This lab's long-term goal is to understand quantitatively how critical molecular events in a variety of essential membrane-involved processes control biological function. Specifically, they study immunoglobulin E (IgE) receptor signaling, which initiates the allergic response in mast cells. They are developing new quantitative tools, particularly those exploiting fluorescence, to probe spatial and temporal dynamics of the molecular interactions involved in immunoreceptor signaling. This multidisciplinary laboratory uses state-of-the-art fluorescence microscopy and spectroscopy, optical trapping, and nanotechnology to manipulate and interrogate single molecules in living cells and biomimetic systems. Questions they are investigating range from the physical chemistry of functional interfacial lipid-lipid and lipid-protein interactions to the initiation of signal transduction and exocytosis. More recently, they have been investigating the roles of macromolecular crowding and dynamic changes of ionic strength in bulk solution, in living cells, and on protein-membrane interactions and intermembrane interactions that mimic exocytotic processes. They are also applying their experimental approaches to intermolecular interactions at biosurfaces and biosensors. These biosensors detect changes in macromolecular crowding and ionic strength.