The mitosis-regulating and protein-protein interaction activities of Astrin are controlled by Aurora-A-induced phosphorylation

2014 ◽  
Vol 307 (5) ◽  
pp. C466-C478 ◽  
Author(s):  
Shao-Chih Chiu ◽  
Jo-Mei Maureen Chen ◽  
Tong-You Wade Wei ◽  
Tai-Shan Cheng ◽  
Ya-Hui Candice Wang ◽  
...  
Keyword(s):  
Regulatory Networks ◽  
Spindle Assembly Checkpoint ◽  
Morphological Changes ◽  
Spindle Assembly ◽  
Aurora A ◽  
Protein Protein Interaction ◽  
Daughter Cells ◽  
Sister Chromatids ◽  
Complicated Process ◽  
Spindle Stability

Cells display dramatic morphological changes in mitosis, where numerous factors form regulatory networks to orchestrate the complicated process, resulting in extreme fidelity of the segregation of duplicated chromosomes into two daughter cells. Astrin regulates several aspects of mitosis, such as maintaining the cohesion of sister chromatids by inactivating Separase and stabilizing spindle, aligning and segregating chromosomes, and silencing spindle assembly checkpoint by interacting with Src kinase-associated phosphoprotein (SKAP) and cytoplasmic linker-associated protein-1α (CLASP-1α). To understand how Astrin is regulated in mitosis, we report here that Astrin acts as a mitotic phosphoprotein, and Aurora-A phosphorylates Astrin at Ser115. The phosphorylation-deficient mutant Astrin S115A abnormally activates spindle assembly checkpoint and delays mitosis progression, decreases spindle stability, and induces chromosome misalignment. Mechanistic analyses reveal that Astrin phosphorylation mimicking mutant S115D, instead of S115A, binds and induces ubiquitination and degradation of securin, which sequentially activates Separase, an enzyme required for the separation of sister chromatids. Moreover, S115A fails to bind mitosis regulators, including SKAP and CLASP-1α, which results in the mitotic defects observed in Astrin S115A-transfected cells. In conclusion, Aurora-A phosphorylates Astrin and guides the binding of Astrin to its cellular partners, which ensures proper progression of mitosis.

scholarly journals Recent advances in understanding the role of Cdk1 in the Spindle Assembly Checkpoint

F1000Research ◽  
2020 ◽  
Vol 9 ◽  
pp. 57 ◽  
Author(s):  
Angela Flavia Serpico ◽  
Domenico Grieco
Keyword(s):  
Mitotic Spindle ◽  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Daughter Cells ◽  
Spindle Poles ◽  
Anaphase Onset ◽  
Sister Chromatids ◽  
Chromatid Cohesion ◽  
M Phase ◽  
Safeguard Mechanism

The goal of mitosis is to form two daughter cells each containing one copy of each mother cell chromosome, replicated in the previous S phase. To achieve this, sister chromatids held together back-to-back at their primary constriction, the centromere, have to interact with microtubules of the mitotic spindle so that each chromatid takes connections with microtubules emanating from opposite spindle poles (we will refer to this condition as bipolar attachment). Only once all replicated chromosomes have reached bipolar attachments can sister chromatids lose cohesion with each other, at the onset of anaphase, and move toward opposite spindle poles, being segregated into what will soon become the daughter cell nucleus. Prevention of errors in chromosome segregation is granted by a safeguard mechanism called Spindle Assembly Checkpoint (SAC). Until all chromosomes are bipolarly oriented at the equator of the mitotic spindle, the SAC prevents loss of sister chromatid cohesion, thus anaphase onset, and maintains the mitotic state by inhibiting inactivation of the major M phase promoting kinase, the cyclin B-cdk1 complex (Cdk1). Here, we review recent mechanistic insights about the circuitry that links Cdk1 to the SAC to ensure correct achievement of the goal of mitosis.

scholarly journals The equatorial position of the metaphase plate ensures symmetric cell divisions

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Chia Huei Tan ◽  
Ivana Gasic ◽  
Sabina P Huber-Reggi ◽  
Damian Dudka ◽  
Marin Barisic ◽  
...  
Keyword(s):  
Spindle Assembly Checkpoint ◽  
Metaphase Plate ◽  
Spindle Assembly ◽  
Equatorial Position ◽  
Asymmetric Cell Divisions ◽  
Daughter Cells ◽  
Cell Divisions ◽  
Microtubule Stability ◽  
Chromosome Alignment ◽  
Metazoan Cell

