scholarly journals How cyclin A destruction escapes the spindle assembly checkpoint

2010 ◽  
Vol 190 (4) ◽  
pp. 501-509 ◽  
Author(s):  
Barbara Di Fiore ◽  
Jonathon Pines
Keyword(s):  
Ubiquitin Ligase ◽  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Cyclin A ◽  
Cyclin Dependent Kinase ◽  
Anaphase Promoting Complex ◽  
N Terminus ◽  
Specific Proteins ◽  
Necessary And Sufficient

The anaphase-promoting complex/cyclosome (APC/C) is the ubiquitin ligase essential to mitosis, which ensures that specific proteins are degraded at specific times to control the order of mitotic events. The APC/C coactivator, Cdc20, is targeted by the spindle assembly checkpoint (SAC) to restrict APC/C activity until metaphase, yet early substrates, such as cyclin A, are degraded in the presence of the active checkpoint. Cdc20 and the cyclin-dependent kinase cofactor, Cks, are required for cyclin A destruction, but how they enable checkpoint-resistant destruction has not been elucidated. In this study, we answer this problem: we show that the N terminus of cyclin A binds directly to Cdc20 and with sufficient affinity that it can outcompete the SAC proteins. Subsequently, the Cks protein is necessary and sufficient to promote cyclin A degradation in the presence of an active checkpoint by binding cyclin A–Cdc20 to the APC/C.

scholarly journals The HECT E3 ligase Smurf2 is required for Mad2-dependent spindle assembly checkpoint

2008 ◽  
Vol 183 (2) ◽  
pp. 267-277 ◽  
Author(s):  
Evan C. Osmundson ◽  
Dipankar Ray ◽  
Finola E. Moore ◽  
Qingshen Gao ◽  
Gerald H. Thomsen ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Spindle Assembly Checkpoint ◽  
Spindle Checkpoint ◽  
E3 Ligase ◽  
Spindle Assembly ◽  
Cyclin B ◽  
Carboxyl Terminus ◽  
Anaphase Promoting Complex ◽  
Mitotic Spindles ◽  
Anaphase Onset

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.

scholarly journals The APC/C recruits cyclin B1–Cdk1–Cks in prometaphase before D box recognition to control mitotic exit

2010 ◽  
Vol 190 (4) ◽  
pp. 587-602 ◽  
Author(s):  
Wouter van Zon ◽  
Janneke Ogink ◽  
Bas ter Riet ◽  
René H. Medema ◽  
Hein te Riele ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Spindle Checkpoint ◽  
Cyclin A ◽  
Cyclin B1 ◽  
Mitotic Exit ◽  
Dependent Manner ◽  
Anaphase Promoting Complex ◽  
Checkpoint Control ◽  
N Terminus ◽  
Mitotic Phosphorylation

The ubiquitin ligase anaphase-promoting complex/cyclosome (APC/C) is activated at prometaphase by mitotic phosphorylation and binding of its activator, Cdc20. This initiates cyclin A degradation, whereas cyclin B1 is stabilized by the spindle checkpoint. Upon checkpoint release, the RXXL destruction box (D box) was proposed to direct cyclin B1 to core APC/C or Cdc20. In this study, we report that endogenous cyclin B1–Cdk1 is recruited to checkpoint-inhibited, phosphorylated APC/C in prometaphase independently of Cdc20 or the cyclin B1 D box. Like cyclin A, cyclin B1 binds the APC/C by the Cdk cofactor Cks and the APC3 subunit. Prior binding to APC/CCdc20 makes cyclin B1 a better APC/C substrate in metaphase, driving mitotic exit and cytokinesis. We conclude that in prometaphase, the phosphorylated APC/C can recruit both cyclin A and cyclin B1 in a Cks-dependent manner. This suggests that the spindle checkpoint blocks D box recognition of APC/C-bound cyclin B1, whereas distinctive complexes between the N terminus of cyclin A and Cdc20 evade checkpoint control.

scholarly journals Anaphase-Promoting Complex/Cyclosome–Dependent Proteolysis of Human Cyclin a Starts at the Beginning of Mitosis and Is Not Subject to the Spindle Assembly Checkpoint

2001 ◽  
Vol 153 (1) ◽  
pp. 137-148 ◽  
Author(s):  
Stephan Geley ◽  
Edgar Kramer ◽  
Christian Gieffers ◽  
Julian Gannon ◽  
Jan-Michael Peters ◽  
...  
Keyword(s):  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Cyclin A ◽  
Cyclin B1 ◽  
Cyclin B ◽  
Anaphase Promoting Complex ◽  
Wild Type ◽  
Destruction Box

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.

