SMRT / NCoR2 (Nuclear receptor corepressor 2, CTG repeat protein 26, SMAP270, Silencing mediator of retinoic acid and thyroid hormone receptor, Thyroid and retinoic-acid-receptor-associated corepressor, TRAC) is a transcriptional corepressor for nuclear receptors. SMRT / NCoR2 has been shown to play a role in regulating immune response, mediating DNA repair, and in neuronal differentiation and cardiac development. SMRT / NCoR2 is part of a large corepressor complex that contains SIN3A/B and histone deacetylases HDAC1 and HDAC2.