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A role for the mitochondrial deacetylase Sirt3 in regulating energy homeostasis.

Here, we demonstrate a role for the mitochondrial NAD-dependent deacetylase Sirt3 in the maintenance of basal ATP levels and as a regulator of mitochondrial electron transport. We note that Sirt3(-/-) mouse embryonic fibroblasts have a reduction in basal ATP levels. Reconstitution with wild-type but not a deacetylase-deficient form of Sirt3 restored ATP levels in these cells. Furthermore in wild-type mice, the resting level of ATP correlates with organ-specific Sirt3 protein expression. Remarkably, in mice lacking Sirt3, basal levels of ATP in the heart, kidney, and liver were reduced >50%. We further demonstrate that mitochondrial protein acetylation is markedly elevated in Sirt3(-/-) tissues. In addition, in the absence of Sirt3, multiple components of Complex I of the electron transport chain demonstrate increased acetylation. Sirt3 can also physically interact with at least one of the known subunits of Complex I, the 39-kDa protein NDUFA9. Functional studies demonstrate that mitochondria from Sirt3(-/-) animals display a selective inhibition of Complex I activity. Furthermore, incubation of exogenous Sirt3 with mitochondria can augment Complex I activity. These results implicate protein acetylation as an important regulator of Complex I activity and demonstrate that Sirt3 functions in vivo to regulate and maintain basal ATP levels.

Pubmed ID: 18794531


  • Ahn BH
  • Kim HS
  • Song S
  • Lee IH
  • Liu J
  • Vassilopoulos A
  • Deng CX
  • Finkel T


Proceedings of the National Academy of Sciences of the United States of America

Publication Data

September 23, 2008

Associated Grants

  • Agency: Intramural NIH HHS, Id:

Mesh Terms

  • Acetylation
  • Adenosine Triphosphate
  • Animals
  • Cells, Cultured
  • Electron Transport Complex I
  • Energy Metabolism
  • Female
  • Fibroblasts
  • HeLa Cells
  • Homeostasis
  • Humans
  • Male
  • Mice
  • Mitochondria
  • Mitochondrial Proteins
  • Sirtuin 3
  • Sirtuins