Modification of the cytoplasmic domain of influenza virus hemagglutinin affects enlargement of the fusion pore.
AuthorsKozerski C,Ponimaskin E,Schroth-Diez B,Schmidt MF,Herrmann A
JournalJournal of virology
PubMed ID10906206
The fusion activity of chimeras of influenza virus hemagglutinin (HA) (from A/fpv/Rostock/34; subtype H7) with the transmembrane domain (TM) and/or cytoplasmic tail (CT) either from the nonviral, nonfusogenic T-cell surface protein CD4 or from the fusogenic Sendai virus F-protein was studied. Wild-type or chimeric HA was expressed in CV-1 cells ... More
Fusion activity of transmembrane and cytoplasmic domain chimeras of the influenza virus glycoprotein hemagglutinin.
AuthorsSchroth-Diez B, Ponimaskin E, Reverey H, Schmidt MF, Herrmann A
JournalJ Virol
PubMed ID9420208
The role of the sequence of transmembrane and cytoplasmic/intraviral domains of influenza virus hemagglutinin (HA, subtype H7) for HA-mediated membrane fusion was explored. To analyze the influence of the two domains on the fusogenic properties of HA, we designed HA-chimeras in which the cytoplasmic tail and/or transmembrane domain of HA ... More
Exocytotic insertion of calcium channels constrains compensatory endocytosis to sites of exocytosis.
AuthorsSmith RM, Baibakov B, Ikebuchi Y, White BH, Lambert NA, Kaczmarek LK, Vogel SS
JournalJ Cell Biol
PubMed ID10684256
'Proteins inserted into the cell surface by exocytosis are thought to be retrieved by compensatory endocytosis, suggesting that retrieval requires granule proteins. In sea urchin eggs, calcium influx through P-type calcium channels is required for retrieval, and the large size of sea urchin secretory granules permits the direct observation of ... More
Thiol/disulfide exchange is required for membrane fusion directed by the Newcastle disease virus fusion protein.
AuthorsJain S, McGinnes LW, Morrison TG
JournalJ Virol
PubMed ID17151113
'Newcastle disease virus (NDV), an avian paramyxovirus, initiates infection with attachment of the viral hemagglutinin-neuraminidase (HN) protein to sialic acid-containing receptors, followed by fusion of viral and cell membranes, which is mediated by the fusion (F) protein. Like all class 1 viral fusion proteins, the paramyxovirus F protein is thought ... More
Mild proteolysis induces a ready-to-fuse state on Sendai virus envelope.
AuthorsTomasi M, Baiocchi M, Moscufo N, Parolini I, Squatriti T, Bellini T, Dallocchio F
JournalFEBS Lett
PubMed ID9515725
'The Sendai virus fuses with host cell membranes in a pH-independent manner through an unknown mechanism. Here we report that mild trypsin pre-treatments of Sendai virions, for example 15 min at 4 degrees C, give Sendai virions the ability to fuse at a rate up to 10-fold higher than control. ... More
Effect of erythrocyte transbilayer phospholipid distribution on fusion with vesicular stomatitis virus.
AuthorsHerrmann A, Clague MJ, Puri A, Morris SJ, Blumenthal R, Grimaldi S
JournalBiochemistry
PubMed ID2163270
'To identify the specific component(s) in the target membrane involved in fusion of vesicular stomatitis virus (VSV), we examined the interaction of the virus with human erythrocyte membranes with asymmetric and symmetric bilayer distributions of phospholipids. Fusion was monitored spectrofluorometrically by the octadecylrhodamine dequenching assay. Fusion of VSV with lipid-symmetric ... More
Location of the epidermal growth factor binding site on the EGF receptor. A resonance energy transfer study.
AuthorsCarraway KL, Koland JG, Cerione RA
JournalBiochemistry
PubMed ID2271554
'As a first step toward developing a structural map of key sites on the epidermal growth factor (EGF) receptor, we have used resonance energy transfer to measure the distance of closest approach between the receptor-bound growth factor molecule and lipid molecules at the surface of the plasma membrane. EGF, specifically ... More
Initial stages of influenza hemagglutinin-induced cell fusion monitored simultaneously by two fluorescent events: cytoplasmic continuity and lipid mixing.
AuthorsSarkar DP, Morris SJ, Eidelman O, Zimmerberg J, Blumenthal R
JournalJ Cell Biol
PubMed ID2745545
'We have monitored the mixing of both aqueous intracellular and membrane-bound fluorescent dyes during the fusion of human red blood cells to influenza hemagglutinin-expressing fibroblasts using fluorescence spectroscopy and low light, image-enhanced video microscopy. The water-soluble fluorescent dye, N-(7-nitrobenzofurazan-4-yl)taurine, was incorporated into intact human red blood cells. The fluorescence of ... More
Fusion of liposomes and rat brain microsomes examined by two assays.
AuthorsCorazzi L, Fratto G, Pistolesi R, Arienti G
JournalJ Membr Biol
PubMed ID2621744
'Liposomes are prepared from rat brain microsomal lipid and loaded with either Tb3+ or dipicolinic acid (DPA) to test fusion with the Tb-DPA assay. They are also loaded with octadecyl Rhodamine B chloride (R18) to test fusion with the R18 assay. The addition of either Ca2+ or Mg2+ to loaded ... More
Small unilamellar vesicles are able to fuse with Mycoplasma capricolum cells.
AuthorsSalman M, Tarshis M, Rottem S
JournalBiochim Biophys Acta
PubMed ID1901498
'We have investigated the fusion characteristics of intact Mycoplasma capricolum cells and small unilamellar vesicles (SUV). The rate and extent of fusion was monitored continuously by octadecylrhodamine B (R18) fluorescence dequenching assay, as well as by intracellular contents mixing, and by sucrose density gradient analysis. The fusion of SUV with ... More
Ionic strength of the intermembrane space of intact mitochondria as estimated with fluorescein-BSA delivered by low pH fusion.
AuthorsCortese JD, Voglino AL, Hackenbrock CR
JournalJ Cell Biol
PubMed ID2045415
'The electrostatic interactions of cytochrome c with its redox partners and membrane lipids, as well as other protein interactions and biochemical reactions, may be modulated by the ionic strength of the intermembrane space of the mitochondrion. FITC-BSA was used to determine the relative value of the mitochondrial intermembrane ionic strength ... More
Kinetics of virus adsorption to single cells using fluorescent membrane probes and multiparameter flow cytometry.
AuthorsLeary JF, Notter MF
JournalCell Biophys
PubMed ID6176329
'Different genetic stains of avian RNA tumor virus (ATV) were labeled with the fluorescent membrane probe R-18 (rhodamine conjugated to a hydrocarbon chain) and cellular receptors for virus infection were analyzed on a rapid, single-cell basis by a multiparameter cell sorter. Chicken cells genetically susceptible to various R-18 ATV were ... More
The kinetics of phagosome maturation as a function of phagosome/lysosome fusion and acquisition of hydrolytic activity.
