scholarly journals Rabies Virus-Induced Membrane Fusion Pathway

2000 ◽  
Vol 150 (3) ◽  
pp. 601-612 ◽  
Author(s):  
Yves Gaudin
Keyword(s):  
Lipid Bilayers ◽  
Rabies Virus ◽  
Fusion Process ◽  
Fusion Pore ◽  
Viral Glycoprotein ◽  
Rate Limiting Step ◽  
Glycoprotein G ◽  
Lipid Organization ◽  
Target Membrane ◽  
Peptide Insertion

Fusion of rabies virus with membranes is triggered at low pH and is mediated by the viral glycoprotein (G). The rabies virus-induced fusion pathway was studied by investigating the effects of exogenous lipids having various dynamic molecular shapes on the fusion process. Inverted cone-shaped lysophosphatidylcholines (LPCs) blocked fusion at a stage subsequent to fusion peptide insertion into the target membrane. Consistent with the stalk-hypothesis, LPC with shorter alkyl chains inhibited fusion at lower membrane concentrations and this inhibition was compensated by the presence of oleic acid. However, under suboptimal fusion conditions, short chain LPCs, which were translocated in the inner leaflet of the membranes, considerably reduced the lag time preceding membrane merging, resulting in faster kinetics of fusion. This indicated that the rate limiting step for fusion is the formation of a fusion pore in a diaphragm of restricted hemifusion. The previously described cold-stabilized prefusion complex was also characterized. This intermediate is at a well-advanced stage of the fusion process when the hemifusion diaphragm is destabilized, but lipid mixing is still restricted, probably by a ring-like complex of glycoproteins. I provide evidence that this state has a dynamic character and that its lipid organization can reverse back to two lipid bilayers.

scholarly journals Evidence that Rabies Virus Forms Different Kinds of Fusion Machines with Different pH Thresholds for Fusion

2004 ◽  
Vol 78 (16) ◽  
pp. 8746-8752 ◽  
Author(s):  
Stéphane Roche ◽  
Yves Gaudin
Keyword(s):  
Rabies Virus ◽  
Early Stage ◽  
Fusion Reaction ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Low Ph ◽  
Viral Glycoprotein ◽  
Glycoprotein G ◽  
Partial Fusion ◽  
Ph Conditions

ABSTRACT Fusion of rabies virus with membranes is triggered at a low pH and is mediated by a viral glycoprotein (G). Fusion of rabies virus with liposomes was monitored by using a lipid mixing assay based on fluorescence resonance energy transfer. Fusion was detected below pH 6.4, and its extent increased with H+ concentrations to be maximal around pH 6.15. The origin of the partial fusion activity of rabies virus under suboptimal pH conditions (i.e., between pH 6.15 and 6.4) was investigated. We demonstrate unambiguously that fusion at a suboptimal pH is distinct from the phenomenon of low-pH-induced inactivation and that it is not due to heterogeneity of the virus population. We also show that viruses that do not fuse under suboptimal pH conditions are indeed bound to the target liposomes and that the fusion complexes they have formed are blocked at an early stage of the fusion pathway. Our conclusion is that along the fusion reaction, different kinds of fusion machines with different pH thresholds for fusion can be formed. Possible explanations of this difference of pH sensitivity are discussed.

Intracellular Behavior of Rabies Virus Matrix Protein (M) Is Determined by the Viral Glycoprotein (G)

1999 ◽  
Vol 43 (3) ◽  
pp. 259-270 ◽  
Author(s):  
Koichiro Nakahara ◽  
Hiroki Ohnuma ◽  
Shigeo Sugita ◽  
Kayou Yasuoka ◽  
Tomomi Nakahara ◽  
...  
Keyword(s):  
Rabies Virus ◽  
Matrix Protein ◽  
Viral Glycoprotein ◽  
Glycoprotein G

Shedding of Gs Protein (A Soluble Form of the Viral Glycoprotein) by the Rabies Virus-Infected BHK-21 Cells

Virology ◽  
1993 ◽  
Vol 195 (2) ◽  
pp. 541-549 ◽  
Author(s):  
Kinjiro Morimoto ◽  
Yasumasa Iwatani ◽  
Akihiko Kawai
Keyword(s):  
Rabies Virus ◽  
Protein A ◽  
Soluble Form ◽  
Viral Glycoprotein ◽  
Gs Protein

scholarly journals Phylogenetic analysis of glycoprotein (G) gene of rabies virus isolated from spotted deer, Delhi, 2016

2018 ◽  
Vol 73 ◽  
pp. 385
Author(s):  
G. Singh ◽  
R. Jaiswal ◽  
M. Chhabra ◽  
N.K. Gupta ◽  
M. Singhai ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Rabies Virus ◽  
Glycoprotein G ◽  
Spotted Deer

Expression of the ectodomain of the rabies virus glycoprotein G in insect cells for diagnostic purposes in vaccinated llamas

2018 ◽  
Vol 44 ◽  
pp. S158
Author(s):  
A.M. Targovnik ◽  
G. Mc Callum ◽  
M.B. Arregui ◽  
L.F. Bracco ◽  
M. Micucci ◽  
...  
Keyword(s):  
Rabies Virus ◽  
Insect Cells ◽  
Rabies Virus Glycoprotein ◽  
Virus Glycoprotein ◽  
Glycoprotein G

scholarly journals Daptomycin Pore Formation and Stoichiometry Depend on Membrane Potential of Target Membrane

