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Physical and functional interactions between Daxx and STAT3

R Muromoto1, K Nakao, T Watanabe

  • 1Department of Immunology, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Hokkaido, Japan.

Oncogene
|December 7, 2005
PubMed

Insights

Type I interferon (IFN) suppresses interleukin-6/Signal transducer and activator of transcription 3 (STAT3) signaling. A Daxx protein, induced by type I IFN, physically interacts with STAT3 to regulate this suppression.

Area of Science:

  • Molecular Biology
  • Cellular Signaling
  • Immunology

Background:

  • Signal transducer and activator of transcription 3 (STAT3) is crucial for interleukin-6 (IL-6) cytokine family signaling, impacting cell proliferation and differentiation.
  • Dysregulated IL-6/STAT3 signaling is implicated in autoimmune diseases and cancer.
  • Type I interferon (IFN) exhibits anti-tumor effects by inducing proapoptotic genes.

Purpose of the Study:

  • To investigate the mechanism by which type I IFN suppresses IL-6/STAT3 signaling.
  • To determine the role of the type I IFN-induced protein Daxx in this suppressive pathway.

Main Methods:

  • Investigated the effect of type I IFN on IL-6/STAT3-mediated transcription and gene expression.
  • Examined the function of Daxx in STAT3 transcriptional activation using overexpression and small-interfering RNA (siRNA).
  • Utilized co-immunoprecipitation and nuclear co-localization studies to assess Daxx-STAT3 interaction.

Main Results:

  • Type I IFN suppressed IL-6/STAT3-mediated transcription and gene expression.
  • Daxx, induced by type I IFN, inhibited STAT3 transcriptional activation.
  • Reduction of Daxx expression enhanced IL-6/leukemia inhibitory factor (LIF)-induced STAT3-dependent transcription.
  • Daxx physically interacted with STAT3 and co-localized in the nucleus.

Conclusions:

  • Daxx plays a significant role in mediating type I IFN's suppression of the IL-6/STAT3 signaling pathway.
  • Daxx acts as a transcriptional regulator, linking type I IFN signaling to the inhibition of IL-6/STAT3 activity.

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