NAD-dependent protein deacetylase involved in various processes including telomere maintenance and gene expression, and consequently has roles in genomic stability, cell senescence and apoptosis (PubMed:18337721, PubMed:19135889, PubMed:19625767, PubMed:21362626). Has very weak deacetylase activity and can bind NAD(+) in the absence of acetylated substrate (PubMed:21362626). Has deacetylase activity towards histone H3K9Ac and H3K56Ac (PubMed:19625767, PubMed:21362626). Modulates acetylation of histone H3 in telomeric chromatin during the S-phase of the cell cycle (PubMed:19625767). May also be required for the association of WRN with telomeres during S-phase and for normal telomere maintenance (PubMed:18337721). Deacetylates histone H3K9Ac at NF-kappa-B target promoters and may down-regulate the expression of a subset of NF-kappa-B target genes (PubMed:21362626). Deacetylation of nucleosomes interferes with RELA binding to target DNA (PubMed:19135889). Acts as a corepressor of the transcription factor Hif1a to control the expression of multiple glycolytic genes to regulate glucose homeostasis (By similarity). Required for normal IGF1 serum levels and normal glucose homeostasis (By similarity). Regulates the production of TNF protein (By similarity). Has a role in the regulation of life span (By similarity).