Collaborative Arabidopsis 2010 Project : Genomics and Proteomics Approaches to the Function of Tyrosine Phosphatases in Arabidopsis

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

Reversible protein phosphorylation is the most common mechanism for cellular regulation in eukaryotic systems. Studies have demonstrated that serine/threonine phosphorylation plays a key role in the regulation of plant physiology and development. However, tyrosine phosphorylation, despite its overwhelming importance in animals, was largely neglected in higher plants. Recently the first protein tyrosine phosphatase (PTP) has been characterized from higher plants. Furthermore, a diverse group of 21 genes encoding putative PTPs have been identified from the Arabidopsis genome. Genetic analyses of 4 PTPs have demonstrated that they serve critical functions in plant development, hormone signaling, and stress responses. These studies have broken new ground in the understanding of tyrosine phosphorylation in plants and opened up a new area of signal transduction research. In this project, a multifaceted approach is taken that combines most advanced technology in proteomics and genomics with existing procedures in biochemistry, molecular and cellular biology, and genetics to address the function of tyrosine phosphatases in Arabidopsis. The cDNAs for all PTPs will isolated, enzymatic properties of these putative PTPs will be characterized, their expression pattern and subcellular localization will be determined, and genetic models will be produced and characterized. To understand the molecular mechanism underlying PTP function, the in vivo substrates of PTPs will be identified using mass spectrometry. A useful database on phosphoproteome of Arabidopsis will be built and will be publicly accessible through PlantP website (http://plantsp.sdsc.edu/). The goal of this project is to understand the function and interplay of all tyrosine phosphatases in plant growth and developmental processes at both whole plant and molecular levels. Such information will contribute to the overall goal of 2010 program: to understand the function of all Arabidopsis genes. This project will also integrate educational activities into the research program by establishing a summer workshop for high school biology teachers.