scholarly journals The Membrane-Proximal Domain of Vesicular Stomatitis Virus G Protein Functions as a Membrane Fusion Potentiator and Can Induce Hemifusion

2002 ◽  
Vol 76 (23) ◽  
pp. 12300-12311 ◽  
Author(s):  
E. Jeetendra ◽  
Clinton S. Robison ◽  
Lorraine M. Albritton ◽  
Michael A. Whitt
Keyword(s):  
Membrane Fusion ◽  
G Protein ◽  
Vesicular Stomatitis Virus ◽  
Fusion Proteins ◽  
Fold Increase ◽  
Wild Type Virus ◽  
Viral Fusion ◽  
Fusion Activity ◽  
Viral Glycoprotein ◽  
Vesicular Stomatitis

ABSTRACT Recently we showed that the membrane-proximal stem region of the vesicular stomatitis virus (VSV) G protein ectodomain (G stem [GS]), together with the transmembrane and cytoplasmic domains, was sufficient to mediate efficient VSV budding (C. S. Robison and M. A. Whitt, J. Virol. 74:2239-2246, 2000). Here, we show that GS can also potentiate the membrane fusion activity of heterologous viral fusion proteins when GS is coexpressed with those proteins. For some fusion proteins, there was as much as a 40-fold increase in syncytium formation when GS was coexpressed compared to that seen when the fusion protein was expressed alone. Fusion potentiation by GS was not protein specific, since it occurred with both pH-dependent as well as pH-independent fusion proteins. Using a recombinant vesicular stomatitis virus encoding GS that contained an N-terminal hemagglutinin (HA) tag (GSHA virus), we found that the GSHA virus bound to cells as well as the wild-type virus did at pH 7.0; however, the GSHA virus was noninfectious. Analysis of cells expressing GSHA in a three-color membrane fusion assay revealed that GSHA could induce lipid mixing but not cytoplasmic mixing, indicating that GS can induce hemifusion. Treatment of GSHA virus-bound cells with the membrane-destabilizing drug chlorpromazine rescued the hemifusion block and allowed entry and subsequent replication of GSHA virus, demonstrating that GS-mediated hemifusion was a functional intermediate in the membrane fusion pathway. Using a series of truncation mutants, we also determined that only 14 residues of GS, together with the VSV G transmembrane and cytoplasmic tail, were sufficient for fusion potentiation. To our knowledge, this is the first report which shows that a small domain of one viral glycoprotein can promote the fusion activity of other, unrelated viral glycoproteins.

scholarly journals Mechanism of membrane fusion induced by vesicular stomatitis virus G protein

2016 ◽  
Vol 114 (1) ◽  
pp. E28-E36 ◽  
Author(s):  
Irene S. Kim ◽  
Simon Jenni ◽  
Megan L. Stanifer ◽  
Eatai Roth ◽  
Sean P. J. Whelan ◽  
...  
Keyword(s):  
Membrane Fusion ◽  
G Protein ◽  
Vesicular Stomatitis Virus ◽  
Fusion Proteins ◽  
Low Ph ◽  
Viral Fusion ◽  
Protein Fusion ◽  
West Nile ◽  
Vesicular Stomatitis ◽  
Viral Fusion Proteins

The glycoproteins (G proteins) of vesicular stomatitis virus (VSV) and related rhabdoviruses (e.g., rabies virus) mediate both cell attachment and membrane fusion. The reversibility of their fusogenic conformational transitions differentiates them from many other low-pH-induced viral fusion proteins. We report single-virion fusion experiments, using methods developed in previous publications to probe fusion of influenza and West Nile viruses. We show that a three-stage model fits VSV single-particle fusion kinetics: (i) reversible, pH-dependent, G-protein conformational change from the known prefusion conformation to an extended, monomeric intermediate; (ii) reversible trimerization and clustering of the G-protein fusion loops, leading to an extended intermediate that inserts the fusion loops into the target-cell membrane; and (iii) folding back of a cluster of extended trimers into their postfusion conformations, bringing together the viral and cellular membranes. From simulations of the kinetic data, we conclude that the critical number of G-protein trimers required to overcome membrane resistance is 3 to 5, within a contact zone between the virus and the target membrane of 30 to 50 trimers. This sequence of conformational events is similar to those shown to describe fusion by influenza virus hemagglutinin (a “class I” fusogen) and West Nile virus envelope protein (“class II”). Our study of VSV now extends this description to “class III” viral fusion proteins, showing that reversibility of the low-pH-induced transition and architectural differences in the fusion proteins themselves do not change the basic mechanism by which they catalyze membrane fusion.

scholarly journals Prediction and Identification of a Permissive Epitope Insertion Site in the Vesicular Stomatitis Virus Glycoprotein

2004 ◽  
Vol 78 (10) ◽  
pp. 5079-5087 ◽  
Author(s):  
Lisa D. Schlehuber ◽  
John K. Rose
Keyword(s):  
Cell Surface ◽  
Membrane Fusion ◽  
G Protein ◽  
Vesicular Stomatitis Virus ◽  
Transmembrane Domain ◽  
Insertion Site ◽  
Rational Approach ◽  
Fusion Activity ◽  
Vesicular Stomatitis ◽  
Foreign Epitope

