Component of the BRCA1-A complex, a complex that specifically recognizes 'Lys-63'-linked ubiquitinated histones H2A and H2AX at DNA lesions sites, leading to target the BRCA1-BARD1 heterodimer to sites of DNA damage at double-strand breaks (DSBs). The BRCA1-A complex also possesses deubiquitinase activity that specifically removes 'Lys-63'-linked ubiquitin on histones H2A and H2AX. In the BRCA1-A complex, it is required for the complex integrity and its localization at DSBs. Probably also plays a role as a component of the BRISC complex, a multiprotein complex that specifically cleaves 'Lys-63'-linked ubiquitin. In these 2 complexes, it is probably required to maintain the stability of BRE/BRCC45 and help the 'Lys-63'-linked deubiquitinase activity mediated by BRCC3/BRCC36. component.
Synonyms: BRCA1-A complex subunit MERIT40, Mediator of RAP80 interactions and targeting subunit of 40 kDa, New component of the BRCA1-A complex, HSPC142, NBA1, C19orf62, MERIT40