DNA-binding protein that accumulates at DNA double-strand breaks (DSBs) following DNA damage and promotes DNA resection and homologous recombination (PubMed:29042561). Serves as a sensor of DNA damage: binds DNA with a strong preference for DNA substrates that mimic structures generated at stalled replication forks, and anchors RBBP8/CtIP to DSB sites to promote DNA end resection and ensuing homologous recombination repair (PubMed:29042561). Inhibits non-homologous end joining (NHEJ) (PubMed:29042561). Required for the dynamic movement of AURKA at the centrosomes and spindle apparatus during the cell cycle (PubMed:20596670). Interacts (via C-terminus) with AURKA (via C-terminus) (PubMed:20596670). Interacts (via N-terminus) with NIN; this interaction blocks NIN phosphorylation by both AURKA and GSK3B (PubMed:20596670). Identified in a complex with NIN and AURKA (PubMed:20596670). Interacts with RBBP8/CtIP (PubMed:29042561). Accumulates at sites of DNA damage by binding to DNA substrates that mimick structures generated at stalled replication forks (PubMed:29042561). Localizes to the centrosome in interphase and to the spindle pole in metaphase (PubMed:20596670). Expressed in heart, skeletal muscles, placenta and testis. Overexpressed in brain tumors. Belongs to the AUNIP family.