SIRT1 Functionally Interacts with the Metabolic Regulator and Transcriptional Coactivator PGC-1α

Abstract

In lower organisms, increased expression of the NADdependent deacetylase Sir2 augments lifespan. The mechanism through which this life extension is mediated remains incompletely understood. Here we have examined the cellular effects of overexpression of SIRT1, the closest mammalian ortholog of Sir2. In PC12 cells, increased expression of the NAD-dependent deacetylase SIRT1 reduces cellular oxygen consumption by ϳ25%. We further demonstrate that SIRT1 expression can alter the transcriptional activity of the mitochondrial biogenesis coactivator PGC-1␣. In addition, SIRT1 and PGC-1␣ directly interact and can be co-immunoprecipitated as a molecular complex. A single amino acid mutation in the putative ADP-ribosyltransferase domain of SIRT1 inhibits the interaction of SIRT1 with PGC-1␣ but does not effect the interaction of SIRT1 with either p53 or Foxo3a. We further show that PGC-1␣ is acetylated in vivo. This acetylation is augmented by treatment with the SIRT1 inhibitor nicotinamide or by expression of the transcriptional coactivator p300. Finally we demonstrate that SIRT1 catalyzes PGC-1␣ deacetylation both in vitro and in vivo. These results provide a direct link between the sirtuins, a family of proteins linked to lifespan determination and PGC-1␣, a coactivator that regulates cellular metabolism.

Mitochondrial biogenesis is decreased in skeletal muscle of pig fetuses exposed to maternal high-energy diets

“…Recently, SIRT1 has been known to regulate myogenesis and mitochondrial biogenesis in skeletal muscle (Hong et al, 2014). SIRT1 expression level and its deacetylase activity are also modulated by the NAD + / NADH ratio (Nemoto et al, 2005). In the current study, we detected significantly lower SIRT1 mRNA level in HE fetuses, supporting the potential role of SIRT1 as a direct regulator of PGC-1α (Nemoto et al, 2005).…”

“…SIRT1 expression level and its deacetylase activity are also modulated by the NAD + / NADH ratio (Nemoto et al, 2005). In the current study, we detected significantly lower SIRT1 mRNA level in HE fetuses, supporting the potential role of SIRT1 as a direct regulator of PGC-1α (Nemoto et al, 2005). The intracellular NAD + /NADH ratio, a marker of enhanced cellular oxidative capacity, was significantly decreased in HE fetuses, which is consistent with previous reports (Fainberg et al, 2014).…”

Sir2 Protein Deacetylases: Evidence for Chemical Intermediates and Functions of a Conserved Histidine

“…18 O-labelled water was purchased from Cambridge Isotope Laboratories, Inc. (Andover, MA). All other chemicals used were of the highest purity commercially available and were purchased from Sigma (St. Louis, MO), Aldrich (Milwaukee, WI), or Fisher Scientific (Pittsburgh, PA).…”

“…Conserved among all forms of life with five homologs in yeast (ySir2 and HST1−4) and seven in humans (SIRT1−7) (11,12), most sirtuins display NAD + -dependent protein deacetylase activity (13-16). SIRT1 has received the most attention and is reported to deacetylate a growing number of substrates including 18), FOXO proteins † This work was supported by National Institutes of Health grant GM065386 (to J.M.D.) and by National Institutes of Health Biotechnology Training Grant NIH 5 T32 GM08349 (to B.C.S.).…”

“…Synthetic 18 O-labelled acetylated H3 peptide ( 18 O-AcH3), H 2 N-KSTGGK( 18 O-Ac)APRKQ-CONH 2 , was synthesized using standard tBu/Fmoc solid-phase peptide synthesis techniques and HBTU/HOBt coupling conditions (42). The 18 O-label was specifically incorporated at the desired lysine sidechain by using an ivDde protecting group that was orthogonally deprotected with 2% hydrazine in DMF.…”