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 (SLF1tBRCT) bound with the interacting Rad18 peptide. Our structure and biochemical studies demonstrate that SLF1tBRCT interacts with two phosphoserines and adjacent residues in Rad18 for high-affinity and specificity Rad18 recognition. We found that SLF1tBRCT 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.
Subject(s)
DNA Damage , Ubiquitin-Protein Ligases , Protein Binding , Protein Domains , Peptides , DNA RepairABSTRACT
The budding yeast protein Rad5 is highly conserved among eukaryotes. Rad5 and its orthologs including helicase like transcription factor (HLTF) and SNF2 histone linker PHD RING helicase (SHPRH) in humans constitute a unique family of enzymes that play critical roles in the cellular response to DNA replication stresses. The function of the Rad5 family of enzymes is fulfilled by their multiple activities, including ubiquitin ligase, replication fork regression activities and others. Herein, we review recent studies that provided mechanistic insights into their multiple activities and their coordination.
