| Protein acetylation has emerged as a major post-translational modification and accumulating evidence indicates that lysine acetylation is a prevalent regulatory mechanism of numerous cellular processes. Mitochondrial proteins, including metabolic enzymes, are among the most highly acetylated and are dynamically altered in response to nutritional status. The mitochondrial nicotinamide adenine dinucleotide dependent deacetylase Sirtuin 3 (SIRT3) is implicated as a possible regulator of the cellular adaptation to nutrient variation and directly deacetylates and regulates the function of proteins involved in lipid metabolism, energy production, and the antioxidant response system. Mitochondrial function has been linked with aging and age-related disease. SIRT3 may play a major role in the maintenance of healthy mitochondria and act as a key molecular regulator of the lifespan benefits of caloric restriction, fasting, and exercise. SIRT3 is postulated to be the main, if only, mitochondrial protein deacetylase, but the extent of its capacity to modulate mitochondrial processes remains unclear. While numerous post-translational modifications exist in the mitochondria, much remains to be understood about the enzymes that add and remove these chemical marks, how this serves to regulate protein function, and how these modifications vary in response to both acute and chronic alterations in nutrient availability. Employing biochemistry and systems biology to test defined hypotheses will allow for exploration of a number of unexplored and unknown questions in the field of mitochondrial biology and will further elucidate the role of mitochondria in aging and disease. This thesis describes the characterization of physiological, site-specific alterations in lysine acetylation in the mitochondria. Using mouse models, quantitative proteomics, detailed biochemistry, and cell culture systems this work stands to elucidate mechanistic details of the regulatory role of protein acetylation. |
