Eukaryotic cells are composed of different compartments with defined biological functions. Transport of molecules from one compartment to another, as well as from and to the plasma membrane, occurs via membrane vesicles. Clathrin-mediated endocytosis is the most studied pathway for the formation of such a vesicle. The GTPase dynamin mediates the final membrane fission step in this process. This thesis describes the experimental work to clarify how a specific class of crescent-shaped proteins called N-BAR proteins regulate dynamin-mediated membrane fission. Endophilin, one of the N-BAR proteins, was taken as an example. The major experimental technique is the nanotube pulling assay, an in-vitro essay using purified proteins. Other chapters of this thesis explore curvature-inducing properties of the clathrin adapter AP180 and the curvature-dependent activity of yeast Vps34 complex I. Additionally, this thesis analyses structural consequences of mutations in dynamin and another N-BAR protein, BIN1/amphiphysin 2, which cause the hereditary muscle disease CNM (centronuclear myopathy).