Hepatitis C virus nonstructural 5B protein regulates tumor necrosis factor alpha signaling through effects on cellular IκB kinase

Soo H. Choi, Kyu J. Park, Byung-Yoon Ahn, Guhung Jung, M. M C Lai, Soon B. Hwang

Research output: Contribution to journalArticle

41 Citations (Scopus)


Hepatitis C virus (HCV) NS5B protein is a membrane-associated phosphoprotein that possesses an RNA-dependent RNA polymerase activity. We recently reported that NS5A protein interacts with TRAF2 and modulates tumor necrosis factor alpha (TNF-α)-induced NF-κB and Jun N-terminal protein kinase (JNK). Since NS5A and NS5B are the essential components of the HCV replication complex, we examined whether NS5B could modulate TNF-α-induced NF-κB and JNK activation. In this study, we have demonstrated that TNF-α-induced NF-κB activation is inhibited by NS5B protein in HEK293 and hepatic cells. Furthermore, NS5B protein inhibited both TRAF2- and IKK-induced NF-κB activation. Using coimmunoprecipitation assays, we show that NS5B interacts with IKKα. Most importantly, NS5B protein in HCV subgenomic replicon cells interacted with endogenous IKKα, and then TNF-α-mediated IKKα kinase activation was significantly decreased by NS5B. Using in vitro kinase assay, we have further found that NS5B protein synergistically activated TNF-α-mediated JNK activity in HEK293 and hepatic cells. These data suggest that NS5B protein modulates TNF-α signaling pathways and may contribute to HCV pathogenesis.

Original languageEnglish
Pages (from-to)3048-3059
Number of pages12
JournalMolecular and Cellular Biology
Issue number8
Publication statusPublished - 2006 Apr 1


ASJC Scopus subject areas

  • Cell Biology
  • Genetics
  • Molecular Biology

Cite this