Devoided of intrinsic deacetylase activity, promotes the deacetylation of lysine residues on the N-terminal part of the core histones (H2A, H2B, H3 and H4) by recruiting HDAC1 and HDAC3. Histone deacetylation gives a tag for epigenetic repression and plays an important role in transcriptional regulation, cell cycle progression and developmental events. Represses MEF2-dependent transcription, inhibits skeletal myogenesis and may be involved in heart development. Protects neurons from apoptosis, both by inhibiting JUN phosphorylation by MAPK10 and by repressing JUN transcription via HDAC1 recruitment to JUN promoter. H2O + N(6)-acetyl-L-lysyl-[histone] = acetate + L-lysyl-[histone] Homodimer. Interacts with ETV6 (By similarity). Interacts with MEF2, HDAC1, HDAC3, HDAC4, HDAC5, CTBP1 and MAPK10. The phosphorylated form interacts with 14-3-3. Interacts with FOXP3 in the absence of T-cell stimulation (By similarity). Expressed at high levels in heart, brain and spleen. Expressed in skeletal muscle. At 10.5 dpc, expressed in heart, skeletal muscle and neural lineages. At 11.5d pc, expressed in heart, dorsal root ganglia and neural tube. At 12.5 dpc, expressed in heart, skeletal muscle, dorsal root ganglia, neural tube and retina. Strongly up-regulated in muscle between 14 and 19 dpc as a result of motor innervation. By MEF2 during muscle differentiation. Down-regulated by muscle denervation. Down-regulated by trichostatin A or sodium butyrate, and during neuronal apoptosis (at protein level). Sumoylated. Phosphorylated on Ser-220 and Ser-450; which promotes 14-3-3-binding, impairs interaction with MEF2, and antagonizes antimyogenic activity. Phosphorylated on Ser-240 by DYRK1B; which impairs nuclear accumulation. Phosphorylated by the PKC kinases PKN1 and PKN2, impairing nuclear import. Mice do not present any abnormality at early age but develop cardiac hypertrophy by eight months of age. Belongs to the histone deacetylase family. HD type 2 subfamily.