scholarly journals Hepatitis C Virus Core Protein Interacts with 14-3-3 Protein and Activates the Kinase Raf-1

2000 ◽  
Vol 74 (4) ◽  
pp. 1736-1741 ◽  
Author(s):  
Hiroshi Aoki ◽  
Junpei Hayashi ◽  
Mitsuhiko Moriyama ◽  
Yasuyuki Arakawa ◽  
Okio Hino

ABSTRACT Persistent hepatitis C virus (HCV) infection is a major cause of chronic liver dysfunction in humans and is epidemiologically closely associated with the development of human hepatocellular carcinoma. Among HCV components, core protein has been reported to be implicated in cell growth regulation both in vitro and in vivo, although mechanisms explaining those effects are still unclear. In the present study, we identified that members of the 14-3-3 protein family associate with HCV core protein. 14-3-3 protein bound to HCV core protein in a phosphoserine-dependent manner. Introduction of HCV core protein caused a substantial increase in Raf-1 kinase activity in HepG2 cells and in a yeast genetic assay. Furthermore, the HCV core–14-3-3 interaction was essential for Raf-1 kinase activation by HCV core protein. These results suggest that HCV core protein may represent a novel type of Raf-1 kinase-activating protein through its interaction with 14-3-3 protein and may contribute to hepatocyte growth regulation.

Traffic ◽  
2008 ◽  
Vol 9 (8) ◽  
pp. 1268-1282 ◽  
Author(s):  
Steeve Boulant ◽  
Mark W. Douglas ◽  
Laura Moody ◽  
Agata Budkowska ◽  
Paul Targett-Adams ◽  
...  

2001 ◽  
Vol 74 (1-2) ◽  
pp. 89-98 ◽  
Author(s):  
Kyu-Jin Park ◽  
Soo-Ho Choi ◽  
Moon Soo Koh ◽  
Dong Joon Kim ◽  
Se Won Yie ◽  
...  

Gut ◽  
2007 ◽  
Vol 56 (9) ◽  
pp. 1302-1308 ◽  
Author(s):  
C Hourioux ◽  
R Patient ◽  
A Morin ◽  
E Blanchard ◽  
A Moreau ◽  
...  

2018 ◽  
Vol 19 (9) ◽  
pp. 2771 ◽  
Author(s):  
Yoo Cho ◽  
Hwan Lee ◽  
Hyojeung Kang ◽  
Hyosun Cho

HCV genotype 2a strain JFH-1 replicates and produces viral particles efficiently in human hepatocellular carcinoma (huh) 7.5 cells, which provide a stable in vitro cell infection system for the hepatitis C virus (HCVcc system). Natural killer (NK) cells are large lymphoid cells that recognize and kill virus-infected cells. In this study, we investigated the interaction between NK cells and the HCVcc system. IL-10 is a typical immune regulatory cytokine that is produced mostly by NK cells and macrophages. IL-21 is one of the main cytokines that stimulate the activation of NK cells. First, we used anti-IL-10 to neutralize IL-10 in a coculture of NK cells and HCVcc. Anti-IL-10 treatment increased the maturation of NK cells by enhancing the frequency of the CD56+dim population in NK-92 cells. However, with anti-IL-10 treatment of NK cells in coculture with J6/JFH-1-huh 7.5 cells, there was a significant decrease in the expression of STAT1 and STAT5 proteins in NK-92 cells and an increase in the HCV Core and NS3 proteins. In addition, rIL-21 treatment increased the frequency of the CD56+dim population in NK-92 cells, Also, there was a dramatic increase in the expression of STAT1 and STAT5 proteins in rIL-21 pre-stimulated NK cells and a decrease in the expression of HCV Core protein in coculture with J6/JFH-1-huh 7.5 cells. In summary, we found that the functional activation of NK cells can be modulated by anti-IL-10 or rIL-21, which controls the expression of HCV proteins as well as HCV RNA replication.


