Elastic Coupling Effects in Cooperative Transport by a Pair of Molecular Motors

Engineered constructs coupling a defined number of molecular motors provide an opportunity to study the cooperative transport of cargoes. Theoretical descriptions for the dynamics of such complexes can help to understand experimental data or to quantitatively formulate expectations for such experiments and provide a general framework for such analysis. Here, we review and extend recent theoretical studies that focused on pairs of molecular motors to study effects of coupling between the motors. We derive explicit results for two elastically coupled kinesin-1 motors as a function of the coupling strength using both linear and nonlinear springs. In addition, we discuss the general dynamics of such motor pairs, which is governed by characteristic time scales for the spontaneous unbinding of motors and for the built-up of strain forces that are sufficiently large to affect the run length and/or the velocity of the motors. We show how the comparison of these time scales can be used to predict the distinct behavior of different motor species, the effects of coupling, and the impact of the single motor velocity on the observable dynamics of a motor pair.