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PKR protein kinase is activated by hepatitis C virus and inhibits viral replication through translational control

Ju-Il Kang1, Shi-Nae Kwon, Se-Hoon Park

  • 1School of Life Sciences & Biotechnology, Korea University, 5-1 Anamdong, Seoul 136-701, Republic of Korea.

Virus Research
|February 5, 2009
PubMed

Insights

Hepatitis C virus (HCV) infection activates protein kinase PKR, which inhibits viral replication by blocking protein translation. This finding reveals a key antiviral mechanism against HCV.

Area of Science:

  • Virology
  • Molecular Biology
  • Immunology

Background:

  • Hepatitis C virus (HCV) infection treatment relies on IFNalpha-based therapies.
  • The precise mechanism by which IFNalpha inhibits HCV replication remains largely unknown.

Purpose of the Study:

  • To elucidate the role of Interferon-alpha (IFNalpha)-inducible protein kinase PKR in Hepatitis C virus (HCV) replication.
  • To investigate the interaction between PKR, eIF2alpha phosphorylation, and HCV replication dynamics.

Main Methods:

  • HCV JFH1 infection of human hepatoma Huh-7 cells.
  • PKR-knockdown cell experiments to assess viral replication.
  • Transient expression of PKR and a phospho-mimetic eIF2alpha mutant.

Main Results:

  • HCV infection activates PKR and phosphorylates eIF2alpha.
  • PKR knockdown significantly increases HCV replication and reduces sensitivity to IFNalpha.
  • PKR expression inhibits HCV replication in a kinase-dependent manner, correlating with eIF2alpha phosphorylation.

Conclusions:

  • PKR is activated by HCV infection and acts as a crucial antiviral factor.
  • PKR inhibits HCV replication primarily by suppressing viral protein translation via eIF2alpha phosphorylation.

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