Chromosome alignment in the middle of the bipolar spindle is a hallmark of metazoan cell divisions. When we offset the metaphase plate position by creating an asymmetric centriole distribution on each pole, we find that metaphase plates relocate to the middle of the spindle before anaphase. The spindle assembly checkpoint enables this centering mechanism by providing cells enough time to correct metaphase plate position. The checkpoint responds to unstable kinetochore–microtubule attachments resulting from an imbalance in microtubule stability between the two half-spindles in cells with an asymmetric centriole distribution. Inactivation of the checkpoint prior to metaphase plate centering leads to asymmetric cell divisions and daughter cells of unequal size; in contrast, if the checkpoint is inactivated after the metaphase plate has centered its position, symmetric cell divisions ensue. This indicates that the equatorial position of the metaphase plate is essential for symmetric cell divisions.

scholarly journals Disruption of Astral Microtubule Contact with the Cell Cortex Activates a Bub1, Bub3, and Mad3-dependent Checkpoint in Fission Yeast

2004 ◽  
Vol 15 (7) ◽  
pp. 3345-3356 ◽  
Author(s):  
Sylvie Tournier ◽  
Yannick Gachet ◽  
Vicky Buck ◽  
Jeremy S. Hyams ◽  
Jonathan B.A. Millar
Keyword(s):  
Actin Cytoskeleton ◽  
Fission Yeast ◽  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Yeast Cells ◽  
Cell Cortex ◽  
Checkpoint Proteins ◽  
Sister Chromatids ◽  
Astral Microtubule ◽  
Spindle Rotation

In animal and yeast cells, the mitotic spindle is aligned perpendicularly to the axis of cell division. This ensures that sister chromatids are separated to opposite sides of the cytokinetic actomyosin ring. In fission yeast, spindle rotation is dependent upon the interaction of astral microtubules with the cortical actin cytoskeleton. In this article, we show that addition of Latrunculin A, which prevents spindle rotation, delays the separation of sister chromatids and anaphase promoting complex-mediated destruction of spindle-associated Securin and Cyclin B. Moreover, we find that whereas sister kinetochore pairs normally congress to the spindle midzone before anaphase onset, this congression is disrupted when astral microtubule contact with the actin cytoskeleton is disturbed. By analyzing the timing of kinetochore separation, we find that this anaphase delay requires the Bub3, Mad3, and Bub1 but not the Mad1 or Mad2 spindle assembly checkpoint proteins. In agreement with this, we find that Bub1 remains associated with kinetochores when spindles are mispositioned. These data indicate that, in fission yeast, astral microtubule contact with the medial cell cortex is monitored by a subset of spindle assembly checkpoint proteins. We propose that this checkpoint ensures spindles are properly oriented before anaphase takes place.

scholarly journals Aurora A kinase activity is required to maintain an active spindle assembly checkpoint during prometaphase

2018 ◽  
Vol 131 (7) ◽  
pp. jcs191353 ◽  
Author(s):  
Thibault Courtheoux ◽  
Alghassimou Diallo ◽  
Arun Prasath Damodaran ◽  
David Reboutier ◽  
Erwan Watrin ◽  
...  
Keyword(s):  
Spindle Assembly Checkpoint ◽  
Kinase Activity ◽  
Spindle Assembly ◽  
Aurora A Kinase ◽  
Aurora A

scholarly journals Aberrantly segregating centromeres activate the spindle assembly checkpoint in budding yeast.

1996 ◽  
Vol 133 (1) ◽  
pp. 75-84 ◽  
Author(s):  
W A Wells ◽  
A W Murray
Keyword(s):  
Copy Number ◽  
Spindle Assembly Checkpoint ◽  
Budding Yeast ◽  
Spindle Assembly ◽  
Pedigree Analysis ◽  
Eukaryotic Cells ◽  
Gene Products ◽  
Chromosome Behavior ◽  
Daughter Cells ◽  
Chromosome Alignment

The spindle assembly checkpoint is the mechanism or set of mechanisms that prevents cells with defects in chromosome alignment or spindle assembly from passing through mitosis. We have investigated the effects of mini-chromosomes on this checkpoint in budding yeast by performing pedigree analysis. This method allowed us to observe the frequency and duration of cell cycle delays in individual cells. Short, centromeric linear mini-chromosomes, which have a low fidelity of segregation, cause frequent delays in mitosis. Their circular counterparts and longer linear mini-chromosomes, which segregate more efficiently, show a much lower frequency of mitotic delays, but these delays occur much more frequently in divisions where the mini-chromosome segregates to only one of the two daughter cells. Using a conditional centromere to increase the copy number of a circular mini-chromosome greatly increases the frequency of delayed divisions. In all cases the division delays are completely abolished by the mad mutants that inactivate the spindle assembly checkpoint, demonstrating that the Mad gene products are required to detect the subtle defects in chromosome behavior that have been observed to arrest higher eukaryotic cells in mitosis.

