Brca1 C-terminal (BRCT) domains are a common protein-protein interaction regions in proteins involved in the DNA damage response and DNA repair [1,2]. For example 53BP1 which plays multiple roles in mammalian DNA damage repair, has a C-terminal tandem BRCT domain (BRCT2), which in its orthologs, Saccharomyces cerevisiae Rad9p and Schizosaccharomyces pombe Crb2, mediates binding to the equivalents of gammaH2AX. Structural and functional studies indicate that the 53BP1-BRCT2 domain is a competent binding module for phosphorylated peptides with a clear specificity for the DNA-damage marker gammaH2AX, and in isolation from other parts of 53BP1 is sufficient for localization to sites of DNA damage in cells associated with gammaH2AX [3].

1: Crystal structure of human 53BP1 BRCT domains bound to p53 tumour suppressor. Derbyshire DJ, Basu BP, Serpell LC, Joo WS, Date T, Iwabuchi K, Doherty AJ; EMBO J. 2002;21:3863-3872. PMID:12110597

2: Structure of the 53BP1 BRCT region bound to p53 and its comparison to the Brca1 BRCT structure. Joo WS, Jeffrey PD, Cantor SB, Finnin MS, Livingston DM, Pavletich NP; Genes Dev. 2002;16:583-593. PMID:11877378

3: ATM Localization and Heterochromatin Repair Depend on Direct Interaction of the 53BP1-BRCT2 Domain with gammaH2AX. Baldock RA, Day M, Wilkinson OJ, Cloney R, Jeggo PA, Oliver AW, Watts FZ, Pearl LH; Cell Rep. 2015;13:2081-2089. PMID:26628370