DNA helicase that acts as a chromatin remodeling factor and regulates transcription. Acts as a transcription repressor by remodeling chromatin structure and recruiting histone H1 to target genes. Suppresses p53/tp53-mediated apoptosis by recruiting histone H1 and preventing p53/tp53 transactivation activity. Acts as a negative regulator of Wnt signaling pathway by regulating beta-catenin (ctnnb1) activity. Negatively regulates ctnnb1-targeted gene expression by being recruited specifically to the promoter regions of several ctnnb1 responsive genes. May also act as a transcription activator by participating in efficient U6 RNA polymerase III transcription. ATP + H2O = ADP + H(+) + phosphate Component of some MLL1/MLL complex. Belongs to the SNF2/RAD54 helicase family. CHD8 subfamily.