What are the mutations, harmful or beneficial, that may occur in a protein? The answers to this fundamental question underpin the ability to understand and predict evolution. While trying to study this question by introducing mutations in the lab, it was learned that mutations very often result in the production of protein variants that do not fold correctly in space. In the living cell, there are several systems that assist the protein folding process (known as the cellular proteostasis network), and they help some of the mutant proteins fold correctly. By perturbing the proteostasis systems, the investigator hopes to learn more about the mutations that actually happen during protein evolution. This project will use the influenza viruses, which can evolve rapidly in the lab and chemical probes that can turn on and off various parts of the proteostasis machinery. The research is linked to developing and testing an outreach program targeted at the local homeschooled student community. Opportunities offered include high school student internships related to the research, chemistry demonstration shows, and the development and testing of biomolecule models for take-home experiments that teach students about evolution and protein folding.
This research is uncovering how metazoan proteostasis mechanisms beyond the HSP90 chaperone influence protein evolution at the molecular level. A battery of custom-designed chemical biology tools is used to perturb the composition and activities of key components of the metazoan proteostasis network with high precision using small molecules. The effects of these different proteostasis environments on protein evolutionary trajectories are studied by leveraging rapidly evolving RNA viruses propagating in metazoan cells, with a focus on influenza A. The highly interdisciplinary experimental approach encompasses deep mutational scanning of individual viral proteins, and optimized sequencing, modeling, and biophysical analysis strategies to enable quantitative assessment of the results. The outcomes will be a new appreciation for the complex interplay between the proteostasis network and client protein evolution, with important implications for understanding and predicting viral evolution at the molecular level. Testing roles of the proteostasis network in buffering protein evolution will also elucidate previously unknown functions of specific proteostasis network components. Thus, fundamental science contributions will impact fields ranging from virology and evolutionary biology to biophysics.
