DNA helicase that possesses intrinsic ATP-dependent nucleosome-remodeling activity and is both required for DNA repair and heterochromatin organization. Promotes DNA end resection of double-strand breaks (DSBs) following DNA damage: probably acts by weakening histone DNA interactions in nucleosomes flanking DSBs. Required for the restoration of heterochromatin organization after replication. Acts at replication sites to facilitate the maintenance of heterochromatin by directing H3 and H4 histones deacetylation, H3 'Lys-9' trimethylation (H3K9me3) and restoration of silencing (By similarity). ATP + H2O = ADP + H(+) + phosphate Binds to DNA preferentially in the vicinity of transcriptional start sites. Interacts with MSH2 and TRIM28. Part of a complex composed of TRIM28, HDAC1, HDAC2 and EHMT2. Interacts with PCNA (By similarity). Colocalizes with PCNA at replication forks during S phase. Recruited to double-strand breaks (DSBs) sites of DNA damage (By similarity). Belongs to the SNF2/RAD54 helicase family.