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Domain within the C protein of human parainfluenza virus type 3 that regulates interferon signaling

Hongxia Mao1, Santanu Chattopadhyay, Amiya K Banerjee

  • 1Virology Section, Department of Molecular Genetics, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA.

Gene Expression
|November 11, 2010
PubMed

Insights

Human parainfluenza virus type 3 (HPIV3) C protein hinders innate immunity. Truncating its N-terminus partially restores interferon signaling, highlighting the N-terminal region

Area of Science:

  • Virology
  • Immunology
  • Molecular Biology

Background:

  • Human parainfluenza virus type 3 (HPIV3) is a paramyxovirus that employs its accessory C protein to counteract host innate immunity.
  • The HPIV3 C protein inhibits interferon (IFN)-mediated signaling pathways, including the phosphorylation of Signal Transducer and Activator of Transcription (Stat) 1 and gamma Interferon Activation Factor (GAF) complex formation.
  • This inhibition abrogates the antiviral activity of IFNs against viral replication, such as vesicular stomatitis virus (VSV).

Purpose of the Study:

  • To investigate the role of the N-terminal region of the HPIV3 C protein in antagonizing interferon signaling.
  • To identify specific domains or residues within the C protein critical for its interaction with the host innate immune response.

Main Methods:

  • Site-directed mutagenesis was employed to create N-terminal truncated mutants of the HPIV3 C protein (CNdelta25 and CNdelta50).
  • Interferon-induced responses, including Stat1 phosphorylation and GAF complex formation, were analyzed in the presence of wild-type and mutant C proteins.
  • The impact of charged amino acid residues within the N-terminal region on C protein function was assessed.

Main Results:

  • N-terminal truncation of the HPIV3 C protein (CNdelta25 and CNdelta50) resulted in a substantial recovery (approximately 50%) of IFN-induced responses.
  • These findings indicate that the N-terminal region of the C protein plays a critical role in its antagonistic activity against IFN signaling.
  • Charged amino acid residues within the N-terminal region were identified as key regulators of the C protein's inhibitory effect on IFN signaling.

Conclusions:

  • The N-terminal region of the HPIV3 C protein is essential for its function as an antagonist of the host interferon-mediated innate immune response.
  • Specific charged amino acid residues within this N-terminal region are crucial for modulating the C protein's ability to suppress IFN signaling.
  • Understanding these interactions provides insights into HPIV3 pathogenesis and potential therapeutic targets.

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