Kinesin expands and stabilises the GDP-microtubule lattice

Kinesin-1 is a nanoscale molecular motor that walks towards the fast growing (plus) ends of microtubules, hauling molecular cargo to specific reaction sites in cells. Kinesin-driven transport is central to the self-organisation of eukaryotic cells and shows great promise as a tool for nano-engineering1. Recent work hints that kinesin may also play a role in modulating the stability of its microtubule track, both in vitro2,3 and in vivo4, but results are conflicting5–7 and mechanisms are unclear. Here we report a new dimension to the kinesin-microtubule interaction, whereby strong-binding state (ATP-bound and apo) kinesin-1 motor domains inhibit the shrinkage of GDP-microtubules by up to 2 orders of magnitude and expand their lattice spacing by ~1.6%. Our data reveal an unexpected mechanism by which the mechanochemical cycles of kinesin and tubulin interlock, allowing motile kinesins to influence the structure, stability and mechanics of their microtubule track.