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The Levinson Emerging Scholars Program
Joanne Hsu - Neurobiology
Growing up in the forests of Battle Ground, WA, Joanne frequently encountered flora and fauna of diverse phenotypes as she explored the woody backyard, which was what first inspired her passion for the biological sciences. Her interest in exploring biological processes and function on level of proteins inspired her to conduct proteomics research with Dr. Judit Villen in the Department of Genome Sciences, where she studies the evolution of phosphoregulation across yeast species using proteomic techniques and mass spectrometry. The goal of this project is study the conservation of phosphorylation sites across representative yeast species from different phylogenetic lineages, to identify specific orthologs that regulate key cellular functions and also better understand the evolution of phenotypic diversity.
Joanne is very grateful for the support from the Levinson scholarship on her research.
Mentor: Judit Villen, Genome Sciences
Project Title: Elucidating the Conservation of Phosphorylation Patterns Across Yeast Species with Phosphoproteomics
Abstract: The reversible phosphorylation of proteins mediates a wide range of biological processes that range from signal transduction cascades to regulation of protein abundance. However, little is known about the mechanisms and evolution of phosphorylation networks. Despite the extraordinary advances in genome sequencing of many yeast species, evolutionary studies on the phosphoproteome of yeast species have been limited to the experimental analysis of phosphorylation in one species and computational analysis of the conservation of phosphor-acceptor residues with other species. To properly study evolutionary conservation across yeast proteomes, we are utilizing mass spectrometry to study and compare the phosphoproteome of over 15 species of yeast, including species representative from each clade on the yeast phylogeny. Most of these species have not been studied before by proteomics. This high-throughput phosphoproteomic study on the yeast species will contribute to the construction of phosphoproteome datasets, which can be exploited for comparative analysis of phosphorylation between yeast species. In this phosphoproteomic study, I will first analyze the reproducibility of the sample preparation techniques and data acquisition methodologies, which are key factors in the ability to distinguish true differences between samples. After developing an optimally reproducible methodology, I will construct growth curves for all the yeast species, in order to standardize an optimal optical density for the yeast cultures. Next, I will analyze the phosphoproteome of the yeast species using the optimized phosphoproteomic methodology, in order to construct the phosphoproteome datasets. To supplement the datasets, I will also analyze the protein abundances in each of the species. The relative overlap between the phosphoproteome datasets and the comparison of protein abundances between the yeast species will shine light on the evolutionary and functional relevance of phosphorylation in regulating protein concentration and mediating cellular signaling pathways.