Abstract
The steric repulsion between proteins on biological membranes is one of the most generic mechanisms that cause membrane shape changes. We present a minimal model where a spontaneous curvature is induced by steric repulsion between membrane-associated proteins. Our results show that the interplay between the induced spontaneous curvature and the membrane tension determine the energy minimizing shapes, which describe the wide range of experimentally observed membrane shapes, i.e. flat membranes, spherical vesicles, elongated tubular protrusions, and pearling structures. Moreover, the model gives precise predictions on how membrane shape changes by protein crowding can be tuned by controlling the protein size, the density of proteins and the size of the crowded domain.
Statement of Significance Membranes are a complex environment in which proteins are often densely packed. In a crowded membrane domain, volume exclusion leads to steric repulsion between proteins, which in turn drives membrane deformation. Experiments have revealed various different shapes: spherical vesicles, pearls and tubes. We present a theoretical model, where protein crowding induces a spontaneous curvature that depends on the protein density. The interplay between the induced spontaneous curvature and membrane tension captures the wide variety of membrane shapes found in experiments. We predict the membrane shape transformation from a flat patch to spherical buds and elongated bead-like and tubular shapes as a function of the size of the crowded domain, the membrane tension and the protein density.