ARID1A (AT-Rich Interaction Domain 1A) encodes a member of the SWI/SNF family whose members have helicase and ATPase activities and are thought to regulate transcription of specific genes by altering chromatin structure. The encoded protein is part of the large ATP-dependent chromatin remodeling complex SNF/SWI, which is required for transcriptional activation of genes normally repressed by chromatin. It has at least two conserved domains that may be important for its function.
Genes encoding subunits of SWI/SNF chromatin remodeling complexes are mutated in 20% of all human cancers. ARID1A is the SWI/SNF subunit gene that is most frequently mutated, with varying frequencies in all molecular and histological subtypes of cancer. When ARID1A is absent, defects in the control of enhancer activity impair developmental programs and lead to widespread dysregulation of gene expression, which in turn promotes tumor formation. The role of ARID1A has also been described in other processes associated with tumor suppression, including cell cycle/DNA damage checkpoint control, regulation of P53 targets, and telomerase activation (Mathur R 2018).