In addition to being a key factor for DNA repair, the BRCA1 (breast cancer 1)–BARD1 (BRCA1-associated RING domain 1) heterodimer affects other cellular processes, including centrosome regulation. Using mass spectrometry, Matsuzawa et al. identify OLA1 (Obg-like ATPase 1) as a novel binding partner of BARD1 and then show that its loss results in amplification of centrosomes. It binds directly to BARD1, BRCA1 and γ-tubulin, and resides at both centrosomes and spindle poles. Notably, the authors show that a mutation of OLA1 found in the breast cancer cell line E168Q cannot restore control of centrosome number on OLA1 knockdown. Both this mutant and a familial BRCA1 cancer mutant show loss of the OLA1 interactions with BRCA1 and BARD1, suggesting that this is physiologically important.