Cryo-EM Reveals the Structural Basis of Microtubule Depolymerization by Kinesin-13s

Abstract

Kinesin-13s constitute a distinct group within the kinesin superfamily of motor proteins that promotes microtubule depolymerization and lacks motile activity. The molecular mechanism by which the kinesins depolymerize microtubules and are adapted to perform a seemingly very different activity from other kinesins is still unclear. To address this issue we obtained near atomic resolution cryo-electron microscopy (cryo-EM) structures of Drosophila melanogaster kinesin-13 KLP10A constructs bound to curved or straight tubulin in different nucleotide states. The structures show how nucleotide induced conformational changes near the catalytic site are coupled with kinesin-13-specific structural elements to induce tubulin curvature leading to microtubule depolymerization. The data highlight a modular structure that allows similar kinesin core motor-domains to be used for different functions, such as motility or microtubule depolymerization.