Network Complexity and Parametric Simplicity for Cargo Transport by Two Molecular Motors

© The Author(s) 2012. This article is published with open access at Springerlink.com Abstract Cargo transport by two molecular motors is studied by constructing a chemome-chanical network for the whole transport system and analyzing the cargo and motor tra-jectories generated by this network. The theoretical description starts from the different nucleotide states of a single motor supplemented by chemical and mechanical transitions between these states. As an instructive example, we focus on kinesin-1, for which a de-tailed single-motor network has been developed previously. This network incorporates the chemical transitions arising from ATP hydrolysis on both motor heads. In addition, both the chemical and the mechanical transition rates of a single kinesin motor were found to depend on the load force experienced by the motor. When two such motors are attached via their stalks to a cargo particle, they become elastically coupled. This coupling can be effectively described by an elastic spring between the two motors. The spring extension, which is given by the deviation of the actual spring length from its rest length, determines the mutual in-teraction force between the motors and, thus, affects all chemical and mechanical transition rates of both motors. As a result, cargo transport by two motors leads to a combined chemo