Geometrical Properties of Antiparallel Arrays Regulate Microtubule Sliding and Stalling by PRC1 and Kif4A

Abstract

Motor and non-motor crosslinking proteins play critical roles in determining the size and stability of microtubule-based architectures. However, we have a limited understanding of how the geometrical properties of microtubule arrays, in turn, regulate the output of crosslinking proteins. Here we investigate the relative sliding of antiparallel microtubules by two interacting proteins: the non-motor crosslinker PRC1 and kinesin Kif4A. The collective activity of PRC1 and Kif4A also results in the accumulation of both proteins at the microtubule plus-end (‘end-tag’). Sliding stalls when the end-tags on the antiparallel microtubules collide. Interestingly, we find that structural properties of the initial array regulate two aspects of PRC1-Kif4A mediated microtubule organization. First, sliding velocity scales with initial microtubule-overlap length. Second, the width of the final stable overlap scales with microtubule lengths. Our analyses reveal how nanometer-sized proteins can decode micron-scale geometrical features of antiparallel bundles to define the structure and mechanics of microtubule-based architectures.