NAD-dependent protein deacetylase sirtuin family (SIRT) (SIRT)

The sirtuin family consists of seven highly conserved NAD+-dependent enzymes (SIRT1–SIRT7) that function as critical metabolic sensors and regulators of cellular health (Imai & Guarente, 2014, PMID: 24766830). By removing acetyl groups from various proteins, sirtuins coordinate the cellular response to nutrient availability and environmental stress, influencing processes such as mitochondrial function, DNA repair, and longevity (Bonkowski & Sinclair, 2016, PMID: 27882448). SIRT1, SIRT6, and SIRT7 are primarily nuclear, while SIRT3, SIRT4, and SIRT5 are mitochondrial, and SIRT2 is predominantly cytoplasmic (UniProt Consortium, 2023). These enzymes link the metabolic state of the cell, specifically the NAD+/NADH ratio, to the epigenetic and post-translational regulation of key transcription factors (Imai & Guarente, 2014, PMID: 24766830). Their involvement in age-related pathologies makes them attractive targets for drug development, with SIRT1 activators being explored for metabolic and neurodegenerative diseases (Grabowska et al., 2017, PMID: 28410500). Conversely, certain sirtuin inhibitors are being investigated for their potential anti-cancer applications due to the role of sirtuins in promoting survival in stressed tumor cells (Grabowska et al., 2017, PMID: 28410500). The therapeutic challenge lies in achieving isoform specificity and understanding the complex, often tissue-specific, roles these enzymes play in human physiology. Overall, the sirtuin family represents a pivotal bridge between metabolism and cellular maintenance, offering a unique pathway for therapeutic intervention in chronic diseases.

Other names

Silent information regulatorSIRT familyClass III histone deacetylasesNAD-dependent deacetylasesSIR2-like proteins

Sirtuins catalyze the NAD+-dependent deacetylation of lysine residues on histone and non-histone protein substrates, producing nicotinamide and O-acetyl-ADP-ribose as byproducts (UniProt Consortium, 2023). This activity modulates the function of key regulatory proteins involved in metabolism, DNA repair, and cell survival, such as p53, PGC-1alpha, and NF-kappaB (Imai & Guarente, 2014, PMID: 24766830). Some members also exhibit additional enzymatic activities, including ADP-ribosyltransferase, desuccinylase, and demalonylase functions, which further expand their regulatory influence over cellular pathways (UniProt Consortium, 2023).