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

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.

Phosphorylation of PP1 Regulator Sds22 by PLK1 Ensures Accurate Chromosome Segregation

“…The FRET emission ratio (FRET/CFP) was calculated by dividing CFP ex /CFP em (CFP) to CFP ex /YFP em (FRET) using SoftWoRx (Applied Precision Inc.). For statistical analyses, individual centromere/kinetochore was defined automatically from confocal image stacks, and FRET emission ratio on each centromere/kinetochore was measured as previously described (47). The ratios were normalized by dividing by the maximum value of FRET emission ratio for each experiment.…”

KIF2C exerts an oncogenic role in nonsmall cell lung cancer and is negatively regulated by miR‐325‐3p

“…KIF2C is very important for normal spindle assembly. KIF2C repairs abnormalities in microtubule centromere and chromosome separation, so the activity and localization of KIF2C are regulated by many kinases and phosphatases . However, mitotic kinase and phosphatase dysregulation result in mitotic abnormalities, chromosomal instability, and uncontrolled transcription.…”

Plk1 Inhibitors in Cancer Therapy: From Laboratory to Clinics

“…Less is known regarding the interaction of Plk1 with the other members of the Aurora kinase family. It was recently demonstrated that Aurora B-mediated phosphorylation of Plk1 at Threonine 210 activates its kinase activity at the kinetochore to promote precise chromosome segregation (18). Phosphorylation of mitotic centromere-associated kinesin (MCAK) by Plk1 was also determined to be necessary for efficient separation of the chromatids (18).…”