Interaction of synaptic vesicles with lipid membranes modulated by synapsin: a structural investigation by x-ray reflectivity and GISAXS

Towards an understanding of the interaction of synaptic vesicles with the inner leaflet of the synaptic membrane, and to explore the modulating role of the cytosolic protein synapsin, we propose an advanced interface sensitive x-ray scattering experiment on a well controlled model system, using a Langmuir lipid monolayer with synaptic vesicles and synapsin in the subphase. Synapsin is held responsible for the formation of SV pools and believed to strongly interact with lipid membranes. This model system can capture essential steps and structural mechanisms of vesicle adhesion to a membrane, e.g. like interaction range, contact area, adhesion state, lateral correlation in adhering SVs, as well as structural changes of the bilayer induced by adhering vesicles. For the first time, this assay will also address the pivotal role of the protein synapsin.