scholarly journals Antiviral effects of the interferon-induced protein guanylate binding protein 1 and its interaction with the hepatitis C virus NS5B protein

Hepatology ◽  
2009 ◽  
Vol 50 (6) ◽  
pp. 1727-1737 ◽  
Author(s):  
Yasuhiro Itsui ◽  
Naoya Sakamoto ◽  
Sei Kakinuma ◽  
Mina Nakagawa ◽  
Yuko Sekine-Osajima ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Binding Protein ◽  
Antiviral Effects ◽  
Ns5b Protein ◽  
Guanylate Binding Protein

scholarly journals Control of PKR Protein Kinase by Hepatitis C Virus Nonstructural 5A Protein: Molecular Mechanisms of Kinase Regulation

1998 ◽  
Vol 18 (9) ◽  
pp. 5208-5218 ◽  
Author(s):  
Michael Gale ◽  
Collin M. Blakely ◽  
Bart Kwieciszewski ◽  
Seng-Lai Tan ◽  
Michelle Dossett ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Protein Kinase ◽  
Mammalian Cells ◽  
Molecular Mechanisms ◽  
Functional Assay ◽  
Binding Region ◽  
Dimerization Domain ◽  
Antiviral Effects

ABSTRACT The PKR protein kinase is a critical component of the cellular antiviral and antiproliferative responses induced by interferons. Recent evidence indicates that the nonstructural 5A (NS5A) protein of hepatitis C virus (HCV) can repress PKR function in vivo, possibly allowing HCV to escape the antiviral effects of interferon. NS5A presents a unique tool by which to study the molecular mechanisms of PKR regulation in that mutations within a region of NS5A, termed the interferon sensitivity-determining region (ISDR), are associated with sensitivity of HCV to the antiviral effects of interferon. In this study, we investigated the mechanisms of NS5A-mediated PKR regulation and the effect of ISDR mutations on this regulatory process. We observed that the NS5A ISDR, though necessary, was not sufficient for PKR interactions; we found that an additional 26 amino acids (aa) carboxyl to the ISDR were required for NS5A-PKR complex formation. Conversely, we localized NS5A binding to within PKR aa 244 to 296, recently recognized as a PKR dimerization domain. Consistent with this observation, we found that NS5A from interferon-resistant HCV genotype 1b disrupted kinase dimerization in vivo. NS5A-mediated disruption of PKR dimerization resulted in repression of PKR function and inhibition of PKR-mediated eIF-2α phosphorylation. Introduction of multiple ISDR mutations abrogated the ability of NS5A to bind to PKR in mammalian cells and to inhibit PKR in a yeast functional assay. These results indicate that mutations within the PKR-binding region of NS5A, including those within the ISDR, can disrupt the NS5A-PKR interaction, possibly rendering HCV sensitive to the antiviral effects of interferon. We propose a model of PKR regulation by NS5A which may have implications for therapeutic strategies against HCV.

scholarly journals Nonstructural 5A Protein of Hepatitis C Virus Regulates Soluble Resistance-Related Calcium-Binding Protein Activity for Viral Propagation

2015 ◽  
Vol 90 (6) ◽  
pp. 2794-2805 ◽  
Author(s):  
Giao V. Q. Tran ◽  
Trang T. D. Luong ◽  
Eun-Mee Park ◽  
Jong-Wook Kim ◽  
Jae-Woong Choi ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Protein Interaction ◽  
Calcium Binding ◽  
Crucial Role ◽  
Binding Protein ◽  
Binding Activity ◽  
Calcium Binding Protein ◽  
Virus Propagation ◽  
Ns5a Protein

ABSTRACTHepatitis C virus (HCV) is a major cause of chronic liver disease and is highly dependent on cellular proteins for virus propagation. To identify the cellular factors involved in HCV propagation, we recently performed protein microarray assays using the HCV nonstructural 5A (NS5A) protein as a probe. Of 90 cellular protein candidates, we selected the soluble resistance-related calcium-binding protein (sorcin) for further characterization. Sorcin is a calcium-binding protein and is highly expressed in certain cancer cells. We verified that NS5A interacted with sorcin through domain I of NS5A, and phosphorylation of the threonine residue 155 of sorcin played a crucial role in protein interaction. Small interfering RNA (siRNA)-mediated knockdown of sorcin impaired HCV propagation. Silencing of sorcin expression resulted in a decrease of HCV assembly without affecting HCV RNA and protein levels. We further demonstrated that polo-like kinase 1 (PLK1)-mediated phosphorylation of sorcin was increased by NS5A. We showed that both phosphorylation and calcium-binding activity of sorcin were required for HCV propagation. These data indicate that HCV modulates sorcin activity via NS5A protein for its own propagation.IMPORTANCESorcin is a calcium-binding protein and regulates intracellular calcium homeostasis. HCV NS5A interacts with sorcin, and phosphorylation of sorcin is required for protein interaction. Gene silencing of sorcin impaired HCV propagation at the assembly step of the HCV life cycle. Sorcin is phosphorylated by PLK1 via protein interaction. We showed that sorcin interacted with both NS5A and PLK1, and PLK1-mediated phosphorylation of sorcin was increased by NS5A. Moreover, calcium-binding activity of sorcin played a crucial role in HCV propagation. These data provide evidence that HCV regulates host calcium metabolism for virus propagation, and thus manipulation of sorcin activity may represent a novel therapeutic target for HCV.

