簡要描述：HDAC9 (Histone Deacetylase 9) catalyses the deacetylation of lysine residues on the core histones (H2A, H2B, H3 and H4). It belongs to the Class IIa HDAC family, which are key regulators of several developmental and differentiation processes such as cardiac growth. HDAC9 represses MEF2 (myocyte enhancer factor 2)-dependent transcription, playing an important role in cardiac hypertrophy.

The HDAC9 isoform MITR/HDRP lacks active site residues and is therefore catalytically inactive. It rep