Long-range cargo transport on crowded microtubules: The motor jamming mechanism

• Cargo transport by molecular motors is examined in the context of ASEP models.
• Both cargo hopping and movement through cargo–motor complex are considered.
• Predicted changes in cargo direction in the presence of single-polarity motors.
• Motor density is suggested as a control parameter.
• Simulated kymographs illustrate the trajectories of motors and cargos resulting from these processes.

The hopping model for cargo transport by molecular motors introduced in Goldman and Sena (2009), Goldman (2010) is extended here in order to incorporate the movement of cargo–motor complexes (C–MC). Hopping processes in this context express the possibility for cargo to be exchanged between neighboring motors at a microtubule where the transport takes place. Jamming of motors is essential for cargos to execute long-range movement in this way. Results from computer simulations accompanied by a mean-field analysis of the extended model confirm our previous analytical results and suggests that an interplay between cargo hopping and the movement of the C–MC’s would control the efficiency of cargo transfer and cargo delivery in these model systems.