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Purification of Ubiquitinated p53 Proteins from Mammalian Cells
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Purification of Ubiquitinated p53 Proteins from Mammalian Cells

Published on: March 21, 2022

MUC1 oncoprotein suppresses activation of the ARF-MDM2-p53 pathway

Deepak Raina1, Rehan Ahmad, Dongshu Chen

  • 1Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA.

Cancer Biology & Therapy
|November 5, 2008
PubMed

Insights

A mutated MUC1 protein (MUC1(Y60F)) activates the ARF tumor suppressor, leading to p53 upregulation and apoptosis. This discovery reveals MUC1

Area of Science:

  • Oncology
  • Molecular Biology
  • Cellular Signaling

Background:

  • The MUC1 oncoprotein interacts with c-Abl tyrosine kinase, inhibiting apoptosis.
  • Nuclear targeting of c-Abl is crucial for the apoptotic response to DNA damage.

Purpose of the Study:

  • To investigate the role of MUC1 Tyr-60 mutation in c-Abl interaction and its impact on tumor suppressor pathways.
  • To elucidate the mechanism by which MUC1(Y60F) influences ARF, p53, and apoptosis.

Main Methods:

  • Site-directed mutagenesis of MUC1 at Tyr-60 (Y60F).
  • Analysis of MUC1-c-Abl interaction and nuclear localization.
  • Assessment of ARF, MDM2, p53, HIPK2, p21, and PUMA gene expression.
  • Evaluation of MUC1(Y60F) in tumorigenicity assays.

Main Results:

  • MUC1(Y60F) mutation disrupts MUC1-c-Abl interaction, inducing ARF.
  • MUC1(Y60F) promotes c-Abl-dependent nuclear export of Cdc6 via CUL-4A.
  • ARF induction by MUC1(Y60F) inhibits MDM2, upregulating p53 and HIPK2.
  • HIPK2 phosphorylates p53, shifting gene expression from cell cycle arrest (p21) to apoptosis (PUMA).
  • MUC1(Y60F) acts as a dominant-negative inhibitor of tumorigenicity.

Conclusions:

  • The oncogenic function of MUC1 is mediated by suppressing the ARF-MDM2-p53 pathway.
  • Targeting the MUC1-c-Abl interaction or MUC1(Y60F)-induced pathways may offer novel cancer therapeutic strategies.

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