Dresden 2017 – wissenschaftliches Programm
CPP 4.1: Hauptvortrag
Montag, 20. März 2017, 10:15–10:45, ZEU 114
Membrane nanotube formation in giant vesicles — •Rumiana Dimova — Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany
Nanotubes are ubiquitous in cells. Examples for tubular structures are provided not only by organelles such as the Golgi body and the endoplasmic reticulum but also by intercellular connections between different cells. Their geometry and large area-to-volume ratio make them an excellent natural tool for membrane storage, sorting and transport. Such nanotubes can also be formed from synthetic lipid bilayers. Here, we discuss two systems based on giant vesicles, within which lipid nanotubes are generated and stabilized by spontaneous curvature. In the first case, we employ membranes doped with the ganglioside GM1 (Biophys. J. 111:1935, 2016). Upon dilution, the vesicle membrane exhibits asymmetric composition set by the different surface GM1 coverage on the two membrane leaflets. Employing vesicle micromanipulation and electroporation, we could assess the GM1 asymmetry and the associated spontaneous curvature. In the second system, the two leaflets of the bilayer have the same composition, but the solutions in contact with the inner and outer leaflet differ in the concentration of polyethylene glycol (PEG). We show that the spontaneous curvature is now generated by weak adsorption of PEG onto the membranes (ACS Nano 10:463, 2016). The tube shapes, cylindrical or necklace-like, and their diameters can be varied by the membrane composition and bending rigidity. We demonstrate this variation by employing membranes in the liquid-ordered and liquid-disordered phase state.