HDAC | Histone deacetylase

Histone deacetylases are a class of enzymes that remove acetyl groups from a ε-N-acetyl lysine amino acid on a histone deacetylating the histones and thus increasing the positive charge of histone tails and encouraging high-affinity binding between the histones and DNA backbone. The increased DNA binding condenses DNA structure, preventing transcription. Action of HDAC is opposite to that of histone acetyltransferase. HDAC proteins are found in three groups, the first two groups belong to the classical HDACs and their activities are inhibited by trichostatin A (TSA) whereas the third group is a family of NAD+-dependent proteins not affected by TSA. The class I HDACs, comprises of HDAC 1, 2 and 8 and are primarily found in the nucleus, whereas HDAC 3 is found both in the nucleus, cytoplasm and also membrane associated whereas the Class II HDACs (HDAC 4, 5, 6, 7 9 and 10) are able to shuttle between the nucleus and the cytoplasm depending on different signals.