Dynamic regulation of kinetochore-microtubule interaction during mitosis.

Chromosome segregation is carried out by dynamic interplay between kinetochores and microtubules. First, kinetochores are efficiently captured by microtubules. Then, flexible interactions between kinetochores and microtubules allow proper orientation of chromosomes aligned on the centre of the spindle. Finally, microtubules stably attached to kinetochores drag the chromosomes towards the spindle poles. During these processes, the mode of interaction of kinetochores with microtubules changes from lateral to end-on attachment, accompanied by changes in kinetochore structure/composition and microtubule dynamics. The molecular mechanisms for stable kinetochore-microtubule attachment have been progressively revealed in recent years. On the other hand, the mechanism of dynamic regulation of kinetochore-microtubule interaction in early mitosis, which is crucial for faithful chromosome segregation, continues to be elusive. Here I focus on this early step of chromosome segregation and discuss how kinetochores establish proper attachments to microtubules.