During interphase, required for microtubule organizing and anchoring activities. During mitosis, required for the organization and stabilization of the spindle pole (PubMed:28394342). May promote cell cycle arrest by enhancing the inhibition of CDK2 activity by CDKN1A. May be required for repair of DNA damage by homologous recombination in conjunction with BRCA2. May not be involved in non-homologous end joining (NHEJ) (By similarity). Interacts with BRCA2, CDKN1A and MTDH/LYRIC. Interacts with DCTN1/p150-glued and ACTR1A/ARP1. Interacts with alpha-, beta- and gamma-tubulins. Interacts with TENT5C; the interaction has no effect on TENT5C poly(A) polymerase function (By similarity). Colocalizes with BRCA2 in discrete nuclear foci (By similarity). In interphase, preferential localizes to the mother centriole (PubMed:28394342). Recruited to the spindle pole matrix and centrosome by microtubules and dynein/dynactin activity (By similarity). Belongs to the BCP1 family.