scholarly journals Plk1- and β-TrCP–dependent degradation of Bora controls mitotic progression

2008 ◽  
Vol 181 (1) ◽  
pp. 65-78 ◽  
Author(s):  
Akiko Seki ◽  
Judith A. Coppinger ◽  
Haining Du ◽  
Chang-Young Jang ◽  
John R. Yates ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Mitotic Progression ◽  
Cell Cycle Protein ◽  
Cycle Progression ◽  
Microtubule Polymerization ◽  
Anaphase Onset ◽  
Chromatid Segregation ◽  
Spindle Stability ◽  
Synthesis And Degradation

Through a convergence of functional genomic and proteomic studies, we identify Bora as a previously unknown cell cycle protein that interacts with the Plk1 kinase and the SCF–β-TrCP ubiquitin ligase. We show that the Bora protein peaks in G2 and is degraded by proteasomes in mitosis. Proteolysis of Bora requires the Plk1 kinase activity and is mediated by SCF–β-TrCP. Plk1 phosphorylates a conserved DSGxxT degron in Bora and promotes its interaction with β-TrCP. Mutations in this degron stabilize Bora. Expression of a nondegradable Bora variant prolongs the metaphase and delays anaphase onset, indicating a physiological requirement of Bora degradation. Interestingly, the activity of Bora is also required for normal mitotic progression, as knockdown of Bora activates the spindle checkpoint and delays sister chromatid segregation. Mechanistically, Bora regulates spindle stability and microtubule polymerization and promotes tension across sister kinetochores during mitosis. We conclude that tight regulation of the Bora protein by its synthesis and degradation is critical for cell cycle progression.

scholarly journals IRX3/5 regulate mitotic chromatid segregation and limb bud shape

Development ◽  
2020 ◽  
Vol 147 (19) ◽  
pp. dev180042
Author(s):  
Hirotaka Tao ◽  
Jean-Philippe Lambert ◽  
Theodora M. Yung ◽  
Min Zhu ◽  
Noah A. Hahn ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Transcriptional Regulation ◽  
Cell Division ◽  
Pattern Formation ◽  
Cell Cycle Progression ◽  
Limb Bud ◽  
Cycle Progression ◽  
Chromatid Segregation ◽  
Skeletal Pattern

ABSTRACTPattern formation is influenced by transcriptional regulation as well as by morphogenetic mechanisms that shape organ primordia, although factors that link these processes remain under-appreciated. Here we show that, apart from their established transcriptional roles in pattern formation, IRX3/5 help to shape the limb bud primordium by promoting the separation and intercalation of dividing mesodermal cells. Surprisingly, IRX3/5 are required for appropriate cell cycle progression and chromatid segregation during mitosis, possibly in a nontranscriptional manner. IRX3/5 associate with, promote the abundance of, and share overlapping functions with co-regulators of cell division such as the cohesin subunits SMC1, SMC3, NIPBL and CUX1. The findings imply that IRX3/5 coordinate early limb bud morphogenesis with skeletal pattern formation.

scholarly journals The prolyl isomerase FKBP25 regulates microtubule polymerization impacting cell cycle progression and genomic stability

2018 ◽  
Vol 46 (5) ◽  
pp. 2459-2478 ◽  
Author(s):  
David Dilworth ◽  
Geoff Gudavicius ◽  
Xiaoxue Xu ◽  
Andrew K J Boyce ◽  
Connor O’Sullivan ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Genomic Stability ◽  
Prolyl Isomerase ◽  
Cycle Progression ◽  
Microtubule Polymerization

scholarly journals Kinetochore chemistry is sensitive to tension and may link mitotic forces to a cell cycle checkpoint.