2009 ◽  
Vol 145 (2) ◽  
pp. 285-292 ◽  
Author(s):  
Kyung Lee Yu ◽  
Soo In Jang ◽  
Ji Chang You

2004 ◽  
Vol 78 (21) ◽  
pp. 12047-12053 ◽  
Author(s):  
Meirav Matto ◽  
Charles M. Rice ◽  
Benjamin Aroeti ◽  
Jeffrey S. Glenn

ABSTRACT A subpopulation of hepatitis C virus (HCV) core protein in cells harboring full-length HCV replicons is biochemically associated with detergent-resistant membranes (DRMs) in a manner similar to that of markers of classical lipid rafts. Core protein does not, however, colocalize in immunofluorescence studies with classical plasma membrane raft markers, such as caveolin-1 and the B subunit of cholera toxin, suggesting that core protein is bound to cytoplasmic raft microdomains distinct from caveolin-based rafts. Furthermore, while both the structural core protein and the nonstructural protein NS5A associate with membranes, they do not colocalize in the DRMs. Finally, the ability of core protein to localize to the DRMs did not require other elements of the HCV polyprotein. These results may have broad implications for the HCV life cycle and suggest that the HCV core may be a valuable probe for host cell biology.


2010 ◽  
Vol 88 (2) ◽  
pp. 315-323 ◽  
Author(s):  
Jean-Baptiste Duvignaud ◽  
Denis Leclerc ◽  
Stéphane M. Gagné

The Core protein of hepatitis C virus is involved in several interactions other than the encapsidation of viral RNA. We recently proposed that this is related to the fact that the N-terminal half of this protein (C82) is an intrinsically unstructured protein (IUP) domain. IUP domains can adopt a secondary structure when they are interacting with another molecule, such as a nucleic acid or a protein. It is also possible to mimic these conditions by modifying the environment of the protein. We investigated the propensity of this protein to fold as a function of salt concentration, detergent, pH, and 2,2,2-trifluoro-ethanol (TFE); only the addition of TFE resulted in a structural change. The effect of TFE addition was studied by circular dichroism, structural, and dynamic data obtained by NMR. The data indicate that C82 can adopt an α-helical structure; this conformation is likely relevant to one of the functional roles of the HCV Core protein.


1999 ◽  
Vol 73 (12) ◽  
pp. 9718-9725 ◽  
Author(s):  
Takashi Shimoike ◽  
Shigetaka Mimori ◽  
Hideki Tani ◽  
Yoshiharu Matsuura ◽  
Tatsuo Miyamura

ABSTRACT To clarify the binding properties of hepatitis C virus (HCV) core protein and its viral RNA for the encapsidation, morphogenesis, and replication of HCV, the specific interaction of HCV core protein with its genomic RNA synthesized in vitro was examined in an in vivo system. The positive-sense RNA from the 5′ end to nucleotide (nt) 2327, which covers the 5′ untranslated region (5′UTR) and a part of the coding region of HCV structural proteins, interacted with HCV core protein, while no interaction was observed in the same region of negative-sense RNA and in other regions of viral and antiviral sense RNAs. The internal ribosome entry site (IRES) exists around the 5′UTR of HCV; therefore, the interaction of the core protein with this region of HCV RNA suggests that there is some effect on its cap-independent translation. Cells expressing HCV core protein were transfected with reporter RNAs consisting of nt 1 to 709 of HCV RNA (the 5′UTR of HCV and about two-thirds of the core protein coding regions) followed by a firefly luciferase gene (HCV07Luc RNA). The translation of HCV07Luc RNA was suppressed in cells expressing the core protein, whereas no significant suppression was observed in the case of a reporter RNA possessing the IRES of encephalomyocarditis virus followed by a firefly luciferase. This suppression by the core protein occurred in a dose-dependent manner. The expression of the E1 envelope protein of HCV or β-galactosidase did not suppress the translation of both HCV and EMCV reporter RNAs. We then examined the regions that are important for suppression of translation by the core protein and found that the region from nt 1 to 344 was enough to exert this suppression. These results suggest that the HCV core protein interacts with viral genomic RNA at a specific region to form nucleocapsids and regulates the expression of HCV by interacting with the 5′UTR.


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