P5: Brownian Motion and Internal Dynamics in Polymer-Decorated Phospholipid Membranes

The observation of anomalous diffusion or hop-diffusion of certain proteins in native cell membranes has led to the question whether this phenomenon can be attributed to potential functional membrane domains (termed lipid rafts), or whether it might rather be due to the underlying cytoskeleton that acts like a micro- to nanoscale fence or meshwork for membrane lipids and proteins. In the here proposed study, both hypotheses will be tested on phase-separating model membrane systems such as Giant Unilamellar Vesicles (GUVs) mimicking functional domain formation. To shed light on the actual effect of the cytoskeleton, or other polymer particles and networks anchored (or otherwise attached) to a phospholipid membrane, on lipid and protein diffusion, we propose to reconstitute a cytoskeleton- or cortex-like structure of actin or other polymers on the model membranes, and study the diffusion behavior of single molecules within this membrane by a modified form of fluorescence correlation spectroscopy (FCS), which allows to directly identify corralling or confinement to sub-resolution domains. At the same time, intramolecular dynamics of both the diffusing particles and the polymers can be monitored. To relate the obtained values of potential corral size to structural and spatial information, the anchored polymer network on the membrane will be simultaneously observed by atomic force microscopy (AFM).

Project Leaders

Prof. Dr. Petra Schwille
Dr. Eugene Petrov
TU Dresden
Biotechnology Center



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