scholarly journals Deubiquitylase UCHL3 drives error correction at kinetochores and chromosome segregation independent of spindle assembly checkpoint

2020 ◽  
Author(s):  
Katerina Jerabkova ◽  
Yongrong Liao ◽  
Charlotte Kleiss ◽  
Sadek Fournane ◽  
Matej Durik ◽  
...  
Keyword(s):  
Error Correction ◽  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Cellular Transformation ◽  
Aurora B ◽  
Mitotic Kinase ◽  
Daughter Cells ◽  
Microtubule Attachment ◽  
Anaphase Onset ◽  
Segregation Of Chromosomes

AbstractEqual segregation of chromosomes during mitosis ensures euploidy of daughter cells. Defects in this process may result in imbalance in chromosomal composition and cellular transformation. Two surveillance pathways, the spindle assembly checkpoint (SAC) and the error-correction (EC), exist at kinetochores that monitor microtubule attachment and faithful segregation of chromosomes at the metaphase to anaphase transition. However, the molecular understanding of the interplay between EC and SAC signaling remains limited. Here we describe a role of deubiquitylase UCHL3 in the regulation of EC pathway during mitosis. Downregulation or inhibition of UCHL3 leads to improper attachments of chromosomes to spindle microtubules and to chromosome alignment defects during metaphase. Frequent segregation errors during anaphase and consequently aneuploidy is also observed upon inactivation of UCHL3. Surprisingly, UCHL3 is not involved in SAC signaling as both recruitment of SAC proteins to kinetochores and timely anaphase onset are not perturbed in UCHL3-deficient cells. Mechanistically, UCHL3 interacts with and deubiquitylates the mitotic kinase Aurora B known to drive both SAC and EC signaling. UCHL3 promotes interaction of Aurora B with MCAK, important EC factor but does not regulate Aurora B binding to other interacting partners or subcellular localization of Aurora B. Our results thus suggest that UCHL3-mediated deubiquitylation functionally separates EC from SAC signaling during mitosis and is critical for maintenance of euploidy in human cells.

scholarly journals Aurora B phosphorylates Bub1 to promote spindle assembly checkpoint signaling

2021 ◽  
Author(s):  
Babhrubahan Roy ◽  
Simon J. Y. Han ◽  
Adrienne N. Fontan ◽  
Ajit P. Joglekar
Keyword(s):  
Error Correction ◽  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Mitotic Checkpoint ◽  
Aurora B ◽  
Aurora B Kinase ◽  
Checkpoint Signaling ◽  
Binding Interface ◽  
Anaphase Onset ◽  
Error Correction Mechanism

SummaryAccurate chromosome segregation during cell division requires amphitelic attachment of each chromosome to the spindle apparatus. This is ensured by the Spindle Assembly Checkpoint (SAC) [1], which delays anaphase onset in response to unattached chromosomes, and an error correction mechanism, which eliminates syntelic chromosome attachments [2]. The SAC is activated by the Mps1 kinase. Mps1 sequentially phosphorylates the kinetochore protein Spc105/KNL1 to license the recruitment of several signaling proteins including Bub1. These proteins produce the Mitotic Checkpoint Complex (MCC), which delays anaphase onset [3-8]. The error correction mechanism is regulated by the Aurora B kinase, which phosphorylates the microtubule-binding interface of the kinetochore. Aurora B is also known to promote SAC signaling indirectly [9-12]. Here we present evidence that Aurora B kinase activity directly promotes MCC production in budding yeast and human cells. Using the ectopic SAC activation (eSAC) system, we find that the conditional dimerization of Aurora B (or an Aurora B recruitment domain) with either Bub1 or Mad1, but not the ‘MELT’ motifs in Spc105/KNL1, leads to a SAC-mediated mitotic arrest [13-16]. Importantly, ectopic MCC production driven by Aurora B requires the ability of Bub1 to bind both Mad1 and Cdc20. These and other data show that Aurora B cooperates with Bub1 to promote MCC production only after Mps1 licenses Bub1 recruitment to the kinetochore. This direct involvement of Aurora B in SAC signaling is likely important for syntelically attached sister kinetochores that must delay anaphase onset in spite of reduced Mps1 activity due to their end-on microtubule attachment.

