Optimising search times for motor driven cargo within cytoskeletal traps by tuning attachment and detachment kinetics

Cytoskeletal networks in cells often have junctions where filament ends of the same polarity come together. This results in a basin of attraction or trap for cargoes carried by molecular motors along filaments. These are biologically significant. For example, in neurons, the accumulation of vesicles in such a trap promotes the formation of growth cones. In pancreatic beta cells, microtubule traps help regulate insulin secretion. Here we study the effectiveness of such traps using minimal one and two-dimensional models of cargo transport with a basin of attraction created by oppositely oriented microtubules. In our model, a cargo switches between advection on microtubules and one-dimensional diffusion in the cytoplasm with specific on and off rates. We then measure the time it takes for the cargo to reach absorbing boundaries or specific target locations in the cytoplasm. We find that when the trap or target is asymmetrically placed, the time to escape or find the target is minimized for certain optimum values of on and off rates. Interestingly this effect has analogies in the stochastic resetting processes. Our results give insights into how cells might exploit cytoskeletal traps to regulate intracellular transport processes.