Modeling the temporal evolution of the spindle assembly checkpoint and role of Aurora B kinase

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.

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Enrichment of Aurora B kinase at the inner kinetochore controls outer kinetochore assembly

The Journal of Cell Biology ◽

10.1083/jcb.201901004 ◽

2019 ◽

Vol 218 (10) ◽

pp. 3237-3257 ◽

Cited By ~ 10

Author(s):

Mary Kate Bonner ◽

Julian Haase ◽

Jason Swinderman ◽

Hyunmi Halas ◽

Lisa M. Miller Jenkins ◽

...

Keyword(s):

Xenopus Laevis ◽

Central Region ◽

Spindle Assembly Checkpoint ◽

Spindle Assembly ◽

Aurora B ◽

Aurora B Kinase ◽

Kinetochore Assembly ◽

Egg Extracts ◽

Chromosome Attachment

Outer kinetochore assembly enables chromosome attachment to microtubules and spindle assembly checkpoint (SAC) signaling in mitosis. Aurora B kinase controls kinetochore assembly by phosphorylating the Mis12 complex (Mis12C) subunit Dsn1. Current models propose Dsn1 phosphorylation relieves autoinhibition, allowing Mis12C binding to inner kinetochore component CENP-C. Using Xenopus laevis egg extracts and biochemical reconstitution, we found that autoinhibition of the Mis12C by Dsn1 impedes its phosphorylation by Aurora B. Our data indicate that the INCENP central region increases Dsn1 phosphorylation by enriching Aurora B at inner kinetochores, close to CENP-C. Furthermore, centromere-bound CENP-C does not exchange in mitosis, and CENP-C binding to the Mis12C dramatically increases Dsn1 phosphorylation by Aurora B. We propose that the coincidence of Aurora B and CENP-C at inner kinetochores ensures the fidelity of kinetochore assembly. We also found that the central region is required for the SAC beyond its role in kinetochore assembly, suggesting that kinetochore enrichment of Aurora B promotes the phosphorylation of other kinetochore substrates.

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

International Journal of Molecular Sciences ◽

10.3390/ijms22168818 ◽

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.

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Aurora B phosphorylates Bub1 to promote spindle assembly checkpoint signaling

10.1101/2021.01.05.425459 ◽

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.

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Dissecting the role of INCENP-Aurora B in spindle assembly checkpoint function, chromosomal alignment and cytokinesis

Cell Cycle ◽

10.4161/cc.9.9.11514 ◽

2010 ◽

Vol 9 (9) ◽

pp. 1678-1683 ◽

Cited By ~ 3

Author(s):

Roland P. Piekorz

Keyword(s):

Spindle Assembly Checkpoint ◽

Spindle Assembly ◽

Aurora B

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Sds22 regulates aurora B activity and microtubule–kinetochore interactions at mitosis

The Journal of Cell Biology ◽

10.1083/jcb.200912046 ◽

2010 ◽

Vol 191 (1) ◽

pp. 61-74 ◽

Cited By ~ 90

Author(s):

Markus Posch ◽

Guennadi A. Khoudoli ◽

Sam Swift ◽

Emma M. King ◽

Jennifer G. DeLuca ◽

...

Keyword(s):

Protein Phosphatase ◽

Spindle Assembly Checkpoint ◽

Spindle Assembly ◽

Force Generation ◽

Protein Phosphatase 1 ◽

Aurora B ◽

Aurora B Kinase ◽

Sister Kinetochore ◽

Rate Of Recovery

We have studied Sds22, a conserved regulator of protein phosphatase 1 (PP1) activity, and determined its role in modulating the activity of aurora B kinase and kinetochore–microtubule interactions. Sds22 is required for proper progression through mitosis and localization of PP1 to mitotic kinetochores. Depletion of Sds22 increases aurora B T-loop phosphorylation and the rate of recovery from monastrol arrest. Phospho–aurora B accumulates at kinetochores in Sds22-depleted cells juxtaposed to critical kinetochore substrates. Sds22 modulates sister kinetochore distance and the interaction between Hec1 and the microtubule lattice and, thus, the activation of the spindle assembly checkpoint. These results demonstrate that Sds22 specifically defines PP1 function and localization in mitosis. Sds22 regulates PP1 targeting to the kinetochore, accumulation of phospho–aurora B, and force generation at the kinetochore–microtubule interface.

