Mediates transcriptional repression by certain nuclear receptors. Part of a complex which promotes histone deacetylation and the formation of repressive chromatin structures which may impede the access of basal transcription factors. Participates in the transcriptional repressor activity produced by BCL6. Recruited by ZBTB7A to the androgen response elements/ARE on target genes, negatively regulates androgen receptor signaling and androgen-induced cell proliferation (By similarity). Mediates the NR1D1-dependent repression and circadian regulation of TSHB expression (PubMed:24794873). The NCOR1-HDAC3 complex regulates the circadian expression of the core clock gene ARTNL/BMAL1 and the genes involved in lipid metabolism in the liver (PubMed:19037247). Forms a large corepressor complex that contains SIN3A/B and histone deacetylases HDAC1 and HDAC2. This complex associates with the thyroid receptor (TR) and the retinoid acid receptor (RAR) in the absence of ligand. Interacts directly with RARA; the interaction is facilitated with RARA trimethylation. Component of the N-Cor repressor complex, at least composed of CBFA2T3, HEXIM1, NCOR1, NCOR2, HDAC3, TBL1X, TBL1XR1, CORO2A and GPS2. Interacts with ZBTB33; the interaction serves to recruit the N-CoR complex to promoter regions containing methylated CpG dinucleotides. Interacts with TRIM28 and KDM3A. Interacts (via the RD1 domain) with BAZ1A (via its N-terminal); the interaction corepresses a number of NCOR1-regulated genes. Interacts with BCL6, C1D, DACH1, HEXIM1, HDAC7, RORA, RORC, SAP30, SIAH2, SIN3A and SIN3B (PubMed:10984530). May interact with DEAF1. Interacts with RXRA. Interacts with SETD5 (PubMed:27864380). Interacts with VDR (By similarity). Interacts with ZBTB7A (By similarity). Interacts with AR (By similarity). Interacts with HDAC3 (PubMed:19037247). Ubiquitous. The N-terminal region contains three independent domains that are capable of mediating transcriptional repression (RD1, RD2 and RD3). The C-terminal region contains two separate nuclear receptor-interacting domains (ID1 and ID2), each of which contains a conserved sequence referred to as the CORNR box. This motif is necessary and sufficient for binding to unligated nuclear hormone receptors, while sequences flanking the CORNR box determine the precise nuclear hormone receptor specificity. Ubiquitinated; mediated by SIAH2 and leading to its subsequent proteasomal degradation. Belongs to the N-CoR nuclear receptor corepressors family.