AuthorsYates RM, Hermetter A, Russell DG
JournalTraffic
PubMed ID15813751
'Professional phagocytes function at the hinge of innate and acquired immune responses by internalizing particulate material that is digested and sampled within the phagosome of the cell. Despite intense interest, assays to measure phagosome maturation remain insensitive and few in number. In this current study, we describe three novel assays ... More
Inactivation of PR8 influenza virus through the octadecylrhodamine B chloride membrane marker.
AuthorsWunderli-Allenspach H, Günthert M, Ott S
JournalBiochemistry
PubMed ID8422394
'The octadecylrhodamine B chloride (R18) membrane marker was incorporated into PR8 influenza viruses and virus receptor (GD1a-) containing small unilamellar vesicles (SUV). Both were tested in a fusion/lipid transfer assay [Wunderli-Allenspach, H., & Ott, S. (1990) Biochemistry 29, 1990-1997] to find out whether incorporation into artificial and biological membranes yields ... More
Fusion of influenza virions with a planar lipid membrane detected by video fluorescence microscopy.
AuthorsNiles WD, Cohen FS
JournalJ Gen Physiol
PubMed ID1875185
'The fusion of individual influenza virions with a planar phospholipid membrane was detected by fluorescence video microscopy. Virion envelopes were loaded with the lipophilic fluorescent marker octadecylrhodamine B (R18) to a density at which the fluorescence of the probe was self-quenched. Labeled virions were ejected toward the planar membrane from ... More
Scanning near-field fluorescence resonance energy transfer microscopy.
AuthorsVickery SA, Dunn RC
JournalBiophys J
PubMed ID10096880
'A new microscopic technique is demonstrated that combines attributes from both near-field scanning optical microscopy (NSOM) and fluorescence resonance energy transfer (FRET). The method relies on attaching the acceptor dye of a FRET pair to the end of a near-field fiber optic probe. Light exiting the NSOM probe, which is ... More
Transfer of phospholipid and protein into the envelope of gram-negative bacteria by liposome fusion.
AuthorsTomlinson S, Taylor PW, Luzio JP
JournalBiochemistry
PubMed ID2690939
'A liposome-bacterial fusion system was developed in order to introduce preformed terminal complement complexes, C5b-9, into the outer membrane of Gram-negative bacteria. Liposomes were prepared from a total phospholipid extract of Salmonella minnesota Re595. Fusion between liposomes and Salmonella sp. or Escherichia coli 17 was dependent on time, temperature, pH, ... More
A domain of membrane-bound blood coagulation factor Va is located far from the phospholipid surface. A fluorescence energy transfer measurement.
AuthorsIsaacs BS, Husten EJ, Esmon CT, Johnson AE
JournalBiochemistry
PubMed ID3768326
'The larger subunit of blood coagulation factor Va was covalently labeled with iodoacetamido derivatives of fluorescein and rhodamine without loss of functional activity, as measured by either the one-stage clotting assay or the ability to accelerate prothrombin activation in a purified system. The spectral properties of the dyes were not ... More
Human immunodeficiency virus type 1 (HIV-1) fusion with model membranes: kinetic analysis and the role of lipid composition, pH and divalent cations.
AuthorsLarsen CE, Nir S, Alford DR, Jennings M, Lee KD, Düzgünes N
JournalBiochim Biophys Acta
PubMed ID8476916
'The kinetics and extent of HIV-1 fusion with model membranes was studied. HIV-1 was labeled with octadecyl rhodamine B chloride, and fusion was monitored continuously as the dilution of the probe into target membranes. The results were analyzed by a mass action model which yielded good simulations and predictions for ... More
In vitro fusion of rabbit liver Golgi membranes with liposomes.
AuthorsKagiwada S, Murata M, Hishida R, Tagaya M, Yamashina S, Ohnishi S
JournalJ Biol Chem
PubMed ID8419344
'Fusion of Golgi membranes isolated from rabbit liver with liposomes was studied by lipid mixing of fluorescent lipid analogues and internal content mixing and by electron microscopic observation of transfer of horseradish peroxidase from liposomes into Golgi membranes. A monoclonal antibody was used to confirm fusion of Golgi membranes but ... More
Voltage-dependent translocation of R18 and DiI across lipid bilayers leads to fluorescence changes.
AuthorsMelikyan GB, Deriy BN, Ok DC, Cohen FS
JournalBiophys J
PubMed ID8913605
'We show that the lipophilic, cationic fluorescent dyes R18 and Dil translocate from one monolayer of a phospholipid bilayer membrane to the other in a concentration and voltage-dependent manner. When the probes were incorporated into voltage-clamped planar membranes and potentials were applied, displacement currents resulted. The charged probes sensed a ... More
Movements of fluorescent probes in the mechanism of cell fusion induced by poly(ethylene glycol).
AuthorsAhkong QF, Desmazes JP, Georgescauld D, Lucy JA
JournalJ Cell Sci
PubMed ID3448101
'It has been claimed that purified poly(ethylene glycol) (PEG) is able only to aggregate cells and not to fuse them. In our hands, purified PEG 6000 (recrystallized/dialysed) induces both aggregation and fusion of human erythrocytes, and the mechanism of fusion by the purified polymer has been investigated with fluorescent probes. ... More
Real-time multi-wavelength fluorescence imaging of living cells.
AuthorsMorris SJ
JournalBiotechniques
PubMed ID2331370
'We describe a new real-time fluorescence video microscope design for capturing intensified images of cells containing dual wavelength "ratio" dyes or multiple dyes. The microscope will perform real-time capture of two separate fluorescence emission images simultaneously, improving the time resolution of spatial distribution of fluorescence to video frame rates (30 ... More
von Willebrand factor mediates protection of factor VIII from activated protein C-catalyzed inactivation.
AuthorsFay PJ, Coumans JV, Walker FJ
JournalJ Biol Chem
PubMed ID1846615
'Factor VIII, a cofactor of the intrinsic clotting pathway, is proteolytically inactivated by the vitamin K-dependent serine protease, activated protein C in a reaction requiring Ca2+ and a phospholipid surface. Factor VIII was inactivated 15 times faster than factor VIII in complex with either von Willebrand factor (vWf) or the ... More
A novel pH-sensitive liposome formulation containing oleyl alcohol.
AuthorsSudimack JJ, Guo W, Tjarks W, Lee RJ
JournalBiochim Biophys Acta
PubMed ID12100993
'pH-sensitive liposomes are designed to undergo acid-triggered destabilization. First generation pH-sensitive liposomes, based on the cone-shaped lipid dioleoylphosphatidylethanolamine (DOPE), have been shown to lose fusogenicity in the presence of serum. Here, we report the design and evaluation of novel serum-resistant pH-sensitive liposome formulations that are based on the composition of ... More
The location of fluorescence probes with charged groups in model membranes.
