scholarly journals Dual recognition of chromatin and microtubules by INCENP is important for mitotic progression

2017 ◽  
Vol 216 (4) ◽  
pp. 925-941 ◽  
Author(s):  
Michael S. Wheelock ◽  
David J. Wynne ◽  
Boo Shan Tseng ◽  
Hironori Funabiki
Keyword(s):  
Cell Fate ◽  
Binding Capacity ◽  
Mitotic Checkpoint ◽  
Mitotic Arrest ◽  
Cyclin Dependent Kinase ◽  
Mitotic Progression ◽  
Microtubule Binding ◽  
Chromosomal Passenger ◽  
Α Helix

The chromosomal passenger complex (CPC), composed of inner centromere protein (INCENP), Survivin, Borealin, and the kinase Aurora B, contributes to the activation of the mitotic checkpoint. The regulation of CPC function remains unclear. Here, we reveal that in addition to Survivin and Borealin, the single α-helix (SAH) domain of INCENP supports CPC localization to chromatin and the mitotic checkpoint. The INCENP SAH domain also mediates INCENP’s microtubule binding, which is negatively regulated by Cyclin-dependent kinase–mediated phosphorylation of segments flanking the SAH domain. The microtubule-binding capacity of the SAH domain is important for mitotic arrest in conditions of suppressed microtubule dynamics, and the duration of mitotic arrest dictates the probability, but not the timing, of cell death. Although independent targeting of INCENP to microtubules or the kinetochore/centromere promotes the mitotic checkpoint, it is insufficient for a robust mitotic arrest. Altogether, our results demonstrate that dual recognition of chromatin and microtubules by CPC is important for checkpoint maintenance and determination of cell fate in mitosis.

scholarly journals Mitotic progression, arrest, exit or death relies on centromere structural integrity, rather than de novo transcription

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Marco Novais-Cruz ◽  
Maria Alba Abad ◽  
Wilfred FJ van IJcken ◽  
Niels Galjart ◽  
A Arockia Jeyaprakash ◽  
...  
Keyword(s):  
Cell Fate ◽  
Spindle Assembly Checkpoint ◽  
Structural Integrity ◽  
De Novo ◽  
Dna Intercalation ◽  
Aurora B ◽  
Rna Seq ◽  
Mitotic Progression ◽  
Chromosomal Passenger ◽  
Intercalating Agents

Recent studies have challenged the prevailing dogma that transcription is repressed during mitosis. Transcription was also proposed to sustain a robust spindle assembly checkpoint (SAC) response. Here, we used live-cell imaging of human cells, RNA-seq and qPCR to investigate the requirement for de novo transcription during mitosis. Under conditions of persistently unattached kinetochores, transcription inhibition with actinomycin D, or treatment with other DNA-intercalating drugs, delocalized the chromosomal passenger complex (CPC) protein Aurora B from centromeres, compromising SAC signaling and cell fate. However, we were unable to detect significant changes in mitotic transcript levels. Moreover, inhibition of transcription independently of DNA intercalation had no effect on Aurora B centromeric localization, SAC response, mitotic progression, exit or death. Mechanistically, we show that DNA intercalating agents reduce the interaction of the CPC with nucleosomes. Thus, mitotic progression, arrest, exit or death is determined by centromere structural integrity, rather than de novo transcription.

scholarly journals Multisite phosphorylation by Cdk1 initiates delayed negative feedback to control mitotic transcription

2021 ◽  
Author(s):  
Jonathan B. Asfaha ◽  
Mihkel Örd ◽  
Mart Loog ◽  
David O. Morgan
Keyword(s):  
Gene Expression ◽  
Negative Feedback ◽  
Transcriptional Activation ◽  
Mitotic Arrest ◽  
Cyclin Dependent Kinase ◽  
Feedback Circuit ◽  
Mitotic Progression ◽  
Transcriptional Program ◽  
Multisite Phosphorylation ◽  
Negative Feedback Circuit