scholarly journals Modular elements of the TPR domain in the Mps1 N terminus differentially target Mps1 to the centrosome and kinetochore

2016 ◽  
Vol 113 (28) ◽  
pp. 7828-7833 ◽  
Author(s):  
Joseph R. Marquardt ◽  
Jennifer L. Perkins ◽  
Kyle J. Beuoy ◽  
Harold A. Fisk
Keyword(s):  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Anion Channel ◽  
Voltage Dependent Anion Channel ◽  
Monopolar Spindle ◽  
N Terminus ◽  
Voltage Dependent ◽  
And Function ◽  
Necessary And Sufficient ◽  
Spindle Function

Faithful segregation of chromosomes to two daughter cells is regulated by the formation of a bipolar mitotic spindle and the spindle assembly checkpoint, ensuring proper spindle function. Here we show that the proper localization of the kinase Mps1 (monopolar spindle 1) is critical to both these processes. Separate elements in the Mps1 N-terminal extension (NTE) and tetratricopeptide repeat (TPR) domains govern localization to either the kinetochore or the centrosome. The third TPR (TPR3) and the TPR-capping helix (C-helix) are each sufficient to target Mps1 to the centrosome. TPR3 binds to voltage-dependent anion channel 3, but although this is sufficient for centrosome targeting of Mps1, it is not necessary because of the presence of the C-helix. A version of Mps1 lacking both elements cannot localize to or function at the centrosome, but maintains kinetochore localization and spindle assembly checkpoint function, indicating that TPR3 and the C-helix define a bipartite localization determinant that is both necessary and sufficient to target Mps1 to the centrosome but dispensable for kinetochore targeting. In contrast, elements required for kinetochore targeting (the NTE and first two TPRs) are dispensable for centrosomal localization and function. These data are consistent with a separation of Mps1 function based on localization determinants within the N terminus.

scholarly journals Higher eukaryote-specific APC/C composition is a determinant of spindle assembly checkpoint importance

2017 ◽  
Author(s):  
Thomas Wild ◽  
Magda Budzowska ◽  
Gopal Karemore ◽  
Chunaram Choudhary
Keyword(s):  
Ubiquitin Ligase ◽  
Genome Stability ◽  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Cyclin B1 ◽  
Anaphase Promoting Complex ◽  
Mitotic Progression ◽  
Proper Timing ◽  
Dependent Inhibition ◽  
Cellular Fate

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.

scholarly journals The Role of Cdh1p in Maintaining Genomic Stability in Budding Yeast

Genetics ◽  
2003 ◽  
Vol 165 (2) ◽  
pp. 489-503 ◽  
Author(s):  
Karen E Ross ◽  
Orna Cohen-Fix
Keyword(s):  
Cell Cycle ◽  
Chromosome Segregation ◽  
Spindle Assembly Checkpoint ◽  
Chromosome Loss ◽  
Cyclin Dependent Kinase ◽  
Anaphase Promoting Complex ◽  
Growth Defects ◽  
Genes Encoding ◽  
Specificity Factor

Abstract Cdh1p, a substrate specificity factor for the cell cycle-regulated ubiquitin ligase, the anaphase-promoting complex/cyclosome (APC/C), promotes exit from mitosis by directing the degradation of a number of proteins, including the mitotic cyclins. Here we present evidence that Cdh1p activity at the M/G1 transition is important not only for mitotic exit but also for high-fidelity chromosome segregation in the subsequent cell cycle. CDH1 showed genetic interactions with MAD2 and PDS1, genes encoding components of the mitotic spindle assembly checkpoint that acts at metaphase to prevent premature chromosome segregation. Unlike cdh1Δ and mad2Δ single mutants, the mad2Δ cdh1Δ double mutant grew slowly and exhibited high rates of chromosome and plasmid loss. Simultaneous deletion of PDS1 and CDH1 caused extensive chromosome missegregation and cell death. Our data suggest that at least part of the chromosome loss can be attributed to kinetochore/spindle problems. Our data further suggest that Cdh1p and Sic1p, a Cdc28p/Clb inhibitor, have overlapping as well as nonoverlapping roles in ensuring proper chromosome segregation. The severe growth defects of both mad2Δ cdh1Δ and pds1Δ cdh1Δ strains were rescued by overexpressing Swe1p, a G2/M inhibitor of the cyclin-dependent kinase, Cdc28p/Clb. We propose that the failure to degrade cyclins at the end of mitosis leaves cdh1Δ mutant strains with abnormal Cdc28p/Clb activity that interferes with proper chromosome segregation.

scholarly journals Dual-mode regulation of the APC/C by CDK1 and MAPK controls meiosis I progression and fidelity

