Mitotic motor CENP-E cooperates with PRC1 in temporal control of central spindle assembly

Abstract

Chromosome movements during mitosis are orchestrated primarily by the interaction of spindle microtubules with the kinetochore, the site for attachment of spindle microtubules to the centromere. Kinetochore‐associated mitotic kinesin CENP‐E plays key roles in chromosome congression and spindle checkpoint satisfaction. We have recently identified and characterized syntelin, a novel selective CENP‐E inhibitor (Ding et al., 2010. Cell Res. 20, 1386‐1390). Cells treated with syntelin progress through interphase, enter mitosis normally with a bipolar spindle and lagging chromosomes around the poles. Syntelin is an allosteric inhibitor which tightens CENP‐E‐microtubule interaction by slowing inorganic phosphate release. To delineate the role of CENP‐E in reorganization of interpolar microtubules into an organized central spindle, metaphase synchronized cells were exposed to syntelin and other mitotic motor inhibitors. Syntelin does not perturb interpolar microtubule assembly but abrogates the anti‐parallel microtubule bundle formation. Real‐time image shows that CENP‐E inhibited cells undergo central spindle splitting and exhibits chromosome instability phenotypes. Interestingly, inhibition of CENP‐E did not alter the interaction between CENP‐E and PRC1 but perturbed temporal assembly of PRC1 to the midzone. Surprisingly, inhibition of CENP‐E perturbs the temporal control of PRC1 dephosphorylation which led to a persistent phosphorylation of PRC1 and an inhibition of central spindle assembly. These findings reveal a previously uncharacterized role of CENP‐E motor in temporal control of central spindle assembly. Grant Funding Source: DK56292; CA164133

Methylation of PLK1 by SET7/9 ensures accurate kinetochore–microtubule dynamics

“…The fact that Lys191 is evolutionarily conserved from yeast to human suggest a functional conservation of Lys191 as an essential fitness machinery in eukaryotic cell division control while other two methylation sites may exhibit context-dependent regulation. It would be of great interest in the future studies to model the methylation site-specific function using physiological system such as organoids ( Liu et al, 2019 ; Yao and Smolka, 2019 ). Our present study delineated SET7/9 function in mitosis in which SET7/9-elicited methylation of PLK1 orchestrated phosphorylation kinetics at kinetochore for accurate chromosome alignment and segregation.…”

Phase separation drives decision making in cell division

“…By use of the CENP-E inhibitor syntelin, Ding and colleagues discovered that inhibition of CENP-E arrested cells in the prometaphase, with the chromosome syntelically attached to the spindle microtubules (71). Further delineation of CENP-E function in epithelial cell division in 3D organoids led the authors to uncover the role of CENP-E in central spindle organization (73). Surprisingly, the relocation of CENP-E from the kinetochore to the central spindle is regulated by BubR1 phosphorylation ( Figure 2B) (74).…”

“…Three-dimensional images are compiled from successive light-sheet illuminations of thin, two-dimensional optical sections. The high spatial and temporal resolution of the imaging enables tracking of intracellular components in relatively thick samples, such as single chromosome trajectories in 3D gastric organoids ( Figure 6A) (73). At a higher magnification, compartments in a single chromosome can be visualized ( Figure 6B).…”

Mps1 dimerization and multisite interactions with Ndc80 complex enable responsive spindle assembly checkpoint signaling

“…Previously, our group also demonstrated that the dynamic localization of Mps1 to the kinetochore is essential for accurate spindle microtubule attachment ( Dou et al, 2015 ). It would be of great interest, down the road, to model Mps1 function using recently established 3D organoids model combined with chemical biological tools ( Drost and Clevers, 2018 ; Liu et al, 2019 ; Yao and Smolka, 2019 ), which will unravel the context-dependent function of Mps1 such as pathogenesis of solid tumors.…”