Figure 6.

Model for regulation of Kinesin-14 function in spindle organization. During interphase, Kinesin-14s are transported into the nucleus through association of the NLS in its tail with importin α/β, which prevents the bundling of cytoplasmic MTs. After nuclear envelope breakdown, a Ran-GTP gradient is formed in the vicinity of chromosomes, which results in the dissociation of Kinesin-14s from importin α/β. Once Kinesin-14s are activated by Ran, they likely cross-link MTs and transport MTs to the spindle pole through the minus-end movement of the motor domain. This activity is mediated through parallel MTs within a half spindle.