forkhead associated (FHA) domain found in mediator of DNA damage checkpoint protein 1 (MDC1) and similar proteins
MDC1, also called nuclear factor with BRCT domains 1 (NFBD1), is a nuclear chromatin-associated protein that is required for checkpoint mediated cell cycle arrest in response to DNA damage within both the S and G2/M phases of the cell cycle. It directly binds phosphorylated histone H2AX to regulate cellular responses to DNA double-strand breaks. MDC1 contains a forkhead-associated (FHA) domain and two BRCT domains, as well as an internal 41-amino acid repeat sequence. The FHA domain is a small phosphopeptide recognition module.