Functional Genomics of the Protein Disulfide Isomerase Family: Unraveling Protein Folding and Redox-Regulatory Networks

University Of Hawaii, Honolulu

Investigators

Abstract

This project will systematically define the functions and regulatory networks mediated by the protein disulfide isomerase gene family in the model plant Arabidopsis thaliana. In the endoplasmic reticulum, protein disulfide isomerases catalyze the reversible formation and isomerization of disulfide bonds necessary for the proper folding, assembly, activity, and secretion of numerous enzymes and structural proteins. Protein disulfide isomerases have also evolved to adapt to novel cellular functions, as single enzymes and as subunits of protein complexes, in chloroplasts, mitochondria, nuclei, and vacuoles. Through redox-based mechanisms involving their thioredoxin domains, they are implicated in regulating transcription, translation, organelle biogenesis, photosynthetic efficiency, and cell differentiation in a variety of tissues and stages of development. This research will elucidate the function of all 11 members of the protein disulfide isomerase family by determining the subcellular locations and tissue-specific expression levels of each protein disulfide isomerase isoform and by identifying a wide range of substrates and partners with which each protein disulfide isomerase interacts. The project is also analyzing the T-DNA mutants available for nine different pdi genes and is constructing double and triple mutants and pdi over- and under-expresser lines. These plants are being examined for cellular and developmental alterations associated with modified protein disulfide isomerase levels. A systems biology model of metabolic networks and cellular functions that are impacted by protein disulfide isomerases will be produced. The resources from this project will be distributed via websites, The Arabidopsis Information Resource and partnering with small colleges. Broader Impacts: This project will provide a comprehensive understanding of the cellular function of each PDI in plants and will give critical insights into fundamental aspects of protein disulfide isomerase metabolism, enzyme folding and thermostability, redox networks and molecular evolution in eukaryotes. The post-doctoral exchange between Colorado and Hawaii will facilitate interdisciplinary training in molecular genetics and cell biology, problem solving and the transfer of research ideas for project advancement. Central to the mission of this project is to integrate the resulting technologies with learning experiences that will inspire faculty and student development from small colleges lacking research programs. Faculty will obtain certificates of professional training, while students will obtain mentoring, research credit and training. Participants will become aware of the fascinating array of activities and career choices in modern life science research. Hands-on training in genomics, bioinformatics and cellular biological research coupled with synergistic interactions, partnerships and collaboratively developed teaching resources (CD-ROM, web-based, lecture material) will have far-reaching educational impacts on faculty and students far beyond the project period.