Regulation of succinate dehydrogenase activity by SIRT3 in mammalian mitochondria.
A member of the sirtuin family of NAD(+)-dependent deacetylases, SIRT3, is identified as one of the major mitochondrial deacetylases located in mammalian mitochondria responsible for deacetylation of several metabolic enzymes and components of oxidative phosphorylation. Regulation of protein deacetylation by SIRT3 is important for mitochondrial metabolism, cell survival, and longevity. In this study, we identified one of the Complex II subunits, succinate dehydrogenase flavoprotein (SdhA) subunit, as a novel SIRT3 substrate in SIRT3 knockout mice. Several acetylated Lys residues were mapped by tandem mass spectrometry, and we determined the role of acetylation in Complex II activity in SIRT3 knockout mice. In agreement with SIRT3-dependent activation of Complex I, we observed that deacetylation of the SdhA subunit increased the Complex II activity in wild-type mice. In addition, we treated K562 cell lines with nicotinamide and kaempferol to inhibit deacetylase activity of SIRT3 and stimulate SIRT3 expression, respectively. Stimulation of SIRT3 expression decreased the level of acetylation of the SdhA subunit and increased Complex II activity in kaempherol-treated cells compared to control and nicotinamide-treated cells. Evaluation of acetylated residues in the SdhA crystal structure from porcine and chicken suggests that acetylation of the hydrophilic surface of SdhA may control the entry of the substrate into the active site of the protein and regulate the enzyme activity. Our findings constitute the first evidence of the regulation of Complex II activity by the reversible acetylation of the SdhA subunit as a novel substrate of the NAD(+)-dependent deacetylase, SIRT3.
Cimen
Huseyin
H
Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Han
Min-Joon
MJ
Yang
Yongjie
Y
Tong
Qiang
Q
Koc
Hasan
H
Koc
Emine C
EC
D000107:Acetylation; D000818:Animals; D002460:Cell Line; D017931:DNA Primers; D006706:Homeostasis; D051379:Mice; D018345:Mice, Knockout; D008928:Mitochondria / Q000201:enzymology*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry; D016133:Polymerase Chain Reaction; D011487:Protein Conformation; D011499:Protein Processing, Post-Translational; D056566:Sirtuin 3 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013385:Succinate Dehydrogenase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D017931:DNA Primers; D010446:Peptide Fragments; C525046:Sirt3 protein, mouse; D013385:Succinate Dehydrogenase; D056566:Sirtuin 3