Kinesin-13s constitute a distinct group within the kinesin superfamily of motor
proteins that promote microtubule depolymerization and lack motile activity. The
molecular mechanism by which kinesin-13s depolymerize microtubules and are
adapted to perform a seemingly very different activity from other kinesins is
still unclear. To address this issue, here we report the near atomic resolution
cryo-electron microscopy (cryo-EM) structures of Drosophila melanogaster
kinesin-13 KLP10A protein constructs bound to curved or straight tubulin in
different nucleotide states. These structures show how nucleotide induced
conformational changes near the catalytic site are coupled with movement of the
kinesin-13-specific loop-2 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.
