Probes
We produce generally applicable approaches to molecular imaging tools. These include new fluorescent biosensor designs to visualize conformational changes of endogenous proteins and to study the conformation of individual molecules in living cells. We are developing bright dyes that report protein conformational changes, and engineered domains that can be inserted into target proteins to control protein function using either light or small molecules.
Chemogenetics
Engineering macromolecules to interact with previously unrecognized small molecules in cells
GFP Vinculin reveals adhesion dynamics and dorsal ruffles
by Louis Hodgson
Optogenetics
Genetically encoding light sensitive proteins that effect functional change in cells
HEK293 cell follows a light spot that activates Rac1
by Yi Wu
Nature, 461:104-110, 2009
Dyes
Not genetically encoded, dyes can be engineered to be environment-responsive and paired with our other probe types.
(LEFT) This Cdc42 biosensor was constructed from a fragment of WASP that binds selectively to activated Cdc42 (due to the green CRIB domain). The WASP fragment was derivatized with an environment-sensing dye that changed fluorescence when the biosensor bound Cdc42. Dye at position 271 (red) was in a hydrophobic pocket formed by amino acids from both WASP (blue) and Cdc42 (orange). (RIGHT) A library of FN3 monobodies is screened to find a library member with the appropriate binding selectivity and affinity for the targeted protein state. The library is based on a uniform scaffold stable in living cells and suitable for conversion to biosensors. The appropriate library member is derivatized with an environmentally sensitive dye to report target binding. Here, binding to active Src family kinases leads to increased fluorescence from a merocyanine dye.
Copyright Hahn Lab at UNC Chapel Hill
Biosensors
Engineering tools that can visualize conformational changes of endogenous proteins, examine conformations of individual molecules, & domains that can be inserted into target proteins to modulate function using light or chemical cues
GEF-H1 Microtubules (L) control GEF-H1 activity (R)
by Mihai Azoitei
J. Cell Biol., 218 (9):3077–3097, 2019
Copyright Hahn Lab at UNC Chapel Hill