1995 ◽  
Vol 130 (4) ◽  
pp. 929-939 ◽  
Author(s):  
R B Nicklas ◽  
S C Ward ◽  
G J Gorbsky
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Cell Cycle Checkpoint ◽  
Cycle Progression ◽  
Anaphase Onset ◽  
Cycle Checkpoint ◽  
A Cell ◽  
Protein Dephosphorylation ◽  
Regulation Of Cell Cycle ◽  
Checkpoint Signal

Some cells have a quality control checkpoint that can detect a single misattached chromosome and delay the onset of anaphase, thus allowing time for error correction. The mechanical error in attachment must somehow be linked to the chemical regulation of cell cycle progression. The 3F3 antibody detects phosphorylated kinetochore proteins that might serve as the required link (Gorbsky, G. J., and W. A. Ricketts. 1993. J. Cell Biol. 122:1311-1321). We show by direct micromanipulation experiments that tension alters the phosphorylation of kinetochore proteins. Tension, whether from a micromanipulation needle or from normal mitotic forces, causes dephosphorylation of the kinetochore proteins recognized by 3F3. If tension is absent, either naturally or as a result of chromosome detachment by micromanipulation, the proteins are phosphorylated. Equally direct experiments identify tension as the checkpoint signal: tension from a microneedle on a misattached chromosome leads to anaphase (Li, X., and R. B. Nicklas. 1995. Nature (Lond.). 373:630-632), and we show here that the absence of tension caused by detaching chromosomes from the spindle delays anaphase indefinitely. Thus, the absence of tension is linked to both kinetochore phosphorylation and delayed anaphase onset. We propose that the kinetochore protein dephosphorylation caused by tension is the all clear signal to the checkpoint. The evidence is circumstantial but rich. In any event, tension alters kinetochore chemistry. Very likely, tension affects chemistry directly, by altering the conformation of a tension-sensitive protein, which leads directly to dephosphorylation.

scholarly journals A negative reciprocal regulatory axis between cyclin D1 and HNF4α modulates cell cycle progression and metabolism in the liver

2020 ◽  
Vol 117 (29) ◽  
pp. 17177-17186 ◽  
Author(s):  
Heng Wu ◽  
Yitzhak Reizel ◽  
Yue J. Wang ◽  
Jessica L. Lapiro ◽  
Betsy T. Kren ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cyclin D1 ◽  
Cell Cycle Progression ◽  
Glycogen Synthesis ◽  
Hepatocyte Proliferation ◽  
In Vivo Model ◽  
Large Network ◽  
Cell Cycle Protein ◽  
Cycle Progression

Hepatocyte nuclear factor 4α (HNF4α) is a master regulator of liver function and a tumor suppressor in hepatocellular carcinoma (HCC). In this study, we explore the reciprocal negative regulation of HNF4α and cyclin D1, a key cell cycle protein in the liver. Transcriptomic analysis of cultured hepatocyte and HCC cells found that cyclin D1 knockdown induced the expression of a large network of HNF4α-regulated genes. Chromatin immunoprecipitation-sequencing (ChIP-seq) demonstrated that cyclin D1 inhibits the binding of HNF4α to thousands of targets in the liver, thereby diminishing the expression of associated genes that regulate diverse metabolic activities. Conversely, acute HNF4α deletion in the liver induces cyclin D1 and hepatocyte cell cycle progression; concurrent cyclin D1 ablation blocked this proliferation, suggesting that HNF4α maintains proliferative quiescence in the liver, at least, in part, via repression of cyclin D1. Acute cyclin D1 deletion in the regenerating liver markedly inhibited hepatocyte proliferation after partial hepatectomy, confirming its pivotal role in cell cycle progression in this in vivo model, and enhanced the expression of HNF4α target proteins. Hepatocyte cyclin D1 gene ablation caused markedly increased postprandial liver glycogen levels (in a HNF4α-dependent fashion), indicating that the cyclin D1-HNF4α axis regulates glucose metabolism in response to feeding. In AML12 hepatocytes, cyclin D1 depletion led to increased glucose uptake, which was negated if HNF4α was depleted simultaneously, and markedly elevated glycogen synthesis. To summarize, mutual repression by cyclin D1 and HNF4α coordinately controls the cell cycle machinery and metabolism in the liver.

