Comparative Proteome Analysis of Protein Expression and Phosphorylation in Arabidopsis

Mississippi State University, Mississippi State MS

Investigators

Abstract

Precise control of the expression level and phosphorylation state of regulator and effector proteins is critical for many biological processes such as the cell cycle, circadian rhythm, and hormone responses. To date, technologies for proteome-wide analysis of protein expression and phosphorylation have not been established in plants. The objective of this project is to develop, apply, and establish new tools for comparative proteomics by systematically studying proteins whose expression level or phosphorylation state or both are regulated by the plant hormone abscisic acid in the model plant Arabidopsis. Isotope-coded affinity tagging and metabolic labeling will be applied for quantitation of protein expression. Phosphorylation state of proteins will be determined by mass spectrometry after enrichment of phosphopeptides. By analyzing both protein expression and phosphorylation state, proteins that undergo a change in phosphorylation without a corresponding change in expression or vice versa can be identified. This project is most likely to lead to discovery of novel abscisic acid-regulated proteins and the development of testable hypotheses about these proteins in abscisic acid signaling. Broader Impacts: The technologies developed from this project will serve as useful tools for plant biologists to systematically analyze protein expression and phosphorylation in their favorite systems. All in vivo protein phosphorylation sites determined in this project will be posted on the PlantsP database (http://plantsp.sdsc.edu). Detailed protocols developed from this project will be posted on a publicly accessable website. This project will provide excellent opportunities to train undergraduates, graduate students, and postdoctoral fellows from an EPSCoR state to perform state-of-the art research in quantitative proteomics.