scholarly journals Overexpression of Aurora-A bypasses cytokinesis through phosphorylation of suppressed in lung cancer

2019 ◽  
Vol 317 (3) ◽  
pp. C600-C612
Author(s):  
Shao-Chih Chiu ◽  
Kun-Chieh Chen ◽  
Jiun-Yi Hsia ◽  
Cheng-Yen Chuang ◽  
Chang-Xin Wan ◽  
...  
Keyword(s):  
Eukaryotic Cells ◽  
Aurora A ◽  
Dual Roles ◽  
Daughter Cells ◽  
Multinucleated Cells ◽  
Complicated Process ◽  
Microtubule Motor ◽  
Spindle Midzone ◽  
Underlying Mechanisms ◽  
Potential Tumor Suppressor

Mitosis is a complicated process by which eukaryotic cells segregate duplicated genomes into two daughter cells. To achieve the goal, numerous regulators have been revealed to control mitosis. The oncogenic Aurora-A is a versatile kinase responsible for the regulation of mitosis including chromosome condensation, spindle assembly, and centrosome maturation through phosphorylating a range of substrates. However, overexpression of Aurora-A bypasses cytokinesis, thereby generating multiple nuclei by unknown the mechanisms. To explore the underlying mechanisms, we found that SLAN, a potential tumor suppressor, served as a substrate of Aurora-A and knockdown of SLAN induced immature cytokinesis. Aurora-A phosphorylates SLAN at T573 under the help of the scaffold protein 14-3-3η. The SLAN phosphorylation-mimicking mutants T573D or T573E, in contrast to the phosphorylation-deficiency mutant T573A, induced higher level of multinucleated cells, and the endogenous SLAN p573 resided at spindle midzone and midbody with the help of the microtubule motor MKLP1. The Aurora-A- or SLAN-induced multiple nuclei was prevented by the knockdown of 14-3-3η or Aurora-A respectively, thereby revealing a 14-3-3η/Aurora-A/SLAN cascade negatively controlling cytokinesis. Intriguingly, SLAN T573D or T573E inactivated and T573A activated the key cytokinesis regulator RhoA. RhoA interacted with SLAN np573, i.e., the nonphosphorylated form of SLAN at T573, which localized to the spindle midzone dictated by RhoA and ECT2. Therefore, we report here that SLAN mediates the Aurora-A-triggered cytokinesis bypass and SLAN plays dual roles in that process depending on its phosphorylation status.

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 Excess TPX2 Interferes with Microtubule Disassembly and Nuclei Reformation at Mitotic Exit

Cells ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 374 ◽  
Author(s):  
Francesco D. Naso ◽  
Valentina Sterbini ◽  
Elena Crecca ◽  
Italia A. Asteriti ◽  
Alessandra D. Russo ◽  
...  
Keyword(s):  
Mitotic Spindle ◽  
Spindle Assembly ◽  
Transformed Cells ◽  
Aurora A Kinase ◽  
Aurora A ◽  
Truncated Form ◽  
Daughter Cells ◽  
Lamin B1 ◽  
Mitotic Spindle Assembly ◽  
Nuclear Reconstitution

The microtubule-associated protein TPX2 is a key mitotic regulator that contributes through distinct pathways to spindle assembly. A well-characterised function of TPX2 is the activation, stabilisation and spindle localisation of the Aurora-A kinase. High levels of TPX2 are reported in tumours and the effects of its overexpression have been investigated in cancer cell lines, while little is known in non-transformed cells. Here we studied TPX2 overexpression in hTERT RPE-1 cells, using either the full length TPX2 or a truncated form unable to bind Aurora-A, to identify effects that are dependent—or independent—on its interaction with the kinase. We observe significant defects in mitotic spindle assembly and progression through mitosis that are more severe when overexpressed TPX2 is able to interact with Aurora-A. Furthermore, we describe a peculiar, and Aurora-A-interaction-independent, phenotype in telophase cells, with aberrantly stable microtubules interfering with nuclear reconstitution and the assembly of a continuous lamin B1 network, resulting in daughter cells displaying doughnut-shaped nuclei. Our results using non-transformed cells thus reveal a previously uncharacterised consequence of abnormally high TPX2 levels on the correct microtubule cytoskeleton remodelling and G1 nuclei reformation, at the mitosis-to-interphase transition.

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