scholarly journals Proper division plane orientation and mitotic progression together allow normal growth of maize

2017 ◽  
Vol 114 (10) ◽  
pp. 2759-2764 ◽  
Author(s):  
Pablo Martinez ◽  
Anding Luo ◽  
Anne Sylvester ◽  
Carolyn G. Rasmussen
Keyword(s):  
Cell Cycle ◽  
Cell Biology ◽  
Cell Cycle Progression ◽  
Normal Growth ◽  
Mitotic Progression ◽  
Wild Type ◽  
Cycle Progression ◽  
Division Plane ◽  
Plane Orientation ◽  
Division Plane Orientation

How growth, microtubule dynamics, and cell-cycle progression are coordinated is one of the unsolved mysteries of cell biology. A maize mutant,tangled1, with known defects in growth and proper division plane orientation, and a recently characterized cell-cycle delay identified by time-lapse imaging, was used to clarify the relationship between growth, cell cycle, and proper division plane orientation. Thetangled1mutant was fully rescued by introduction of cortical division site localized TANGLED1-YFP. A CYCLIN1B destruction box was fused to TANGLED1-YFP to generate a line that mostly rescued the division plane defect but still showed cell-cycle delays when expressed in thetangled1mutant. Although an intermediate growth phenotype between wild-type and thetangled1mutant was expected, these partially rescued plants grew as well as wild-type siblings, indicating that mitotic progression delays alone do not alter overall growth. These data indicate that division plane orientation, together with proper cell-cycle progression, is critical for plant growth.

scholarly journals Subcellular localization and mitotic interactome analyses identify SIRT4 as a centrosomally localized and microtubule associated protein

2020 ◽  
Author(s):  
Laura Bergmann ◽  
Alexander Lang ◽  
Christoph Bross ◽  
Simone Altinoluk-Hambüchen ◽  
Iris Fey ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Tumor Suppressor ◽  
Mitotic Spindle ◽  
Cell Cycle Progression ◽  
Mitotic Progression ◽  
Cycle Progression ◽  
Functional Roles ◽  
The Family ◽  
Spindle Apparatus ◽  
Regulation Of Cell Cycle

AbstractThe stress-inducible and senescence-associated tumor suppressor SIRT4, a member of the family of mitochondrial sirtuins (SIRT3, SIRT4, and SIRT5), regulates bioenergetics and metabolism via NAD+-dependent enzymatic activities. Next to the known mitochondrial location, we found that a fraction of endogenous or ectopically expressed SIRT4, but not SIRT3, is located at the mitotic spindle apparatus in the cytosol. Confocal spinning disk microscopy revealed that SIRT4 localizes during the cell cycle dynamically at centrosomes with an intensity peak in G2 and early mitosis. Moreover, SIRT4 binds to microtubules and interacts with structural (α,β-tubulin, γ-tubulin, TUBGCP2, TUBGCP3) and regulatory (HDAC6) microtubule components as detected by co-immunoprecipitation and mass spectrometric analyses of the mitotic SIRT4 interactome. Overexpression of SIRT4 resulted in a pronounced decrease of acetylated α-tubulin (K40) associated with altered microtubule dynamics in mitotic cells. SIRT4 or the N-terminally truncated variant SIRT4(ΔN28), which is unable to translocate into mitochondria, delayed mitotic progression and reduced cell proliferation. This study extends the functional roles of SIRT4 beyond mitochondrial metabolism, and suggests that SIRT4 acts as a novel centrosomal / microtubule-associated protein in the regulation of cell cycle progression. Thus, stress-induced SIRT4 may exert its role as tumor suppressor through mitochondrial as well as extramitochondrial functions, the latter associated with its localization at the mitotic spindle apparatus.

scholarly journals The E3 ubiquitin ligase HECTD1 contributes to cell cycle progression through an effect on mitosis

