Hepatitis C Virus E1 Protein Induces Modification of Membrane Permeability inE. coliCells

ABSTRACT The hepatitis C virus (HCV) glycoproteins E1 and E2 should be anchored in the viral membrane by their C-terminal domains. During synthesis, they are translocated to the endoplasmic reticulum (ER) lumen where they remain. The 31 C-terminal residues of the E1 protein and the 29 C-terminal residues of the E2 protein are implicated in the ER retention. Moreover, the E1 and E2 C termini are implicated in E1-E2 heterodimerization. We studied the E1 and E2 C-terminal sequences of 25 HCV strains in silico using molecular modeling techniques. We conclude that both C-terminal domains should adopt a similar and peculiar configuration: one amphipathic α-helix followed by a pair of transmembrane β-strands. Several three-dimensional (3-D) models were generated. After energy minimization, their ability to interact with membranes was studied using the molecular hydrophobicity potentials calculation and the IMPALA procedure. The latter simulates interactions with a membrane by a Monte Carlo minimization of energy. These methods suggest that the β-hairpins could anchor the glycoproteins in the ER membrane at least transiently. Anchoring could be stabilized by the adsorption of the nearby amphipathic α-helices at the membrane surface. The 3-D models correlate with experimental results which indicate that the E1-E2 transmembrane domains are involved in the heterodimerization and have ER retention properties.

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Hepatitis C Virus-Like Particle Budding: Role of the Core Protein and Importance of Its Asp111

Journal of Virology ◽

10.1128/jvi.77.18.10131-10138.2003 ◽

2003 ◽

Vol 77 (18) ◽

pp. 10131-10138 ◽

Cited By ~ 42

Author(s):

Emmanuelle Blanchard ◽

Christophe Hourioux ◽

Denys Brand ◽

Malika Ait-Goughoulte ◽

Alain Moreau ◽

...

Keyword(s):

Hepatitis C Virus ◽

Hepatitis C ◽

Semliki Forest Virus ◽

Core Protein ◽

Virus Assembly ◽

Signal Sequence ◽

E1 Protein ◽

Hcv Core Protein ◽

Virus Like Particle ◽

Genes Encoding

ABSTRACT In the absence of a hepatitis C virus (HCV) culture system, the use of a Semliki Forest virus replicon expressing genes encoding HCV structural proteins that assemble into HCV-like particles provides an opportunity to study HCV morphogenesis. Using this system, we showed that the HCV core protein constitutes the budding apparatus of the virus and that its targeting to the endoplasmic reticulum by means of the signal sequence of E1 protein is essential for budding. In addition, the aspartic acid at position 111 in the HCV core protein sequence was found to be crucial for virus assembly, demonstrating the usefulness of this system for mapping amino acids critical to HCV morphogenesis.

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Hepatitis C Virus E1 protein promotes cell migration and invasion by modulating cellular metastasis suppressor Nm23-H1

Virology ◽

10.1016/j.virol.2017.03.014 ◽

2017 ◽

Vol 506 ◽

pp. 110-120 ◽

Cited By ~ 13

Author(s):

Lohit Khera ◽

Catherine Paul ◽

Rajeev Kaul

Keyword(s):

Cell Migration ◽

Hepatitis C Virus ◽

Hepatitis C ◽

Migration And Invasion ◽

Metastasis Suppressor ◽

Cell Migration And Invasion ◽

E1 Protein

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Induction of Hepatitis C Virus E1 Envelope Protein-Specific Immune Response Can Be Enhanced by Mutation of N-Glycosylation Sites

Journal of Virology ◽

10.1128/jvi.75.24.12088-12097.2001 ◽

2001 ◽

Vol 75 (24) ◽

pp. 12088-12097 ◽

Cited By ~ 57

Author(s):

A. Fournillier ◽

C. Wychowski ◽

D. Boucreux ◽

T. F. Baumert ◽

J.-C. Meunier ◽

...

Keyword(s):