AuthorsKachel K, Asuncion-Punzalan E, London E
JournalBiochim Biophys Acta
PubMed ID9814853
'The location of commonly used charged fluorescent membrane probes in membranes was determined in order to: (1) investigate the relationship between the structure of hydrophobic molecules and their depth within membranes; and (2) aid interpretation of experiments in which these fluorescent probes are used to examine membrane structure. Membrane depth ... More
Specific single or double proline substitutions in the "spring-loaded" coiled-coil region of the influenza hemagglutinin impair or abolish membrane fusion activity.
AuthorsQiao H, Pelletier SL, Hoffman L, Hacker J, Armstrong RT, White JM
JournalJ Cell Biol
PubMed ID9628890
'We tested the role of the "spring-loaded" conformational change in the fusion mechanism of the influenza hemagglutinin (HA) by assessing the effects of 10 point mutants in the region of high coiled-coil propensity, HA2 54-81. The mutants included proline substitutions at HA2 55, 71, and 80, as well as a ... More
Kinetic modeling of Sendai virus fusion with PC-12 cells. Effect of pH and temperature on fusion and viral inactivation.
AuthorsPedroso de Lima MC, Ramalho-Santos J, Martins MF, Pato de Carvalho A, Bairos V, Nir S
JournalEur J Biochem
PubMed ID1313363
'We have studied the fusion activity of Sendai virus, a lipid-enveloped paramyxovirus, towards a line of adherent cells designated PC-12. Fusion was monitored by the dequenching of octadecyl-rhodamine, a fluorescent non-exchangeable probe. The results were analysed with a mass action kinetic model which could explain and predict the kinetics of ... More
Membrane fusion mediated by the influenza virus hemagglutinin requires the concerted action of at least three hemagglutinin trimers.
AuthorsDanieli T, Pelletier SL, Henis YI, White JM
JournalJ Cell Biol
PubMed ID8636231
'In this study we tested the hypothesis that fusion mediated by the influenza virus hemagglutinin (HA) is a cooperative event. To so this we characterized 3T3 cell lines that express HA at nine different defined surface densities. HA densities ranged from 1.0 to 12.6 x 10(3) HA trimers/microns2 as determined ... More
Morphological changes induced by phospholipase C and by sphingomyelinase on large unilamellar vesicles: a cryo-transmission electron microscopy study of liposome fusion.
AuthorsBasáñez G, Ruiz-Argüello MB, Alonso A, Goñi FM, Karlsson G, Edwards K
JournalBiophys J
PubMed ID9168038
'Cryo-transmission electron microscopy has been applied to the study of the changes induced by phospholipase C on large unilamellar vesicles containing phosphatidylcholine, as well as to the action of sphingomyelinase on vesicles containing sphingomyelin. In both cases vesicle aggregation occurs as the earliest detectable phenomenon; later, each system behaves differently. ... More
Tracking of cell surface receptors by fluorescence digital imaging microscopy using a charge-coupled device camera. Low-density lipoprotein and influenza virus receptor mobility at 4 degrees C.
AuthorsAnderson CM, Georgiou GN, Morrison IE, Stevenson GV, Cherry RJ
JournalJ Cell Sci
PubMed ID1629253
'A fluorescence imaging system, based on using a cooled slow-scan CCD camera, has been developed for tracking receptors on the surfaces of living cells. The technique is applicable to receptors for particles such as lipoproteins and viruses that can be labeled with a few tens of fluorophores. The positions of ... More
Lipid requirement of the branched-chain amino acid transport system of Streptococcus cremoris.
AuthorsDriessen AJ, Zheng T, In't Veld G, Op den Kamp JA, Konings WN
JournalBiochemistry
PubMed ID3284574
'The role of the membrane lipid composition on the transport protein of branched-chain amino acids of the homofermentative lactic acid bacterium Streptococcus cremoris has been investigated. The major membrane lipid species identified in S. cremoris were acidic phospholipids (phosphatidylglycerol and cardiolipin), glycolipids, and glycerophosphoglycolipids. Phosphatidylethanolamine (PE) was completely absent. Protonmotive ... More
Membrane potential-driven translocation of a lipid-conjugated rhodamine.
AuthorsLeenhouts JM, De Kruijff B
JournalBiochim Biophys Acta
PubMed ID7632704
'The present study demonstrates that the permanently positively charged, lipid-conjugated rhodamine, R18, can be transported from the outer to the inner leaflet of lipid bilayers in response of a transmembrane potential (negative inside). This conclusion was based on the following observations. (i) A fast decrease of the R18 fluorescence, when ... More
Tension of membranes expressing the hemagglutinin of influenza virus inhibits fusion.
AuthorsMarkosyan RM, Melikyan GB, Cohen FS
JournalBiophys J
PubMed ID10423439
'The effects of membrane tension on fusion between cells expressing the hemagglutinin (HA) of influenza virus and red blood cells were studied by capacitance measurements. Inflation of an HA-expressing cell was achieved by applying a positive hydrostatic pressure to its interior through a patch-clamp pipette in the whole-cell configuration. Inflating ... More
Attachment of growth cones on substrate observed by multi-mode light microscopy.
AuthorsTatsumi H, Katayama Y, Sokabe M
JournalNeurosci Res
PubMed ID10605943
'Evanescent light illumination was introduced into a multi-mode microscope to construct a new type of total internal reflection fluorescence microscope (TIRFM). This microscope, capable of TIRFM, high resolution video-enhanced differential interference contrast (DIC), epifluorescence, interference reflection (IR) imaging, was combined with an image acquisition system for time-lapse microscopy. Neuronal growth ... More
Gating kinetics of pH-activated membrane fusion of vesicular stomatitis virus with cells: stopped-flow measurements by dequenching of octadecylrhodamine fluorescence.
AuthorsClague MJ, Schoch C, Zech L, Blumenthal R
JournalBiochemistry
PubMed ID2157487
'To identify the initial stages of membrane fusion induced by vesicular stomatitis virus, we performed stopped-flow kinetic measurement with fluorescently labeled virus attached to human erythrocyte ghosts that contained symmetric bilayer distributions of phospholipids. Fusion was monitored spectrofluorometrically using an assay based on mixing of the lipid fluorophore octadecylrhodamine. At ... More
Lateral mobility of reconstituted Sendai virus envelope glycoproteins on human erythrocytes: correlation with cell-cell fusion.
