Essential component of the BHC complex, a corepressor complex that represses transcription of neuron-specific genes in non-neuronal cells. The BHC complex is recruited at RE1/NRSE sites by REST and acts by deacetylating and demethylating specific sites on histones, thereby acting as a chromatin modifier. In the BHC complex, it serves as a molecular beacon for the recruitment of molecular machinery, including MeCP2 and SUV39H1, that imposes silencing across a chromosomal interval. Plays a central role in demethylation of Lys-4 of histone H3 by promoting demethylase activity of KDM1A on core histones and nucleosomal substrates. It also protects KDM1A from the proteasome. Component of a RCOR/GFI/KDM1A/HDAC complex that suppresses, via histone deacetylase (HDAC) recruitment, a number of genes implicated in multilineage blood cell development and controls hematopoietic differentiation. Component of a BHC histone deacetylase complex that contains HDAC1, HDAC2, HMG20B/BRAF35, KDM1A, RCOR1/CoREST and PHF21A/BHC80. The BHC complex may also contain ZMYM2, ZNF217, ZMYM3, GSE1 and GTF2I. Interacts with REST. Interacts with the SMARCE1/BAF57, suggesting that the BHC complex may recruit the ATP-dependent chromatin-remodeling SWI-SNF complex (By similarity). Interacts directly with GFI1 AND GFI1B in a RCOR/GFI/KDM1A/HDAC complex. Interacts with INMS1. Expressed in the external germinal layer (EGL) and internal granular layer (IGL) of the cerebellum and in Purkinje cells (at protein level). At embryonic day 8.5, it is highly expressed in the head mesenchyme, but neither in the somites nor in the presomitic mesoderm. By day 11.5 it is expressed fairly ubiquitously throughout the embryo. Down-regulated by the transcriptional repressor ZEB1 during NEUROD2-induced neurogenesis. The SANT domains may bridge the nucleosomal substrates and the demethylase KDM1A. Belongs to the CoREST family. Truncated N-terminus.