scholarly journals Overlapping kinetochore targets of CK2 and Aurora B kinases in mitotic regulation

2011 ◽  
Vol 22 (15) ◽  
pp. 2680-2689 ◽  
Author(s):  
Yutian Peng ◽  
Catherine C. L. Wong ◽  
Yuko Nakajima ◽  
Randall G. Tyers ◽  
Ali S. Sarkeshik ◽  
...  
Keyword(s):  
Protein Kinase Ck2 ◽  
Cell Cycle Progression ◽  
Spindle Assembly Checkpoint ◽  
Aurora B ◽  
Cycle Progression ◽  
Spindle Microtubules ◽  
Spindle Elongation ◽  
Mitotic Regulation ◽  
Kinase Ck2 ◽  
Kinetochore Function

Protein kinase CK2 is one of the most conserved kinases in eukaryotic cells and plays essential roles in diverse processes. While we know that CK2 plays a role(s) in cell division, our understanding of how CK2 regulates cell cycle progression is limited. In this study, we revealed a regulatory role for CK2 in kinetochore function. The kinetochore is a multi-protein complex that assembles on the centromere of a chromosome and functions to attach chromosomes to spindle microtubules. To faithfully segregate chromosomes and maintain genomic integrity, the kinetochore is tightly regulated by multiple mechanisms, including phosphorylation by Aurora B kinase. We found that a loss of CK2 kinase activity inhibits anaphase spindle elongation and results in chromosome missegregation. Moreover, a lack of CK2 activates the spindle assembly checkpoint. We demonstrate that CK2 associates with Mif2, the Saccharomyces cerevisiae homologue of human CENP-C, which serves as an important link between the inner and outer kinetochore. Furthermore, we show Mif2 and the inner kinetochore protein Ndc10 are phosphorylated by CK2, and this phosphorylation plays antagonistic and synergistic roles with Aurora B phosphorylation of these targets, respectively.

scholarly journals The regulatory β-subunit of protein kinase CK2 regulates cell-cycle progression at the onset of mitosis

Oncogene ◽  
2008 ◽  
Vol 27 (37) ◽  
pp. 4986-4997 ◽  
Author(s):  
C W Yde ◽  
B B Olsen ◽  
D Meek ◽  
N Watanabe ◽  
B Guerra
Keyword(s):  
Cell Cycle ◽  
Protein Kinase ◽  
Protein Kinase Ck2 ◽  
Cell Cycle Progression ◽  
Β Subunit ◽  
Cycle Progression ◽  
Kinase Ck2

scholarly journals Gcn5p Plays an Important Role in Centromere Kinetochore Function in Budding Yeast

2007 ◽  
Vol 28 (3) ◽  
pp. 988-996 ◽  
Author(s):  
Stefano Vernarecci ◽  
Prisca Ornaghi ◽  
AnaCristina Bâgu ◽  
Enrico Cundari ◽  
Paola Ballario ◽  
...  
Keyword(s):  
Cell Cycle Progression ◽  
Critical Role ◽  
Chromosome Loss ◽  
Cycle Progression ◽  
Kinetochore Assembly ◽  
Spindle Elongation ◽  
And Function ◽  
Insight Into ◽  
Kinetochore Function

ABSTRACT We report that the histone acetyltransferase Gcn5p is involved in cell cycle progression, whereas its absence induces several mitotic defects, including inefficient nuclear division, chromosome loss, delayed G2 progression, and spindle elongation. The fidelity of chromosome segregation is finely regulated by the close interplay between the centromere and the kinetochore, a protein complex hierarchically assembled in the centromeric DNA region, while disruption of GCN5 in mutants of inner components results in sick phenotype. These synthetic interactions involving the ADA complex lay the genetic basis for the critical role of Gcn5p in kinetochore assembly and function. We found that Gcn5p is, in fact, physically linked to the centromere, where it affects the structure of the variant centromeric nucleosome. Our findings offer a key insight into a Gcn5p-dependent epigenetic regulation at centromere/kinetochore in mitosis.

scholarly journals Key phosphorylation events in Spc29 and Spc42 guide multiple steps of yeast centrosome duplication

2018 ◽  
Vol 29 (19) ◽  
pp. 2280-2291 ◽  
Author(s):  
Michele Haltiner Jones ◽  
Eileen T. O’Toole ◽  
Amy S. Fabritius ◽  
Eric G. Muller ◽  
Janet B. Meehl ◽  
...  
Keyword(s):  
Cell Cycle Progression ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Centrosome Duplication ◽  
Phosphorylation Sites ◽  
Cycle Progression ◽  
Cellular Processes ◽  
Pole Body ◽  
Core Components ◽  
Spindle Elongation

