Physics Colloquium – Thomas D. Killeen

Novel Imaging Techniques for Studying Interactions of Membrane Receptors Among Themselves and with Downstream Signaling Partners

Thomas D. Killeen, PhD Candidate
University of Wisconsin-Milwaukee Department of Physics & Astronomy

Cells rely on complex signaling networks to sense and respond to environmental stimuli, but the bigger picture of how molecular assembly leads to robust cellular signaling is only beginning to emerge. A major challenge in characterizing cellular signaling is the ability to directly observe the dynamic interactions between membrane receptors and intracellular signaling partners in living cells. To address this challenge, this work presents the development of advanced fluorescence imaging and computational analysis tools designed to improve the precision and quantitative power of live-cell micro-spectroscopy for studying protein dynamics in real time.

I will show how these tools can be used to investigate the interactions between the muscarinic acetylcholine receptor M2 (M2R) and two intracellular signaling partners, arrestin-2 and arrestin-3, in living cells. Quantitative imaging revealed distinct differences in arrestin recruitment and membrane association following receptor activation, providing new insight into receptor regulation and signaling behavior.

Overall, this work demonstrates how innovations in fluorescence microscopy and data analysis can expand our ability to probe molecular signaling networks in living systems.