The SWI/SNF-related, matrix-associated, actin-dependent regulators of chromatin (SMARC), also called BRG1-associated factors (BAFs), have been identified as components of the human SWI/SNF-like chromatin-remodeling protein complexes. SWI/SNF complexes possess ATPase and DNA helicase activity that promotes transcriptional activation of genes normally repressed by chromatin structure. ARID1A/BAF250 is a noncatalytic subunit that is a member of the ARID (AT-rich interactive domain-containing protein) family of DNA binding proteins. ARID1A/BAF250 has been shown to play a role in the tumor suppressor activity of the SWI/SNF complexes. ARID1A/BAF250 is required for differentiation-associated cell cycle arrest.