Research Expertise and Interest
chemistry, physical chemistry of cell membranes, molecular organization in cell membranes, receptor-ligand binding, spatial rearrangement of receptors, ligands
Cells interact with each other and their environment through myriad membrane associated receptors and signaling molecules. In addition to individual receptor-ligand binding, spatial rearrangement of receptors into complex patterns is rapidly emerging as a broadly significant aspect of cell recognition. We are mounting a quantitative investigation of the physical characteristics and principles governing molecular reorganization events during initial stages of cellular recognition and signaling. The basic problem to be addressed is the collective interaction between populations of receptors and ligands in two apposed fluid membranes. We wish to understand how the binding kinetics, lateral mobility of the membrane proteins, membrane bending effects, etc. influence molecular organization and recognition. Our approach is aimed toward elucidating how these physico-chemical parameters determine the formation of spatio-temporal patterns at cell signaling junctions. A three-pronged investigative platform which combines novel membrane experiments in reconstituted lipid membranes and cell biology with theoretical calculations and computer simulations has been formulated to meet our goals. In the experimental aspect of this project, we are utilizing a variety of supported membrane configurations to examine spontaneous pattern formation in a controlled setting. The use of supported membrane systems is an especially powerful aspect of these studies in that micron and nanometer-scale structures can be fabricated onto the substrate and used to confine and control the fluid membrane in practically any desired geometry. In addition to our studies of processes in cellular membranes, we are developing a variety of hybrid bio-solidstate devices which incorporate fluid membranes. The basic goal is to construct chip-based components which can manipulate, control, and measure membranes and associated molecules. We employ a range of microfabrication techniques including photo- and electron-beam lithography to fabricate micron- and nanometer-scale structures which interface with fluid membranes.