Role of the kinesin-2 family protein, KIF3, during mitosis

During mitosis, kinesin and dynein motor proteins play critical roles in the equal segregation of chromosomes between two daughter cells. Kinesin-2 is composed of two microtubule-based motor subunits, KIF3A/3B, and a kinesin-associated protein known as KAP3, which links KIF3A/3B to cargo that is carried to cellular organelles along microtubules in interphase cells. We have shown here that the kinesin-2 complex is localized with components of the mitotic apparatus such as spindle microtubules and centrosomes. Furthermore, we found that expression of amutant KIF3B, which is able to associate with KIF3A but not KAP3 in NIH3T3 cells, caused chromosomal aneuploidy and abnormal spindle formation. Our data suggested that the kinesin-2 complex plays an important role not only in interphase but also in mitosis.