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Stimulus-dependent and domain-dependent cell death acceleration by an IFN-inducible protein, human MxA

Akiko Numajiri1, Masaki Mibayashi, Kyosuke Nagata

  • 1Department of Infection Biology, Graduate School of Comprehensive Human Sciences and Institute of Basic Medical Sciences, University of Tsukuba, Tsukuba 305-8575, Japan.

Journal of Interferon & Cytokine Research : the Official Journal of the International Society for Interferon and Cytokine Research
|May 18, 2006
PubMed

Insights

Human MxA protein, an antiviral, accelerates cell death during influenza virus infection. This process involves both caspase-dependent and independent pathways, with different MxA regions mediating these effects.

Area of Science:

  • Virology
  • Cell Biology
  • Immunology

Background:

  • Human MxA is an interferon-induced protein inhibiting RNA virus replication.
  • MxA has been shown to accelerate cell death induced by various stimuli, including viral infections.
  • The precise mechanisms underlying MxA's role in promoting cell death are not fully understood.

Purpose of the Study:

  • To elucidate the mechanism of MxA-mediated enhancement of cell death.
  • To investigate the involvement of caspases in MxA-induced cell death.
  • To identify the regions of MxA responsible for promoting cell death during influenza viral infection.

Main Methods:

  • Investigated MxA's role in cell death induced by UV irradiation, cycloheximide (CHX), and influenza viral infection.
  • Assessed the caspase dependency of MxA-mediated cell death.
  • Utilized deletion mutants to map the functional regions of MxA involved in cell death promotion.

Main Results:

  • MxA-mediated cell death was caspase-dependent when induced by UV or CHX.
  • During influenza viral infection, MxA promoted both caspase-dependent and caspase-independent cell death.
  • The C-terminal region of MxA mediated CHX-induced cell death, while both N-terminal and C-terminal regions were involved in influenza-induced cell death.
  • GTP-binding and hydrolysis activity of MxA was not essential for its cell death promotion function.

Conclusions:

  • MxA accelerates cell death through distinct pathways depending on the death-inducing stimulus.
  • Influenza viral infection triggers MxA-mediated cell death via at least two separate mechanisms.
  • Understanding these pathways could offer insights into viral pathogenesis and host-cell interactions.

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