AuthorsHenis YI, Gutman O
JournalBiochemistry
PubMed ID3032238
'We have recently employed fluorescence photobleaching recovery (FPR) to demonstrate that the envelope glycoproteins of Sendai virions become laterally mobile on the surface of human erythrocytes following fusion [Henis, Y. I., Gutman, O., & Loyter, A. (1985) Exp. Cell Res. 160, 514-526]. In order to investigate whether this lateral mobilization ... More
Fusion of human immunodeficiency virus type 1 (HIV-1) with human cells as measured by membrane fluorescence dequenching (DQ) method; roles of HIV-1-cell fusion in AIDS pathogenesis.
AuthorsVolsky DJ
JournalProg Clin Biol Res
PubMed ID2198580
'HIV-1, the primary etiologic agent of AIDS, is a non-transforming human retrovirus which shares many physical and functional characteristics with viruses from the lentivirus family. One of these characteristics is that HIV-1 infection has profound cytopathic effects on host cells. Studies by the membrane fluorescence dequenching (DQ) method using HIV-1 ... More
Leaky vesicle fusion induced by phosphatidylinositol-specific phospholipase C: observation of mixing of vesicular inner monolayers.
AuthorsVillar AV, Alonso A, Goñi FM
JournalBiochemistry
PubMed ID11087348
'Large unilamellar vesicles containing phosphatidylinositol (PI), neutral phospholipids, and cholesterol are induced to fuse by the catalytic activity of phosphatidylinositol-specific phospholipase C (PI-PLC). PI cleavage by PI-PLC is followed by vesicle aggregation, intervesicular lipid mixing, and mixing of vesicular aqueous contents. An average of 2-3 vesicles merge into a large ... More
Characteristics of self-quenching of the fluorescence of lipid-conjugated rhodamine in membranes.
AuthorsMacDonald RI
JournalJ Biol Chem
PubMed ID2380172
'Self- or concentration quenching of octadecylrhodamine B (C18-Rh) fluorescence increases linearly in egg phosphatidylcholine (PC) vesicles but exponentially in vesicles composed of egg PC:cholesterol, 1:1, as the probe concentration is raised to 10 mol%. Cholesterol-dependent enhancement of self-quenching also occurs when N-(lissamine-rhodamine-B-sulfonyl)dioleoylphosphatidylethanolamine is substituted for C18-Rh and resembles that in ... More
Lysosomes can fuse with a late endosomal compartment in a cell-free system from rat liver.
'The passage of pulse doses of asialoglycoproteins through the endosomal compartments of rat liver hepatocytes was studied by subcellular fractionation and EM. The kinetics of disappearance of radiolabeled asialofetuin from light endosomes prepared on Ficoll gradients were the same as the kinetics of disappearance of asialoorosomucoid-horse radish peroxidase reaction products ... More
Fluorescence method for measuring the kinetics of fusion between biological membranes.
AuthorsHoekstra D, de Boer T, Klappe K, Wilschut J
JournalBiochemistry
PubMed ID6098295
'An assay is presented that allows continuous and sensitive monitoring of membrane fusion in both artificial and biological membrane systems. The method relies upon the relief of fluorescence self-quenching of octadecyl Rhodamine B chloride. When the probe is incorporated into a lipid bilayer at concentrations up to 9 mol% with ... More
Analysis of receptor clustering on cell surfaces by imaging fluorescent particles.
AuthorsMorrison IE, Anderson CM, Georgiou GN, Stevenson GV, Cherry RJ
JournalBiophys J
PubMed ID7811943
'Fluorescently labeled low density lipoproteins (LDL) and influenza virus particles were bound to the surface of human fibroblasts and imaged with a cooled slow-scan CCD camera attached to a fluorescence microscope. Particles were also imaged after attachment to polylysine-coated microscope slides. The digital images were analyzed by fitting data points ... More
Transverse localization of the quinacrine binding site on the Torpedo acetylcholine receptor.
AuthorsArias HR, Valenzuela CF, Johnson DA
JournalJ Biol Chem
PubMed ID8454605
'We demonstrated previously that a phencyclidine-displaceable quinacrine binding site exists at the lipid-protein interface of the Torpedo acetylcholine receptor (AcChR) (Valenzuela, C. F., Kerr, J. A., and Johnson, D. A. (1992) J. Biol. Chem. 267, 8238-8244). In this manuscript, we assess (1) the transverse position of this site in the ... More
Endocytosis of poly(ethylene oxide)-modified liposome by human lymphoblastoid cells.
AuthorsHigashi N, Sunamoto J
JournalBiochim Biophys Acta
PubMed ID7537102
'Egg PC liposome as reconstituted with poly(ethylene oxide)-bearing lipid (coded as PEO-lipid (n = 15)) was remarkably endocytosed by Jurkat cell, which was a lymphoblastoma derived from human T cell. To confirm the endocytosis, two kinds of fluorescent probes (FITC-dextran and octadecyl rhodamine B) were employed. The former was loaded ... More
The compound DATEM inhibits respiratory syncytial virus fusion activity with epithelial cells.
AuthorsOhki S, Liu JZ, Schaller J, Welliver RC
JournalAntiviral Res
PubMed ID12742571
'The effect of diacetyltartaric acid esters of mono and diglycerides (DATEM) on fusion of respiratory syncytial virus (RSV) with HEp-2 cells was studied using the R18 fluorescence dequenching fusion assay. At DATEM concentrations less than 2.0 microg/ml, the inhibition of fusion increased with the concentration of DATEM. At 2 microg/ml ... More
Modification of the N-terminus of membrane fusion-active peptides blocks the fusion activity.
AuthorsMurata M, Kagiwada S, Hishida R, Ishiguro R, Ohnishi S, Takahashi S
JournalBiochem Biophys Res Commun
PubMed ID1898385
'The amphiphilic anionic peptides E5 and E5L can mimic the fusogenic activity of influenza hemagglutinin(HA). These peptides induced fusion of egg yolk phosphatidylcholine small or large unilamellar vesicles only at acidic pH in a similar manner to viral HA. Acetylation or acetimidylation of the N-terminus of the peptides drastically reduced ... More
Calcium and calmodulin stimulate phospholipase A2 and fusion of H,K-ATPase-containing membrane vesicles isolated from pig gastric mucosa.
AuthorsOlaisson H, Mårdh S, Arvidson G
JournalActa Physiol Scand
PubMed ID1964532
'Fusion of pig gastric H,K-ATPase- and phospholipase A2-containing vesicles in vitro was studied by electron microscopy and by monitoring the change in fluorescence of octadecyl rhodamine B-labelled vesicles. Ca2+ stimulated fusion of the vesicles, and the fusion rate showed a positive correlation with the activity of the phospholipase A2. Both ... More
Truncation of the COOH-terminal region of the paramyxovirus SV5 fusion protein leads to hemifusion but not complete fusion.
