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The repressing function of the oncoprotein BCL-3 requires CtBP, while its polyubiquitination and degradation involve

Aurore Keutgens1, Kateryna Shostak, Pierre Close

  • 1Interdisciplinary Cluster for Applied Genoproteomics (GIGA-Research), University of Liege, CHU, Sart-Tilman, Liege, Belgium.

Molecular and Cellular Biology
|June 16, 2010
PubMed

Insights

BCL-3 protein

Area of Science:

  • Molecular and Cellular Biology
  • Cancer Research
  • Gene Regulation

Background:

  • The BCL-3 protein's role in gene transcription and oncogenesis is incompletely understood.
  • Key interacting partners and degradation pathways of BCL-3 remain largely uncharacterized.

Purpose of the Study:

  • To identify novel BCL-3 interacting proteins.
  • To elucidate the molecular mechanisms underlying BCL-3's transcriptional repression and oncogenic functions.
  • To characterize the pathways involved in BCL-3 degradation.

Main Methods:

  • Biochemical purification of BCL-3 interacting partners.
  • Functional assays to assess transcriptional activity and oncogenic potential.
  • Investigation of protein degradation pathways.

Main Results:

  • CtBP was identified as a crucial co-factor for BCL-3-mediated transcriptional repression and oncogenic activity.
  • CtBP is essential for BCL-3's ability to inhibit UV-induced apoptosis in keratinocytes.
  • The E3 ligase TBLR1 was identified as a component of a GSK3-independent BCL-3 degradation pathway.

Conclusions:

  • The LSD1/CtBP complex is essential for the transcriptional repressing function of the oncogenic I kappaB protein, BCL-3.
  • A functional link between the E3 ligase TBLR1 and NF-kappaB signaling is established.
  • These findings provide new insights into the regulation of BCL-3 and its role in cancer.

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