PRC1 Cooperates with CLASP1 to Organize Central Spindle Plasticity in Mitosis

Jing Liu,Zhikai Wang,Kai Jiang,Liangyu Zhang,Lingli Zhao,Shasha Hua,Feng Yan,Yong Yang,Dongmei Wang,Chuanhai Fu,Xia Ding,Zhen Guo,Xuebiao Yao

doi:10.1074/jbc.m109.009670

Abstract

During cell division, chromosome segregation is governed by the interaction of spindle microtubules with the kinetochore. A dramatic remodeling of interpolar microtubules into an organized central spindle between the separating chromatids is required for the initiation and execution of cytokinesis. Central spindle organization requires mitotic kinesins, microtubule-bundling protein PRC1, and Aurora B kinase complex. However, the precise role of PRC1 in central spindle organization has remained elusive. Here we show that PRC1 recruits CLASP1 to the central spindle at early anaphase onset. CLASP1 belongs to a conserved microtubule-binding protein family that mediates the stabilization of overlapping microtubules of the central spindle. PRC1 physically interacts with CLASP1 and specifies its localization to the central spindle. Repression of CLASP1 leads to sister-chromatid bridges and depolymerization of spindle midzone microtubules. Disruption of PRC1-CLASP1 interaction by a membrane-permeable peptide abrogates accurate chromosome segregation, resulting in sister chromatid bridges. These findings reveal a key role for the PRC1-CLASP1 interaction in achieving a stable anti-parallel microtubule organization essential for faithful chromosome segregation. We propose that PRC1 forms a link between stabilization of CLASP1 association with central spindle microtubules and anti-parallel microtubule elongation.

Highlights

To ensure that each daughter cell receives the full complement of the genome in each cell division, chromosomes move poleward, and non-kinetochore fibers become bundled at the onset of anaphase, initiating assembly of the central spindle, a set of anti-parallel microtubules that serves to concentrate key regulators of cytokinesis [1,2,3]
Disruption of PRC1-CLASP1 interaction by a membrane-permeable peptide abrogates accurate chromosome segregation, resulting in sister chromatid bridges. These findings reveal a key role for the PRC1-CLASP1 interaction in achieving a stable anti-parallel microtubule organization essential for faithful chromosome segregation
We propose that PRC1 forms a link between stabilization of CLASP1 association with central spindle microtubules and anti-parallel microtubule elongation

Summary

Introduction

To ensure that each daughter cell receives the full complement of the genome in each cell division, chromosomes move poleward, and non-kinetochore fibers become bundled at the onset of anaphase, initiating assembly of the central spindle, a set of anti-parallel microtubules that serves to concentrate key regulators of cytokinesis [1,2,3]. Chromosomal passengers are a group of evolutionarily conserved proteins that orchestrates chromosome segregation and central spindle plasticity [4, 5] This protein complex containing Aurora B, Survivin, INCENP, and Borealin is relocated from the kinetochore to the central spindle upon anaphase onset [5,6,7,8,9]. Perturbation of their function results in defects in metaphase chromosome alignment, chromosome segregation, and cytokinesis [10]. The molecular mechanisms underlying its regulation of microtubule dynamics remain elusive, it is generally believed that CLASP orchestrates microtubule dynamics via its physical interacting with EB1, CLIP170, and microtubules [17, 24]

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