scholarly journals Centromere-localized Aurora B kinase is required for the fidelity of chromosome segregation

2019 ◽  
Vol 219 (2) ◽  
Author(s):  
Cai Liang ◽  
Zhenlei Zhang ◽  
Qinfu Chen ◽  
Haiyan Yan ◽  
Miao Zhang ◽  
...  
Keyword(s):  
Chromosome Segregation ◽  
Essential Role ◽  
Spindle Assembly Checkpoint ◽  
Histone H3 ◽  
Spindle Assembly ◽  
Aurora B ◽  
Aurora B Kinase ◽  
Chromosome Missegregation ◽  
Proper Timing ◽  
Segregation Of Chromosomes

Aurora B kinase plays an essential role in chromosome bi-orientation, which is a prerequisite for equal segregation of chromosomes during mitosis. However, it remains largely unclear whether centromere-localized Aurora B is required for faithful chromosome segregation. Here we show that histone H3 Thr-3 phosphorylation (H3pT3) and H2A Thr-120 phosphorylation (H2ApT120) can independently recruit Aurora B. Disrupting H3pT3-mediated localization of Aurora B at the inner centromere impedes the decline in H2ApT120 during metaphase and causes H2ApT120-dependent accumulation of Aurora B at the kinetochore-proximal centromere. Consequently, silencing of the spindle assembly checkpoint (SAC) is delayed, whereas the fidelity of chromosome segregation is negligibly affected. Further eliminating an H2ApT120-dependent pool of Aurora B restores proper timing for SAC silencing but increases chromosome missegregation. Our data indicate that H2ApT120-mediated localization of Aurora B compensates for the loss of an H3pT3-dependent pool of Aurora B to correct improper kinetochore–microtubule attachments. This study provides important insights into how centromeric Aurora B regulates SAC and kinetochore attachment to microtubules to ensure error-free chromosome segregation.

scholarly journals Interactions between N-Terminal Modules in MPS1 Enable Spindle Checkpoint Silencing

2018 ◽  
Author(s):  
Spyridon T. Pachis ◽  
Yoshitaka Hiruma ◽  
Anastassis Perrakis ◽  
Geert J.P.L. Kops
Keyword(s):  
Chromosome Segregation ◽  
Mitotic Spindle ◽  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Intramolecular Interactions ◽  
Mitotic Progression ◽  
Microtubule Attachment ◽  
Anaphase Onset ◽  
Regulatory Input ◽  
Tpr Domain

ABSTRACTFaithful chromosome segregation relies on the ability of the spindle assembly checkpoint (SAC) to delay anaphase onset until all chromosomes are attached to the mitotic spindle via their kinetochores. MPS1 kinase is recruited to unattached kinetochores to initiate SAC signaling, and is removed from kinetochores once stable microtubule attachments have been formed to allow normal mitotic progression. Here we show that a helical fragment within the kinetochore-targeting NTE module of MPS1 is required for interactions with kinetochores, and also forms intramolecular interactions with its adjacent TPR domain. Bypassing this NTE-TPR interaction results in high MPS1 levels at kinetochores due to loss of regulatory input into MPS1 localization, ineffecient MPS1 delocalization from kinetochores upon microtubule attachment, and SAC silencing defects. These results show that SAC responsiveness to attachments relies on regulated intramolecular interactions in MPS1 and highlight the sensitivity of mitosis to perturbations in the dynamics of the MSP1-NDC80-C interactions.

scholarly journals Delineating the contribution of Spc105-bound PP1 to spindle checkpoint silencing and kinetochore microtubule attachment regulation

2019 ◽  
Vol 218 (12) ◽  
pp. 3926-3942 ◽  
Author(s):  
Babhrubahan Roy ◽  
Vikash Verma ◽  
Janice Sim ◽  
Adrienne Fontan ◽  
Ajit P. Joglekar
Keyword(s):  
Cell Division ◽  
Error Correction ◽  
Chromosome Segregation ◽  
Protein Phosphatase ◽  
Spindle Assembly Checkpoint ◽  
Spindle Checkpoint ◽  
Spindle Assembly ◽  
Protein Phosphatase 1 ◽  
Microtubule Attachment ◽  
Error Correction Mechanism

