Component of a RCOR/GFI/KDM1A/HDAC complex. Interacts directly with GFI1 and GFI1B. Interacts with SNW1, HDAC7, PRDM6, SAP30, SETDB1 and SUV39H1. Interacts with the H2AFY (via the non-histone region) (By similarity). Part of the core histone deacetylase (HDAC) complex composed of HDAC1, HDAC2, RBBP4 and RBBP7. The core complex associates with MTA2, MBD3, MTA1L1, CHD3 and CHD4 to form the nucleosome remodeling and histone deacetylation (NuRD) complex, or with SIN3, SAP18 and SAP30 to form the SIN3 HDAC complex. Component of a BHC histone deacetylase complex that contains HDAC1, HDAC2, HMG20B, KDM1A, RCOR1 and PHF21A. The BHC complex may also contain ZMYM2, ZNF217, ZMYM3, GSE1 and GTF2I. Part of a complex containing the core histones H2A, H2B, H3 and H4, DEK and unphosphorylated DAXX. Part of a complex containing ATR and CHD4. Forms a heterologous complex at least with YY1. Interacts with ATR, CBFA2T3, DNMT1, MINT, HDAC10, HCFC1, NRIP1, KDM4A and PELP1. Component of a mSin3A corepressor complex that contains SIN3A, SAP130, SUDS3, ARID4B, HDAC1 and HDAC2. Interacts with CHFR and SAP30L. Interacts (CK2 phosphorylated form) with SP3. Interacts with TSHZ3 (via its N-terminus). Interacts with APEX1; the interaction is not dependent on the acetylated status of APEX1. Part of a complex composed of TRIM28, HDAC1, HDAC2 and EHMT2.