Relocation of Aurora B from centromeres to the central spindle at the metaphase to anaphase transition requires MKIp2

Mitotic kinases of the Polo and Aurora families are key regulators of chromosome segregation and cytokinesis. Here, we have investigated the role of MKIp1 and MKIp2, two vertebrate mitotic kinesins essential for cytokinesis, in the spatial regulation of the Aurora B kinase. Previously, we have demonstrated that MKIp2 recruits Polo-like kinase 1 (PIk1) to the central spindle in anaphase. We now find that in MKIp2 but not MKIp1-depleted cells the Aurora B-INCENP complex remains at the centromeres and fails to relocate to the central spindle. MKIp2 exerts dual control over Aurora B localization, because it is a binding partner for Aurora B, and furthermore for the phosphatase Cdc14A. Cdc14A can dephosphorylate INCENP and may contribute to its relocation to the central spindle in anaphase. We propose that MKIp2 is involved in the localization of PIk1, Aurora B, and Cdc14A to the central spindle during anaphase, and that the integration of signaling by these proteins is necessary for proper cytokinesis.