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Sir2 regulated deacetylation and activation of mammalian Acetyl CoA Synthetase 1
Author(s) -
Hallows William Casey,
Denu John M
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a959-c
Subject(s) - acetylation , biochemistry , sirt2 , nad+ kinase , acetyl coa , sirt3 , enzyme , biology , lysine , sirtuin , acetyltransferase , peptide sequence , amino acid , metabolism , gene
The Silent Information Regulator 2 (Sir2) enzyme family are conserved NAD‐dependant deacetylases that include seven human homologues (SirT1‐7). Sir2 homologues in bacteria and yeast have been implicated in the regulation of Acetyl CoA synthetase (AceCS) activity by reversible acetylation. AceCS is evolutionarily conserved and utilizes acetate, ATP, and CoA for production of acetyl CoA. Mammals contain two AceCS homologues, AceCS1 and AceCS2, which produce acetyl CoA for fatty acid metabolism and the TCA cycle, respectively. The acetylation site of bacterial AceCS shows sequence homology to lysine 661 of AceCS1 to which a specific anti‐acetyl‐AceCS1 antibody was developed from a corresponding 13mer acetylated peptide. This antibody detected acetylated AceCS1 in Cos‐7 cells transiently transfected with mammalian AceCS1. To determine which of the seven SIRtuins displayed the highest in vivo specificity for acetylated‐AceCS1, we conducted transient co‐expression experiments and found that SirT1 had the greatest specificity for acetyl‐AceCS1. Recombinant acetyl‐AceCS1 displayed negligible activity, whereas deacetylation by Sir2 enzymes restored AceCS1 activity. Using purified proteins, we examined the specificity of certain SIRtuins for stoichiometrically acetylated AceCS1. SirT1 and SirT3 exhibited high catalytic efficiency on purified acetyl‐AceCS1, while SirT2 was 3‐fold less efficient, and SirT5 and SirT6 displayed no detectable deacetylation. Thus, mammalian AceCS1 activity can be posttranslationally regulated by SirT1, which has important implications in the generation of Acetyl CoA pools and in fatty acid metabolism. NIH grant GM065386