Blink determined that different CTLs rarely occupy the same nanodomain, although they appear colocalized using wide-field microscopy. What to our knowledge is a novel domain structure emerges in which elemental nanodomains, potentially capable of binding viruses, are organized in a random fashion; evidently, these nanodomains can be clustered into larger microdomains that act as receptor platforms for larger pathogens like yeasts.
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Affiliation(s)
- Michelle S Itano
- Department of Cell and Developmental Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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Wilson RL, Frisz JF, Hanafin WP, Carpenter KJ, Hutcheon ID, Weber PK, Kraft ML. Fluorinated colloidal gold immunolabels for imaging select proteins in parallel with lipids using high-resolution secondary ion mass spectrometry. Bioconjug Chem 2012; 23:450-60. [PMID: 22284327 PMCID: PMC3951754 DOI: 10.1021/bc200482z] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The local abundance of specific lipid species near a membrane protein is hypothesized to influence the protein's activity. The ability to simultaneously image the distributions of specific protein and lipid species in the cell membrane would facilitate testing these hypotheses. Recent advances in imaging the distribution of cell membrane lipids with mass spectrometry have created the desire for membrane protein probes that can be simultaneously imaged with isotope labeled lipids. Such probes would enable conclusive tests to determine whether specific proteins colocalize with particular lipid species. Here, we describe the development of fluorine-functionalized colloidal gold immunolabels that facilitate the detection and imaging of specific proteins in parallel with lipids in the plasma membrane using high-resolution SIMS performed with a NanoSIMS. First, we developed a method to functionalize colloidal gold nanoparticles with a partially fluorinated mixed monolayer that permitted NanoSIMS detection and rendered the functionalized nanoparticles dispersible in aqueous buffer. Then, to allow for selective protein labeling, we attached the fluorinated colloidal gold nanoparticles to the nonbinding portion of antibodies. By combining these functionalized immunolabels with metabolic incorporation of stable isotopes, we demonstrate that influenza hemagglutinin and cellular lipids can be imaged in parallel using NanoSIMS. These labels enable a general approach to simultaneously imaging specific proteins and lipids with high sensitivity and lateral resolution, which may be used to evaluate predictions of protein colocalization with specific lipid species.
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Affiliation(s)
- Robert L. Wilson
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Jessica F. Frisz
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - William P. Hanafin
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Kevin J. Carpenter
- Glenn Seaborg Institute, Lawrence Livermore National Laboratory, Livermore, CA 94551
| | - Ian D. Hutcheon
- Glenn Seaborg Institute, Lawrence Livermore National Laboratory, Livermore, CA 94551
| | - Peter K. Weber
- Glenn Seaborg Institute, Lawrence Livermore National Laboratory, Livermore, CA 94551
| | - Mary L. Kraft
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801
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Thaa B, Tielesch C, Möller L, Schmitt AO, Wolff T, Bannert N, Herrmann A, Veit M. Growth of influenza A virus is not impeded by simultaneous removal of the cholesterol-binding and acylation sites in the M2 protein. J Gen Virol 2012; 93:282-292. [DOI: 10.1099/vir.0.038554-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Influenza virus assembly and budding occur in the ‘budozone’, a coalesced raft domain in the plasma membrane. The viral transmembrane protein M2 is implicated in virus particle scission, the ultimate step in virus budding, probably by wedge-like insertion of an amphiphilic helix into the membrane. In order to do this, M2 is hypothesized to be targeted to the edge of the budozone, mediated by acylation and cholesterol binding. It was recently shown that acylation and cholesterol binding affect the membrane association of the cytoplasmic tail of M2 and targeting of the protein to coalesced rafts. This study tested whether combined removal of the acylation site (C50) and the cholesterol recognition/interaction amino acid consensus motifs (key residues Y52 and Y57) in the amphiphilic helix of M2 influenced virus formation. Recombinant influenza viruses were generated in the influenza strain A/WSN/33 background with mutations in one or both of these features. In comparison with the wild-type, all mutant viruses showed very similar growth kinetics in various cell types. Wild-type and mutant viruses differed in their relative M2 content but not regarding the major structural proteins. The morphology of the viruses was not affected by mutating M2. Moreover, wild-type and mutant viruses showed comparable competitive fitness in infected cells. Lastly, a global comparison of M2 sequences revealed that there are natural virus strains with M2 devoid of both lipid-association motifs. Taken together, these results indicate that the acylation and cholesterol-binding motifs in M2 are not crucial for the replication of influenza virus in cell culture, indicating that other factors can target M2 to the budding site.
