scholarly journals Altering microtubule dynamics is synergistically toxic with spindle assembly checkpoint inhibition

2020 ◽  
Vol 3 (2) ◽  
pp. e201900499 ◽  
Author(s):  
Klaske M Schukken ◽  
Yu-Chih Lin ◽  
Petra L Bakker ◽  
Michael Schubert ◽  
Stephanie F Preuss ◽  
...  
Keyword(s):  
Spindle Assembly Checkpoint ◽  
Kinase Inhibitor ◽  
Src Kinase ◽  
Spindle Assembly ◽  
Microtubule Dynamics ◽  
Target Cells ◽  
Microtubule Polymerization ◽  
Powerful Means ◽  
Small Molecule Compound ◽  
Microtubule Poisons

Chromosomal instability (CIN) and aneuploidy are hallmarks of cancer. As most cancers are aneuploid, targeting aneuploidy or CIN may be an effective way to target a broad spectrum of cancers. Here, we perform two small molecule compound screens to identify drugs that selectively target cells that are aneuploid or exhibit a CIN phenotype. We find that aneuploid cells are much more sensitive to the energy metabolism regulating drug ZLN005 than their euploid counterparts. Furthermore, cells with an ongoing CIN phenotype, induced by spindle assembly checkpoint (SAC) alleviation, are significantly more sensitive to the Src kinase inhibitor SKI606. We show that inhibiting Src kinase increases microtubule polymerization rates and, more generally, that deregulating microtubule polymerization rates is particularly toxic to cells with a defective SAC. Our findings, therefore, suggest that tumors with a dysfunctional SAC are particularly sensitive to microtubule poisons and, vice versa, that compounds alleviating the SAC provide a powerful means to treat tumors with deregulated microtubule dynamics.

scholarly journals Altering microtubule dynamics is synergistically toxic with inhibition of the spindle checkpoint

2019 ◽  
Author(s):  
Klaske M. Schukken ◽  
Yi-Chih Lin ◽  
Michael Schubert ◽  
Stephanie F. Preuss ◽  
Judith E. Simon ◽  
...  
Keyword(s):  
Spindle Assembly Checkpoint ◽  
Kinase Inhibitor ◽  
Chromosome Instability ◽  
Src Kinase ◽  
Microtubule Dynamics ◽  
Target Cells ◽  
Microtubule Polymerization ◽  
Powerful Means ◽  
Small Molecule Compound ◽  
Microtubule Poisons

AbstractChromosome instability (CIN) and aneuploidy are hallmarks of cancer. As the majority of cancers are aneuploid, targeting aneuploidy or CIN may be an effective way to target a broad spectrum of cancers. Here, we perform two small molecule compound screens to identify drugs that selectively target cells that are aneuploid or exhibit a CIN phenotype. We find that aneuploid cells are much more sensitive to the energy metabolism regulating drug ZLN005 than their euploid counterparts. Furthermore, cells with an ongoing CIN phenotype, induced by spindle assembly checkpoint (SAC) alleviation, are significantly more sensitive to the Src kinase inhibitor SKI606. We show that inhibiting Src kinase increases microtubule polymerization rates and, more generally, that deregulating microtubule polymerization rates is particularly toxic to cells with a defective SAC. Our findings therefore suggest that tumors with a dysfunctional SAC are particularly sensitive to microtubule poisons and, vice versa, that compounds alleviating the SAC provide a powerful means to treat tumors with deregulated microtubule dynamics.

scholarly journals Dynamic microtubules are essential for efficient chromosome capture and biorientation in S. cerevisiae

2006 ◽  
Vol 175 (1) ◽  
pp. 17-23 ◽  
Author(s):  
Baoying Huang ◽  
Tim C. Huffaker
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mitotic Spindle ◽  
Spindle Assembly Checkpoint ◽  
Direct Evidence ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Spindle Assembly ◽  
Spindle Pole ◽  
Microtubule Dynamics ◽  
Three Dimensional Space

Attachment of chromosomes to the mitotic spindle has been proposed to require dynamic microtubules that randomly search three-dimensional space and become stabilized upon capture by kinetochores. In this study, we test this model by examining chromosome capture in Saccharomyces cerevisiae mutants with attenuated microtubule dynamics. Although viable, these cells are slow to progress through mitosis. Preanaphase cells contain a high proportion of chromosomes that are attached to only one spindle pole and missegregate in the absence of the spindle assembly checkpoint. Measurement of the rates of chromosome capture and biorientation demonstrate that both are severely decreased in the mutants. These results provide direct evidence that dynamic microtubules are critical for efficient chromosome capture and biorientation and support the hypothesis that microtubule search and capture plays a central role in assembly of the mitotic spindle.

scholarly journals TOG–tubulin binding specificity promotes microtubule dynamics and mitotic spindle formation

