Figure 5.

P-movement and bi-orientation of chromosomes in S. pombe. As normal mitosis begins, the SPBs (green ovals) are close to the kinetochores (red circles; only one chromosome (blue) is shown); this situation may explain why all three minus-end directed motors are not required for mitotic progression. In the absence of Klp2p, or during transient MT depolymerization, the kinetochores can move some distance away from the poles. Their subsequent movement to the pole is driven by MT depolymerization, facilitated by Klp2.