Related Experiment Video
Updated: Jun 20, 2025
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Purification of Ubiquitinated p53 Proteins from Mammalian Cells
Published on: March 21, 2022
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GRAIL1 Stabilizes Misfolded Mutant p53 through a Ubiquitin Ligase-Independent, Chaperone Regulatory Function
Paramita Ray1, Sangeeta Jaiswal2, Daysha Ferrer-Torres2
1Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan.
Molecular Cancer Research : MCR
|July 17, 2024
Summary
Researchers found a new way to degrade mutant p53, a protein driving esophageal cancer. A novel peptide targets heat shock protein 40/DNAJ, inhibiting its chaperone activity to reduce cancer cell survival.
Area of Science:
- Molecular Biology
- Oncology
- Biochemistry
Background:
- TP53 mutations are common in esophageal adenocarcinoma (EAC), leading to protein stabilization, poor prognosis, and therapy resistance.
- The E3 ubiquitin ligase RNF128 (GRAIL) isoform 1 stabilizes mutant p53 during Barrett's esophagus progression to EAC.
- The mechanism by which GRAIL stabilizes mutant p53 was previously unknown.
Purpose of the Study:
- To elucidate the mechanism by which GRAIL stabilizes mutant p53.
- To identify a novel therapeutic strategy targeting mutant p53 stabilization in EAC.
Main Methods:
- Biochemical and cell biology studies were performed.
- Interaction between GRAIL and DNAJ was investigated.
- Overexpression of a GRAIL fragment (Frag-J) and a cell-permeable peptide (Pep-J) were used to inhibit DNAJ-Hsp70 co-chaperone activity.
- Effects on cell survival and organoid growth were assessed.
Main Results:
- GRAIL possesses a DNAJ binding domain (315-PMCKCDILKA-325).
- This interaction modulates DNAJ chaperone activity, influencing misfolded mutant p53 stability.
- Frag-J and Pep-J degraded misfolded mutant p53, reduced survival of EAC and dysplastic Barrett's esophagus cells, and inhibited patient-derived organoid growth.
- Pep-J's effects were comparable to simvastatin.
Conclusions:
- A novel, ubiquitin ligase-independent, chaperone-regulating domain in GRAIL was identified.
- A first-in-class peptide (Pep-J) was synthesized that degrades misfolded mutant p53.
- This peptide demonstrates translational potential for treating EAC and related conditions.
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