Coordination of Bending and Wedging in Membrane Fission

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Protein complexes controlling intracellular membrane scission generally utilize multiple membrane insertions to enforce structural rearrangements of lipid monolayers. In general, the deformation fields created by individual insertions might interact destructively or constructively so that the resulting stress distribution depends strongly on the spatial organization and orientation of the individual insertions. We show here that in cylindrical topology the interaction between two ring-like membrane insertions can be both attractive and repulsive, dependently on the ratio between the curvatures of the membrane and the ring as well as on the insertion parameters. The attractive interaction drives clusterization of the rings leading to substantial stored elastic stress. This stored energy can be further used for localized membrane remodeling if the rings can interact changing the system geometry and boundary constraints. The model was applied to calculate energy barriers for dynamin-mediated membrane fission, substantial reduction of the barrier was found for a particular parameters range, indicating that the molecular design of the fission machinery involves optimization of the membrane insertion geometry.