Figure 7.

Strategies to regulate mitotic kinesin activity in the cell cycle. (A) Nuclear sequestration of Klp67A or Ncd protects cytoplasmic microtubules from the undesired depolymerizing or cross-linking activities of these motors. Nuclear envelope breakdown enables the motors to perform their actions on microtubules. (B) Phosphorylation of Thr 933 residue by Cdc2 kinase is essential for Klp61F targeting to microtubules during mitosis. (C) Cdc2 phosphorylations around the motor domain of Pav prevent this motor for prematurely binding to the central spindle during metaphase. Dephosphorylation of these sites is required for central spindle targeting after anaphase. (D) Change of localization of Klp10A and Klp67A depolymerases after mitotic progression. Klp10A-GFP shows clear microtubule plus end tracking in interphase. Plus end tracking is still clearly detected during prophase, while centrosome/centromere localization also is seen. After nuclear envelope breakdown, plus end tracking becomes much less evident, and the majority of Klp10A localizes to centrosomes, centromeres, and interior pole regions. Klp67A enriched at the outer region of kinetochores during metaphase, followed by central spindle accumulation immediately upon anaphase onset.