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In Vitro Ubiquitination and Deubiquitination Assays of Nucleosomal Histones
Published on: July 25, 2019
Rad4 regulates protein turnover at a postubiquitylation step
1Department of Molecular Medicine, Institute of Biotechnology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78245, USA.
Molecular Biology of the Cell
|November 6, 2009
Summary
Rad4, a DNA repair protein, also regulates protein degradation by working with Rad23. This reveals a new role for Rad4 in proteolysis and links DNA repair with protein turnover.
Area of Science:
- Cellular Biology
- Molecular Biology
- Biochemistry
Background:
- Rad23 (ubiquitin-binding protein) facilitates substrate transfer to the proteasome.
- The precise mechanism of Rad23 in proteolysis is not fully understood.
- Rad4 is a known DNA repair factor that recognizes DNA damage.
Purpose of the Study:
- To investigate the role of Rad4 in proteolysis.
- To elucidate the mechanism of Rad23's function in protein degradation.
- To explore the interplay between DNA repair and proteolysis.
Main Methods:
- Analysis of ubiquitylated substrates in rad4Delta cells.
- Investigating Rad4's participation in Rad23-Ufd2 and Rad23-Png1 pathways.
- Assessing the impact of DNA damage on Rad4 localization and Pex29 degradation.
Main Results:
- Rad4 and Rad23 share common substrates, indicating a role for Rad4 in post-ubiquitylation events.
- Rad4 functions in the Rad23-Ufd2 pathway, not the Rad23-Png1 pathway.
- The Rad4-binding domain of Rad23 is essential for its role in degradation.
- Rad4's nuclear accumulation during DNA damage impairs non-nuclear protein degradation.
Conclusions:
- Rad4 possesses a novel function in regulating ubiquitylated substrate turnover.
- Rad4 and Rad23 collaborate in proteolysis, linking DNA repair and protein degradation.
- Rad4 influences the coordination of cellular processes, including DNA repair and proteolysis.
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