Toward a quantitative understanding of metabolic homeostasis - Project summary/abstract The long-term goal of my research is to understand how the kinetic and thermodynamic properties of enzymes maintain metabolic homeostasis. The function of metabolic homeostasis is to maintain appropriate levels of ATP and biosynthetic precursors. Understanding metabolic homeostasis is important as it is a fundamental property of all cells and its dysregulation leads to metabolic syndrome, which contributes to several common disorders, including diabetes, cardiovascular disease, cancer, and nonalcoholic fatty liver disease. Metabolic homeostasis is achieved by controlling enzyme activity through mass action and allosteric regulation. Studies of purified enzymes have yielded extensive knowledge of the structure, reaction mechanism, and allosteric regulation of enzymes in several metabolic pathways. However, metabolic homeostasis is the result of non-linear interactions between many enzymes and metabolites, which are difficult to fully understand by studying individual enzymes in isolation. As a result, the specific functions of most allosteric regulators is not well understood and it is largely unknown how allosteric regulation and mass action achieve metabolic homeostasis in cells. In this proposal, our main objectives are to 1) develop mathematical models to characterize metabolic homeostasis, and 2) develop experimental approaches to test model predictions by measuring and manipulating metabolic homeostasis in live cells and in vitro reconstituted pathways. We will use a combination of modeling and experiments to address key gaps in our understanding of the regulation of glycolysis, pentose phosphate pathway, tricarboxylic acid cycle, and mitochondrial oxidative phosphorylation. The big-picture questions that we plan to investigate are: How do glycolysis and respiration maintain cellular ATP homeostasis? How do cells resolve the conflicting demands of ATP production and biosynthesis? How do metabolic pathways that share products and substrates coordinate with each other? What is the role of compartmentalization and metabolite channeling in regulating metabolic homeostasis? Our lab is well-positioned to make advances in the understanding of metabolic homeostasis as we have extensive experience in developing and using LC-MS, fluorescence sensors, genetically-encoded tools for manipulation of metabolism, in vitro protein characterization, engineering cell lines using CRISPR-Cas9, and mathematical models to study metabolism.