2021 ◽  
Author(s):  
Natalie Vaughan ◽  
Nico Scholz ◽  
Catherine Lindon ◽  
Julien D, F Licchesi
Keyword(s):  
Cell Cycle ◽  
Ubiquitin Ligase ◽  
Cell Cycle Progression ◽  
Spindle Assembly Checkpoint ◽  
Time Lapse ◽  
Ubiquitin Chain ◽  
Cycle Progression ◽  
Anaphase Onset ◽  
Ubiquitin Ligase Activity ◽  
Complex Protein

Mechanistic studies of how protein ubiquitylation regulates the cell cycle, in particular during mitosis, has provided unique insights which have contributed to the emergence of the Ubiquitin code. In contrast to RING E3 ubiquitin ligases such as the APC/c ligase complex, the contribution of other E3 ligase families during cell cycle progression remains less well understood. Similarly, the contribution of ubiquitin chain types beyond homotypic K48 chains in S-phase or branched K11/K48 chains assembled by APC/c during mitosis, also remains to be fully determined. Our recent findings that HECTD1 ubiquitin ligase activity assembles branched K29/K48 ubiquitin linkages prompted us to evaluate its function during the cell cycle. We used transient knockdown and genetic knockout to show that HECTD1 depletion in HEK293T and HeLa cells decreases cell proliferation and we established that this is mediated through loss of its ubiquitin ligase activity. Interestingly, we found that HECTD1 depletion increases the proportion of cells with aligned chromosomes (Prometa/Metaphase). We confirmed this molecularly using phospho-Histone H3 (Ser28) as a marker of mitosis. Time-lapse microscopy of NEBD to anaphase onset established that HECTD1-depleted cells take on average longer to go through mitosis. To explore the mechanisms involved, we used proteomics to explore the endogenous HECTD1 interactome in mitosis and validated the Mitosis Checkpoint Complex protein BUB3 as a novel HECTD1 interactor. In line with this, we found that HECTD1 depletion reduces the activity of the Spindle Assembly Checkpoint. Overall, our data suggests a novel role for HECTD1 ubiquitin ligase activity in mitosis.

scholarly journals Human cells lacking CDC14A and CDC14B show differences in ciliogenesis but not in mitotic progression

2020 ◽  
pp. jcs.255950
Author(s):  
Patrick Partscht ◽  
Borhan Uddin ◽  
Elmar Schiebel
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Cycle Progression ◽  
Cell Cycle Control ◽  
Mitotic Exit ◽  
Human Cells ◽  
Mitotic Progression ◽  
Cycle Progression ◽  
Double Deletion ◽  
Redundant Functions

Budding yeast Cdc14 phosphatase has a central role in mitotic exit and cytokinesis. Puzzlingly, a uniform picture for the three human CDC14 paralogues hCDC14A, B and C in cell cycle control has not emerged to date. Redundant functions between the three hCDC14 phosphatases could explain this unclear picture. To address the possibility of redundancy, we tested expression of hCDC14 and analysed cell cycle progression of cells with single- and double-deletion in hCDC14 genes. Our data suggest that hCDC14C is not expressed in human RPE1 cells excluding a function in this cell line. Single- and double-knockouts (KO) of hCDC14A and hCDC14B in RPE1 cells indicate that both phosphatases are not important for the timing of mitotic phases, cytokinesis and cell proliferation. However, cycling hCDC14A KO and hCDC14B KO cells show altered ciliogenesis compared to WT cells. The cilia of cycling hCDC14A KO cells are longer, whereas hCDC14B KO cilia are more frequent and disassemble faster. In conclusion, this study demonstrates that the cell cycle functions of CDC14 proteins are not conserved between yeast and human cells.

scholarly journals RNA Interference Knockdown of hU2AF35 Impairs Cell Cycle Progression and Modulates Alternative Splicing of Cdc25 Transcripts

