Hsp90 inhibitors reduce influenza virus replication in cell culture

Chase, Geoffrey; Deng, Tao; Fodor, Ervin; Leung, Bo Wah; Mayer, Daniel; Schwemmle, Martin; Brownlee, George G.

doi:10.1016/j.virol.2008.04.040

Cited by 133 publications

(109 citation statements)

References 25 publications

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“…Coexpression of UAP56 also did not influence the inhibition of the PB2-NP interaction by Mx1 (data not shown), suggesting that UAP56 is not directly involved in the activity of the Mx1 protein. Other cellular factors that might be involved include nucleophosmin (32), one of the importin-alpha isoforms (2, 10), CDK9 (52), USP11 (29), and Hsp90 (4,35,36), all of which have been shown to interact with PB2 and/or NP. Only a few proteins have been reported to interact with the Mx1 protein, and these interacting proteins are potential candidates as bridging factors (9).…”

Section: Discussionmentioning

confidence: 99%

Interferon-Inducible Protein Mx1 Inhibits Influenza Virus by Interfering with Functional Viral Ribonucleoprotein Complex Assembly

Verhelst

Parthoens

Schepens

et al. 2012

J Virol

200

168

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bMx1 is a GTPase that is part of the antiviral response induced by type I and type III interferons in the infected host. It inhibits influenza virus infection by blocking viral transcription and replication, but the molecular mechanism is not known. Polymerase basic protein 2 (PB2) and nucleoprotein (NP) were suggested to be the possible target of Mx1, but a direct interaction between Mx1 and any of the viral proteins has not been reported. We investigated the interplay between Mx1, NP, and PB2 to identify the mechanism of Mx1's antiviral activity. We found that Mx1 inhibits the PB2-NP interaction, and the strength of this inhibition correlated with a decrease in viral polymerase activity. Inhibition of the PB2-NP interaction is an active process requiring enzymatically active Mx1. We also demonstrate that Mx1 interacts with the viral proteins NP and PB2, which indicates that Mx1 protein has a direct effect on the viral ribonucleoprotein complex. In a minireplicon system, avian-like NP from swine virus isolates was more sensitive to inhibition by murine Mx1 than NP from human influenza A virus isolates. Likewise, murine Mx1 displaced avian NP from the viral ribonucleoprotein complex more easily than human NP. The stronger resistance of the A/H1N1 pandemic 2009 virus against Mx1 also correlated with reduced inhibition of the PB2-NP interaction. Our findings support a model in which Mx1 interacts with the influenza ribonucleoprotein complex and interferes with its assembly by disturbing the PB2-NP interaction.

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Section: Discussionmentioning

confidence: 99%

Interferon-Inducible Protein Mx1 Inhibits Influenza Virus by Interfering with Functional Viral Ribonucleoprotein Complex Assembly

Verhelst

Parthoens

Schepens

et al. 2012

J Virol

200

168

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“…Treatment of cells with Hsp90 inhibitors, e.g., geldanamycin, resulted in the reduced half-life of the PB2 protein, suggesting that Hsp90 acts as a chaperone for PB2 (4). A role for Hsp90 in the assembly and nuclear import of the RNA polymerase has also been suggested (40).…”

Section: Discussionmentioning

confidence: 99%

Association of the Influenza Virus RNA Polymerase Subunit PB2 with the Host Chaperonin CCT

Fislová

Thomas

Graef

et al. 2010

J Virol

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The RNA polymerase of influenza A virus is a host range determinant and virulence factor. In particular, the PB2 subunit of the RNA polymerase has been implicated as a crucial factor that affects cell tropism as well as virulence in animal models. These findings suggest that host factors associating with the PB2 protein may play an important role during viral replication. In order to identify host factors that associate with the PB2 protein, we purified recombinant PB2 from transiently transfected mammalian cells and identified copurifying host proteins by mass spectrometry. We found that the PB2 protein associates with the cytosolic chaperonin containing TCP-1 (CCT), stress-induced phosphoprotein 1 (STIP1), FK506 binding protein 5 (FKBP5), ␣-and ␤-tubulin, Hsp60, and mitochondrial protein p32. Some of these binding partners associate with each other, suggesting that PB2 might interact with these proteins in multimeric complexes. More detailed analysis of the interaction of the PB2 protein with CCT revealed that PB2 associates with CCT as a monomer and that the CCT binding site is located in a central region of the PB2 protein. PB2 proteins from various influenza virus subtypes and origins can associate with CCT. Silencing of CCT resulted in reduced viral replication and reduced PB2 protein and viral RNA accumulation in a ribonucleoprotein reconstitution assay, suggesting an important function for CCT during the influenza virus life cycle. We propose that CCT might be acting as a chaperone for PB2 to aid its folding and possibly its incorporation into the trimeric RNA polymerase complex.Influenza A viruses, members of the family of Orthomyxoviridae, contain a segmented RNA genome of negative polarity. The genomic RNA segments together with the three subunits of the viral RNA-dependent RNA polymerase (PB1, PB2, and PA protein) and the nucleoprotein (NP) form viral ribonucleoprotein complexes (vRNPs). The PB1 subunit is the polymerase itself, while the PB2 and PA subunits are involved in the generation of 5Ј capped RNA primers through binding to and endonucleolytic cleavage of host pre-mRNAs (8,10,11,41,61). After the virus enters the cell via endocytosis, vRNPs are released into the cytoplasm and transported into the nucleus. In the nucleus, vRNPs catalyze the synthesis of viral mRNAs and complementary RNAs (cRNA) which, in turn, are used as templates for the synthesis of vRNAs. The newly formed vRNPs in association with other viral proteins (M1 and nonstructural protein 2/nuclear export factor [NS2/NEP]) are transported into the cytoplasm and subsequently to the cell membrane, where the assembly process takes place, followed by the release of progeny virions by budding (44).The PB1, PB2, and PA proteins are synthesized in the cytoplasm whereupon PB1 and PA form a dimeric complex that is transported into the nucleus. In the nucleus the dimer assembles with the PB2 subunit, which is transported separately (7,14). RanBP5 was identified as a factor that is involved in the import of the PB1-PA dimer into the nucleus ...

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“…An antibiotic geldanamycin (GA), which was initially characterized as an anticancer agent, has been reported to exhibit broadspectrum antiviral activity in vitro against several viruses by targeting the ADP/ATP binding site of Hsp90 [21]. The target viruses include herpes simplex virus type-1 (HSV-1) [10], severe acute respiratory syndrome corona virus, vaccinia virus [23], influenza virus, vesicular stomatitis virus [22], hepatitis C virus [24] and ebola virus [11].…”

Section: Discussionmentioning

confidence: 99%

“…Hsp90 has been believed to facilitate viral protein folding and activity of non-structural proteins such as polymerase, protease and helicase as well as the structural proteins [3]. The polymerase of several viruses require Hsp90 for genome replication which include influenza virus A [12], herpes simplex virus [26], flock house virus [27] and vesicular stomatitis virus and treatment with Hsp90 inhibitors such as geldanamycin and 17-AAG lead to degradation of polymerase complexes [28,22].…”

Section: Discussionmentioning

confidence: 99%