AuthorsBagai S, Lamb RA
JournalJ Cell Biol
PubMed ID8858164
'The role of the simian virus 5 (SV5) fusion (F) protein 20 residue COOH-terminal region, thought to represent the cytoplasmic tail, in fusion activity was examined by constructing a series of COOH-terminal truncation mutants. When the altered F proteins were expressed in eukaryotic cells, by using the vaccinia virus-T7 transient ... More
GPI-anchored influenza hemagglutinin induces hemifusion to both red blood cell and planar bilayer membranes.
AuthorsMelikyan GB, White JM, Cohen FS
JournalJ Cell Biol
PubMed ID7593189
'Under fusogenic conditions, fluorescent dye redistributed from the outer monolayer leaflet of red blood cells (RBCs) to cells expressing glycophosphatidylinositol-anchored influenza virus hemagglutinin (GPI-HA) without transfer of aqueous dye. This suggests that hemifusion, but not full fusion, occurred (Kemble, G. W., T. Danieli, and J. M. White. 1994. Cell. 76:383-391). ... More
Plasmenylethanolamine facilitates rapid membrane fusion: a stopped-flow kinetic investigation correlating the propensity of a major plasma membrane constituent to adopt an HII phase with its ability to promote membrane fusion.
AuthorsGlaser PE, Gross RW
JournalBiochemistry
PubMed ID8180209
'A critical step in membrane fusion involves the formation of a lipid intermediate which shares a conformational similarity with an inverted hexagonal phase (HII). Since plasmenylethanolamines possess a marked propensity for hexagonal phase formation and represent a major lipid constituent of several membrane systems which undergo rapid membrane fusion (e.g., ... More
The active site of the thrombin-thrombomodulin complex. A fluorescence energy transfer measurement of its distance above the membrane surface.
AuthorsLu RL, Esmon NL, Esmon CT, Johnson AE
JournalJ Biol Chem
PubMed ID2546942
'The location of the active site of the membrane-bound anticoagulant complex of thrombin and thrombomodulin has been determined relative to the membrane surface using fluorescence energy transfer. Thrombin was reacted with 5-(dimethylamino)-1-naphthalenesulfonylglutamylglycylarginyl chloromethyl ketone (DEGR-CK) to yield DEGR-thrombin, an analogue of thrombin with a fluorescent dye covalently attached to its ... More
Large-scale co-aggregation of fluorescent lipid probes with cell surface proteins.
AuthorsThomas JL, Holowka D, Baird B, Webb WW
JournalJ Cell Biol
PubMed ID8188747
'Large scale aggregation of fluorescein-labeled immunoglobulin E (IgE) receptor complexes on the surface of RBL cells results in the co-aggregation of a large fraction of the lipophilic fluorescent probe 3,3''-dihexadecylindocarbocyanine (diI) that labels the plasma membranes much more uniformly in the absence of receptor aggregation. Most of the diI molecules ... More
Insights into the action of the superfamily of cholesterol-dependent cytolysins from studies of intermedilysin.
'The cholesterol-dependent cytolysins (CDCs), a superfamily of pore-forming toxins, are characterized by a conserved undecapeptide motif that is believed to be critical for membrane recognition by means of cholesterol. Intermedilysin (ILY), an unusual member of the CDCs, exhibits specificity for human cells and contains nonconservative substitutions in the motif. We ... More
Membrane interactions of a constitutively active GFP-Ki-Ras 4B and their role in signaling. Evidence from lateral mobility studies.
AuthorsNiv H, Gutman O, Henis YI, Kloog Y
JournalJ Biol Chem
PubMed ID9880539
'Membrane anchorage of Ras proteins in the inner leaflet of the plasma membrane is an important factor in their signaling and oncogenic potential. Despite these important roles, the precise mode of Ras-membrane interactions is not yet understood. It is especially important to characterize these interactions at the surface of intact ... More
A specific point mutant at position 1 of the influenza hemagglutinin fusion peptide displays a hemifusion phenotype.
AuthorsQiao H, Armstrong RT, Melikyan GB, Cohen FS, White JM
JournalMol Biol Cell
PubMed ID10436026
'We showed previously that substitution of the first residue of the influenza hemagglutinin (HA) fusion peptide Gly1 with Glu abolishes fusion activity. In the present study we asked whether this striking phenotype was due to the charge or side-chain volume of the substituted Glu. To do this we generated and ... More
FRET measurements of cell-traction forces and nano-scale clustering of adhesion ligands varied by substrate stiffness.
AuthorsKong HJ, Polte TR, Alsberg E, Mooney DJ
JournalProc Natl Acad Sci U S A
PubMed ID15767572
'The mechanical properties of cell adhesion substrates regulate cell phenotype, but the mechanism of this relation is currently unclear. It may involve the magnitude of traction force applied by the cell, and/or the ability of the cells to rearrange the cell adhesion molecules presented from the material. In this study, ... More
Computer detection of the rapid diffusion of fluorescent membrane fusion markers in images observed with video microscopy.
AuthorsNiles WD, Li Q, Cohen FS
JournalBiophys J
PubMed ID1420909
'We have developed an algorithm for automated detection of the dynamic pattern characterizing flashes of fluorescence in video images of membrane fusion. The algorithm detects the spatially localized, transient increases and decreases in brightness that result from the dequenching of fluorescent dye in phospholipid vesicles or lipid-enveloped virions fusing with ... More
Determination of the fractal dimension of membrane protein aggregates using fluorescence energy transfer.
AuthorsDewey TG, Datta MM
JournalBiophys J
PubMed ID2528385
'It is demonstrated that fluorescence resonance energy transfer may be used to determine the fractal dimension of aggregates of membrane-bound proteins. Theoretical and experimental results are presented for two different experimental designs: energy transfer between proteins and energy transfer from lipids to proteins. For energy transfer between proteins the lattice ... More
Differential contribution of cytoplasmic Ca2+ and Ca2+ influx to gamete fusion and egg activation in maize.
AuthorsAntoine AF, Faure JE, Dumas C, Feijó JA
JournalNat Cell Biol
PubMed ID11781574
'In multicellular organisms, gamete fusion triggers a set of events, collectively known as egg activation, that leads to the development of a new individual. Every species that has been studied shows at least one rise in cytoplasmic Ca2+ concentration ([Ca2+]Cyt) after gamete fusion which is believed to be involved in ... More
Calcium-dependent association of calmodulin with the C-terminal domain of the tetraspanin protein peripherin/rds.
AuthorsEdrington TC, Yeagle PL, Gretzula CL, Boesze-Battaglia K
JournalBiochemistry
PubMed ID17323925
'Peripherin/rds (p/rds), an integral membrane protein from the transmembrane 4 (TMF4) superfamily, possesses a multi-functional C-terminal domain that plays crucial roles in rod outer segment (ROS) disk renewal and structure. Here, we report that the calcium binding protein calmodulin (CaM) binds to the C-terminal domain of p/rds. Fluorescence spectroscopy reveals ... More
Charge and pH effect on the early events of Epstein-Barr virus fusion with lymphoblastoid cells (Raji).
