Histone deacetylase (HDAC), class I, IIa, IIb, and IV (HDAC (for the family); individual isoforms abbreviated as HDAC1, HDAC2, ..., HDAC11, corresponding to specific genes)

Histone deacetylases (HDACs) are a family of enzymes—divided into multiple classes (I, IIa, IIb, IV) based on sequence homology and domain organization—that mediate the removal of acetyl groups from lysine residues on histone and non-histone proteins, leading to chromatin compaction and transcriptional repression. These enzymes are central regulators of gene expression by modulating chromatin structure and altering the interaction of histones and DNA. Beyond histone deacetylation, HDACs also target many non-histone proteins involved in processes such as cell cycle progression, apoptosis, and signal transduction. Dysregulation or aberrant function of HDACs is linked to several diseases, including cancer, neurodegeneration, and inflammatory conditions. Inhibitors of HDAC activity have been developed as therapeutics for various malignancies, exploiting their ability to re-activate silenced genes and trigger tumor cell death.

Other names

HDACsHistone deacetylase familyClass I HDACs: HDAC1, HDAC2, HDAC3, HDAC8Class IIa HDACs: HDAC4, HDAC5, HDAC7, HDAC9Class IIb HDACs: HDAC6, HDAC10Class IV HDAC: HDAC11

Inhibition of HDAC activity, leading to hyperacetylation of histones and non-histone proteins; Chromatin relaxation and reactivation of silenced genes; Induction of cell cycle arrest and apoptosis