Hepatitis C Virus ◽

Hepatitis C ◽

Cellular Response ◽

Humoral Response ◽

Glycosylation Site ◽

Immune Recognition ◽

E1 Protein ◽

Glycosylation Sites ◽

Antibody Titers

ABSTRACT Deglycosylation of viral glycoproteins has been shown to influence the number of available epitopes and to modulate immune recognition of antigens. We investigated the role played by N-glycans in the immunogenicity of hepatitis C virus (HCV) E1 envelope glycoprotein, a naturally poor immunogen. Eight plasmids were engineered, encoding E1 protein mutants in which the four N-linked glycosylation sites of the protein were mutated separately or in combination. In vitro expression studies showed an influence of N-linked glycosylation on expression efficiency, instability, and/or secretion of the mutated proteins. Immunogenicity of the E1 mutants was studied in BALB/c mice following intramuscular and intraepidermal injection of the plasmids. Whereas some mutations had no or only minor effects on the antibody titers induced, mutation of the fourth glycosylation site (N4) significantly enhanced the anti-E1 humoral response in terms of both seroconversion rates and antibody titers. Moreover, antibody induced by the N4 mutant was able to recognize HCV-like particles with higher titers than those induced by the wild-type construct. Epitope mapping indicated that the E1 mutant antigens induced antibody directed at two major domains: one, located at amino acids (aa) 313 to 332, which is known to be reactive with sera from HCV patients, and a second one, located in the N-terminal domain of E1 (aa 192 to 226). Analysis of the induced immune cellular response confirmed the induction of gamma interferon-producing cells by all mutants, albeit to different levels. These results show that N-linked glycosylation can limit the antibody response to the HCV E1 protein and reveal a potential vaccine candidate with enhanced immunogenicity.

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Activation of the grp78 andgrp94 Promoters by Hepatitis C Virus E2 Envelope Protein

Journal of Virology ◽

10.1128/jvi.73.5.3718-3722.1999 ◽

1999 ◽

Vol 73 (5) ◽

pp. 3718-3722 ◽

Cited By ~ 81

Author(s):

Eva Liberman ◽

Yiu-Lian Fong ◽

Mark J. Selby ◽

Qui-Lim Choo ◽

Lawrence Cousens ◽

...

Keyword(s):

Endoplasmic Reticulum ◽

Hepatitis C Virus ◽

Hepatitis C ◽

Mammalian Cells ◽

Secretory Proteins ◽

Cellular Gene ◽

E2 Protein ◽

E1 Protein ◽

Golgi Compartment ◽

Reporter Gene System

ABSTRACT The hepatitis C virus E1 and E2 envelope proteins are targeted to the endoplasmic reticulum, but instead of being secreted, they are retained in a pre-Golgi compartment, at least partly in a misfolded state. Since secretory proteins which are retained in the endoplasmic reticulum frequently can activate the transcription of intraluminal chaperone proteins, we measured the effect of the E1 and E2 proteins on the promoters of two such chaperones, GRP78 (BiP) and GRP94. We found that E2 but not E1 protein activates these two promoters, as assayed by a reporter gene system. Furthermore, E2 but not E1 protein induces the synthesis of GRP78 from the endogenous cellular gene. We also found that E2 but not E1 protein expressed in mammalian cells is bound tightly to GRP78. This association may explain the ability of E2 protein to activate transcription, since GRP78 has been postulated to be a sensor of stress in the endoplasmic reticulum. Since overexpression of GRP78 has been shown to decrease the sensitivity of cells to killing by cytotoxic T lymphocytes and to increase tumorigenicity and resistance to antitumor drugs, this activity of E2 protein may be involved in the pathogenesis of hepatitis C virus-induced diseases.

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The first hydrophobic domain of the hepatitis C virus E1 protein is important for interaction with the capsid protein

Journal of General Virology ◽

10.1099/0022-1317-83-12-3085 ◽

2002 ◽

Vol 83 (12) ◽

pp. 3085-3092 ◽

Cited By ~ 24

Author(s):

Hsin-Chieh Ma ◽

Cheng-Hung Ke ◽

Tsai-Yuan Hsieh ◽

Shih-Yen Lo

Keyword(s):

Hepatitis C Virus ◽

Hepatitis C ◽

Capsid Protein ◽

Endoplasmic Reticulum Membrane ◽

Binding Region ◽

Hydrophobic Domain ◽

E1 Protein ◽

Virus Capsid Protein

The interaction between the hepatitis C virus capsid protein and the envelope protein E1 has been demonstrated previously in vivo. To determine the binding region of the E1 protein with the capsid protein, this interaction was characterized in vitro. This study shows that the interaction between these proteins should occur in the endoplasmic reticulum membrane rather than in the cytosol and that the first hydrophobic domain of the E1 protein (aa 261–291) is important for the interaction with the capsid protein.

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A computational approach identifies two regions of Hepatitis C Virus E1 protein as interacting domains involved in viral fusion process

BMC Structural Biology ◽

10.1186/1472-6807-9-48 ◽

2009 ◽

Vol 9 (1) ◽

pp. 48 ◽

Cited By ~ 7

Author(s):

Roberto Bruni ◽

Angela Costantino ◽

Elena Tritarelli ◽

Cinzia Marcantonio ◽

Massimo Ciccozzi ◽

...

