Von-Willebrand factor A (vWA) domain found in BRISC and BRCA1-A complex member 1
BRISC and BRCA1 A complex member 1 (BABAM1) is also known as Mediator of RAP80 interactions and targeting subunit of 40 kDa (MERIT40), New component of the BRCA1-A complex (NBA1), HSPC142, or C19orf620. It is a core component of the BRCA1-A and BRISC complexes that function in DNA double-strand break repair and immune signaling, and contain the lysine-63 linkage-specific BRCC36 subunit that is functionalized by scaffold subunits Abraxas and ABRO1, respectively. BABAM1 interacts with Rap80, BRCC36, BRCC45, and Abraxas to form the BRCA1-A complex, a lysine-63-Ub specific deubiquitinating enzyme (DUB) which specifically recognizes lysine-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). BRISC is a DUB complex containing three other subunits, BRCC36, ABRO1 and BRCC45. It specifically hydrolyzes lysine-63 polyubiquitin chains, and is involved in multiple biological processes, including IFN-mediated antiviral immune regulation and inflammatory reaction. BABAM1 likely serves as a scaffold protein by integrating other components to form a functional complex. Furthermore, BABAM1 has been shown to play a critical role in BRISC-mediated regulation of Tankyrase1 (TNKS1) function during spindle assembly; it directly binds to the ankyrin repeat cluster V (ARC-V) domain of TNKS1 via its RXXPEG motif. BABAM1 contains a Von-Willebrand factor A (vWA) domain that is distantly related to classical vWA domains.
Jiyao W et al.(2023). "The conserved domain database in 2023.",