Run-length distribution of self-assembling cargos in crowded environments

Abstract Intracellular transport, carried out by motor proteins, is crucial for numerous biological functions of the cell. Cytoskeletal motor proteins such as kinesins and dyneins move on the biopolymer, microtubule, carrying different kinds of biomolecules as cargo to deliver these at required destinations. Such transport is often impeded by a crowded environment along the microtubule due to other motor proteins and various cellular organelles. Here, we study the motion of a self-assembling cargo that, during its translocation, can associate kinesins bound to the microtubules. This strategy is believed to help the cargo move efficiently along the microtubule crowded by free kinesins. Using the idea of first-passage time and the backward master equation approach, we determine the run-length distribution of such cargo under different crowding densities. We show that for high kinesin-association rates, the average run-length shows a peak with the crowding density while, for low kinesin-association rates, it decreases monotonically with the crowding density.