Collective Dynamics of Kinesin-1 Motor Proteins Transporting a Common Load

Kinesin-1 is a motor protein essential to intracellular transport that converts the energy from ATP hydrolysis to directed movement along microtubules. Experimental and theoretical characterization of kinesin-1 has focused on single-molecule experiments. These experiments show that one motor is capable of transporting a cargo at speeds of about 1 μm/sec and maintaining contact with the microtubule for about 100 steps. In the cell, it is widely thought that several kinesin-1 motors cooperate to transport a cargo. Through a mechanistic model, we have extended the theoretical analysis of kinesin to describing transient and steady state behavior. A transient description is essential when studying collective behavior, as interaction between motors introduces time-varying loads. Herein, we interpret the kinesin motors as nonlinear, non-smooth oscillators and we employ metrics to characterize their cooperativity and to quantify their synchronization. These metrics are used to investigate the effect of the cargo linker stiffness, the load, and the difference in intrinsic velocity on the synchronization of two mechanically coupled motors.© 2007 ASME