2014 ◽  
Vol 204 (6) ◽  
pp. 891-900 ◽  
Author(s):  
Ibtissem Nabti ◽  
Petros Marangos ◽  
Jenny Bormann ◽  
Nobuaki R. Kudo ◽  
John Carroll
Keyword(s):  
Protein Kinase ◽  
Spindle Assembly Checkpoint ◽  
Mitogen Activated Protein Kinase ◽  
Cyclin Dependent Kinase ◽  
Anaphase Promoting Complex ◽  
Female Meiosis ◽  
Dual Mode ◽  
Mitogen Activated Protein ◽  
Meiosis I

Female meiosis is driven by the activities of two major kinases, cyclin-dependent kinase 1 (Cdk1) and mitogen-activated protein kinase (MAPK). To date, the role of MAPK in control of meiosis is thought to be restricted to maintaining metaphase II arrest through stabilizing Cdk1 activity. In this paper, we find that MAPK and Cdk1 play compensatory roles to suppress the anaphase-promoting complex/cyclosome (APC/C) activity early in prometaphase, thereby allowing accumulation of APC/C substrates essential for meiosis I. Furthermore, inhibition of MAPK around the onset of APC/C activity at the transition from meiosis I to meiosis II led to accelerated completion of meiosis I and an increase in aneuploidy at metaphase II. These effects appear to be mediated via a Cdk1/MAPK-dependent stabilization of the spindle assembly checkpoint, which when inhibited leads to increased APC/C activity. These findings demonstrate new roles for MAPK in the regulation of meiosis in mammalian oocytes.

scholarly journals NF-κB activation is a turn on for vaccinia virus phosphoprotein A49 to turn off NF-κB activation

2019 ◽  
Vol 116 (12) ◽  
pp. 5699-5704 ◽  
Author(s):  
Sarah Neidel ◽  
Hongwei Ren ◽  
Alice A. Torres ◽  
Geoffrey L. Smith
Keyword(s):  
Vaccinia Virus ◽  
Ubiquitin Ligase ◽  
Molecular Mimicry ◽  
E3 Ubiquitin Ligase ◽  
Virus Protein ◽  
Biological Regulation ◽  
Turn On ◽  
N Terminus ◽  
Iκbα Phosphorylation ◽  
Necessary And Sufficient

Vaccinia virus protein A49 inhibits NF-κB activation by molecular mimicry and has a motif near the N terminus that is conserved in IκBα, β-catenin, HIV Vpu, and some other proteins. This motif contains two serines, and for IκBα and β-catenin, phosphorylation of these serines enables recognition by the E3 ubiquitin ligase β-TrCP. Binding of IκBα and β-catenin by β-TrCP causes their ubiquitylation and thereafter proteasome-mediated degradation. In contrast, HIV Vpu and VACV A49 are not degraded. This paper shows that A49 is phosphorylated at serine 7 but not serine 12 and that this is necessary and sufficient for binding β-TrCP and antagonism of NF-κB. Phosphorylation of A49 S7 occurs when NF-κB signaling is activated by addition of IL-1β or overexpression of TRAF6 or IKKβ, the kinase needed for IκBα phosphorylation. Thus, A49 shows beautiful biological regulation, for it becomes an NF-κB antagonist upon activation of NF-κB signaling. The virulence of viruses expressing mutant A49 proteins or lacking A49 (vΔA49) was tested. vΔA49 was attenuated compared with WT, but viruses expressing A49 that cannot bind β-TrCP or bind β-TrCP constitutively had intermediate virulence. So A49 promotes virulence by inhibiting NF-κB activation and by another mechanism independent of S7 phosphorylation and NF-κB antagonism. Last, a virus lacking A49 was more immunogenic than the WT virus.

scholarly journals Uncoupling Anaphase-Promoting Complex/Cyclosome Activity from Spindle Assembly Checkpoint Control by Deregulating Polo-Like Kinase 1

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 ◽  
...  
Keyword(s):  
Double Mutant ◽  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Mitotic Catastrophe ◽  
Anaphase Promoting Complex ◽  
Checkpoint Control ◽  
Mitotic Progression ◽  
Specific Antibodies ◽  
Mitotic Entry

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.

scholarly journals Regulated Separation of Sister Centromeres depends on the Spindle Assembly Checkpoint but not on the Anaphase Promoting Complex/Cyclosome

Cell Cycle ◽  
2005 ◽  
Vol 4 (11) ◽  
pp. 1561-1575 ◽  
Author(s):  
Juan F. Gimenez-Abian ◽  
Laura A. Díaz-Martínez ◽  
Karin G. Wirth ◽  
Catherine A. Andrews ◽  
Gonzalo Giménez-Martín ◽  
...  
Keyword(s):  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Anaphase Promoting Complex
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