2017 ◽  
Vol 216 (6) ◽  
pp. 1641-1657 ◽  
Author(s):  
Amy E. Byrnes ◽  
Kevin C. Slep
Keyword(s):  
Mitotic Spindle ◽  
Spindle Assembly Checkpoint ◽  
Polymerase Activity ◽  
Microtubule Dynamics ◽  
Spindle Formation ◽  
Microtubule Binding ◽  
Microtubule Polymerization ◽  
Tubulin Binding ◽  
Specific Order ◽  
Spindle Function

XMAP215, CLASP, and Crescerin use arrayed tubulin-binding tumor overexpressed gene (TOG) domains to modulate microtubule dynamics. We hypothesized that TOGs have distinct architectures and tubulin-binding properties that underlie each family’s ability to promote microtubule polymerization or pause. As a model, we investigated the pentameric TOG array of a Drosophila melanogaster XMAP215 member, Msps. We found that Msps TOGs have distinct architectures that bind either free or polymerized tubulin, and that a polarized array drives microtubule polymerization. An engineered TOG1-2-5 array fully supported Msps-dependent microtubule polymerase activity. Requisite for this activity was a TOG5-specific N-terminal HEAT repeat that engaged microtubule lattice-incorporated tubulin. TOG5–microtubule binding maintained mitotic spindle formation as deleting or mutating TOG5 compromised spindle architecture and increased the mitotic index. Mad2 knockdown released the spindle assembly checkpoint triggered when TOG5–microtubule binding was compromised, indicating that TOG5 is essential for spindle function. Our results reveal a TOG5-specific role in mitotic fidelity and support our hypothesis that architecturally distinct TOGs arranged in a sequence-specific order underlie TOG array microtubule regulator activity.

scholarly journals Ubc1 turnover contributes to the spindle assembly checkpoint in Saccharomyces cerevisiae

2021 ◽  
Author(s):  
Heather E Arsenault ◽  
Julie M Ghizzoni ◽  
Cassandra M Leech ◽  
Anne R Diers ◽  
Stephane Gesta ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mitotic Spindle ◽  
Spindle Assembly Checkpoint ◽  
Spindle Checkpoint ◽  
Spindle Assembly ◽  
Anaphase Promoting Complex ◽  
Checkpoint Activation ◽  
Checkpoint Signaling ◽  
Cycle Arrest ◽  
Microtubule Poisons

Abstract The spindle assembly checkpoint protects the integrity of the genome by ensuring that chromosomes are properly attached to the mitotic spindle before they are segregated during anaphase. Activation of the spindle checkpoint results in inhibition of the Anaphase Promoting Complex (APC), an E3 ubiquitin ligase that triggers the metaphase-anaphase transition. Here we show that levels of Ubc1, an E2 enzyme that functions in complex with the APC, modulate the response to spindle checkpoint activation in Saccharomyces cerevisiae. Overexpression of Ubc1 increased resistance to microtubule poisons, whereas Ubc1 shut-off sensitized cells. We also found that Ubc1 levels are regulated by the spindle checkpoint. Checkpoint activation or direct APC inhibition led to a decrease in Ubc1 levels, charging and half-life. Additionally, stabilization of Ubc1 prevented its downregulation by the spindle checkpoint and increased resistance to checkpoint-activating drugs. These results suggest that downregulation of Ubc1 in response to spindle checkpoint signaling is necessary for a robust cell cycle arrest.

scholarly journals The Aurora kinase inhibitor ZM447439 accelerates first meiosis in mouse oocytes by overriding the spindle assembly checkpoint

Reproduction ◽  
2010 ◽  
Vol 140 (4) ◽  
pp. 521-530 ◽  
Author(s):  
Simon I R Lane ◽  
Heng-Yu Chang ◽  
Phoebe C Jennings ◽  
Keith T Jones
Keyword(s):  
Spindle Assembly Checkpoint ◽  
Kinase Inhibitor ◽  
Polar Body ◽  
Spindle Assembly ◽  
Aurora Kinase ◽  
Mitotic Cell ◽  
Cyclin B1 ◽  
Anaphase Promoting Complex ◽  
Mouse Oocytes ◽  
Polar Body Extrusion

Previous studies have established that when maturing mouse oocytes are continuously incubated with the Aurora inhibitor ZM447439, meiotic maturation is blocked. In this study, we observe that by altering the time of addition of the inhibitor, oocyte maturation can actually be accelerated by 1 h as measured by the timing of polar body extrusion. ZM447439 also had the ability to overcome a spindle assembly checkpoint (SAC) arrest caused by nocodazole and so rescue polar body extrusion. Consistent with the ability of the SAC to inhibit cyclin B1 degradation by blocking activation of the anaphase-promoting complex, we could also observe a rescue in cyclin B1 degradation when ZM447439 was added to nocodazole-treated oocytes. The acceleration of the first meiotic division by ZM447439, which has not been achieved previously, and its effects on the SAC are all consistent with the proposed mitotic role of Aurora B in activating the SAC. We hypothesize that Aurora kinase activity controls the SAC in meiosis I, despite differences to the mitotic cell cycle division in spindle architecture brought about by the meiotic mono-orientation of sister kinetochores.

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