The sirtuins represent a distinct class of trichostatin A-insensitive lysyl-deacetylases (class III HDACs) and have been shown to catalyze a reaction that couples lysine deacetylation to the formation of nicotinamide and O-acetyl-ADP-ribose from NAD+ and the abstracted acetyl group. This SIRT family of genes is highly conserved from prokaryotes to eukaryotes and is involved in diverse processes including transcriptional regulation, cell cycle progression, DNA damage repair and aging. SIRT2, a human homolog of the yeast SIR2 (silent information regulator­2), functions as transcriptional silencing mediator at mating­type loci, telomeres and ribosomal gene clusters. SIRT2 expression increases dramatically during mitosis and is multiply phosphorylated at the G (2)/M transition of the cell cycle. SIRT2 is part of a phosphorylation cascade where it is phosphorylated late in G (2), during M, and into the period of cytokinesis. Inhibition of SIRT2 is reported to rescue alpha­synuclein toxicity and modify inclusion morphology in a cellular model of Parkinson's disease.