Microtubule Destabilizing Kinesins: A Historical Perspective and Thoughts for the Future

The microtubule cytoskeleton plays critical roles in multiple cellular processes such as mitotic spindle assembly and chromosome segregation. Cells contain a number of microtubule-associated proteins that regulate microtubule dynamics both temporally and spatially in cells. The microtubule depolymerizing kinesins include members of the Kinesin-8 (Kif18A, Kif18B, Kif19) and Kinesin-13 (Kif2A, Kif2B, Kif2C, Kif24) families of molecular motor proteins. Whereas Kinesin-8s are plus-end directed microtubule motors as well as microtubule destabilizing enzymes, the Kinesin-13 proteins use their catalytic cycle to depolymerize microtubules independent of motility. In this piece I will provide a historical perspective on the discovery of the microtubule depolymerizing kinesins and their functions within mitosis. I also provide my ideas on some of the key unanswered questions in the field.