Simulation of membrane-bound cargo transport by teams of kinesin motors*

In eukaryotic cells, membrane-bound cargoes are transported by teams of molecular motors. Motors on such cargoes diffuse on the lipid membrane. How the fluidity of the membrane affects transport characteristics is still not well understood. Here we develop a stochastic dynamical simulation of kinesin-based cargo transport along microtubules that explicitly considers the Langevin dynamics of motors on the surface of cargo. We study how the number of bound motors, run length, the velocity of cargo and binding rates are influenced by parameters like the diffusion coefficient of motors on cargo surface, ATP concentration, and the cargo size. We show that the distribution of free motors on microtubule-bound cargo surface depends on these parameters and affects the rebinding of cargo to microtubule after its detachment, thus affecting overall transport. Our work suggests that the consideration of motor diffusivity should be important in the cellular context.