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Corrected and Republished from: The COP9 Signalosome Interacts with and Regulates Interferon Regulatory Factor 5

Justyna Korczeniewska1,2, Betsy J Barnes3,2

  • 1Department of Biochemistry & Molecular Biology, New Jersey Medical School, UMDNJ, Newark, New Jersey, USA.

Molecular and Cellular Biology
|January 18, 2018
PubMed

Insights

The COP9 signalosome (CSN) stabilizes the key immune regulator interferon regulatory factor 5 (IRF5). CSN binding maintains IRF5 protein levels, which are degraded when CSN interaction is lost during immune activation.

Area of Science:

  • Immunology
  • Molecular Biology
  • Cell Biology

Background:

  • Interferon regulatory factor 5 (IRF5) is critical for immune responses, apoptosis, and macrophage polarization.
  • Precise regulation of IRF5 is essential for effective immunity and preventing autoimmune diseases.

Purpose of the Study:

  • To investigate the regulatory mechanisms controlling IRF5 protein stability.
  • To identify novel interacting partners of IRF5 involved in its regulation.

Main Methods:

  • Proteomics to identify IRF5 interacting proteins.
  • Endogenous immunoprecipitation to confirm interactions.
  • siRNA-mediated knockdown of CSN subunits.
  • Treatment with proteasome inhibitors.
  • Analysis of IRF5 stability upon TRAIL stimulation.

Main Results:

  • The COP9 signalosome (CSN) constitutively associates with IRF5, enhancing its protein stability.
  • CSN3 directly interacts with IRF5; its knockdown, along with CSN1, accelerates IRF5 degradation.
  • IRF5 stability is regulated by the ubiquitin-proteasome system.
  • Activation of IRF5 by TRAIL leads to dissociation from CSN and subsequent degradation.

Conclusions:

  • The CSN is a novel regulator of IRF5 stability.
  • CSN binding is crucial for maintaining IRF5 protein levels.
  • Immune activation triggers IRF5 degradation through loss of CSN interaction, impacting cellular responses.
Keywords:
COP9IRF5

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