Family With Sequence Similarity 175, Member A (FAM175A)

The 409-amino acid ABRA1 protein contains an ABR domain and a coiled-coil domain followed by the phospho-ser-X-X-phe motif at the C-terminal end of the protein. ABRA1 shares 39% amino acid identity in the N-terminal region with ABRO1, which also contains an ABR domain and a coiled-coil domain.Abraxas binds BRCA1 to the mutual exclusion of BACH1 and CTIP, forming a third type of BRCA1 complex. Abraxas recruits the ubiquitin-interacting motif (UIM)-containing protein RAP80 to BRCA1. Both Abraxas and RAP80 were required for DNA damage resistance, G2/M checkpoint control, and DNA repair. RAP80 was required for optimal accumulation of BRCA1 on damaged DNA (foci) in response to ionizing radiation, and the UIM domains alone were capable of foci formation.