Looking for putative functions of the Leishmania cytosolic SIR2 deacetylase.

During the past few years, the silent information regulator SIR2 protein family has attracted great interest due to its implication in an organism's life span extension. They bear diverse subcellular localization and play a role in transcriptional silencing and DNA repair. The biochemical reaction catalysed by these enzymes (nicotinamide adenine dinucleotide-dependant deacetylase/adenosine diphosphate-ribosyl transferase) is supposed to be linked to metabolism. Members of this protein family were described in parasitic organisms, but little information is available on potential functions of such enzymes in these organisms. In this article, we review recent information on structure and peculiar functions of SIR2s in eukaryotes, with emphasis on parasitic protozoa, particularly the Trypanosomatidae. Through the enzyme localization and the diverse substrates and by-products of the enzymatic reactions, we approach the potential pathways in which the Leishmania cytosolic SIR2 protein can be involved.