Binds to the promoters of target genes and functions as repressor. Promotes cell proliferation and antagonizes cell death. Promotes phosphorylation of AKT1 at 'Ser-473'. Component of a histone deacetylase complex that contains HDAC2, KDM1A, CTBP1 and ZNF217. May be a component of a BHC histone deacetylase complex that contains HDAC1, HDAC2, HMG20B/BRAF35, KDM1A, RCOR1/CoREST, PHF21A/BHC80, ZMYM2, ZNF217, ZMYM3, GSE1 and GTF2I. Interacts with CTBP1 and CTBP2. Belongs to the krueppel C2H2-type zinc-finger protein family.