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The right place at the right time: Aurora B kinase localization to centromeres and kinetochores

Essays in Biochemistry ◽

10.1042/ebc20190081 ◽

2020 ◽

Vol 64 (2) ◽

pp. 299-311 ◽

Cited By ~ 2

Author(s):

Amanda J. Broad ◽

Jennifer G. DeLuca

Keyword(s):

Spindle Assembly Checkpoint ◽

Protein Complexes ◽

Centromeric Heterochromatin ◽

Aurora B ◽

Mitotic Chromosomes ◽

Large Protein ◽

Aurora B Kinase ◽

Centromeric Protein ◽

Spindle Microtubules ◽

The Right

Abstract The fidelity of chromosome segregation during mitosis is intimately linked to the function of kinetochores, which are large protein complexes assembled at sites of centromeric heterochromatin on mitotic chromosomes. These key “orchestrators” of mitosis physically connect chromosomes to spindle microtubules and transduce forces through these connections to congress chromosomes and silence the spindle assembly checkpoint. Kinetochore-microtubule attachments are highly regulated to ensure that incorrect attachments are not prematurely stabilized, but instead released and corrected. The kinase activity of the centromeric protein Aurora B is required for kinetochore-microtubule destabilization during mitosis, but how the kinase acts on outer kinetochore substrates to selectively destabilize immature and erroneous attachments remains debated. Here, we review recent literature that sheds light on how Aurora B kinase is recruited to both centromeres and kinetochores and discuss possible mechanisms for how kinase interactions with substrates at distinct regions of mitotic chromosomes are regulated.

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Aurora B kinase activity is regulated by SET/TAF1 on Sgo2 at the inner centromere

The Journal of Cell Biology ◽

10.1083/jcb.201811060 ◽

2019 ◽

Vol 218 (10) ◽

pp. 3223-3236 ◽

Cited By ~ 4

Author(s):

Yuichiro Asai ◽

Koh Fukuchi ◽

Yuji Tanno ◽

Saki Koitabashi-Kiyozuka ◽

Tatsuyuki Kiyozuka ◽

...

Keyword(s):

Chromosome Segregation ◽

Chromosomal Instability ◽

Kinase Activity ◽

Fine Tuning ◽

Aurora B ◽

The Novel ◽

Aurora B Kinase ◽

Microtubule Attachment ◽

Molecular Events

The accurate regulation of phosphorylation at the kinetochore is essential for establishing chromosome bi-orientation. Phosphorylation of kinetochore proteins by the Aurora B kinase destabilizes improper kinetochore–microtubule attachments, whereas the phosphatase PP2A has a counteracting role. Imbalanced phosphoregulation leads to error-prone chromosome segregation and aneuploidy, a hallmark of cancer cells. However, little is known about the molecular events that control the balance of phosphorylation at the kinetochore. Here, we show that localization of SET/TAF1, an oncogene product, to centromeres maintains Aurora B kinase activity by inhibiting PP2A, thereby correcting erroneous kinetochore–microtubule attachment. SET localizes at the inner centromere by interacting directly with shugoshin 2, with SET levels declining at increased distances between kinetochore pairs, leading to establishment of chromosome bi-orientation. Moreover, SET overexpression induces chromosomal instability by disrupting kinetochore–microtubule attachment. Thus, our findings reveal the novel role of SET in fine-tuning the phosphorylation level at the kinetochore by balancing the activities of Aurora B and PP2A.

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Interplay between mitotic kinesins and the Aurora kinase–PP1 (protein phosphatase 1) axis

Biochemical Society Transactions ◽

10.1042/bst20130191 ◽

2013 ◽

Vol 41 (6) ◽

pp. 1761-1765 ◽

Cited By ~ 11

Author(s):

John C. Meadows

Keyword(s):

Protein Phosphatase ◽

Spindle Assembly Checkpoint ◽

Spindle Checkpoint ◽

Aurora Kinase ◽

Protein Phosphatase 1 ◽

Aurora B ◽

Spatial Gradient ◽

Cell Cycle Regulators ◽

Aurora B Kinase ◽

Surveillance Mechanism

Correct transmission of genetic information from mother to daughter cells is necessary for development and survival. Accurate segregation is achieved by bipolar attachment of sister kinetochores in each chromatid pair to spindle microtubules emanating from opposite spindle poles, a process known as chromosome bi-orientation. Achieving this requires dynamic interplay between kinetochore proteins, kinesin motor proteins and cell cycle regulators. Chromosome bi-orientation is monitored by a surveillance mechanism known as the SAC (spindle assembly checkpoint). The Aurora B kinase, which is bound to the inner centromere during early mitosis, plays a central role in both chromosome bi-orientation and the spindle checkpoint. The application of tension across centromeres establishes a spatial gradient of high phosphorylation activity at the inner centromere and low phosphorylation activity at the outer kinetochore. This gradient is further refined by the association of PP1 (protein phosphatase 1) to the outer kinetochore, which stabilizes kinetochore–microtubule interactions and silences the spindle checkpoint by dephosphorylating Aurora B kinase targets when chromosome bi-orientation is achieved. In the present review, I discuss emerging evidence that bidirectional cross-talk between mitotic kinesins and the Aurora kinase–PP1 axis is crucial for co-ordinating chromosome bi-orientation and spindle checkpoint signalling in eukaryotes.

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