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Affiliation(s)
- Bastian Thaa
- Freie Universität Berlin, Faculty of Veterinary Medicine, Institute of Immunology and Molecular Biology, Philippstraße 13, 10115 Berlin, Germany
| | - Claudia Tielesch
- Freie Universität Berlin, Faculty of Veterinary Medicine, Institute of Immunology and Molecular Biology, Philippstraße 13, 10115 Berlin, Germany
| | - Lars Möller
- Robert Koch Institute, Nordufer 20, 13353 Berlin, Germany
| | - Armin O. Schmitt
- Humboldt-Universität zu Berlin, Department for Crop and Animal Sciences, Invalidenstraße 42, 10115 Berlin, Germany
| | - Thorsten Wolff
- Robert Koch Institute, Nordufer 20, 13353 Berlin, Germany
| | | | - Andreas Herrmann
- Humboldt-Universität zu Berlin, Institute of Biology, Molecular Biophysics, Invalidenstraße 42, 10115 Berlin, Germany
| | - Michael Veit
- Freie Universität Berlin, Faculty of Veterinary Medicine, Institute of Immunology and Molecular Biology, Philippstraße 13, 10115 Berlin, Germany
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Gerl MJ, Sampaio JL, Urban S, Kalvodova L, Verbavatz JM, Binnington B, Lindemann D, Lingwood CA, Shevchenko A, Schroeder C, Simons K. Quantitative analysis of the lipidomes of the influenza virus envelope and MDCK cell apical membrane. ACTA ACUST UNITED AC 2012; 196:213-21. [PMID: 22249292 PMCID: PMC3265945 DOI: 10.1083/jcb.201108175] [Citation(s) in RCA: 212] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Analysis of the lipid composition of influenza virus–infected cells provides support for the membrane raft-based biogenesis model. The influenza virus (IFV) acquires its envelope by budding from host cell plasma membranes. Using quantitative shotgun mass spectrometry, we determined the lipidomes of the host Madin–Darby canine kidney cell, its apical membrane, and the IFV budding from it. We found the apical membrane to be enriched in sphingolipids (SPs) and cholesterol, whereas glycerophospholipids were reduced, and storage lipids were depleted compared with the whole-cell membranes. The virus membrane exhibited a further enrichment of SPs and cholesterol compared with the donor membrane at the expense of phosphatidylcholines. Our data are consistent with and extend existing models of membrane raft-based biogenesis of the apical membrane and IFV envelope.
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Affiliation(s)
- Mathias J Gerl
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
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D-CAT: Density and Clustering Annotation Tool for three dimensional electron microscopic volumes. J Struct Biol 2011; 177:571-7. [PMID: 22173221 DOI: 10.1016/j.jsb.2011.11.030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Revised: 11/28/2011] [Accepted: 11/30/2011] [Indexed: 11/21/2022]
Abstract
Three dimensional (3D) electron microscopy techniques have become valuable tools for investigating cellular architecture and the processes that govern it. A vast amount of information is available in every 3D tomogram but the options for presenting this information in a clear and visually appealing way are limited. To address this, we developed D-CAT; a MatLab-application to accurately visualize the distribution of membrane proteins and/or membrane-bound structures. Presence (density) and distribution (clustering, depletion) are presented as color-coded areas on membranes. By using IMOD models both as input and output format, we ensure that the application fits within workflows common in the field of 3D electron microscopy.
