SIRT3 Regulates Mitochondrial Protein Acetylation and Intermediary Metabolism

Abstract

The sirtuins are a family of nicotinamide adenine dinucleotide (NAD þ )-dependent protein deacetylases that regulate cell survival, metabolism, and longevity. Humans have seven sirtuins (SIRT1-SIRT7) with distinct subcellular locations and functions. SIRT3 is localized to the mitochondrial matrix and its expression is selectively activated during fasting and calorie restriction. Activated SIRT3 deacetylates several key metabolic enzymes-acetyl-coenzyme A synthetase, long-chain acylcoenzyme A (acyl-CoA) dehydrogenase (LCAD), and 3-hydroxy-3-methylglutaryl CoA synthase 2-and enhances their enzymatic activity. Disruption of SIRT3 activity in mice, either by genetic ablation or during high-fat feeding, is associated with accelerated development of metabolic abnormalities similar to the metabolic syndrome in humans. SIRT3 is therefore emerging as a metabolic sensor that responds to change in the energy status of the cell and modulates the activity of key metabolic enzymes via protein deacetylation.

Identification of Lysine Succinylation Substrates and the Succinylation Regulatory Enzyme CobB in Escherichia coli

“…Cells were harvested when A 600 reached 0.8. The cell pellets were washed twice with M9 medium and subsequently transferred into either M9 medium containing light lysine ( 12 C 6 14 N 2 Lys) and arginine ( 12 C 6 14 N 4 Arg) and no glucose or M9 medium containing heavy lysine ( 13 C 6 15 N 2 Lys) and arginine ( 13 C 6 15 N 4 Arg) and 0.8% glucose. The cells were incubated at 37°C on a rotary shaker (225 rpm) for about 5 h and harvested during the exponential phase with a comparable OD value.…”

“…The cells were resuspended in ice-cold NETN buffer (100 mM NaCl, 20 mM Tris-Cl, pH 8.0, 0.5 mM EDTA, and 0.5% Nonidet P-40) and sonicated for 5 min with cooling at 1-min intervals. Equal amounts of protein lysate from E. coli grown in either heavy ( 13 C 6 15 N 2 Lys and 13 C 6 15 N 4 Arg) media or light ( 12 C 6 14 N 2 Lys and 12 C 6 14 N 4 Arg) media were mixed (40 mg each). The mixture was centrifuged at 100,000g for 10 min.…”

“…Lysine acetylation (Kac) 1 is a dynamic and evolutionarily conserved post-translational modification (PTM) that is known to be involved in the regulation of diverse cellular processes (1)(2)(3)(4)(5)(6)(7)(8)(9). The status of this modification is controlled by two groups of enzymes with opposing enzymatic activities, lysine acetyltransferases that add an acetyl group to the lysine (Lys or K) residue, and histone lysine deacetylases (HDACs) that remove the acetyl group (10 -16).…”

Hallmarks of a new era in mitochondrial biochemistry

“…For acetylation, there is currently only a single wellestablished, mitochondria-localized protein deacetylase, SIRT3, which appears to regulate only a portion of the mitochondrial acetylome (Hirschey et al 2011;Feldman et al 2012;Hebert et al 2013). Even more strikingly, there remains no known mitochondrial acetyltransferase, although recent work from the Sack group (Scott et al 2012) suggests that GCN5-L1 is a key player in what may be a protein acetyltransferase complex.…”

Chromatin landscape and circadian dynamics: Spatial and temporal organization of clock transcription

“…SIRT3 is a key regulator of mitochondrial function, including fatty acid oxidation and intermediary metabolism (112). Some of the SIRT3 targets include rate-limiting enzymes for mitochondrial biochemical processes, and their acetylation levels impact their activity.…”