AuthorsPozzi D, Faggioni A, Zompetta C, De Ros I, Lio S, Lisi A, Ravagnan G, Frati L, Grimaldi S
JournalIntervirology
PubMed ID1326496
'Fusion of Epstein-Barr virus (EBV) with Raji cells was measured after exposure of the virus to neutral or low pH, enzymatic modification of the viral spike glycoproteins, or chemical modification of the target membrane. The relief of octadecylrhodamine (R18) fluorescence self-quenching was used to monitor fusion. Fusion of EBV with ... More
"De novo" design of peptides with specific lipid-binding properties.
AuthorsLins L, Charloteaux B, Heinen C, Thomas A, Brasseur R
JournalBiophys J
PubMed ID16275638
'In this study, we describe an in silico method to design peptides that can be made of non-natural amino acids and elicit specific membrane-interacting properties. The originality of the method holds in the capacities developed to design peptides from any non-natural amino acids as easily as from natural ones, and ... More
The stability and functional properties of proteoliposomes mixed with dextran derivatives bearing hydrophobic anchor groups.
AuthorsElferink MG, de Wit JG, In 't Veld G, Reichert A, Driessen AJ, Ringsdorf H, Konings WN
JournalBiochim Biophys Acta
PubMed ID1374644
'Liposomes composed of Escherichia coli phospholipid were coated with polysaccharides bearing hydrophobic palmitoyl anchors. The effect on the stability of liposomes without or with integral membrane proteins was investigated. A high concentration of hydrophobized dextrans protected the liposomes against detergent degradation, decreased the fluidity of the membranes, prevented fusion of ... More
Role of phosphatidylserine and diacylglycerol in the fusion of chromaffin granules with target membranes.
'The role of phosphatidylserine and diacylglycerol in the fusion of chromaffin granules with target membranes was investigated in vitro, monitoring the mixing of membrane lipids with the octadecyl rhodamine B fluorescence dequenching assay. Polylysine was able to induce fusion of chromaffin granule ghosts with plasma membrane vesicles in the absence ... More
A specific interaction in vitro between pancreatic zymogen granules and plasma membranes: stimulation by G-protein activators but not by Ca2+.
AuthorsNadin CY, Rogers J, Tomlinson S, Edwardson JM
JournalJ Cell Biol
PubMed ID2512300
'The molecular details of the final step in the process of regulated exocytosis, the fusion of the membrane of the secretory granule with the plasma membrane, are at present obscure. As a first step in an investigation of this membrane fusion event, we have developed a cell-free assay for the ... More
Fluorescence photobleaching recovery as a method to quantitate viral envelope-cell fusion: application to study fusion of Sendai virus envelopes with cells.
AuthorsAroeti B, Henis YI
JournalBiochemistry
PubMed ID3021192
'A method to quantitate viral envelope-cell fusion at the single-cell level is presented. The method is based on the incorporation of nonquenching concentrations of a fluorescent lipid probe into the viral envelope; fluorescence photobleaching recovery (FPR) is then applied to measure the lateral mobilization of the probe in the cell ... More
Effects of platelet activating factor on calcium-lipid interactions and lateral phase separations in phospholipid vesicles.
AuthorsBratton DL, Harris RA, Clay KL, Henson PM
JournalBiochim Biophys Acta
PubMed ID3401478
'Recent studies localizing the inflammatory mediator, platelet activating factor (PAF, 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine), to the membranes of stimulated neutrophils, raise the possibility that PAF may, in addition to its activities as a mediator, alter the physical properties of membranes. This, and the increasing evidence that calcium-lipid interactions may have central importance in ... More
Mode of membrane interaction and fusogenic properties of a de novo transmembrane model peptide depend on the length of the hydrophobic core.
AuthorsLorin A, Charloteaux B, Fridmann-Sirkis Y, Thomas A, Shai Y, Brasseur R
JournalJ Biol Chem
PubMed ID17459883
'Model peptides composed of alanine and leucine residues are often used to mimic single helical transmembrane domains. Many studies have been carried out to determine how they interact with membranes. However, few studies have investigated their lipid-destabilizing effect. We designed three peptides designated KALRs containing a hydrophobic stretch of 14, ... More
Digital fluorescence imaging of elementary steps of neurosteroid synthesis in rat brain glial cells.
AuthorsKimoto T, Asou H, Ohta Y, Mukai H, Chernogolov AA, Kawato S
JournalJ Pharm Biomed Anal
PubMed ID9226548
'With fluorescence microscopic imaging, we have examined Ca2+ signaling, LDL uptake and distribution of cytochrome P450 scc on individual rat brain glial cells in order to investigate the molecular mechanisms of neurosteroid synthesis. Astrocytes and oligodendrocytes were cultured from newborn rat brain. Ca2+ signaling was observed in Calcium Green-1 loaded ... More
Diffusion and redistribution of lipid-like molecules between membranes in virus-cell and cell-cell fusion systems.
AuthorsRubin RJ, Chen YD
JournalBiophys J
PubMed ID2291940
'The kinetics of redistribution of lipid-like molecules between the membranes of two fused spherical vesicles is studied by solving the time-dependent diffusion equation of the system. The effects on the probe redistribution rate of pore size at the fusion junction and the relative sizes of the vesicles are examined. It ... More
Transient changes of the conformation of hemagglutinin of influenza virus at low pH detected by time-resolved circular dichroism spectroscopy.
AuthorsKorte T, Ludwig K, Krumbiegel M, Zirwer D, Damaschun G, Herrmann A
JournalJ Biol Chem
PubMed ID9092509
'Membrane fusion of influenza virus is mediated by a conformational change of the viral membrane protein hemagglutinin (HA) triggered by low pH. By near UV CD spectroscopy, which is sensitive to the arrangement and mobility of aromatic amino acids in proteins, we have monitored continuously with a time resolution of ... More
Quantitative determination of virus-membrane fusion events. Fusion of influenza virions with plasma membranes and membranes of endocytic vesicles in living cultured cells.
AuthorsNussbaum O, Loyter A
JournalFEBS Lett
PubMed ID3622762
'Incubation of fluorescently labeled influenza virus particles with living cultured cells such as lymphoma S-49 cells or hepatoma tissue culture cells resulted in a relatively high degree of fluorescence dequenching. Increase in the degree of fluorescence (35-40% fluorescence dequenching) was observed following incubation at pH 5.0 as well as at ... More
Saturable attachment sites for polyhedron-derived baculovirus on insect cells and evidence for entry via direct membrane fusion.
