Construction of a protein interaction database for 275 rice kinases
Reversible protein phosphorylation appears to be the most widely used biochemical mechanism in cellular signaling and has been found to regulate aspects of transcription, translation, and post-translational processes. One measure of this important role is that protein kinases and phosphatases constitute 5 percent of the completed Arabidopsis genome and are estimated to be a similar percentage of the rice (Oryza sativa) genome. Although it is clear that kinases and phosphatases play a key role in many stress responses, functional roles have not been identified for most of the protein kinases and phosphatases in the genome.
We have constructed a phylogenetic tree of ca. 1800 rice kinases that are nowbeing annotated. In collaboration with others (M. Fromm, PI, UN; WY Song, UF; JK Zhu, UCR) we are also generating a protein-protein interaction database for 275 of the rice protein kinases. We will isolate 275 representative full-length protein kinase cDNAs and use these in yeast two-hybrid systems and as affinity-tagged cDNAs in transgenic rice plants to identify the kinase-associated proteins in leaf and root tissues. We have optimized a high throughput yeast two hybrid mating system that we have used to identify ca. 35 XA21 binding proteins. The information from this project, together with the analysis of selected knockout mutants, will facilitate the interpretation of phosphorylation-mediated signaling pathways. Because such pathways control the amounts and activity of the groups of proteins that constitute important physiological traits, the proteins identified through this project are likely important for understanding and improving stress tolerance in cereals.
