Component of the BRISC complex, a multiprotein complex that specifically cleaves 'Lys-63'-linked polyubiquitin, leaving the last ubiquitin chain attached to its substrates. May act as a central scaffold protein that assembles the various components of the BRISC complex and retains them in the cytoplasm (By similarity). Plays a role in regulating the onset of apoptosis via its role in modulating 'Lys-63'-linked ubiquitination of target proteins (By similarity). Required for normal mitotic spindle assembly and microtubule attachment to kinetochores via its role in deubiquitinating numa1 (By similarity). Component of the BRISC complex, at least composed of ABRAXAS2 and the catalytic subunit brcc3/brcc36. Interacts with brcc3/brcc36; the interaction is direct. The BRISC complex binds monoubiquitin and polyubiquitin. A minor proportion is detected in the nucleus. Translocates into the nucleus in response to DNA damage. Directly binds to microtubules and is detected at the minus end of K-fibers. Belongs to the FAM175 family. Abro1 subfamily. Although strongly related to the abraxas1 protein, lacks the C-terminal pSXXF that constitutes a specific recognition motif for the BRCT domain of brca1.