FtsZ protein on bilayer membranes: effects of specific lateral bonds

We use a simple lattice model to explore the self-assembled structures of protein filaments. Monte Carlo simulations show polymorphic structures, formed by the competition between the bundling of filaments, their branching and the spontaneous curvature. In the top-down approach, typical of statistical physics, we compare the simulation results with experimental atomic force microscopy images of the bacterial protein FtsZ anchored on bilayer membranes. We identify the relevant aspects of the interactions between protein monomers, which are amplified as a collective effect of the whole system. From the perspective of soft-matter physics, the experimental system and its model representation provide an interesting example of living polymers with tunable interactions.