Related Experiment Video

Updated: Aug 21, 2026

Purification of Ubiquitinated p53 Proteins from Mammalian Cells
10:55

Purification of Ubiquitinated p53 Proteins from Mammalian Cells

Published on: March 21, 2022

FLT3-ITD signals for CEBPA and p53 proteolysis by the ubiquitin-proteosome pathway

Yogen Saunthararajah1, Xiaorong Gu2, Sudipta Biswas1

  • 1Cleveland Clinic.

Research Square
|August 20, 2026
PubMed

Insights

FLT3-ITD mutations in acute myeloid leukemia (AML) drive cancer cell survival by promoting CEBPA and p53 protein destruction. Ubiquitin-proteasome pathway inhibitors offer a promising therapeutic strategy for AML by stabilizing these key proteins.

Area of Science:

  • Molecular Biology
  • Cancer Biology
  • Hematology

Background:

  • FLT3-ITD mutations in acute myeloid leukemia (AML) lead to uncontrolled cell signaling.
  • Protein degradation pathways, like the ubiquitin-proteasome pathway (UPP), regulate cell fate.
  • CEBPA is a master transcription factor crucial for granulomonocytic lineage differentiation in AML.

Purpose of the Study:

  • To investigate if FLT3-ITD signaling regulates CEBPA protein stability via proteolysis.
  • To identify the role of the ubiquitin-proteasome pathway (UPP) in FLT3-ITD-driven AML.
  • To explore therapeutic strategies targeting UPP in FLT3-ITD AML.

Main Methods:

  • Compared CEBPA protein and mRNA levels in FLT3-ITD versus FLT3-wildtype AML cells.
  • Utilized mass spectrometry to identify interactions between CEBPA and UPP components (UHRF1, USP7).
  • Assessed the effects of tyrosine kinase inhibitors (TKIs) and UPP inhibitors on protein phosphorylation, interactions, and stability.

Main Results:

  • FLT3-ITD AML cells showed low CEBPA protein despite high mRNA; TKIs rapidly restored CEBPA.
  • CEBPA interacts with UHRF1 (ligase) and USP7 (deubiquitinase); TKI treatment shifted interactions from UHRF1 to USP7, stabilizing CEBPA.
  • UPP inhibitors stabilized CEBPA and p53, inducing apoptosis in FLT3-ITD cells, including TKI-resistant cases.

Conclusions:

  • FLT3-ITD signaling promotes the UPP-mediated degradation of CEBPA and p53.
  • Targeting the UPP stabilizes key tumor suppressor proteins, offering a therapeutic avenue.
  • UPP inhibitors are promising candidates for treating FLT3-ITD AML, potentially overcoming TKI resistance.
Keywords:
CEBPAFLT3-ITDUSP7acute myeloid leukemiachemotherapy-resistancep53ubiquitin-proteosome pathway

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