The N-Terminal Region of the Polo Kinase Cdc5 is Required for Downregulation of the Meiotic Recombination Checkpoint

During meiosis, the budding yeast polo-like kinase Cdc5 is a crucial driver of the prophase I to meiosis I (G2/M) transition. The meiotic recombination checkpoint restrains cell cycle progression in response to defective recombination to ensure proper distribution of intact chromosomes to the gametes. This checkpoint detects unrepaired DSBs and initiates a signaling cascade that ultimately inhibits Ndt80, a transcription factor required for CDC5 gene expression. Previous work revealed that overexpression of CDC5 partially alleviates the checkpoint-imposed meiotic delay in the synaptonemal complex-defective zip1Δ mutant. Here, we show that overproduction of a Cdc5 version (Cdc5-ΔN70), lacking the N-terminal region required for targeted degradation of the protein by the APC/C complex, fails to relieve the zip1Δ-induced meiotic delay, despite being more stable and reaching increased protein levels. However, precise mutation of the consensus motifs for APC/C recognition (D-boxes and KEN) has no effect on Cdc5 stability or function during meiosis. Compared to the zip1Δ single mutant, the zip1Δ cdc5-ΔN70 double mutant exhibits an exacerbated meiotic block and reduced levels of Ndt80 consistent with persistent checkpoint activity. Finally, using a CDC5-inducible system, we demonstrate that the N-terminal region of Cdc5 is essential for its checkpoint erasing function. Thus, our results unveil an additional layer of regulation of polo-like kinase function in meiotic cell cycle control.

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The potential of iron chelators of the pyridoxal isonicotinoyl hydrazone class as effective antiproliferative agents, IV: the mechanisms involved in inhibiting cell-cycle progression

Blood ◽

10.1182/blood.v98.3.842 ◽

2001 ◽

Vol 98 (3) ◽

pp. 842-850 ◽

Cited By ~ 158

Author(s):

Jin Gao ◽

Des R. Richardson

Keyword(s):

Cell Cycle ◽

Ribonucleotide Reductase ◽

Cell Cycle Progression ◽

Cell Cycle Control ◽

Susceptibility Gene ◽

Cycle Progression ◽

Protein Levels ◽

Ribonucleotide Reductase Inhibitor ◽

Appreciable Increase ◽

Pyridoxal Isonicotinoyl Hydrazone

Abstract Some chelators of the pyridoxal isonicotinoyl hydrazone class have antiproliferative activity that is far greater than desferrioxamine (DFO). In this study, DFO was compared with one of the most active chelators (311) on the expression of molecules that play key roles in cell-cycle control. This was vital for understanding the role of iron (Fe) in cell-cycle progression and for designing chelators to treat cancer. Incubating cells with DFO, and especially 311, resulted in a decrease in the hyperphosphorylated form of the retinoblastoma susceptibility gene product (pRb). Chelators also decreased cyclins D1, D2, and D3, which bind with cyclin-dependent kinase 4 (cdk4) to phosphorylate pRb. The levels of cdk2 also decreased after incubation with DFO, and especially 311, which may be important for explaining the decrease in hyperphosphorylated pRb. Cyclins A and B1 were also decreased after incubation with 311 and, to a lesser extent, DFO. In contrast, cyclin E levels increased. These effects were prevented by presaturating the chelators with Fe. In contrast to DFO and 311, the ribonucleotide reductase inhibitor hydroxyurea increased the expression of all cyclins. Hence, the effect of chelators on cyclin expression was not due to their ability to inhibit ribonucleotide reductase. Although chelators induced a marked increase in WAF1 and GADD45 mRNA transcripts, there was no appreciable increase in their protein levels. Failure to translate these cell-cycle inhibitors may contribute to dysregulation of the cell cycle after exposure to chelators.