AuthorsHorton HM, Burand JP
JournalJ Virol
PubMed ID8445715
'This research provides the first evidence for specific receptor binding of polyhedron-derived baculovirus (PDV) to host cells and to lepidopteran brush border membrane vesicles (BBMV) and demonstration of entry via a nonendocytotic pathway involving direct membrane fusion. The technique of fluorescence-activated cell sorting analysis was used to investigate the specificity ... More
Fluorescence assays to monitor membrane fusion: potential application in biliary lipid secretion and vesicle interactions.
AuthorsHoekstra D
JournalHepatology
PubMed ID2210660
'Membrane fusion constitutes an essential, intermediate step in numerous cell biological processes, occurring for example during endocytosis, membrane recycling and exocytosis. Also less desirable events such as the infection of cells by animal viruses are mediated by membrane fusion during which the viral envelope merges with a cellular membrane, causing ... More
Effects of spontaneous bilayer curvature on influenza virus-mediated fusion pores.
'Cells expressing the hemagglutinin protein of influenza virus were fused to planar bilayer membranes containing the fluorescent lipid probes octadecylrhodamine (R18) or indocarbocyanine (DiI) to investigate whether spontaneous curvature of each monolayer of a target membrane affects the growth of fusion pores. R18 and DiI lowered the transition temperatures for ... More
A haemagglutinin (HA1)-specific FAb neutralizes influenza A virus by inhibiting fusion activity.
AuthorsEdwards MJ, Dimmock NJ
JournalJ Gen Virol
PubMed ID11369883
'H9-D3-4R2 (referred to as H9), a murine monoclonal HA1-specific IgG3, recognizes an epitope within antigenic site Cb of influenza virus A/PR/8/34 (H1N1). At 50% neutralization, inhibition of virus-mediated fusion was responsible for the majority of neutralization but, at higher antibody concentrations, the attachment of virus to target cells was also ... More
Optimizing and quantifying fusion of liposomes to mammalian sperm using resonance energy transfer and flow cytometric methods.
AuthorsAnzar M, Kakuda N, He L, Pauls KP, Buhr MM
JournalCytometry
PubMed ID12210607
'BACKGROUND: Liposomes are used to carry pharmaceutical agents and to alter the lipid composition of cell membranes. This study compared resonance energy transfer (RET), fluorescence dequenching, and flow cytometry as monitors and quantifiers of fusion between liposomes and mammalian spermatozoa. METHODS: Preliminary experiments used RET to determine the optimum sperm ... More
Expression of influenza B virus hemagglutinin containing multibasic residue cleavage sites.
AuthorsBrassard DL, Lamb RA
JournalVirology
PubMed ID9325231
'The hemagglutinin (HA) protein of influenza B virus contains a single arginine residue at its cleavage site and the HA0 precursor is not cleaved to the HA1 and HA2 subunits by tissue culture cell-associated proteases. To investigate if an HA protein could be obtained that could be cleaved by an ... More
Osmotic swelling allows fusion of sendai virions with membranes of desialyzed erythrocytes and chromaffin granules.
AuthorsCitovsky V, Laster Y, Schuldiner S, Loyter A
JournalBiochemistry
PubMed ID2820480
'Sendai virus particles are able to fuse with Pronase-neuraminidase-treated human erythrocyte membranes as well as with vesicles obtained from chromaffin granules of bovine medulla. Fusion is inferred either from electron microscopic studies or from the observation that incubation of fluorescently labeled (bearing octadecyl Rhodamine B chloride) virions, with right-side-out erythrocyte ... More
Kinetics and extent of fusion between Sendai virus and erythrocyte ghosts: application of a mass action kinetic model.
AuthorsNir S, Klappe K, Hoekstra D
JournalBiochemistry
PubMed ID3011079
'The kinetics and extent of fusion between Sendai virus and erythrocyte ghosts were investigated with an assay for lipid mixing based on the relief of self-quenching of fluorescence. The results were analyzed in terms of a mass action kinetic model, which views the overall fusion reaction as a sequence of ... More
AuthorsChevallier J, Chamoun Z, Jiang G, Prestwich G, Sakai N, Matile S, Parton RG, Gruenberg J,
JournalJ Biol Chem
PubMed ID18644787
'Most cell types acquire cholesterol by endocytosis of circulating low density lipoprotein, but little is known about the mechanisms of intra-endosomal cholesterol transport and about the primary cause of its aberrant accumulation in the cholesterol storage disorder Niemann-Pick type C (NPC). Here we report that lysobisphosphatidic acid (LBPA), an unconventional ... More
A fluorescent lectin array using supramolecular hydrogel for simple detection and pattern profiling for various glycoconjugates.
AuthorsKoshi Y, Nakata E, Yamane H, Hamachi I
JournalJ Am Chem Soc
PubMed ID16895406
'Because sugar and its derivatives play important roles in various biological phenomena, the rapid and high-throughput analysis of various glycoconjugates is keenly desirable. We describe herein the construction of a novel fluorescent lectin array for saccharide detection using a supramolecular hydrogel matrix. In this array, the fluorescent lectins were noncovalently ... More
Reconstitution of the leucine transport system of Lactococcus lactis into liposomes composed of membrane-spanning lipids from Sulfolobus acidocaldarius.
'The effect of bipolar tetraether lipids, extracted from the thermophilic archaebacterium Sulfolobus acidocaldarius, on the branched-chain amino acid transport system of the mesophilic bacterium Lactococcus lactis was investigated. Liposomes were prepared from mixtures of monolayer lipids and the bilayer lipid phosphatidylcholine (PC), analyzed on their miscibility, and fused with membrane ... More
Interaction of reconstituted Sendai viral envelopes with sperm cells: reconstituted Sendai virus envelope-induced fusion-mediated introduction of foreign material into bull sperm cells.
AuthorsNussbaum O, Loyter A
JournalArch Virol
PubMed ID7487492
'Reconstituted Sendai virus envelopes (RSVE), i.e. membrane vesicles bearing the viral envelope glycoproteins and phospholipids, are able to fuse with bull sperm cells. This was inferred from the increase in the degree of fluorescence dequenching (DQ) obtained following incubation of fluorescently labeled (R18 labeled) RSVE with bull sperm cells and ... More
Single event recording shows that docking onto receptor alters the kinetics of membrane fusion mediated by influenza hemagglutinin.
AuthorsNiles WD, Cohen FS
JournalBiophys J
PubMed ID8369426
'The initial steps of membrane fusion, receptor binding and membrane destabilization, are mediated by the envelope glycoprotein hemagglutinin of influenza virus. Interaction between these functions was determined from the time course of individual virion fusions to a planar membrane with and without receptor. With receptor, fusion was described by a ... More
Anti-idiotype antibodies that mimic gp86 of human cytomegalovirus inhibit viral fusion but not attachment.