Phosphorylation modulates many cellular processes during cell cycle progression. The yeast centrosome (called the spindle pole body, SPB) is regulated by the protein kinases Mps1 and Cdc28/Cdk1 as it nucleates microtubules to separate chromosomes during mitosis. Previously we completed an SPB phosphoproteome, identifying 297 sites on 17 of the 18 SPB components. Here we describe mutagenic analysis of phosphorylation events on Spc29 and Spc42, two SPB core components that were shown in the phosphoproteome to be heavily phosphorylated. Mutagenesis at multiple sites in Spc29 and Spc42 suggests that much of the phosphorylation on these two proteins is not essential but enhances several steps of mitosis. Of the 65 sites examined on both proteins, phosphorylation of the Mps1 sites Spc29-T18 and Spc29-T240 was shown to be critical for function. Interestingly, these two sites primarily influence distinct successive steps; Spc29-T240 is important for the interaction of Spc29 with Spc42, likely during satellite formation, and Spc29-T18 facilitates insertion of the new SPB into the nuclear envelope and promotes anaphase spindle elongation. Phosphorylation sites within Cdk1 motifs affect function to varying degrees, but mutations only have significant effects in the presence of an MPS1 mutation, supporting a theme of coregulation by these two kinases.

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

2020 ◽  
Vol 64 (2) ◽  
pp. 299-311 ◽  
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.

The role of gamma-tubulin in mitotic spindle formation and cell cycle progression in Aspergillus nidulans

1997 ◽  
Vol 110 (5) ◽  
pp. 623-633 ◽  
Author(s):  
M.A. Martin ◽  
S.A. Osmani ◽  
B.R. Oakley
Keyword(s):  
Cell Cycle ◽  
Mitotic Spindle ◽  
Cell Cycle Progression ◽  
Spindle Pole ◽  
Microtubule Assembly ◽  
Cytoplasmic Microtubule ◽  
Cycle Progression ◽  
Spindle Microtubules ◽  
Gamma Tubulin

gamma-Tubulin has been hypothesized to be essential for the nucleation of the assembly of mitotic spindle microtubules, but some recent results suggest that this may not be the case. To clarify the role of gamma-tubulin in microtubule assembly and cell-cycle progression, we have developed a novel variation of the gene disruption/heterokaryon rescue technique of Aspergillus nidulans. We have used temperature-sensitive cell-cycle mutations to synchronize germlings carrying a gamma-tubulin disruption and observe the phenotypes caused by the disruption in the first cell cycle after germination. Our results indicate that gamma-tubulin is absolutely required for the assembly of mitotic spindle microtubules, a finding that supports the hypothesis that gamma-tubulin is involved in spindle microtubule nucleation. In the absence of functional gamma-tubulin, nuclei are blocked with condensed chromosomes for about the length of one cell cycle before chromatin decondenses without nuclear division. Our results indicate that gamma-tubulin is not essential for progression from G1 to G2, for entry into mitosis nor for spindle pole body replication. It is also not required for reactivity of spindle pole bodies with the MPM-2 antibody which recognizes a phosphoepitope important to mitotic spindle formation. Finally, it does not appear to be absolutely required for cytoplasmic microtubule assembly but may play a role in the formation of normal cytoplasmic microtubule arrays.

scholarly journals Mitotic spindle disassembly occurs via distinct subprocesses driven by the anaphase-promoting complex, Aurora B kinase, and kinesin-8

2010 ◽  
Vol 191 (4) ◽  
pp. 795-808 ◽  
Author(s):  
Jeffrey B. Woodruff ◽  
David G. Drubin ◽  
Georjana Barnes
Keyword(s):  
Mitotic Spindle ◽  
Cell Cycle Progression ◽  
Dynamic Structure ◽  
Aurora B ◽  
Anaphase Promoting Complex ◽  
Microtubule Depolymerization ◽  
Aurora B Kinase ◽  
Synthetic Lethal ◽  
Spindle Disassembly ◽  
Spindle Elongation

The mitotic spindle is a complex and dynamic structure. Although much has been learned about how spindles assemble and mediate chromosome segregation, how spindles rapidly and irreversibly disassemble during telophase is less clear. We used synthetic lethal screens in budding yeast to identify mutants defective in spindle disassembly. Real-time, live cell imaging analysis of spindle disassembly was performed on nine mutants defective in this process. Results of this analysis suggest that spindle disassembly is achieved by mechanistically distinct but functionally overlapping subprocesses: disengagement of the spindle halves, arrest of spindle elongation, and initiation of interpolar microtubule depolymerization. These subprocesses are largely governed by the anaphase-promoting complex, Aurora B kinase, and kinesin-8. Combinatorial inhibition of these subprocesses yielded cells with hyperstable spindle remnants and dramatic defects in cell cycle progression, establishing that rapid spindle disassembly is crucial for cell proliferation.

scholarly journals Evidence for Regulation of Mitotic Progression through Temporal Phosphorylation and Dephosphorylation of CK2α

