scholarly journals Slip slidin’ away of mitosis with CRL2Zyg11

2016 ◽  
Vol 215 (2) ◽  
pp. 143-145 ◽  
Author(s):  
Michael Brandeis

The spindle assembly checkpoint arrests mitotic cells by preventing degradation of cyclin B1 by the anaphase-promoting complex/cyclosome, but some cells evade this checkpoint and slip out of mitosis. Balachandran et al. (2016. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201601083) show that the E3 ligase CRL2ZYG11 degrades cyclin B1, allowing mitotic slippage.

2008 ◽  
Vol 183 (2) ◽  
pp. 267-277 ◽  
Author(s):  
Evan C. Osmundson ◽  
Dipankar Ray ◽  
Finola E. Moore ◽  
Qingshen Gao ◽  
Gerald H. Thomsen ◽  
...  

Activation of the anaphase-promoting complex/cyclosome (APC/C) by Cdc20 is critical for the metaphase–anaphase transition. APC/C-Cdc20 is required for polyubiquitination and degradation of securin and cyclin B at anaphase onset. The spindle assembly checkpoint delays APC/C-Cdc20 activation until all kinetochores attach to mitotic spindles. In this study, we demonstrate that a HECT (homologous to the E6-AP carboxyl terminus) ubiquitin ligase, Smurf2, is required for the spindle checkpoint. Smurf2 localizes to the centrosome, mitotic midbody, and centromeres. Smurf2 depletion or the expression of a catalytically inactive Smurf2 results in misaligned and lagging chromosomes, premature anaphase onset, and defective cytokinesis. Smurf2 inactivation prevents nocodazole-treated cells from accumulating cyclin B and securin and prometaphase arrest. The silencing of Cdc20 in Smurf2-depleted cells restores mitotic accumulation of cyclin B and securin. Smurf2 depletion results in enhanced polyubiquitination and degradation of Mad2, a critical checkpoint effector. Mad2 is mislocalized in Smurf2-depleted cells, suggesting that Smurf2 regulates the localization and stability of Mad2. These data indicate that Smurf2 is a novel mitotic regulator.


eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Christine C Lee ◽  
Bing Li ◽  
Hongtao Yu ◽  
Michael J Matunis

The Anaphase Promoting Complex/Cyclosome (APC/C) is a ubiquitin E3 ligase that functions as the gatekeeper to mitotic exit. APC/C activity is controlled by an interplay of multiple pathways during mitosis, including the spindle assembly checkpoint (SAC), that are not yet fully understood. Here, we show that sumoylation of the APC4 subunit of the APC/C peaks during mitosis and is critical for timely APC/C activation and anaphase onset. We have also identified a functionally important SUMO interacting motif in the cullin-homology domain of APC2 located near the APC4 sumoylation sites and APC/C catalytic core. Our findings provide evidence of an important regulatory role for SUMO modification and binding in affecting APC/C activation and mitotic exit.


2001 ◽  
Vol 153 (1) ◽  
pp. 137-148 ◽  
Author(s):  
Stephan Geley ◽  
Edgar Kramer ◽  
Christian Gieffers ◽  
Julian Gannon ◽  
Jan-Michael Peters ◽  
...  

Cyclin A is a stable protein in S and G2 phases, but is destabilized when cells enter mitosis and is almost completely degraded before the metaphase to anaphase transition. Microinjection of antibodies against subunits of the anaphase-promoting complex/cyclosome (APC/C) or against human Cdc20 (fizzy) arrested cells at metaphase and stabilized both cyclins A and B1. Cyclin A was efficiently polyubiquitylated by Cdc20 or Cdh1-activated APC/C in vitro, but in contrast to cyclin B1, the proteolysis of cyclin A was not delayed by the spindle assembly checkpoint. The degradation of cyclin B1 was accelerated by inhibition of the spindle assembly checkpoint. These data suggest that the APC/C is activated as cells enter mitosis and immediately targets cyclin A for degradation, whereas the spindle assembly checkpoint delays the degradation of cyclin B1 until the metaphase to anaphase transition. The “destruction box” (D-box) of cyclin A is 10–20 residues longer than that of cyclin B. Overexpression of wild-type cyclin A delayed the metaphase to anaphase transition, whereas expression of cyclin A mutants lacking a D-box arrested cells in anaphase.