2018 ◽  
Vol 63 (1) ◽  
Author(s):  
Gabriela Seydlová ◽  
Albert Sokol ◽  
Petra Lišková ◽  
Ivo Konopásek ◽  
Radovan Fišer
Keyword(s):  
Membrane Potential ◽  
Lipid Bilayers ◽  
Pore Formation ◽  
Content Type ◽  
Calcium Dependent ◽  
Screening Experiment ◽  
Serious Infections ◽  
Fluorescence Methods ◽  
Initial Membrane ◽  
Target Membrane

ABSTRACT Daptomycin is a calcium-dependent lipodepsipeptide antibiotic clinically used to treat serious infections caused by Gram-positive pathogens. Its precise mode of action is somewhat controversial; the biggest issue is daptomycin pore formation, which we directly investigated here. We first performed a screening experiment using propidium iodide (PI) entry to Bacillus subtilis cells and chose the optimum and therapeutically relevant conditions (10 µg/ml daptomycin and 1.25 mM CaCl2) for the subsequent analyses. Using conductance measurements on planar lipid bilayers, we show that daptomycin forms nonuniform oligomeric pores with conductance ranging from 120 pS to 14 nS. The smallest conductance unit is probably a dimer; however, tetramers and pentamers occur in the membrane most frequently. Moreover, daptomycin pore-forming activity is exponentially dependent on the applied membrane voltage. We further analyzed the membrane-permeabilizing activity in B. subtilis cells using fluorescence methods [PI and DiSC3(5)]. Daptomycin most rapidly permeabilizes cells with high initial membrane potential and dissipates it within a few minutes. Low initial membrane potential hinders daptomycin pore formation.

scholarly journals Deficient Incorporation of Rabies Virus Glycoprotein into Virions Enhances Virus-Induced Immune Evasion and Viral Pathogenicity

Viruses ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 218 ◽  
Author(s):  
Chunfu Li ◽  
Hongliang Zhang ◽  
Lina Ji ◽  
Xiao Wang ◽  
Yongjun Wen ◽  
...  
Keyword(s):  
Immune Response ◽  
Rabies Virus ◽  
Recombinant Virus ◽  
Neutralizing Antibodies ◽  
Single Copy ◽  
Wild Type ◽  
Antiviral Immune Response ◽  
Glycoprotein G ◽  
Lethal Infection ◽  
Infected Cells

Previous studies have shown that wild-type (wt) rabies virus (RABV) evades the host immune response by restricting expression of glycoprotein (G), which blocks activation of dendritic cells (DCs) and induces production of virus-neutralizing antibodies (VNAs). In the present study, wt RABVs not only restricted G expression but also reduced incorporation of G into mature virions compared with laboratory-adapted viruses. A recombinant RABV expressing triple G was used to further determine whether G expression relates to incorporation. The recombinant virus showed higher expression and incorporation of G and activated more DCs than the virus that expressed a single copy of G. Removal of G from viruses using subtilisin or Dithiothreitol (DTT)/ Nonidet P-40 (NP40) almost completely abolishes DC activation and VNA production. Consequently, these G-depleted viruses cause lethal infection in mice. Thus, wt RABVs can subvert DC-induced antiviral immune response and maintain pathogenicity by decreasing G expression in infected cells and G incorporation into virions.

scholarly journals Coassembly of SecYEG and SecA Fully Restores the Properties of the Native Translocon

2018 ◽  
Vol 201 (1) ◽  
Author(s):  
Priya Bariya ◽  
Linda L. Randall
Keyword(s):  
Lipid Bilayers ◽  
Rate Constant ◽  
Apparent Rate Constant ◽  
Membrane Vesicles ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Secretory System ◽  
Rate Limiting

ABSTRACTIn all cells, a highly conserved channel transports proteins across membranes. InEscherichia coli, that channel is SecYEG. Many investigations of this protein complex have used purified SecYEG reconstituted into proteoliposomes. How faithfully do activities of reconstituted systems reflect the properties of SecYEG in the native membrane environment? We investigated by comparing threein vitrosystems: the native membrane environment of inner membrane vesicles and two methods of reconstitution. One method was the widely used reconstitution of SecYEG alone into lipid bilayers. The other was our method of coassembly of SecYEG with SecA, the ATPase of the translocase. For nine different precursor species we assessed parameters that characterize translocation: maximal amplitude of competent precursor translocated, coupling of energy to transfer, and apparent rate constant. In addition, we investigated translocation in the presence and absence of chaperone SecB. For all nine precursors, SecYEG coassembled with SecA was as active as SecYEG in native membrane for each of the parameters studied. Effects of SecB on transport of precursors faithfully mimicked observations madein vivo. From investigation of the nine different precursors, we conclude that the apparent rate constant, which reflects the step that limits the rate of translocation, is dependent on interactions with the translocon of portions of the precursors other than the leader. In addition, in some cases the rate-limiting step is altered by the presence of SecB. Candidates for the rate-limiting step that are consistent with our data are discussed.IMPORTANCEThis work presents a comprehensive quantification of the parameters of transport by the Sec general secretory system in the threein vitrosystems. The standard reconstitution used by most investigators can be enhanced to yield six times as many active translocons simply by adding SecA to SecYEG during reconstitution. This robust system faithfully reflects the properties of translocation in native membrane vesicles. We have expanded the number of precursors studied to nine. This has allowed us to conclude that the rate constant for translocation varies with precursor species.

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