BAF250b Background Information
BAF250b (BRG1-associated factor 250b), also known as ARID1B (AT-rich interactive domain-containing protein 1B) or hOsa2 (Osa homolog 2), is a 2,236 amino acid protein that contains 1 ARID domain. BAF250b has a BC box motif, associates with elongin C in a BC box-dependent manner, and, together with cullin 2 and Roc1, assembles into an E3 ubiquitin ligase that participates in ubiquitination of histone H2B. Smad2 and Smad3 interact with BRG1, BAF250b, BAF170 and BAF155, which are core components of the SWI/SNF chromatin-remodeling complex. Localizing to nucleus, BAF250b is widely expressed with high levels in heart, skeletal muscle and kidney. The BAF250b gene is conserved in chimpanzee, dog, mouse, rat, chicken, zebrafish, mosquito and C.elegans, and maps to human chromosome 6q25.3. BAF250b exists as three alternatively spiced isoforms.
