The S. cerevisiae silent information regulator 2 (Sir2) protein is an NAD+-dependent histone deacetylase (HDACs) that plays a critical role in transcriptional silencing, genome stability, and longevity (1-2). Part of the Sirtuin family (Sir2, Sir3, Sir3), yeast Sir2 is the founding member of Class III HDACs. A human homologue of Sir2 , SIRT1, regulates the activity of the p53 tumor suppressor and inhibits apoptosis (3-4).