AbstractOrdered phosphorylation of cyclin-dependent kinase (CDK) substrates leads to the sequential transcriptional activation and inhibition of hundreds of cell cycle-regulated genes. We find that Ndd1, an activator of genes required for mitotic progression, is both positively and negatively regulated by CDK activity. CDK activity initially stimulates Ndd1-dependent transcription as cells enter mitosis, but prolonged high CDK activity in a mitotic arrest inhibits transcription. The result is a time-delayed negative feedback circuit that generates a pulse of mitotic gene expression. Our results suggest that high CDK activity catalyzes the formation of multiple weak phosphodegrons on Ndd1, leading to its destabilization. Cyclin specificity and phosphorylation kinetics contribute to the timing of Ndd1 destruction. Failure to degrade Ndd1 in a mitotic arrest leads to elevated mitotic gene expression. We conclude that a combination of positive and negative Ndd1 regulation by CDKs governs the timing and magnitude of the mitotic transcriptional program.

scholarly journals Mitotic progression, arrest, exit or death is determined by centromere integrity and independent of de novo transcription

2018 ◽  
Author(s):  
Marco Novais-Cruz ◽  
Maria Alba Abad ◽  
Wilfred F.J. van Ijcken ◽  
Niels Galjart ◽  
A. Arockia Jeyaprakash ◽  
...  
Keyword(s):  
Cell Fate ◽  
Live Cell Imaging ◽  
Spindle Assembly Checkpoint ◽  
De Novo ◽  
Human Cells ◽  
Dna Intercalation ◽  
Rna Seq ◽  
Mitotic Progression ◽  
Chromosomal Passenger ◽  
Intercalating Agents

AbstractRecent studies have challenged the prevailing dogma that transcription is repressed during mitosis. Transcription was also proposed to sustain the spindle assembly checkpoint (SAC) for several hours in response to unattached kinetochores. Here we used live-cell imaging of human cells in culture, combined with RNA-seq and qPCR, to investigate the requirement for de novo transcription during mitosis. Under conditions of persistently unattached kinetochores, transcription inhibition with actinomycin D, or treatment with other DNA-intercalating drugs, delocalized the chromosomal passenger complex (CPC) protein Aurora B from centromeres, compromising SAC robustness and cell fate. However, we were unable to detect significant changes in transcript levels. Moreover, inhibition of transcription independently of DNA intercalation had no effect on SAC response, mitotic progression, exit or death. Mechanistically, we show that DNA intercalating agents reduce the interaction of the CPC with nucleosomes. Thus, the capacity of human cells to progress, sustain, exit or die in mitosis relies on centromere integrity, rather than de novo transcription.

scholarly journals RanBP2 and SENP3 Function in a Mitotic SUMO2/3 Conjugation-Deconjugation Cycle on Borealin

2009 ◽  
Vol 20 (1) ◽  
pp. 410-418 ◽  
Author(s):  
Ulf R. Klein ◽  
Markus Haindl ◽  
Erich A. Nigg ◽  
Stefan Muller
Keyword(s):  
Mammalian Cells ◽  
Spindle Assembly Checkpoint ◽  
Critical Role ◽  
Specific Interaction ◽  
Regulatory Function ◽  
Mitotic Progression ◽  
Chromosome Congression ◽  
Chromosomal Passenger

The ubiquitin-like SUMO system controls cellular key functions, and several lines of evidence point to a critical role of SUMO for mitotic progression. However, in mammalian cells mitotic substrates of sumoylation and the regulatory components involved are not well defined. Here, we identify Borealin, a component of the chromosomal passenger complex (CPC), as a mitotic target of SUMO. The CPC, which additionally comprises INCENP, Survivin, and Aurora B, regulates key mitotic events, including chromosome congression, the spindle assembly checkpoint, and cytokinesis. We show that Borealin is preferentially modified by SUMO2/3 and demonstrate that the modification is dynamically regulated during mitotic progression, peaking in early mitosis. Intriguingly, the SUMO ligase RanBP2 interacts with the CPC, stimulates SUMO modification of Borealin in vitro, and is required for its modification in vivo. Moreover, the SUMO isopeptidase SENP3 is a specific interaction partner of Borealin and catalyzes the removal of SUMO2/3 from Borealin. These data thus delineate a mitotic SUMO2/3 conjugation–deconjugation cycle of Borealin and further assign a regulatory function of RanBP2 and SENP3 in the mitotic SUMO pathway.

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