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Updated: Jul 1, 2025
10:27
Functional Characterization of RING-Type E3 Ubiquitin Ligases In Vitro and In Planta
Published on: December 5, 2019
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Structural basis for RAD18 regulation by MAGEA4 and its implications for RING ubiquitin ligase binding by MAGE family
Simonne Griffith-Jones1, Lucía Álvarez2, Urbi Mukhopadhyay1
1European Molecular Biology Laboratory, 71 Avenue des Martyrs, 38042, Grenoble, France.
The EMBO Journal
|March 6, 2024
Summary
Cancer-testis antigen MAGEA4 interacts with RAD18, inhibiting its self-ubiquitination and influencing DNA repair. This interaction, elucidated by NMR and AlphaFold2, reveals a potential target for cancer therapy.
Area of Science:
- Molecular biology
- Structural biology
- Cancer research
Background:
- MAGEA4 is a cancer-testis antigen overexpressed in various cancers.
- MAGEA4 interacts with RAD18, a RING ubiquitin ligase, and influences trans-lesion DNA synthesis (TLS).
Purpose of the Study:
- To elucidate the interaction mode between RAD18 and MAGEA4 using structural biology techniques.
- To understand the regulatory mechanism of RAD18-mediated PCNA mono-ubiquitination.
Main Methods:
- Nuclear Magnetic Resonance (NMR) spectroscopy
- AlphaFold2 (AF) protein structure prediction
- Cross-linking mass spectrometry (XL-MS)
- Interaction proteomics
Main Results:
- The RAD6-binding domain (R6BD) of RAD18 binds to a groove in MAGEA4's C-terminal winged-helix subdomain.
- MAGEA4 inhibits RAD18 autoubiquitination by displacing RAD6.
- An intramolecular interaction within RAD18, essential for PCNA mono-ubiquitination, was identified.
- MAGE-C2 interacts with TRIM28 similarly to MAGEA4/RAD18, suggesting a conserved MAGE protein binding mechanism.
Conclusions:
- MAGEA4 regulates RAD18 activity, impacting DNA repair pathways relevant to cancer.
- The findings provide structural insights into MAGE protein interactions with ubiquitin ligases.
- The study highlights a conserved mechanism for MAGE-type protein binding to ligases.
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