INVESTIGATION OF CELL MEMBRANE DYNAMICS AND ORGANIZATION BY IMAGING FLUORESCENCE CORRELATION SPECTROSCOPY

Abstract

The first project investigates plasma membrane organization in different types of live cells using Imaging Total Internal Reflection-Fluorescence Correlation Spectroscopy (ITIR-FCS). Diffusion coefficients of two different phase-specific membrane probes (GFP-GPI and DiI-C18) are measured at different temperatures. From these values, Arrhenius activation energies are calculated, whereby the magnitude would indicate the level of lipid packing. Lastly, Imaging FCS diffusion law analysis was done to identify the mode of membrane organization through the mode of diffusion probed by the marker (free, domain partitioning or meshwork).

The second project, in collaboration with Luc Veya and Professor Vogel (EPFL), involves the investigation of the binding mechanism of Substance P to the Neurokinin-1 receptor on the plasma membrane of HEK-293 cells. Two mechanisms have been postulated - membrane-mediated or direct binding from the aqueous phase. The dynamics and localization of the Neurokinin-1 receptor in different states (activated or non-activated) were also explored using ITIR-FCS.