Joshua Choi, an IPiB graduate student, will be defending his Ph.D. research on June 5, 2025. His research in the Senes Lab focused on understanding how regions of transmembrane proteins associate with each other.
A major focus of his research was the GASright motif, a structural arrangement commonly found in the regions of transmembrane proteins that span the membrane. The regions allow proteins to associate with each other, and these associations in the transmembrane space are essential for many cellular functions. Disruptions to the ways transmembrane proteins associate can result in diseases such as cancer.
To study associations among transmembrane proteins at scale, Choi helped to develop a high-throughput assay in which interactions among the transmembrane regions of proteins makes the cells glow green. The more transmembrane interactions among proteins, the stronger the green fluorescence. Researchers can then sort cells based on fluorescence intensity and estimate how much green fluorescent protein was produced, which suggests how strongly the proteins interacted.
Choi used this method to screen 100 transmembrane proteins. He used computational methods toidentify those that match the predicted GASright motif. This effort uncovered several homodimers (a complex made of two identical molecules) of proteins displaying GASright motifs, including several not previously known to associate in this manner.
In a separate study, Choi used the same experimental method in combination with computational modeling and machine learning tools to explore the sequence, structural, and energetic factors that stabilize GASright-mediated associations. By integrating experimental data with modeling, he identified specific sequence motifs responsible for inducing certain properties of the proteins.
Choi came to graduate school knowing he wanted to join a lab that had a focus on computational approaches. But, he emphasizes, there were other factors that went into choosing a lab. “When you’re choosing a lab, it’s just as important to find research you’re interested in as it is to focus on finding a PI and lab environment that you’ll enjoy,” says Choi. “You’re going to spend years of your life working with the people in your lab and it’s hard to thrive in a work environment that feels unpleasant to you. The Senes Lab is friendly, welcoming, and helpful so it was the perfect environment for me.”
After graduating, Choi will pursue a career in industry.
To learn more about Choi’s research, attend his Ph.D. defense, “High-throughput characterization of the GASright motif: sequence, structure, and stability determinants of transmembrane helix association” on Thursday, June 5 at 1:00 p.m. CT in Room 1211 of Hector F. DeLuca Biochemical Sciences Building.
Written by Renata Solan.