Figure 1. Proposed model figure describing Sirt3 acetylation and subsequent regulation of MnSOD detoxification enzymatic activity. Sirt3 is localized into the inner mitochondrial membrane and appears to be activated by agents that induce oxidative stress, such as ionizing radiation, or changes in cellular nutrient status, such as caloric restriction or fasting. Our data suggests that MnSOD enzymatic activity is directed by acetylation of lysine 122 following fasting or exposure to radiation via the activation of Sirt3. Sirt3 has also been shown to regulate the activity of other mitochondrial proteins including Acetyl-CoA synthetase 2 (AceCS2) [