scholarly journals Impact of Wisteria floribunda Agglutinin-Positive Mac-2-Binding Protein in Patients with Hepatitis C Virus-Related Compensated Liver Cirrhosis

2016 ◽  
Vol 17 (9) ◽  
pp. 1500 ◽  
Author(s):  
Kunihiro Hasegawa ◽  
Ryo Takata ◽  
Hiroki Nishikawa ◽  
Hirayuki Enomoto ◽  
Akio Ishii ◽  
...  
Keyword(s):  
Liver Cirrhosis ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Binding Protein ◽  
Wisteria Floribunda

scholarly journals RNA binding protein 24 regulates the translation and replication of hepatitis C virus

2018 ◽  
Vol 9 (11) ◽  
pp. 930-944 ◽  
Author(s):  
Huang Cao ◽  
Kaitao Zhao ◽  
Yongxuan Yao ◽  
Jing Guo ◽  
Xiaoxiao Gao ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Rna Binding ◽  
Binding Protein ◽  
Rna Binding Protein

scholarly journals Ribonucleotide reductase M2 promotes RNA replication of hepatitis C virus by protecting NS5B protein from hPLIC1-dependent proteasomal degradation

2019 ◽  
Vol 294 (15) ◽  
pp. 5759-5773 ◽  
Author(s):  
Bouchra Kitab ◽  
Masaaki Satoh ◽  
Yusuke Ohmori ◽  
Tsubasa Munakata ◽  
Masayuki Sudoh ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Ribonucleotide Reductase ◽  
Rna Replication ◽  
Proteasomal Degradation ◽  
Ns5b Protein

Hepatitis C virus core protein interacts with p53-binding protein, 53BP2/Bbp/ASPP2, and inhibits p53-mediated apoptosis

2004 ◽  
Vol 315 (4) ◽  
pp. 788-795 ◽  
Author(s):  
Yongheng Cao ◽  
Tomio Hamada ◽  
Tadashi Matsui ◽  
Takayasu Date ◽  
Kuniyoshi Iwabuchi
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Core Protein ◽  
Binding Protein ◽  
Virus Core

scholarly journals Hepatitis C Virus RNA-Dependent RNA Polymerase Is Regulated by Cysteine S-Glutathionylation

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Marina K. Kukhanova ◽  
Vera L. Tunitskaya ◽  
Olga A. Smirnova ◽  
Olga A. Khomich ◽  
Natalia F. Zakirova ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Recombinant Protein ◽  
Rna Polymerase ◽  
Reducing Agents ◽  
Cysteine Residues ◽  
Rdrp Activity ◽  
Rna Dependent Rna Polymerase ◽  
Redox Switches ◽  
Ns5b Protein

Hepatitis C virus (HCV) triggers massive production of reactive oxygen species (ROS) and affects expression of genes encoding ROS-scavenging enzymes. Multiple lines of evidence show that levels of ROS production contribute to the development of various virus-associated pathologies. However, investigation of HCV redox biology so far remained in the paradigm of oxidative stress, whereas no attention was given to the identification of redox switches among viral proteins. Here, we report that one of such redox switches is the NS5B protein that exhibits RNA-dependent RNA polymerase (RdRp) activity. Treatment of the recombinant protein with reducing agents significantly increases its enzymatic activity. Moreover, we show that the NS5B protein is subjected to S-glutathionylation that affects cysteine residues 89, 140, 170, 223, 274, 521, and either 279 or 295. Substitution of these cysteines except C89 and C223 with serine residues led to the reduction of the RdRp activity of the recombinant protein in a primer-dependent assay. The recombinant protein with a C279S mutation was almost inactive in vitro and could not be activated with reducing agents. In contrast, cysteine substitutions in the NS5B region in the context of a subgenomic replicon displayed opposite effects: most of the mutations enhanced HCV replication. This difference may be explained by the deleterious effect of oxidation of NS5B cysteine residues in liver cells and by the protective role of S-glutathionylation. Based on these data, redox-sensitive posttranslational modifications of HCV NS5B and other proteins merit a more detailed investigation and analysis of their role(s) in the virus life cycle and associated pathogenesis.

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