Hepatitis C virus RNA replication is regulated by FKBP8 and Hsp90

Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan.
The EMBO Journal (Impact Factor: 10.43). 11/2006; 25(20):5015-25. DOI: 10.1038/sj.emboj.7601367
Source: PubMed


Hepatitis C virus (HCV) nonstructural protein 5A (NS5A) is a component of viral replicase and is well known to modulate the functions of several host proteins. Here, we show that NS5A specifically interacts with FKBP8, a member of the FK506-binding protein family, but not with other homologous immunophilins. Three sets of tetratricopeptide repeats in FKBP8 are responsible for interactions with NS5A. The siRNA-mediated knockdown of FKBP8 in a human hepatoma cell line harboring an HCV RNA replicon suppressed HCV RNA replication, and this reduction was reversed by the expression of an siRNA-resistant FKBP8 mutant. Furthermore, immunoprecipitation analyses revealed that FKBP8 forms a complex with Hsp90 and NS5A. Treatment of HCV replicon cells with geldanamycin, an inhibitor of Hsp90, suppressed RNA replication in a dose-dependent manner. These results suggest that the complex consisting of NS5A, FKBP8, and Hsp90 plays an important role in HCV RNA replication.

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Available from: Kohji Moriishi, Oct 04, 2015
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    • "In our previous study we investigated the role of Unfolded Protein Response (UPR) machinery during CHIKV infection and showed that the UPR signaling arms such as the PERK pathway was highly regulated by viral nsP4 protein and the levels of protein folding chaperones such as HSP-90 and p58IPK were significantly induced (Rathore et al., 2013). HSP-90 has known functions in assisting the key steps of virus replication during Influenza and HCV infections (Geller et al., 2012; Okamoto et al., 2006). However, the detailed mechanism of HSP-90 involvement during CHIKV infection is not known. "
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    ABSTRACT: The global emergence of Chikungunya virus (CHIKV) infection is alarming and currently there is no licensed vaccine or antiviral treatment available to mitigate this disease. CHIKV infection typically results in high viral load with an outcome of high fever, skin rashes, muscle pain and sequelae of prolonged arthritis, which occurs in >90% of the infected cases. In this study,using biochemical pull-downs, mass-spectrometry and microscopic imaging techniques, we have identified novel interactions between CHIKV nsP3 or nsP4 proteins with the host stress-pathway chaperone HSP-90 protein. Indeed, silencing of HSP-90 transcripts using siRNA disrupts CHIKV replication in cultured cells. Furthermore, drugs targeting HSP-90, such as commercially available geldanamycin, as well as other specific HSP-90 inhibitor drugsthat had been obtained from a purinome mining approach (HS-10 and SNX-2112) showed dramatic reduction in viral titers and reduced inflammation in a CHIKV mouse model of severe infection and musculopathy. The detailed study of the underlying molecular mechanism of these viral and host protein interactions may provide a platform to develop novel therapeutics against CHIKV infection.
    Antiviral research 12/2013; 103(1). DOI:10.1016/j.antiviral.2013.12.010 · 3.94 Impact Factor
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    • "Although previous reports have shown that host factors such as VAMP-associated protein (VAP)-A, VAP-B, cyclophilin A, FK506 binding protein 8, and heat shock protein 90 participate in HCV replication, these molecules are unlikely to participate in the determination of the liver tropism of HCV, owing to their ubiquitous expression [46, 77–79]. As described above, miR-122 is abundantly expressed specifically in hepatocytes and is essential for the efficient replication of HCV. "
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    ABSTRACT: Hepatitis C virus (HCV) exhibits a narrow host range and a specific tissue tropism. Mice expressing major entry receptors for HCV permit viral entry, and therefore the species tropism of HCV infection is considered to be reliant on the expression of the entry receptors. However, HCV receptor candidates are expressed and replication of HCV-RNA can be detected in several nonhepatic cell lines, suggesting that nonhepatic cells are also susceptible to HCV infection. Recently it was shown that the exogenous expression of a liver-specific microRNA, miR-122, facilitated the efficient replication of HCV not only in hepatic cell lines, including Hep3B and HepG2 cells, but also in nonhepatic cell lines, including Hec1B and HEK-293T cells, suggesting that miR-122 is required for the efficient replication of HCV in cultured cells. However, no infectious particle was detected in the nonhepatic cell lines, in spite of the efficient replication of HCV-RNA. In the nonhepatic cells, only small numbers of lipid droplets and low levels of very-low-density lipoprotein-associated proteins were observed compared with findings in the hepatic cell lines, suggesting that functional lipid metabolism participates in the assembly of HCV. Taken together, these findings indicate that miR-122 and functional lipid metabolism are involved in the tissue tropism of HCV infection. In this review, we would like to focus on the role of miR-122 and lipid metabolism in the cell tropism of HCV.
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    • "HSP90, which can cooperate with other proteins such as p23 and HSP70, has 2–4 copies existing internally in a duck liver virus particle, and might be related to interaction between virus polymerase [68]. Besides, it has been proposed that HSP90 is a major host factor for viral replication of many RNA viruses [69], implying a important role of HSP90 in NDV replication. "
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    ABSTRACT: Newcastle disease virus (NDV) is an enveloped RNA virus, bearing severe economic losses to the poultry industry worldwide. Previous virion proteomic studies have shown that enveloped viruses carry multiple host cellular proteins both internally and externally during their life cycle. To address whether it also occurred during NDV infection, we performed a comprehensive proteomic analysis of highly purified NDV La Sota strain particles. In addition to five viral structural proteins, we detected thirty cellular proteins associated with purified NDV La Sota particles. The identified cellular proteins comprised several functional categories, including cytoskeleton proteins, annexins, molecular chaperones, chromatin modifying proteins, enzymes-binding proteins, calcium-binding proteins and signal transduction-associated proteins. Among these, three host proteins have not been previously reported in virions of other virus families, including two signal transduction-associated proteins (syntenin and Ras small GTPase) and one tumor-associated protein (tumor protein D52). The presence of five selected cellular proteins (i.e., β-actin, tubulin, annexin A2, heat shock protein Hsp90 and ezrin) associated with the purified NDV particles was validated by Western blot or immunogold labeling assays. The current study presented the first standard proteomic profile of NDV. The results demonstrated the incorporation of cellular proteins in NDV particles, which provides valuable information for elucidating viral infection and pathogenesis.
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