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Production, Crystallization, and Structure Determination of the IKK-binding Domain of NEMO
13:02

Production, Crystallization, and Structure Determination of the IKK-binding Domain of NEMO

Published on: December 28, 2019

The NEMO adaptor bridges the nuclear factor-kappaB and interferon regulatory factor signaling pathways

Tiejun Zhao1, Long Yang, Qiang Sun

  • 1Terry Fox Molecular Oncology Group, Lady Davis Institute for Medical Research, McGill University, Montreal H3T 1E2, Canada.

Nature Immunology
|May 1, 2007
PubMed

Insights

The NEMO protein is crucial for RNA virus detection, acting upstream of key kinases to activate immune signaling pathways. NEMO enables RIG-I to initiate both NF-kappaB and IRF signaling, essential for antiviral responses.

Area of Science:

  • Immunology
  • Virology
  • Molecular Biology

Background:

  • Intracellular RNA virus detection relies on RIG-I (Retinoic acid-inducible protein I) and MAVS (Mitochondrial antiviral signaling protein).
  • Activation of transcription factors NF-kappaB, IRF3, and IRF7 is critical for antiviral immune responses.

Purpose of the Study:

  • To investigate the role of NEMO (NF-kappaB essential modulator) in RIG-I-mediated antiviral signaling.
  • To elucidate the precise position of NEMO within the signaling cascade leading to IRF3 and IRF7 activation.

Main Methods:

  • Utilized NEMO-deficient cells to assess the impact on IRF3 and IRF7 activation.
  • Examined IRF3 phosphorylation, dimerization, DNA binding, and gene expression.
  • Restored IRF3 phosphorylation and interferon production via ectopic NEMO expression.

Main Results:

  • Virus-induced activation of IRF3 and IRF7 was abrogated in NEMO-deficient cells.
  • NEMO acts upstream of TBK1 and IKKepsilon kinases in the signaling pathway.
  • Ectopic NEMO expression restored IRF3 phosphorylation and interferon production.

Conclusions:

  • NEMO functions as an adaptor protein essential for RIG-I-mediated activation of both NF-kappaB and IRF signaling pathways.
  • NEMO's role is critical for initiating antiviral gene expression and interferon production following RNA virus infection.

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