2016 ◽  
Vol 215 (2) ◽  
pp. 151-166 ◽  
Author(s):  
Riju S. Balachandran ◽  
Cassandra S. Heighington ◽  
Natalia G. Starostina ◽  
James W. Anderson ◽  
David L. Owen ◽  
...  

The anaphase-promoting complex/cyclosome (APC/C) ubiquitin ligase is known to target the degradation of cyclin B1, which is crucial for mitotic progression in animal cells. In this study, we show that the ubiquitin ligase CRL2ZYG-11 redundantly targets the degradation of cyclin B1 in Caenorhabditis elegans and human cells. In C. elegans, both CRL2ZYG-11 and APC/C are required for proper progression through meiotic divisions. In human cells, inactivation of CRL2ZYG11A/B has minimal effects on mitotic progression when APC/C is active. However, when APC/C is inactivated or cyclin B1 is overexpressed, CRL2ZYG11A/B-mediated degradation of cyclin B1 is required for normal progression through metaphase. Mitotic cells arrested by the spindle assembly checkpoint, which inactivates APC/C, often exit mitosis in a process termed “mitotic slippage,” which generates tetraploid cells and limits the effectiveness of antimitotic chemotherapy drugs. We show that ZYG11A/B subunit knockdown, or broad cullin–RING ubiquitin ligase inactivation with the small molecule MLN4924, inhibits mitotic slippage in human cells, suggesting the potential for antimitotic combination therapy.


Reproduction ◽  
2010 ◽  
Vol 140 (4) ◽  
pp. 521-530 ◽  
Author(s):  
Simon I R Lane ◽  
Heng-Yu Chang ◽  
Phoebe C Jennings ◽  
Keith T Jones

Previous studies have established that when maturing mouse oocytes are continuously incubated with the Aurora inhibitor ZM447439, meiotic maturation is blocked. In this study, we observe that by altering the time of addition of the inhibitor, oocyte maturation can actually be accelerated by 1 h as measured by the timing of polar body extrusion. ZM447439 also had the ability to overcome a spindle assembly checkpoint (SAC) arrest caused by nocodazole and so rescue polar body extrusion. Consistent with the ability of the SAC to inhibit cyclin B1 degradation by blocking activation of the anaphase-promoting complex, we could also observe a rescue in cyclin B1 degradation when ZM447439 was added to nocodazole-treated oocytes. The acceleration of the first meiotic division by ZM447439, which has not been achieved previously, and its effects on the SAC are all consistent with the proposed mitotic role of Aurora B in activating the SAC. We hypothesize that Aurora kinase activity controls the SAC in meiosis I, despite differences to the mitotic cell cycle division in spindle architecture brought about by the meiotic mono-orientation of sister kinetochores.


2017 ◽  
Author(s):  
Thomas Wild ◽  
Magda Budzowska ◽  
Gopal Karemore ◽  
Chunaram Choudhary

AbstractThe multisubunit ubiquitin ligase APC/C (anaphase promoting complex/cyclosome) is essential for mitosis by promoting timely degradation of cyclin B1. Proper timing of APC/C activation is regulated by the spindle assembly checkpoint (SAC), which is initiated by the kinase MPS1 and implemented by MAD2-dependent inhibition of the APC/C. Here we analysed the contribution of the higher eukaryote-specific APC/C subunits APC7 and APC16 to APC/C composition, function and regulation. APC16 is required for APC7 assembly into the APC/C, while APC16 assembles independently of APC7. ΔAPC7 and ΔAPC16 cells display no major defects in mitotic progression, cyclin B1 degradation or SAC response. Strikingly, however, deletion of either APC7 or APC16 is sufficient to provide synthetic viability to MAD2 deletion. ΔAPC7ΔMAD2 cells display an accelerated mitosis and require SAC-independent MPS1 function for maintaining their genome stability. Overall, these results show how human APC/C composition critically influences the cellular fate upon loss of SAC activity.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ana C. Henriques ◽  
Patrícia M. A. Silva ◽  
Bruno Sarmento ◽  
Hassan Bousbaa

