Elucidating the mechanism behind oscillation between glycolysis and gluconeogenesis

Project Summary The overarching research goal of the Park lab is to gain systems-level understanding of metabolism (including its regulation) and rationally engineer mammalian and microbial metabolism for biotechnology and medicine. We are a team of open-minded and hardworking researchers who employ core analytical techniques and ceaselessly innovate (and adopt) new technologies to solve challenging problems associated with various diseases and organisms. Our current research is twofold: microbial conversion of carbon dioxide into value-add products for economic and environmental benefits; and elucidation of thermodynamic and kinetic mode of metabolic control in mammalian gluconeogenesis. One of our goals over the next five years is to develop key technologies to mathematically reconstruct human central carbon metabolism in thermodynamic and kinetic terms. Until recently, characterization of metabolism has relied mainly on comparison of relative metabolite and enzyme levels between control and experimental groups. We will go beyond measuring just the “levels” and quantify rates and energies, which are direct representation of metabolism in action yet difficult to measure because they are substantive yet intangible. To this end, we will employ state-of-the-art liquid chromatography-mass spectrometry, mathematical modeling, and novel isotope tracers that can yield the most thermodynamic and kinetic information in cellular metabolism. We aim to apply these techniques to investigating the two central metabolic pathways: glycolysis and gluconeogenesis. The two pathways largely share a common enzyme set, yet the former converts glucose into cellular energy and biomass precursors while the latter converts non- carbohydrate substrates into glucose. These functionally opposite metabolic pathways support systemic glucose homeostasis in humans and, in microbes, various bioproduct synthesis from a wide range of carbon substrates with varying degrees of oxidation. This project will map kinetic and thermodynamic bottlenecks of the two pathways in mammalian cells and elucidate regulatory mechanisms that enable seamless transitions and coordination between them. As dysregulation of these pathways are implicated in type II diabetes and cancer, we envision that this research program will lead to effective metabolic control and engineering strategies to remedy defective carbon metabolism in diseases. The upshot of successfully completing the proposed research will contribute to advancing therapeutic development for diabetes and cancer.