CAREER: Elucidating the Causal Link Associated with Energy Metabolism and Mitochondrial Ultrastructure

Mitochondria are subcellular organelles that are essential for energy production in so-called higher organisms, like plants and animals, including humans. However, we do not fully understand how the makeup and structure of mitochondria determine their life-sustaining abilities. We do know that biochemical reactions in mitochondria are separated into compartments known as cristae, which become disrupted under stress. To understand the reasons for this disruption, this project will employ advanced microscopy to visualize mitochondrial structural details and molecular methods to mimic disrupted mitochondrial metabolism. The project will provide educational experiences to high school students and teachers and research experiences to undergraduate and graduate students, who will learn how theoretical concepts can be linked through experiments to produce new knowledge of how mitochondria function as the energy factories of cells. Cristae are invaginations of the inner membrane of mitochondria that contain the bulk of the biochemical enzymes required for the oxidative phosphorylation of ADP. Under stress, cristae remodel in a controllable manner, which correlates with the maximum rate of oxidative phosphorylation. This project seeks to identify causal mechanisms behind this correlation. In Aim 1, novel calcium related mitochondrial physiology will be elucidated using bioenergetic data collected from purified mitochondria, interpreted via computer modeling. In Aim 2, cryo-electron tomograms of mitochondria in specific conditions will be used to quantify cristae morphology parameters at near-nanometer resolution. In Aim 3, 3D spatial models constraining a biochemical reaction/diffusion model of oxidative phosphorylation will be used to reveal the biophysical mechanisms regulating energy metabolism and cristae morphology. By uncovering the mechanisms underlying the structure/function relationship of mitochondria, this project will open new avenues of scientific inquiry focused on improving the health and well-being of people across the world. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.