The Arabidopsis Class II Sirtuin Is a Lysine Deacetylase and Interacts with Mitochondrial Energy Metabolism

• DOI: 10.1104/pp.113.232496
• Publication Date: 2014-01-15T06:20:41Z
• Authors: Ann-Christine König; Markus Hartl; Phuong Anh Pham; Miriam Laxa; Paul J. Boersema; Anne Orwat; Ievgeniia Kalitve...; Magdalena Plöchinger; Hans-Peter Braun; Dario Leister; Matthias Mann; Andreas Wachter; Alisdair R. Fernie; Iris Finkemeier
• Keywords: RNA splicing; mitochondrial protein; Arabidopsis; protein binding; Substrate Specificity; Gene Knockout Techniques; Adenosine Triphosphate; Dewey Decimal Classification::500 | Naturwissenschaften::580 | Pflanzen (Botanik); cell respiration; energy metabolism; mitochondrion; Sirtuins; genetics; Carbon Isotopes; 0303 health sciences; messenger RNA; adenosine diphosphate; article; Acetylation; Mitochondria; Adenosine Diphosphate; sirtuin; Protein Transport; Phenotype; gene inactivation; Mitochondrial Membranes; protein transport; nonsense mediated mRNA decay; Protein Binding; SRT2 protein, Arabidopsis; phenotype; enzymology; RNA Splicing; adenosine triphosphate; Cell Respiration; Molecular Sequence Data; chemistry; Histone Deacetylases; Mitochondrial Proteins; 03 medical and health sciences; mitochondrial membrane; Amino Acid Sequence; RNA, Messenger; enzyme specificity; nicotinamide adenine dinucleotide; acetylation; lysine; Arabidopsis protein; Arabidopsis Proteins; carbon; Lysine; NAD; amino acid sequence; Nonsense Mediated mRNA Decay; histone deacetylase; molecular genetics; Energy Metabolism; metabolism

Abstract The posttranslational regulation of proteins by lysine (Lys) acetylation has recently emerged to occur not only on histones, but also on organellar proteins in plants and animals. In particular, the catalytic activities of metabolic enzymes have been shown to be regulated by Lys acetylation. The Arabidopsis (Arabidopsis thaliana) genome encodes two predicted sirtuin-type Lys deacetylases, of which only Silent Information Regulator2 homolog (SRT2) contains a predicted presequence for mitochondrial targeting. Here, we have investigated the function of SRT2 in Arabidopsis. We demonstrate that SRT2 functions as a Lys deacetylase in vitro and in vivo. We show that SRT2 resides predominantly at the inner mitochondrial membrane and interacts with a small number of protein complexes mainly involved in energy metabolism and metabolite transport. Several of these protein complexes, such as the ATP synthase and the ATP/ADP carriers, show an increase in Lys acetylation in srt2 loss-of-function mutants. The srt2 plants display no growth phenotype but rather a metabolic phenotype with altered levels in sugars, amino acids, and ADP contents. Furthermore, coupling of respiration to ATP synthesis is decreased in these lines, while the ADP uptake into mitochondria is significantly increased. Our results indicate that SRT2 is important in fine-tuning mitochondrial energy metabolism.