Collective vesicle transport on biofilaments carried by competing molecular motors

We study a minimal model for bidirectional collective transport of cargo vesicles on a biofilament where the competing motion is characterized by the cargo densities moving toward the opposite filament ends. The model incorporates inter-vesicle interaction (through excluded volume) and active transport as well as motor regulation and environment interactions. From the current profiles we derive the non-equilibrium phase diagram. In terms of the filament end cargo fluxes, the phase diagram allows for re-emergent density shocks. This approach captures qualitatively a number of features of the collective state of the cargoes associated with bidirectional transport: current reversals due to internal regulation, boundary induced phase transitions and domain wall localization in the bulk. Vesicle polarization emerges naturally within the proposed framework.