Functional characterization of the enzyme dipeptide interaction network and its role in the regulation of Arabidopsis carbon metabolism

Metabolism drives the life-sustaining chemical reactions that provide energy and building blocks for plant growth and function. The goal of this project is to investigate how a class of small-molecule compounds called dipeptides control the activity of the central carbon metabolism of plants. This research may lead to innovation in the form of dipeptide-based strategies for improving plant fitness and perhaps generate knowledge that can be used in human and animal health. This project will provide research training for high school students, undergraduate students and post-doctoral associates. Due to its rapid and reversible nature, small-molecule regulation of key enzymatic activities is vital to controlling metabolic fluxes. Systematic identification of regulatory metabolite-enzyme interactions remains one of the grand challenges in metabolism research. This research aims to systematically characterize the newly discovered enzyme-dipeptide interaction network and its role in regulating central carbon metabolism in the model plant Arabidopsis thaliana. To elucidate the metabolic consequences of the studied enzyme-dipeptide interactions, the research will exploit a combination of in vitro bimolecular binding assays, characterization of enzymatic activities, comprehensive metabolomic analysis of steady-state metabolite levels, and 13C metabolic flux analysis after dipeptide treatments. The results of these assays will be overlaid with dipeptide accumulation patterns to demonstrate the physiological relevance of the identified interactions. The basic knowledge accrued through this project will shed light on one of the central questions in biology: how organisms regulate their metabolism as they adapt to the environment. The research will characterize a hidden world of largely uninvestigated enzyme-dipeptide interactions, as well as their role in the critical yet poorly understood regulatory nexus of protein degradation and metabolism. 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.