Keyword(s):

Hepatitis C Virus ◽

Hepatitis C ◽

Computational Approach ◽

Fusion Process ◽

Viral Fusion ◽

E1 Protein

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Hepatitis C Virus E1 Protein Enhances Macrophage iNOS Expression In Vitro

10.1101/2021.02.15.431273 ◽

2021 ◽

Author(s):

Batkhishig Munkhjargal ◽

Bilguun Enkhtuvshin ◽

Uranbileg Ulziisaikhan ◽

Baljinnyam Tuvdenjamts ◽

Khulan Unurbuyan ◽

...

Keyword(s):

Nitric Oxide ◽

Immune Response ◽

Hepatitis C Virus ◽

Hepatitis C ◽

Cell Response ◽

Inos Expression ◽

No Production ◽

E1 Protein ◽

Ifn Γ

AbstractObjectiveHepatitis C virus (HCV) is a single-stranded RNA virus that causes chronic hepatitis, cirrhosis, and liver cancer. Approximately 170 million individuals are infected with HCV worldwide. The pathogenesis of HCV-associated liver injury is thought to be due to the host antiviral immune response, including the T cell response, and excessive production of proinflammatory cytokines, reactive oxygen species, and nitric oxide (NO).Interferon-γ (IFN-γ) is a key cytokine in the adaptive immune response that is primarily secreted from CD4+ T helper cells to induce cytotoxic T lymphocyte (CTL) cell response against HCV infection. Another important role of IFN-γ is the activation of macrophages in the liver resulting in inhibition of viral replication and increased NO production.Enhanced inducible nitric oxide synthase (iNOS) expression and NO production observed in the liver of HCV-infected patients is positively correlated with viral load and hepatic inflammation. HCV-infected macrophages are major producers of NO in the liver. It is not completely understood how HCV proteins affect iNOS expression and what the role of IFN-γ is in HCV protein expression in HCV-infected macrophages. In this study, we examined the effect of INF-γ and HCV proteins on iNOS expression in the Raw264.7 cell line.ResultsConsistent with other studies, HCV core and NS5A proteins induced iNOS expression in macrophages. Moreover, HCV E1 protein-enhanced iNOS expression is highest in the presence and absence of IFN-γ activation.ConclusionThese results indicate that hepatitis C virus core, NS5A, E1 protein regulates iNOS protein expression in IFN-γ-activated and resting macrophage cell lines. These findings points to a future research direction for understanding the pathogenesis of HCV-related liver inflammation.

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Mutagenesis of hepatitis C virus E1 protein affects its membrane-permeabilizing activity

Journal of General Virology ◽

10.1099/0022-1317-82-9-2243 ◽

2001 ◽

Vol 82 (9) ◽

pp. 2243-2250 ◽

Cited By ~ 16

Author(s):

A. R. Ciccaglione ◽

A. Costantino ◽

C. Marcantonio ◽

M. Equestre ◽

A. Geraci ◽

...

Keyword(s):

Amino Acids ◽

Hepatitis C Virus ◽

Hepatitis C ◽

Membrane Permeability ◽

Protein Function ◽

Critical Role ◽

Cell Lysis ◽

Hydrophobic Region ◽

E Coli ◽

Conserved Amino Acids

The E1 glycoprotein of hepatitis C virus is a transmembrane glycoprotein with a C-terminal anchor domain. When expressed in Escherichia coli, E1 induces a change in membrane permeability that is toxic to the bacterial cell. The C-terminal hydrophobic region (aa 331–383) of E1 is mainly responsible for membrane association and for inducing changes in membrane permeability. These observed changes are similar to those produced in E. coli by influenza virus M2, human immunodeficiency virus gp41 and poliovirus 3AB proteins, whose hydrophobic domains are thought to cause pore formation in biological membranes. To further characterize the activity of E1 at a molecular level, the membrane-permeabilizing ability of a second internal hydrophobic region (aa 262–291) was examined by expressing different deletion mutants of E1 in an E. coli system that is widely used for analysing membrane-active proteins from other animal viruses. Moreover, highly conserved amino acids in the C-terminal hydrophobic region were mutated to identify residues that are critical for inducing changes in membrane permeability. Analysis of cell growth curves of recombinant cultures and membrane-permeability assays revealed that synthesis of this fragment increased the flux of small compounds through the membrane and caused progressive cell lysis, suggesting that this domain has membrane-active properties. Furthermore, analysis of C-terminal mutants indicated that the conserved amino acids Arg339, Trp368 and Lys370 play a critical role in protein function, as both cell lysis and changes in membrane permeability induced by the wild-type clone could be blocked by substitutions in these positions.

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