Table 1.

Summary of the mammalian sirtuins

Sirtuin	Location	Interactions	Biology	Null phenotype
SIRT1	Nucleus	FOXO, PGC-1α NF-κB, Ku70, etc.	Metabolism, stress	Developmental defects, lethal in some backgrounds
SIRT2	Cytosol	Tubulin, H4, FOXO	Cell cycle	Developmentally normal
SIRT3	Mitochondria	AceCS2, GDH complex I	Thermogenesis, ATP production	Developmentally normal
SIRT4	Mitochondria	GDH, IDE, ANT	Insulin secretion	Developmentally normal
SIRT5	Mitochondria	CPS1	Urea cycle	Developmentally normal
SIRT6	Nucleus	Histone H3, NF-κB	Base excision repair,   metabolism	Premature aging
SIRT7	Nucleolus	Pol I	rDNA transcription	Smaller size, short lifespan, heart defects

Abbreviations: AceCS2, acetyl-CoA-synthetase 2; ANT, adenide nucleotide translocator; CPS1, carbamoyl phosphate synthetase 1; FOXO, forkhead box, subgroup O; GDH, glutamate dehydrogenase; IDE, insulin degrading enzyme; NF-κB, nuclear factor kappa B; PGC-1α, peroxisome proliferator-activated receptor gamma coactivator 1 alpha; Pol I, DNA polymerase I; rDNA, recombinant DNA.