Human sirtuins are differentially sensitive to inhibition by nitrosating agents and other cysteine oxidants

Sirtuins (e.g.human Sirt1?7) catalyze the removal of acyl groups from lysine residues in proteins in an NAD(+)-dependent manner, and loss of sirtuin deacylase activity correlates with the development of aging-related diseases. Although multiple reports suggest that sirtuin activity is regulated by oxidative post-translational modifications of cysteines during inflammation and aging, no systematic comparative study of potential direct sirtuin cysteine oxidative modifications has been performed. Here, using IC(50)andk(inact)/K(I)analyses, we quantified the ability of nitrosothiols (S-nitrosoglutathione andS-nitroso-N-acetyl-d,l-penicillamine), nitric oxide, oxidized GSH, and hydrogen peroxide to post-translationally modify and inhibit the deacylase activity of Sirt1, Sirt2, Sirt3, Sirt5, and Sirt6. The inhibition was correlated with cysteine modification and assessed with chemical-probe and blot-based assays for cysteineS-nitrosation, sulfenylation, and glutathionylation. We show that the primarily nuclear sirtuins Sirt1 and Sirt6, as well as the primarily cytosolic sirtuin Sirt2, are modified and inhibited by cysteineS-nitrosation in response to exposure to both free nitric oxide and nitrosothiols (k(inact)/K-I? 5m(?1)s(?1)), which is the first report of Sirt2 and Sirt6 inhibition byS-nitrosation. Surprisingly, the mitochondrial sirtuins Sirt3 and Sirt5 were resistant to inhibition by cysteine oxidants. Collectively, these results suggest that nitric oxide?derived oxidants may causatively link nuclear and cytosolic sirtuin inhibition to aging-related inflammatory disease development.