Accurate chromosome segregation during cell division requires the spindle assembly checkpoint (SAC), which detects unattached kinetochores, and an error correction mechanism that destabilizes incorrect kinetochore–microtubule attachments. While the SAC and error correction are both regulated by protein phosphatase 1 (PP1), which silences the SAC and stabilizes kinetochore–microtubule attachments, how these distinct PP1 functions are coordinated remains unclear. Here, we investigate the contribution of PP1, docked on its conserved kinetochore receptor Spc105/Knl1, to SAC silencing and attachment regulation. We find that Spc105-bound PP1 is critical for SAC silencing but dispensable for error correction; in fact, reduced PP1 docking on Spc105 improved chromosome segregation and viability of mutant/stressed states. We additionally show that artificially recruiting PP1 to Spc105/Knl1 before, but not after, chromosome biorientation interfered with error correction. These observations lead us to propose that recruitment of PP1 to Spc105/Knl1 is carefully regulated to ensure that chromosome biorientation precedes SAC silencing, thereby ensuring accurate chromosome segregation.

scholarly journals Aurora B Tension Sensing Mechanisms in the Kinetochore Ensure Accurate Chromosome Segregation

2021 ◽  
Vol 22 (16) ◽  
pp. 8818
Author(s):  
Shelby L. McVey ◽  
Jenna K. Cosby ◽  
Natalie J. Nannas
Keyword(s):  
Chromosome Segregation ◽  
Birth Defects ◽  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Aurora B ◽  
Sister Chromatids ◽  
Congenital Birth Defects ◽  
Biochemical Signals ◽  
Segregation Of Chromosomes

The accurate segregation of chromosomes is essential for the survival of organisms and cells. Mistakes can lead to aneuploidy, tumorigenesis and congenital birth defects. The spindle assembly checkpoint ensures that chromosomes properly align on the spindle, with sister chromatids attached to microtubules from opposite poles. Here, we review how tension is used to identify and selectively destabilize incorrect attachments, and thus serves as a trigger of the spindle assembly checkpoint to ensure fidelity in chromosome segregation. Tension is generated on properly attached chromosomes as sister chromatids are pulled in opposing directions but resisted by centromeric cohesin. We discuss the role of the Aurora B kinase in tension-sensing and explore the current models for translating mechanical force into Aurora B-mediated biochemical signals that regulate correction of chromosome attachments to the spindle.

scholarly journals Spindly, a novel protein essential for silencing the spindle assembly checkpoint, recruits dynein to the kinetochore

2007 ◽  
Vol 177 (6) ◽  
pp. 1005-1015 ◽  
Author(s):  
Eric R. Griffis ◽  
Nico Stuurman ◽  
Ronald D. Vale
Keyword(s):  
Spindle Assembly Checkpoint ◽  
Metaphase Plate ◽  
Spindle Assembly ◽  
Cytoplasmic Dynein ◽  
Checkpoint Proteins ◽  
Drosophila Melanogaster S2 Cells ◽  
Microtubule Attachment ◽  
Anaphase Onset ◽  
Cell Biol ◽  
Novel Protein

The eukaryotic spindle assembly checkpoint (SAC) monitors microtubule attachment to kinetochores and prevents anaphase onset until all kinetochores are aligned on the metaphase plate. In higher eukaryotes, cytoplasmic dynein is involved in silencing the SAC by removing the checkpoint proteins Mad2 and the Rod–Zw10–Zwilch complex (RZZ) from aligned kinetochores (Howell, B.J., B.F. McEwen, J.C. Canman, D.B. Hoffman, E.M. Farrar, C.L. Rieder, and E.D. Salmon. 2001. J. Cell Biol. 155:1159–1172; Wojcik, E., R. Basto, M. Serr, F. Scaerou, R. Karess, and T. Hays. 2001. Nat. Cell Biol. 3:1001–1007). Using a high throughput RNA interference screen in Drosophila melanogaster S2 cells, we have identified a new protein (Spindly) that accumulates on unattached kinetochores and is required for silencing the SAC. After the depletion of Spindly, dynein cannot target to kinetochores, and, as a result, cells arrest in metaphase with high levels of kinetochore-bound Mad2 and RZZ. We also identified a human homologue of Spindly that serves a similar function. However, dynein's nonkinetochore functions are unaffected by Spindly depletion. Our findings indicate that Spindly is a novel regulator of mitotic dynein, functioning specifically to target dynein to kinetochores.

