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Inhibition of STAT 1 phosphorylation by human parainfluenza virus type 3 C protein

Achut G Malur1, Santanu Chattopadhyay, Ratan K Maitra

  • 1Cleveland Clinic Foundation, Section Virology NN-10, Department of Molecular Biology, 9500 Euclid Avenue, Cleveland, OH 44195-5178, USA.

Journal of Virology
|May 28, 2005
PubMed

Insights

The human parainfluenza virus type 3 C protein inhibits the interferon signaling pathway. This accessory protein prevents STAT 1 activation, crucial for antiviral responses.

Area of Science:

  • Virology
  • Immunology
  • Molecular Biology

Background:

  • Paramyxovirinae subfamily viruses produce accessory proteins (C and V proteins) from P mRNA.
  • The human parainfluenza virus type 3 (HPIV 3) C protein is known to play a role in viral transcription.
  • Accessory proteins are increasingly recognized for their importance in virus transcription and interferon signaling.

Purpose of the Study:

  • To investigate the role of the HPIV 3 C protein in interferon signaling.
  • To generate a stable cell line expressing HPIV 3 C protein for experimental analysis.

Main Methods:

  • Generation of a stable lentiviral expression cell line (L-C6) for HPIV 3 C protein.
  • Assessment of interferon-induced antiviral states in L-C6 cells.
  • Analysis of gamma-activated factor complex formation and STAT 1 phosphorylation via Western blot.

Main Results:

  • L-C6 cells showed abrogated alpha and gamma interferon-induced antiviral states.
  • A significant reduction in gamma-activated factor complex formation was observed.
  • Western blot analysis revealed a defect in STAT 1 phosphorylation in L-C6 cells.

Conclusions:

  • HPIV 3 C protein effectively counteracts the interferon signaling pathway.
  • The C protein specifically inhibits STAT 1 activation, a key component of interferon signaling.
  • This study elucidates a novel mechanism by which HPIV 3 evades host antiviral defenses.

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