In vivo visualization and control of information flow through GTPase signaling networks

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Thursday, March 19, 2015 - 4:30pm

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Cell motility requires the orchestration of multiple dynamic cellular systems. To understand the organization of signaling interactions in time and space, we are developing tools to visualize and manipulate protein activity with seconds and micron resolution in living cells and animals. Our hope is that these will be easy to apply and therefore broadly applicable. This talk will describe new biosensors and biosensor designs to quantify information flow through Rho family GTPase networks, and modular design of domains that can be inserted in GEFs, GTPases and kinases to confer control by light or small molecules. Applications in motility and immune cell function will be described.


Dr. Hahn’s laboratory focuses on two synergistic areas: development of novel tools to visualize and manipulate protein activity in living cells and animals, and application of these tools to address questions re the spatiotemporal dynamics of signaling in vivo. His biological studies center on cytoskeletal and adhesion dynamics, their role in signaling crosstalk, and immune cell function. While addressing specific molecules for biology, he has developed generally applicable approaches to visualize and control signaling. These include fluorescent biosensors to quantify conformational changes of endogenous proteins, novel biosensor designs that reduce cell perturbation, and biosensors based on engineered protein scaffolds to access otherwise inaccessible molecules. His laboratory has developed fluorescent dyes for enhanced biosensor sensitivity, multiplexing and single molecule microscopy. He is currently focused on new approaches to activate or inactivate proteins with seconds and submicron resolution in vivo, using engineered domains that respond to light or small molecules. Dr. Hahn studied chemistry at the University of Pennsylvania and University of Virginia, where he received his Ph.D. He then worked as a postdoc at  the Center for Fluorescence Research at Carnegie Mellon University and the Scripps Research Institute. He became an Assistant and Associate Professor at Scripps in the Neuropharmacology and Cell Biology Departments, then moved to UNC-Chapel Hill where he is the Thurman Distinguished Professor of Pharmacology and director of the UNC-Olympus Imaging Center. Dr. Hahn has received the James Shannon Director’s Award from the NIH and is a fellow of the AAAS. His lab’s work on biosensors was named one of the “10 Breakthroughs of the Decade” by Nature Reviews Molecular Cell Biology.