2006 ◽  
Vol 17 (10) ◽  
pp. 4187-4199 ◽  
Author(s):  
Teresa Raquel Pacheco ◽  
Luís Ferreira Moita ◽  
Anita Quintal Gomes ◽  
Nir Hacohen ◽  
Maria Carmo-Fonseca
Keyword(s):  
Cell Cycle ◽  
Alternative Splicing ◽  
Rna Interference ◽  
Cell Cycle Progression ◽  
Protein Isoforms ◽  
Cell Cycle Gene ◽  
Mitotic Progression ◽  
Cycle Progression ◽  
Specific Subset ◽  
Alternatively Spliced

U2AF is a heterodimeric splicing factor composed of a large (U2AF65) and a small (U2AF35) subunit. In humans, alternative splicing generates two U2AF35 variants, U2AF35a and U2AF35b. Here, we used RNA interference to specifically ablate the expression of each isoform in HeLa cells. Our results show that knockdown of the major U2AF35a isoform reduced cell viability and impaired mitotic progression, leading to accumulation of cells in prometaphase. Microarray analysis revealed that knockdown of U2AF35a affected the expression level of ∼500 mRNAs, from which >90% were underrepresented relative to the control. Among mRNAs underrepresented in U2AF35a-depleted cells we identified an essential cell cycle gene, Cdc27, for which there was an increase in the ratio between unspliced and spliced RNA and a significant reduction in protein level. Furthermore, we show that depletion of either U2AF35a or U2AF35b altered the ratios of alternatively spliced isoforms of Cdc25B and Cdc25C transcripts. Taken together our results demonstrate that U2AF35a is essential for HeLa cell division and suggest a novel role for both U2AF35 protein isoforms as regulators of alternative splicing of a specific subset of genes.

scholarly journals Subcellular Localization and Mitotic Interactome Analyses Identify SIRT4 as a Centrosomally Localized and Microtubule Associated Protein

Cells ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1950 ◽  
Author(s):  
Laura Bergmann ◽  
Alexander Lang ◽  
Christoph Bross ◽  
Simone Altinoluk-Hambüchen ◽  
Iris Fey ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Tumor Suppressor ◽  
Mitotic Spindle ◽  
Cell Cycle Progression ◽  
Mitotic Progression ◽  
Cycle Progression ◽  
Functional Roles ◽  
The Family ◽  
Regulation Of Cell Cycle ◽  
Early Mitosis

The stress-inducible and senescence-associated tumor suppressor SIRT4, a member of the family of mitochondrial sirtuins (SIRT3, SIRT4, and SIRT5), regulates bioenergetics and metabolism via NAD+-dependent enzymatic activities. Next to the known mitochondrial location, we found that a fraction of endogenous or ectopically expressed SIRT4, but not SIRT3, is present in the cytosol and predominantly localizes to centrosomes. Confocal spinning disk microscopy revealed that SIRT4 is found during the cell cycle dynamically at centrosomes with an intensity peak in G2 and early mitosis. Moreover, SIRT4 precipitates with microtubules and interacts with structural (α,β-tubulin, γ-tubulin, TUBGCP2, TUBGCP3) and regulatory (HDAC6) microtubule components as detected by co-immunoprecipitation and mass spectrometric analyses of the mitotic SIRT4 interactome. Overexpression of SIRT4 resulted in a pronounced decrease of acetylated α-tubulin (K40) associated with altered microtubule dynamics in mitotic cells. SIRT4 or the N-terminally truncated variant SIRT4(ΔN28), which is unable to translocate into mitochondria, delayed mitotic progression and reduced cell proliferation. This study extends the functional roles of SIRT4 beyond mitochondrial metabolism and provides the first evidence that SIRT4 acts as a novel centrosomal/microtubule-associated protein in the regulation of cell cycle progression. Thus, stress-induced SIRT4 may exert its role as tumor suppressor through mitochondrial as well as extramitochondrial functions, the latter associated with its localization at the mitotic spindle apparatus.

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