2009 ◽  
Vol 29 (8) ◽  
pp. 2068-2081 ◽  
Author(s):  
Nicole A. St-Denis ◽  
D. Richard Derksen ◽  
David W. Litchfield
Keyword(s):  
Protein Kinase Ck2 ◽  
Spindle Assembly Checkpoint ◽  
Mitotic Catastrophe ◽  
Mitotic Progression ◽  
Proliferating Cells ◽  
Cultured Fibroblasts ◽  
Catalytic Subunits ◽  
Chromosomal Segregation ◽  
Mitotic Phosphorylation ◽  
Kinase Ck2

ABSTRACT Proper mitotic progression is crucial for maintenance of genomic integrity in proliferating cells and is regulated through an intricate series of events, including protein phosphorylation governed by a complex network of protein kinases. One kinase family implicated in the regulation of mitotic progression is protein kinase CK2, a small family of enzymes that is overexpressed in cancer and induces transformation in mice and cultured fibroblasts. CK2α, one isoform of the catalytic subunits of CK2, is maximally phosphorylated at four sites in nocodazole-treated cells. To investigate the effects of CK2α phosphorylation on mitotic progression, we generated phosphospecific antibodies against its mitotic phosphorylation sites. In U2OS cells released from S-phase arrest, these antibodies reveal that CK2α is most highly phosphorylated in prophase and metaphase. Phosphorylation gradually decreases during anaphase and becomes undetectable during telophase and cytokinesis. Stable expression of phosphomimetic CK2α (CK2α-4D, CK2α-4E) results in aberrant centrosome amplification and chromosomal segregation defects and loss of mitotic cells through mitotic catastrophe. Conversely, cells expressing nonphosphorylatable CK2α (CK2α-4A) show a decreased ability to arrest in mitosis following nocodazole treatment, suggesting involvement in the spindle assembly checkpoint. Collectively, these studies indicate that reversible phosphorylation of CK2α requires precise regulation to allow proper mitotic progression.

scholarly journals Mammalian kinetochores count attached microtubules in a sensitive and switch-like manner to control cell cycle progression

2018 ◽  
Author(s):  
Jonathan Kuhn ◽  
Sophie Dumont
Keyword(s):  
Cell Cycle Progression ◽  
Spindle Assembly Checkpoint ◽  
Control Cell ◽  
Cycle Progression ◽  
Microtubule Binding ◽  
Input Signals ◽  
Pulling Forces ◽  
And Function ◽  
Robust Response ◽  
Control Cell Cycle Progression

AbstractThe Spindle Assembly Checkpoint (SAC) maintains genomic integrity by preventing anaphase until all kinetochores attach to the spindle. What specific signals are required for SAC satisfaction at mammalian kinetochores, and in what magnitude, are not well understood and central to understanding SAC signal processing and function. Here, we directly and independently tune candidate input signals – spindle forces and Hec1-microtubule binding – and map SAC outputs. By detaching microtubules from the spindle, we first demonstrate that the SAC does not respond to changes in spindle pulling forces. We then tune and fix the fraction of Hec1 molecules capable of microtubule binding, and interpret SAC output changes as coming from changes in binding, and not spindle forces. While the speed of satisfaction reduces with fewer attached microtubules, the kinetochore turns off the SAC even with few – approximately four – such microtubules. Thus, the mammalian kinetochore responds specifically to microtubule binding, and does so as a single, switch-like, sensitive unit. This may allow the kinetochore to rapidly react to attachments and maintain a robust response despite dynamic microtubule numbers.

scholarly journals USP48 Governs Cell Cycle Progression by Regulating the Protein Level of Aurora B

2021 ◽  
Vol 22 (16) ◽  
pp. 8508
Author(s):  
Ainsley Mike Antao ◽  
Kamini Kaushal ◽  
Soumyadip Das ◽  
Vijai Singh ◽  
Bharathi Suresh ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Aurora B ◽  
Deubiquitinating Enzymes ◽  
Cycle Progression ◽  
Protein Levels ◽  
Steady State Levels ◽  
Cycle Regulation ◽  
Normal Cell Cycle

Deubiquitinating enzymes play key roles in the precise modulation of Aurora B—an essential cell cycle regulator. The expression of Aurora B increases before the onset of mitosis and decreases during mitotic exit; an imbalance in these levels has a severe impact on the fate of the cell cycle. Dysregulation of Aurora B can lead to aberrant chromosomal segregation and accumulation of errors during mitosis, eventually resulting in cytokinesis failure. Thus, it is essential to identify the precise regulatory mechanisms that modulate Aurora B levels during the cell division cycle. Using a deubiquitinase knockout strategy, we identified USP48 as an important candidate that can regulate Aurora B protein levels during the normal cell cycle. Here, we report that USP48 interacts with and stabilizes the Aurora B protein. Furthermore, we showed that the deubiquitinating activity of USP48 helps to maintain the steady-state levels of Aurora B protein by regulating its half-life. Finally, USP48 knockout resulted in delayed progression of cell cycle due to accumulation of mitotic defects and ultimately cytokinesis failure, suggesting the role of USP48 in cell cycle regulation.

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