Spatiotemporal dynamics of Aurora B-PLK1-MCAK signaling axis orchestrates kinetochore bi-orientation and faithful chromosome segregation.

Hengyi Shao,Minerva Garcia-Barrio,Xing Liu,Xuebiao Yao,Kai Yuan,Youjun Chu,Zhen Dou,Changjiang Jin,Liangyu Zhang,Yuejia Huang

doi:10.1038/srep12204

Abstract

Chromosome segregation in mitosis is orchestrated by the dynamic interactions between the kinetochore and spindle microtubules. The microtubule depolymerase mitotic centromere-associated kinesin (MCAK) is a key regulator for an accurate kinetochore-microtubule attachment. However, the regulatory mechanism underlying precise MCAK depolymerase activity control during mitosis remains elusive. Here, we describe a novel pathway involving an Aurora B-PLK1 axis for regulation of MCAK activity in mitosis. Aurora B phosphorylates PLK1 on Thr210 to activate its kinase activity at the kinetochores during mitosis. Aurora B-orchestrated PLK1 kinase activity was examined in real-time mitosis using a fluorescence resonance energy transfer-based reporter and quantitative analysis of native PLK1 substrate phosphorylation. Active PLK1, in turn, phosphorylates MCAK at Ser715 which promotes its microtubule depolymerase activity essential for faithful chromosome segregation. Importantly, inhibition of PLK1 kinase activity or expression of a non-phosphorylatable MCAK mutant prevents correct kinetochore-microtubule attachment, resulting in abnormal anaphase with chromosome bridges. We reason that the Aurora B-PLK1 signaling at the kinetochore orchestrates MCAK activity, which is essential for timely correction of aberrant kinetochore attachment to ensure accurate chromosome segregation during mitosis.

Highlights

During cell division, accurate chromosome segregation requires dynamic interactions between kinetochores and spindle microtubules (MTs), which results in accurate chromosome bi-orientation[1,2,3,4]
Our previous study demonstrated that Polo-like kinase 1 (PLK1) phosphorylates six sites (Ser[592], Ser[595], Ser[621], Ser[632], Ser[633] and Ser715) within C-terminus of MCAK27
To avoid the interference of endogenous mitotic centromere-associated kinesin (MCAK), an small-hairpin RNA (shRNA) targeting to the 3′ -UTR of MCAK was constructed and employed

Summary

Introduction

Accurate chromosome segregation requires dynamic interactions between kinetochores and spindle microtubules (MTs), which results in accurate chromosome bi-orientation[1,2,3,4]. Kinesin-13 family is a key regulator required for spindle microtubule dynamics in mitosis[5,6]. The accurate regulation of MCAK depolymerase activity is proposed to be essential for genomic stability as depletion of MCAK results in aberrantly attached kinetochores and missegregated chromosomes[16,17,18]. Our previous study revealed that phosphorylation of MCAK C-terminus by Polo-like kinase 1 (PLK1) stimulates MCAK activity in cells and might be essential for faithful chromosome segregation[27]. We demonstrate that Aurora B phosphorylates PLK1 to maintain PLK1 activity at the kinetochore for accurate kinetochore bi-orientation and chromosome segregation in mitosis via phospho-regulation of MCAK activity. Unlike the previously reported Aurora B-MCAK pathway that functions in early mitosis, this newly characterized Aurora B-PLK1-MCAK signaling axis ensures error-free chromosome segregation during metaphase-anaphase transition

Methods

Results

Conclusion