Transcriptional repressor that binds to the promoter region of target genes. Plays a role in the regulation of the cell cycle and of the Wnt pathway. Binds preferentially to the sequence 5'-TTCATTCATTCA-3'. Binding to the histone H1.0 promoter is enhanced by interaction with RB1. Disrupts the interaction between DNA and TCF4 (By similarity). Binds TCF4 (By similarity). Binds RB1. Binds the second PAH repeat of SIN3A (By similarity). Ubiquitinated by the CTLH E3 ubiquitin-protein ligase complex, leading to subsequent proteasomal degradation.