A nuclear co-repressor protein that shows specificity for RETINOIC ACID RECEPTORS and THYROID HORMONE RECEPTORS. The dissociation of this co-repressor from nuclear receptors is generally ligand-dependent, but can also occur by way of its phosphorylation by members of the map kinase signaling system. The protein contains two nuclear receptor interaction domains and four repressor domains and is closely-related in structure to nuclear receptor co-repressor 1.