AbstractAntimitotic drugs arrest cells in mitosis through chronic activation of the spindle assembly checkpoint (SAC), leading to cell death. However, drug-treated cancer cells can escape death by undergoing mitotic slippage, due to premature mitotic exit. Therefore, overcoming slippage issue is a promising chemotherapeutic strategy to improve the effectiveness of antimitotics. Here, we antagonized SAC silencing by knocking down the MAD2-binding protein p31comet, to delay mitotic slippage, and tracked cancer cells treated with the antimitotic drug paclitaxel, over 3 days live-cell time-lapse analysis. We found that in the absence of p31comet, the duration of mitotic block was increased in cells challenged with nanomolar concentrations of paclitaxel, leading to an additive effects in terms of cell death which was predominantly anticipated during the first mitosis. As accumulation of an apoptotic signal was suggested to prevent mitotic slippage, when we challenged p31comet-depleted mitotic-arrested cells with the apoptosis potentiator Navitoclax (previously called ABT-263), cell fate was shifted to accelerated post-mitotic death. We conclude that inhibition of SAC silencing is critical for enhancing the lethality of antimitotic drugs as well as that of therapeutic apoptosis-inducing small molecules, with distinct mechanisms. The study highlights the potential of p31comet as a target for antimitotic therapies.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Teng-Long Han ◽  
Hang Sha ◽  
Jun Ji ◽  
Yun-Tian Li ◽  
Deng-Shan Wu ◽  
...  

AbstractThe anticancer effects of taxanes are attributed to the induction of mitotic arrest through activation of the spindle assembly checkpoint. Cell death following extended mitotic arrest is mediated by the intrinsic apoptosis pathway. Accordingly, factors that influence the robustness of mitotic arrest or disrupt the apoptotic machinery confer drug resistance. Survivin is an inhibitor of apoptosis protein. Its overexpression is associated with chemoresistance, and its targeting leads to drug sensitization. However, Survivin also acts specifically in the spindle assembly checkpoint response to taxanes. Hence, the failure of Survivin-depleted cells to arrest in mitosis may lead to taxane resistance. Here we show that Survivin depletion protects HeLa cells against docetaxel-induced apoptosis by facilitating mitotic slippage. However, Survivin depletion does not promote clonogenic survival of tumor cells but increases the level of cellular senescence induced by docetaxel. Moreover, lentiviral overexpression of Survivin does not provide protection against docetaxel or cisplatin treatment, in contrast to the anti-apoptotic Bcl-xL or Bcl-2. Our findings suggest that targeting Survivin may influence the cell response to docetaxel by driving the cells through aberrant mitotic progression, rather than directly sensitizing cells to apoptosis.


FEBS Letters ◽  
2019 ◽  
Vol 593 (20) ◽  
pp. 2889-2907 ◽  
Author(s):  
Daniel Hayward ◽  
Tatiana Alfonso‐Pérez ◽  
Ulrike Gruneberg

2005 ◽  
Vol 25 (5) ◽  
pp. 2031-2044 ◽  
Author(s):  
Barbara C. M. van de Weerdt ◽  
Marcel A. T. M. van Vugt ◽  
Catherine Lindon ◽  
Jos J. W. Kauw ◽  
Marieke J. Rozendaal ◽  
...  

ABSTRACT Polo-like kinase 1 (Plk1) plays a role in numerous events in mitosis, but how the multiple functions of Plk1 are separated is poorly understood. We studied regulation of Plk1 through two putative phosphorylation residues, Ser-137 and Thr-210. Using phospho-specific antibodies, we found that Thr-210 phosphorylation precedes Ser-137 phosphorylation in vivo, the latter occurring specifically in late mitosis. We show that expression of two activating mutants of these residues, S137D and T210D, results in distinct mitotic phenotypes. Whereas expression of both phospho-mimicking mutants as well as of the double mutant leads to accelerated mitotic entry, further progression through mitosis is dramatically different: the T210D mutant causes a spindle assembly checkpoint-dependent delay, whereas the expression of the S137D mutant or the double mutant results in untimely activation of the anaphase-promoting complex/cyclosome (APC/C) and frequent mitotic catastrophe. Using nonphosphorylatable Plk1-S137A and Plk1-T210A mutants, we show that both sites contribute to proper mitotic progression. Based on these observations, we propose that Plk1 function is altered at different stages of mitosis through consecutive posttranslational events, e.g., at Ser-137 and Thr-210. Furthermore, our data show that uncontrolled Plk1 activation can uncouple APC/C activity from spindle assembly checkpoint control.


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