HDAC

HDAC or Histone Deacetylases are a class of enzymes that remove acetyl groups from an epsilon-N-acetyl lysine amino acid on a histone, allowing the histones to wrap the DNA more tightly. This is important because DNA is wrapped around histones, and DNA expression is regulated by acetylation and de-acetylation. Its action is opposite to that of histone acetyltransferase.

Types of HDACs

HDAC proteins are grouped into four classes based on function and DNA sequence similarity. These are:

• Class I of HDACs (HDACs 1, 2, 3, and 8)
• Class II of HDACs (HDACs 4, 5, 6, 7, 9, and 10)
• Class III of HDACs are a family of proteins called the sirtuins
• Class IV of HDACs (HDAC 11)

Function

HDACs, along with histone acetyltransferase (HATs), control the homeostasis of lysine acetylation. A balance between HATs and HDACs allows for the regulation of gene expression and, consequently, protein synthesis. This balance can be disrupted in many diseases, such as cancer, and HDAC inhibitors can be used to correct the balance.

HDAC Inhibitors

HDAC inhibitors (HDIs) have a long history of use in psychiatry and neurology as mood stabilizers and anti-epileptics, for example, valproic acid. More recently they are being investigated as possible treatments for cancers, parasitic and inflammatory diseases.

See Also

• Histone acetyltransferase
• Histone
• Enzyme
• DNA
• Cancer

HDAC Resources
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