Related Experiment Video
Updated: Sep 7, 2025
Functionalized Spirocyclic Heterocycle Synthesis and Cytotoxicity Assay
Published on: February 9, 2021
Novel Allosteric Mechanism of Dual p53/MDM2 and p53/MDM4 Inhibition by a Small Molecule
Vera V Grinkevich1, Aparna Vema2, Karin Fawkner1
1Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden.
Abstract:
Restoration of the p53 tumor suppressor for personalised cancer therapy is a promising treatment strategy. However, several high-affinity MDM2 inhibitors have shown substantial side effects in clinical trials. Thus, elucidation of the molecular mechanisms of action of p53 reactivating molecules with alternative functional principle is of the utmost importance. Here, we report a discovery of a novel allosteric mechanism of p53 reactivation through targeting the p53 N-terminus which promotes inhibition of both p53/MDM2 (murine double minute 2) and p53/MDM4 interactions. Using biochemical assays and molecular docking, we identified the binding site of two p53 reactivating molecules, RITA (reactivation of p53 and induction of tumor cell apoptosis) and protoporphyrin IX (PpIX). Ion mobility-mass spectrometry revealed that the binding of RITA to serine 33 and serine 37 is responsible for inducing the allosteric shift in p53, which shields the MDM2 binding residues of p53 and prevents its interactions with MDM2 and MDM4. Our results point to an alternative mechanism of blocking p53 interaction with MDM2 and MDM4 and may pave the way for the development of novel allosteric inhibitors of p53/MDM2 and p53/MDM4 interactions.
Insights
Researchers discovered a new way to reactivate the p53 tumor suppressor protein. This novel allosteric mechanism targets the p53 N-terminus, inhibiting interactions with MDM2 and MDM4, offering a promising avenue for cancer therapy.
Area of Science:
- Oncology
- Molecular Biology
- Drug Discovery
Background:
- Restoring p53 function is a key strategy for personalized cancer therapy.
- Existing MDM2 inhibitors cause side effects, necessitating alternative approaches.
- Understanding novel p53 reactivation mechanisms is crucial for developing safer therapies.
Purpose of the Study:
- To elucidate the molecular mechanism of p53 reactivation by novel molecules.
- To identify an alternative strategy for inhibiting p53 interactions with MDM2 and MDM4.
- To explore the potential of allosteric p53 reactivation for cancer treatment.
Main Methods:
- Biochemical assays and molecular docking to identify binding sites.
- Ion mobility-mass spectrometry to analyze molecular interactions.
- Investigated the effects of RITA and protoporphyrin IX (PpIX) on p53.
Main Results:
- Identified a novel allosteric mechanism of p53 reactivation by targeting the p53 N-terminus.
- RITA binding to serine 33 and 37 induces an allosteric shift, blocking p53/MDM2 and p53/MDM4 interactions.
- Protoporphyrin IX (PpIX) also identified as a p53 reactivating molecule.
Conclusions:
- The study reveals an alternative mechanism for inhibiting p53 interactions with MDM2 and MDM4.
- This discovery may lead to the development of novel allosteric inhibitors for cancer therapy.
- Targeting the p53 N-terminus offers a new strategy for p53 restoration in cancer treatment.
Related Concept Videos
02:23Abnormal Proliferation
02:34Inhibition of Cdk Activity
01:23Negative Regulator Molecules
02:37DNA Damage can Stall the Cell Cycle
01:19Interactions Between Signaling Pathways
Convergence and divergence, and cross-talk between signaling pathways
Two distinct signaling pathways can converge on a single functional unit, which may either be a single protein or a complex of proteins. The response is either functionally distinct or synergistic between the two pathways but different from the response...
01:10Drugs that Destabilize Microtubules