IPiB Thesis Defense August 16, 2023: William Kasberg

William KasbergWilliam Kasberg, an IPiB graduate student, will be defending his Ph.D. research on August 16, 2023.

Kasberg, who is a member of the Audhya Lab, investigates how transport intermediates — the cellular components responsible for trafficking proteins from one destination to another within a cell — are regulated under a variety of conditions, including nutrient deprivation.

“We’ve seen how transport intermediates are formed under controlled conditions in a test tube,” says Kasberg. “But my question is, what happens in a cell, where there is a lot more going on? When we’re looking at components that might be modified in the cell or variations in nutrient availability, for example, how do those things change the process of transport intermediate formation?”

One of the ways Kasberg explored potential for variability in transport intermediate formation was by tracking changes in the speed and efficiency of transport intermediate assembly under nutrient deprivation conditions. Using a variety of fluorescence microscopy techniques, Kasberg monitored the process by which component parts of transport intermediates are assembled under both long- and short-term nutrient deprivation conditions, as well as nutrient rich conditions. When cells were starved for short periods, Kasberg saw delays in the formation of transport intermediates, as he expected. When cells were deprived of nutrients for longer periods of time, however, rates of transport intermediate production approached those found under nutrient-rich conditions. This finding points to the possibility of long-term cellular adaptation mechanisms that allow the cell to re-establish homeostasis during extended periods of starvation.

By comparing the processes of transport intermediate formation under these different conditions, “we were able identify which factor was likely to be positively regulating the rates of transport intermediate formation,” Kasberg explains. “Then, we were able to artificially increase the rate of incorporation of this factor to see if and how it is driving the process.”

Kasberg’s research on regulation of the transport intermediates responsible for trafficking proteins from organelle to organelle has been published in Cell Reports and Traffic, with another manuscript currently under consideration.

After graduating, Kasberg plans to continue exploring the ways proteins are trafficked and secreted as a postdoctoral fellow in the Washington, D.C. area. “I’m interested in studying how cells within tissues and organ systems communicate with one another,” says Kasberg. “How does secretion among cells mediate tissue biology and homeostasis? It’s like taking the processes that I have been studying on the molecular level and kind of scaling it up to organelles and tissues.”

To learn more about Kasberg’s research, attend his Ph.D. defense, “Dynamic Insights into COPII-mediated Trafficking Reveal Novel Modes of Regulation” on Wednesday, August 16, 2023 at 11:00 a.m. CT in Room 1211 of the Hector F. DeLuca Biochemical Sciences Building.