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Detection of Protein Ubiquitination
Published on: August 19, 2009
RING1B ubiquitination and stability are regulated by ARF.
Prim de Bie1, Aaron Ciechanover
1Cancer and Vascular Biology Research Center, The Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa 31096, Israel. primdb@tx.technion.ac.il
Biochemical and Biophysical Research Communications
|August 23, 2012
Summary
ARF regulates the E3 ubiquitin ligase RING1B by preventing its self-ubiquitination. This regulation impacts Polycomb-mediated gene silencing by controlling RING1B stability and activity.
Area of Science:
- Epigenetics and Gene Regulation
- Ubiquitin Biology
- Molecular Oncology
Background:
- The E3 ubiquitin ligase RING1B is crucial for Polycomb-mediated gene silencing via histone H2A monoubiquitination.
- RING1B activity and stability are regulated by distinct ubiquitination events, including self-ubiquitination and degradation pathways.
- The balance between these ubiquitination pathways is critical for controlling gene repression.
Purpose of the Study:
- To identify regulators of RING1B ubiquitination.
- To elucidate the mechanism by which ARF affects RING1B ubiquitination and stability.
- To understand the implications of ARF-mediated regulation on Polycomb-mediated gene silencing.
Main Methods:
- Investigated the interaction between ARF and RING1B.
- Analyzed the effect of ARF on different types of RING1B ubiquitination (self-ubiquitination vs. E6-AP-mediated ubiquitination).
- Assessed the impact of ARF on RING1B homodimerization and stability.
Main Results:
- ARF was identified as a novel regulator of RING1B ubiquitination.
- ARF selectively inhibits RING1B self-ubiquitination, which is required for its ligase activity.
- ARF promotes E6-AP-mediated K48-linked polyubiquitination and subsequent degradation of RING1B.
- ARF binds to the RING domain of RING1B, disrupting its homodimerization.
Conclusions:
- ARF acts as a negative regulator of RING1B activity by promoting its degradation.
- ARF disrupts RING1B homodimerization, providing a mechanism for inhibiting self-ubiquitination.
- ARF-mediated regulation of RING1B ubiquitination offers a new regulatory point for Polycomb-mediated gene repression.
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