AuthorsKeay S, Baldwin B
JournalJ Virol
PubMed ID1651427
'Human cytomegalovirus (CMV) infects cells by sequential processes involving attachment, fusion with the cell membrane, and penetration of the capsid. We used two monoclonal anti-idiotype that mimic one of the CMV envelope glycoproteins, gp86, to study its role in the early phases of CMV infection. Neither of two such antibodies ... More
On the validity of lipid dequenching assays for estimating virus fusion kinetics.
AuthorsArbuzova A, Korte T, Müller P, Herrmann A
JournalBiochim Biophys Acta
PubMed ID8142437
'Octadecylrhodamine (R18) has often been used to measure membrane fusion of enveloped viruses by fluorescence dequenching. In order to see whether non-specific R18 exchange between non-fused membranes occurs we have measured fusion of influenza virus with erythrocyte membranes by utilizing dequenching of the non-exchangeable lipid analogue N-(lissamine-rhodamine B-sulfonyl)diacylphosphatidylethanolamine (N-Rh-PE). Rather ... More
Structural mapping of Fc receptor bound immunoglobulin E: proximity to the membrane surface of the antibody combining site and another site in the Fab segments.
AuthorsBaird B, Holowka D
JournalBiochemistry
PubMed ID4084517
'Resonance energy-transfer methods have been used to investigate the structure of immunoglobulin E (IgE) bound to its high-affinity receptor on plasma membrane vesicles derived from rat basophilic leukemia cells. The structural mapping of receptor-bound IgE was initiated in an earlier study [Holowka, D., & Baird, B. (1983) Biochemistry 22, 3475], ... More
Detection of influenza hemagglutinin interaction with biological membranes by photosensitized activation of [125I]iodonaphthylazide.
AuthorsPak CC, Krumbiegel M, Blumenthal R, Raviv Y
JournalJ Biol Chem
PubMed ID8182068
'Fusion of influenza virus with cells is triggered by a pH-dependent conformational change in the viral envelope protein, hemagglutinin, which results in exposure of the fusion peptide and its insertion into the target membrane. We have investigated the association of hemagglutinin with erythrocyte membranes by photosensitized labeling with [125I]iodonaphthylazide. This ... More
The mechanism of action of GTP on Ca2+ efflux from rat liver microsomal vesicles. Measurement of vesicle fusion by fluorescence energy transfer.
AuthorsComerford JG, Dawson AP
JournalBiochem J
PubMed ID3342018
'1. GTP-promoted fusion between microsomal vesicles was studied by using fluorescence-resonance-energy transfer between the fluorescent membrane probes octadecanoyl-aminofluorescein and octadecyl-rhodamine. 2. The fluorescence increase after GTP addition does not require the presence of ATP, is unaffected by changes in free [Ca2+] in the range 10 microM-1 nM, but requires Mg2+, ... More
Fusion between retinal rod outer segment membranes and model membranes: a role for photoreceptor peripherin/rds.
AuthorsBoesze-Battaglia K, Lamba OP, Napoli AA, Sinha S, Guo Y
JournalBiochemistry
PubMed ID9649331
'Peripherin/rds plays an essential role in the maintenance of photoreceptor rod cell disk membrane structure. The purification of this protein to homogeneity [Boesze-Battaglia, K., et al. (1997) Biochemistry 36, 6835-6846] has allowed us to characterize the functional role of peripherin/rds in the maintenance of rod outer segment (ROS) membrane fusion ... More
Lateral diffusion of lipids in model and natural membranes.
AuthorsTocanne JF, Dupou-Cézanne L, Lopez A
JournalProg Lipid Res
PubMed ID8022844
Entry mechanisms of enveloped viruses. Implications for fusion of intracellular membranes.
AuthorsHoekstra D, Kok JW
JournalBiosci Rep
PubMed ID2673423
Enveloped viruses infect cells by a mechanism involving membrane fusion. This process is mediated and triggered by specific viral membrane glycoproteins. Evidence is accumulating that fusion of intracellular membranes, as occurs during endocytosis and transport between intracellular organelles, also requires the presence of specific proteins. The relevance of elucidating the ... More
Stimulation of exocytotic membrane fusion by modified peptides of the rab3 effector domain: re-evaluation of the role of rab3 in regulated exocytosis.
AuthorsMacLean CM, Law GJ, Edwardson JM
JournalBiochem J
PubMed ID8373347
We have shown previously that fusion between pancreatic zymogen granules and plasma membranes is stimulated by a peptide corresponding to the putative effector domain of rab3. Here we show that this stimulatory effect persists when the amino acid sequence of the peptide is substantially modified. We also show that an ... More
Membrane fusion of mumps virus with ghost erythrocytes and CV-1 cells.
AuthorsDi Simone C, Baldeschwieler JD
JournalVirology
PubMed ID1413510
The octadecyl rhodamine (R18) fluorescent dequenching assay was used to examine membrane fusion between mumps virus and mammalian cells. Rapid fluorescent dequenching, indicative of membrane fusion, was observed when labeled mumps virus was mixed with either ghost erythrocytes or CV-1 cells. After 15 min a saturation limit of 18 virus ... More
Lysophosphatidylcholine reversibly arrests exocytosis and viral fusion at a stage between triggering and membrane merger.
AuthorsVogel SS, Leikina EA, Chernomordik LV
JournalJ Biol Chem
PubMed ID8245012
Little is known of the events occurring between membrane fusion triggering and subsequent fusion steps. To dissect this process we applied a reversible inhibitor of membrane fusion, lysophosphatidylcholine, to arrest exocytosis and virus-mediated syncytia formation. Next Ca2+ or H+ (the respective fusion triggers) was administered and later removed. Then, inhibitor ... More
Calcium-triggered fusion of exocytotic granules requires proteins in only one membrane.
AuthorsVogel SS, Chernomordik LV, Zimmerberg J
JournalJ Biol Chem
PubMed ID1464584
We studied calcium-triggered fusion of sea urchin egg secretory granules to test whether membrane bound fusion proteins are required in both fusing membranes. Using both light scattering assays and video microscopy, we found that native granules fused to granules that had been inactivated with either trypsin or N-ethylmaleimide. Granules also ... More
Fusion of influenza virus in an intracellular acidic compartment measured by fluorescence dequenching.
The fusion of influenza virus with cultured cells has been investigated. The virus was labelled with the fluorescent probe octadecyl rhodamine B and fusion was monitored as fluorescence dequenching due to dilution of the probe from the viral into a cellular target membrane. Fusion with the plasma membrane does not ... More
The emergence of competition between model protocells.
AuthorsChen IA, Roberts RW, Szostak JW
JournalScience
PubMed ID15353806
The transition from independent molecular entities to cellular structures with integrated behaviors was a crucial aspect of the origin of life. We show that simple physical principles can mediate a coordinated interaction between genome and compartment boundary, independent of any genomic functions beyond self-replication. RNA, encapsulated in fatty acid vesicles, ... More