Dynamics of nonequilibrium membrane bud formation.

The dynamical response of a lipid membrane to a local perturbation of its molecular symmetry is investigated theoretically. A density asymmetry between the two membrane leaflets is predominantly released by in-plane lipid diffusion or membrane curvature, depending upon the spatial extent of the perturbation. It may result in the formation of nonequilibrium structures (buds), for which a dynamical size selection is observed. A preferred size in the microm range is predicted, as a signature of the crossover between membrane and solvent dominated dynamical membrane response.