ABSTRACT We developed a rational approach to identify a site in the vesicular stomatitis virus (VSV) glycoprotein (G) that is exposed on the protein surface and tolerant of foreign epitope insertion. The foreign epitope inserted was the six-amino-acid sequence ELDKWA, a sequence in a neutralizing epitope from human immunodeficiency virus type 1. This sequence was inserted into six sites within the VSV G protein (Indiana serotype). Four sites were selected based on hydrophilicity and high sequence variability identified by sequence comparison with other vesiculovirus G proteins. The site showing the highest variability was fully tolerant of the foreign peptide insertion. G protein containing the insertion at this site folded correctly, was transported normally to the cell surface, had normal membrane fusion activity, and could reconstitute fully infectious VSV. The virus was neutralized by the human 2F5 monoclonal antibody that binds the ELDKWA epitope. Additional studies showed that this site in G protein tolerated insertion of at least 16 amino acids while retaining full infectivity. The three other insertions in somewhat less variable sequences interfered with VSV G folding and transport to the cell surface. Two additional insertions were made in a conserved sequence adjacent to a glycosylation site and near the transmembrane domain. The former blocked G-protein transport, while the latter allowed transport to the cell surface but blocked membrane fusion activity of G protein. Identification of an insertion-tolerant site in VSV G could be important in future vaccine and targeting studies, and the general principle might also be useful in other systems.

Charged residues are involved in membrane fusion mediated by a hydrophilic peptide located in vesicular stomatitis virus G protein

2006 ◽  
Vol 23 (5) ◽  
pp. 396-406 ◽  
Author(s):  
Fabiana A. Carneiro ◽  
Guy Vandenbussche ◽  
Maria A. Juliano ◽  
Luiz Juliano ◽  
Jean-Marie Ruysschaert ◽  
...  
Keyword(s):  
Membrane Fusion ◽  
G Protein ◽  
Vesicular Stomatitis Virus ◽  
Charged Residues ◽  
Hydrophilic Peptide ◽  
Vesicular Stomatitis

Inactivation of vesicular stomatitis virus through inhibition of membrane fusion by chemical modification of the viral glycoprotein

2007 ◽  
Vol 73 (1) ◽  
pp. 31-39 ◽  
Author(s):  
Fausto Stauffer ◽  
Joari De Miranda ◽  
Marcos C. Schechter ◽  
Fabiana A. Carneiro ◽  
Leonardo T. Salgado ◽  
...  
Keyword(s):  
Chemical Modification ◽  
Membrane Fusion ◽  
Vesicular Stomatitis Virus ◽  
Viral Glycoprotein ◽  
Vesicular Stomatitis

Glycosylation is not required for the fusion activity of the G protein of vesicular stomatitis virus in insect cells

Virology ◽  
1989 ◽  
Vol 169 (2) ◽  
pp. 323-331 ◽  
Author(s):  
Mark J. Bailey ◽  
Donald A. McLeod ◽  
Chil-Yong Kang ◽  
David H.L. Bishop
Keyword(s):  
G Protein ◽  
Vesicular Stomatitis Virus ◽  
Insect Cells ◽  
Fusion Activity ◽  
Vesicular Stomatitis

The Role of the Transmembrane and of the Intraviral Domain of Glycoproteins in Membrane Fusion of Enveloped Viruses

2000 ◽  
Vol 20 (6) ◽  
pp. 571-595 ◽  
Author(s):  
Britta Schroth-Diez ◽  
Kai Ludwig ◽  
Bolormaa Baljinnyam ◽  
Christine Kozerski ◽  
Qiang Huang ◽  
...  
Keyword(s):  
Membrane Fusion ◽  
Fusion Proteins ◽  
Transmembrane Domain ◽  
Fusion Process ◽  
Fusion Pore ◽  
Minimum Length ◽  
Viral Fusion ◽  
Fusion Activity ◽  
Enveloped Viruses

Fusion of enveloped viruses with their target membrane is mediated by viral integral glycoproteins. A conformational change of their ectodomain triggers membrane fusion. Several studies suggest that an extended, triple-stranded rod-shaped α-helical coiled coil resembles a common structural and functional motif of the ectodomain of fusion proteins. From that, it is believed that essential features of the fusion process are conserved among the various enveloped viruses. However, this has not been established so far for the highly conserved transmembrane and intraviral sequences of fusion proteins. The article will focus on the role of both sequences in the fusion process. Recent studies from various enveloped viruses strongly imply that a transmembrane domain with a minimum length is required for later steps of membrane fusion, i.e., the formation and enlargement of the aqueous fusion pore. Although no specific sequence of the TM is necessary for pore formation, distinct properties and motifs of the domain may be obligatory to ascertain full fusion activity. However, with some exceptions, the intraviral domain seems to be not required for fusion activity of viral fusion proteins.

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