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Lipid peroxidation modifies the picture of membranes from the "Fluid Mosaic Model" to the "Lipid Whisker Model". Biochimie 2011; 94:101-9. [PMID: 21983178 DOI: 10.1016/j.biochi.2011.09.025] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Accepted: 09/27/2011] [Indexed: 11/23/2022]
Abstract
The "Fluid Mosaic Model", described by Singer and Nicolson, explain both how a cell membrane preserves a critical barrier function while it concomitantly facilitates rapid lateral diffusion of proteins and lipids within the planar membrane surface. However, the lipid components of biological plasma membranes are not regularly distributed. They are thought to contain "rafts" - nano-domains enriched in sphingolipids and cholesterol that are distinct from surrounding membranes of unsaturated phospholipids. Cholesterol and fatty acids adjust the transport and diffusion of molecular oxygen in membranes. The presence of cholesterol and saturated phospholipids decreases oxygen permeability across the membrane. Alpha-tocopherol, the main antioxidant in biological membranes, partition into domains that are enriched in polyunsaturated phospholipids increasing the concentration of the vitamin in the place where it is most required. On the basis of these observations, it is possible to assume that non-raft domains enriched in phospholipids containing PUFAs and vitamin E will be more accessible by molecular oxygen than lipid raft domains enriched in sphingolipids and cholesterol. This situation will render some nano-domains more sensitive to lipid peroxidation than others. Phospholipid oxidation products are very likely to alter the properties of biological membranes, because their polarity and shape may differ considerably from the structures of their parent molecules. Addition of a polar oxygen atom to several peroxidized fatty acids reorients the acyl chain whereby it no longer remains buried within the membrane interior, but rather projects into the aqueous environment "Lipid Whisker Model". This exceptional conformational change facilitates direct physical access of the oxidized fatty acid moiety to cell surface scavenger receptors.
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Itano MS, Neumann AK, Liu P, Zhang F, Gratton E, Parak WJ, Thompson NL, Jacobson K. DC-SIGN and influenza hemagglutinin dynamics in plasma membrane microdomains are markedly different. Biophys J 2011; 100:2662-70. [PMID: 21641311 DOI: 10.1016/j.bpj.2011.04.044] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 04/11/2011] [Accepted: 04/14/2011] [Indexed: 11/24/2022] Open
Abstract
DC-SIGN, a Ca(2+)-dependent transmembrane lectin, is found assembled in microdomains on the plasma membranes of dendritic cells. These microdomains bind a large variety of pathogens and facilitate their uptake for subsequent antigen presentation. In this study, DC-SIGN dynamics in microdomains were explored with several fluorescence microscopy methods and compared with dynamics for influenza hemagglutinin (HA), which is also found in plasma membrane microdomains. Fluorescence imaging indicated that DC-SIGN microdomains may contain other C-type lectins and that the DC-SIGN cytoplasmic region is not required for microdomain formation. Fluorescence recovery after photobleaching measurements showed that neither full-length nor cytoplasmically truncated DC-SIGN in microdomains appreciably exchanged with like molecules in other microdomains and the membrane surround, whereas HA in microdomains exchanged almost completely. Line-scan fluorescence correlation spectroscopy indicated an essentially undetectable lateral mobility for DC-SIGN but an appreciable mobility for HA within their respective domains. Single-particle tracking with defined-valency quantum dots confirmed that HA has significant mobility within microdomains, whereas DC-SIGN does not. By contrast, fluorescence recovery after photobleaching indicated that inner leaflet lipids are able to move through DC-SIGN microdomains. The surprising stability of DC-SIGN microdomains may reflect structural features that enhance pathogen uptake either by providing high-avidity platforms and/or by protecting against rapid microdomain endocytosis.
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Affiliation(s)
- Michelle S Itano
- Department of Cell and Developmental Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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