Structural insights into Rad18 targeting by the SLF1 BRCT domains.
Huang, W., Qiu, F., Zheng, L., Shi, M., Shen, M., Zhao, X., Xiang, S.(2023) J Biol Chem 299: 105288-105288
- PubMed: 37748650 
- DOI: https://doi.org/10.1016/j.jbc.2023.105288
- Primary Citation of Related Structures:  
8IR2, 8IR4 - PubMed Abstract: 
Rad18 interacts with the SMC5/6 localization factor 1 (SLF1) to recruit the SMC5/6 complex to DNA damage sites for repair. The mechanism of the specific Rad18 recognition by SLF1 is unclear. Here, we present the crystal structure of the tandem BRCT repeat (tBRCT) in SLF1 (SLF1 tBRCT ) bound with the interacting Rad18 peptide. Our structure and biochemical studies demonstrate that SLF1 tBRCT interacts with two phosphoserines and adjacent residues in Rad18 for high-affinity and specificity Rad18 recognition. We found that SLF1 tBRCT utilizes mechanisms common among tBRCTs as well as unique ones for Rad18 binding, the latter include interactions with an α-helical structure in Rad18 that has not been observed in other tBRCT-bound ligand proteins. Our work provides structural insights into Rad18 targeting by SLF1 and expands the understanding of BRCT-mediated complex assembly.
Organizational Affiliation: 
Department of Biochemistry and Molecular Biology, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Tianjin Medical University, Tianjin, P. R. China.