ETH Polymer Physics seminar


2009-10-14
15:45 at HCI D2

Physical Approaches to Intracellular Trafficking

Patricia Basserau

Institut Curie, Paris

Endocytosis, exocytosis, membrane transport between intracellular compartments, virus or toxin entry or exit out of the cell are cellular events implying membrane deformation. Membrane deformation mechanisms of cell membranes by proteins are currently actively studied. Giant Unilamellar vesicles (GUV) are interesting model membrane systems because they are composed of a very limited number of components compared to cellular membranes. The deformations induced by the interaction with a specific protein, a virus or any other additional components to the system, can then be directly monitored and the deformation mechanism eventually understood. In this talk, I will present a few examples related to membrane trafficking where in vitro systems have contributed to a better understanding and modelling. I will show that toxins (Shiga and Cholera) interacting with GUV containing their lipid receptor, can form tubular structures in absence of any other cellular machinery which are essential for the entry of these toxins in cells. Comparison with nanoparticles functionalized with these toxins will be presented. Membrane nanotubes with controlled diameter can be pulled from GUV, allowing for quantitative measurements of the effects of membrane curvature. Indeed, fluorescence and force measurements can be obtained with an original set-up combining confocal microscopy and optical tweezers. In a second part, I will present recent experiments showing the effect of membrane curvature on sorting of the above toxins and of lipids.


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