Figure 2

Three proteins Abraxas, Bach1 and CtIP contain p-SPxF motif that binds to the BRCT domains of BRCA1. Schematic diagram showing protein domains of three BRCA1-BRCT associated proteins. The phospho-Ser-Pro-X-Phe (p-SPxF) motif is illustrated on each protein. In addition, Abraxas contains a MPN- domain that binds to Ub and a coiled-coil domain that interacts with BRCC36. Abraxas also contains a ATM/ATR phosphorylation site (T368). Bach1 contains a helicase domain. CtIP contains a coiled-coil domain at its N-terminus that is responsible for dimerization of the protein. T847 of CtIP is phosphorylated by CDK and the phosphorylation is required for its ability to promote DNA end resection. CtIP is also phosphorylated by ATM/ATR at S644, S679 and S745. The 509-557 region of CTIP binds to DNA directly in vitro and is required for recruitment to DSB in cells [34]