Histone deacetylases (HDACs) are enzymes that remove acetyl groups from histone and non-histone proteins. To date, 18 different mammalian HDACs have been identified and divided into four classes: the Class I Rpd3-like proteins (HDAC1, HDAC2, HDAC3, and HDAC8); the Class II Hda1-like proteins (HDAC4, HDAC5, HDAC6, HDAC7, HDAC9, and...