Mitosis-specific phosphorylation of Mis18α by Aurora B kinase enhances kinetochore recruitment of polo-like kinase 1

Mis18α, a component of Mis18 complex comprising of Mis18α, Mis18β, and M18BP1, is known to localize at the centromere from late telophase to early G1 phase and plays a priming role in CENP-A deposition. Although its role in CENP-A deposition is well established, the other function of Mis18α remains unknown. Here, we elucidate a new function of Mis18α that is critical for the proper progression of cell cycle independent of its role in CENP-A deposition. We find that Aurora B kinase phosphorylates Mis18α during mitosis not affecting neither centromere localization of Mis18 complex nor centromere loading of CENP-A. However, the replacement of endogenous Mis18α by phosphorylation-defective mutant causes mitotic defects including micronuclei formation, chromosome misalignment, and chromosomal bridges. Together, our data demonstrate that Aurora B kinase-mediated mitotic phosphorylation of Mis18α is a crucial event for faithful cell cycle progression through the enhanced recruitment of polo-like kinase 1 to the kinetochore. © Lee et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License 3.0 (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.1