scholarly journals Mechanisms of chromosome biorientation and bipolar spindle assembly analyzed by computational modeling

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Christopher Edelmaier ◽  
Adam R Lamson ◽  
Zachary R Gergely ◽  
Saad Ansari ◽  
Robert Blackwell ◽  
...  
Keyword(s):  
Mitotic Spindle ◽  
Spindle Assembly ◽  
Extensive Study ◽  
Bipolar Spindle ◽  
Microtubule Attachment ◽  
Anaphase Onset ◽  
Length Regulation ◽  
Mitotic Spindle Assembly ◽  
Early Mitosis ◽  
Segregation Of Chromosomes

The essential functions required for mitotic spindle assembly and chromosome biorientation and segregation are not fully understood, despite extensive study. To illuminate the combinations of ingredients most important to align and segregate chromosomes and simultaneously assemble a bipolar spindle, we developed a computational model of fission-yeast mitosis. Robust chromosome biorientation requires progressive restriction of attachment geometry, destabilization of misaligned attachments, and attachment force dependence. Large spindle length fluctuations can occur when the kinetochore-microtubule attachment lifetime is long. The primary spindle force generators are kinesin-5 motors and crosslinkers in early mitosis, while interkinetochore stretch becomes important after biorientation. The same mechanisms that contribute to persistent biorientation lead to segregation of chromosomes to the poles after anaphase onset. This model therefore provides a framework to interrogate key requirements for robust chromosome biorientation, spindle length regulation, and force generation in the spindle.

scholarly journals Mechanisms of chromosome biorientation and bipolar spindle assembly analyzed by computational modeling

2019 ◽  
Author(s):  
Christopher J. Edelmaier ◽  
Adam R. Lamson ◽  
Zachary R. Gergely ◽  
Saad Ansari ◽  
Robert Blackwell ◽  
...  
Keyword(s):  
Mitotic Spindle ◽  
Spindle Assembly ◽  
Extensive Study ◽  
Bipolar Spindle ◽  
Microtubule Attachment ◽  
Anaphase Onset ◽  
Length Regulation ◽  
Mitotic Spindle Assembly ◽  
Early Mitosis ◽  
Segregation Of Chromosomes

AbstractThe essential functions required for mitotic spindle assembly and chromosome biorientation and segregation are not fully understood, despite extensive study. To illuminate the combinations of ingredients most important to align and segregate chromosomes and simultaneously assemble a bipolar spindle, we developed a computational model of fission-yeast mitosis. Robust chromosome biorientation requires progressive restriction of attachment geometry, destabilization of misaligned attachments, and attachment force dependence. Large spindle length fluctuations can occur when the kinetochore-microtubule attachment lifetime is long. The primary spindle force generators are kinesin-5 motors and crosslinkers in early mitosis, while interkinetochore stretch becomes important after biorientation. The same mechanisms that contribute to persistent biorientation lead to segregation of chromosomes to the poles after anaphase onset. This model therefore provides a framework to interrogate key requirements for robust chromosome biorientation, spindle length regulation, and force generation in the spindle.

The spindle assembly checkpoint: progress and persistent puzzles

2013 ◽  
Vol 41 (6) ◽  
pp. 1755-1760 ◽  
Author(s):  
Silke Hauf
Keyword(s):  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Signalling Pathway ◽  
Model Organisms ◽  
Daughter Cells ◽  
Safety Mechanism ◽  
Key Features ◽  
Intensive Work ◽  
Made In ◽  
Segregation Of Chromosomes

The spindle assembly checkpoint is a conserved mitotic signalling pathway that ensures the equal segregation of chromosomes to daughter cells. Despite intensive work in many model organisms, key features of this safety mechanism remain unexplained. In the present review, I briefly summarize advances made in the last few years, and then focus on unexplored corners of this signalling pathway.

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