Structural basis of ubiquitin recognition by the winged-helix domain of Cockayne syndrome group B protein.

Abstract

Cockayne syndrome group B (CSB, also known as ERCC6) protein is involved in many DNA repair processes and essential for transcription-coupled repair (TCR). The central region of CSB has the helicase motif, whereas the C-terminal region contains important regulatory elements for repair of UV- and oxidative stress-induced damages and double-strand breaks (DSBs). A previous study suggested that a small part (∼30 residues) within this region was responsible for binding to ubiquitin (Ub). Here, we show that the Ub-binding of CSB requires a larger part of CSB, which was previously identified as a winged-helix domain (WHD) and is involved in the recruitment of CSB to DSBs. We also present the crystal structure of CSB WHD in complex with Ub. CSB WHD folds as a single globular domain, defining a class of Ub-binding domains (UBDs) different from 23 UBD classes identified so far. The second α-helix and C-terminal extremity of CSB WHD interact with Ub. Together with structure-guided mutational analysis, we identified the residues critical for the binding to Ub. CSB mutants defective in the Ub binding reduced repair of UV-induced damage. This study supports the notion that DSB repair and TCR may be associated with the Ub-binding of CSB.

• Authors: Tomio S Takahashi, Yusuke Sato, Atsushi Yamagata, Sakurako Goto-Ito, Masafumi Saijo, Shuya Fukai
• Journal: Nucleic acids research (Nucleic Acids Res) Vol. 47 Issue 7 Pg. 3784-3794 (04 23 2019) ISSN: 1362-4962 [Electronic] England
• PMID: 30753618 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © The Author(s) 2019. Published by Oxford University Press on behalf of Nucleic Acids Research.

Chemical References

• Poly-ADP-Ribose Binding Proteins
• Ubiquitin
• Ubiquitins
• Winged-Helix Transcription Factors
• DNA Helicases
• ERCC6 protein, human
• DNA Repair Enzymes

Topics

• Amino Acid Sequence (genetics)
• Cell Survival
• Cockayne Syndrome (genetics, metabolism)
• DNA Breaks, Double-Stranded
• DNA Damage (genetics, radiation effects)
• DNA Helicases (chemistry, genetics)
• DNA Repair (genetics, radiation effects)
• DNA Repair Enzymes (chemistry, genetics)
• Humans
• Mutation
• Poly-ADP-Ribose Binding Proteins (chemistry, genetics)
• Protein Conformation, alpha-Helical (genetics)
• Ubiquitin (chemistry, genetics)
• Ubiquitins (chemistry, genetics)
• Ultraviolet Rays
• Winged-Helix Transcription Factors (chemistry, genetics)