How motors shape their roads: self-organisation in dynamic filament networks

The active remodelling of the cytoskeleton is essential for fundamental cellular processes such as cell division. Different molecular motors that move cytoskeletal filaments, bundle them, and control their length play key roles in the restructuring of the cytoskeleton. Here we propose a microscopic model for the interplay between the spatial microtubule network architecture and molecular motors that control filament length by catalysing their depolymerization. In particular, we investigate how the transport of resources (free motors and tubulin monomers) impacts the dynamics by causing heterogeneous distribution of resources. Strikingly, we find that the interplay between resource redistribution and microtubule length regulation alone, without active contraction, is sufficient to organize the filament network into polar bundles. This polarity sorting in turn influences active transport of motors in the network. We show that the interaction between active motor transport, diffusive mass redistribution and length regulation leads to self-organization of the filament network in large-scale polar structures.