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Cdk1-Dependent Phosphorylation ofNPM Overrides G2/M Checkpoint and Increases Leukemic Blasts in Mice

Blood ◽

10.1182/blood.v112.11.1322.1322 ◽

2008 ◽

Vol 112 (11) ◽

pp. 1322-1322

Author(s):

Wei Du ◽

Yun Zhou ◽

Suzette Pike ◽

Qishen Pang

Keyword(s):

Cell Cycle ◽

Cell Cycle Progression ◽

Cell Cycle Control ◽

Xenograft Model ◽

Phosphorylation Sites ◽

M Cell ◽

Cycle Progression ◽

Hematopoietic Stem ◽

Cycle Arrest ◽

Regulation Of Cell Cycle

Abstract An elevated level of nucleophosmin (NPM) is often found in actively proliferative cells including human tumors. To identify the regulatory role for NPM phosphorylation in proliferation and cell cycle control, a series of mutants targeting the consensus cyclin-dependent kinase (CKD) phosphorylation sites was created to mimic or abrogate either single-site or multi-site phosphorylation. Cells expressing the phosphomimetic NPM mutants showed enhanced proliferation and G2/M cell-cycle transition; whereas nonphosphorylatable mutants induced G2/M cell-cycle arrest. Simultaneous inactivation of two CKD phosphorylation sites at Ser10 and Ser70 (S10A/S70A, NPM-AA) induced phosphorylation of Cdk1 at Tyr15 (Cdc2Tyr15) and increased cytoplasmic accumulation of Cdc25C. Strikingly, stress-induced Cdk1Tyr15 and Cdc25C sequestration were completely suppressed by expression of a double phosphomimetic NPM mutant (S10E/S70E, NPM-EE). Further analysis revealed that phosphorylation of NPM at both Ser10 and Ser70 sites were required for proper interaction between Cdk1 and Cdc25C in mitotic cells. Moreover, the NPM-EE mutant directly bound to Cdc25C and prevented phosphorylation of Cdc25C at Ser216 during mitosis. Finally, NPM-EE overrided stress-induced G2/M arrest, increased peripheral-blood blasts and splenomegaly in a NOD/SCID xenograft model, and promoted leukemia development in Fanconi mouse hematopoietic stem/progenitor cells. Thus, these findings reveal a novel function of NPM on regulation of cell-cycle progression, in which Cdk1-dependent phosphorylation of NPM controls cell-cycle progression at G2/M transition through modulation of Cdc25C activity.

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Regulation of Skp2 Expression and Activity and Its Role in Cancer Progression

The Scientific World JOURNAL ◽

10.1100/tsw.2010.89 ◽

2010 ◽

Vol 10 ◽

pp. 1001-1015 ◽

Cited By ~ 66

Author(s):

Chia-Hsin Chan ◽

Szu-Wei Lee ◽

Jing Wang ◽

Hui-Kuan Lin

Keyword(s):

Cell Cycle ◽

Cancer Progression ◽

Cell Cycle Progression ◽

Cycle Progression ◽

Protein Levels ◽

Human Cancers ◽

Attractive Therapeutic Target ◽

Skp2 Protein ◽

Regulation Of Cell Cycle ◽

F Box Protein

The regulation of cell cycle entry is critical for cell proliferation and tumorigenesis. One of the key players regulating cell cycle progression is the F-box protein Skp2. Skp2 forms a SCF complex with Skp1, Cul-1, and Rbx1 to constitute E3 ligase through its F-box domain. Skp2 protein levels are regulated during the cell cycle, and recent studies reveal that Skp2 stability, subcellular localization, and activity are regulated by its phosphorylation. Overexpression of Skp2 is associated with a variety of human cancers, indicating that Skp2 may contribute to the development of human cancers. The notion is supported by various genetic mouse models that demonstrate an oncogenic activity of Skp2 and its requirement in cancer progression, suggesting that Skp2 may be a novel and attractive therapeutic target for cancers.

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

International Journal of Molecular Sciences ◽

10.3390/ijms22168508 ◽

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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The Multiple Roles of the Cdc14 Phosphatase in Cell Cycle Control

International Journal of Molecular Sciences ◽

10.3390/ijms21030709 ◽

2020 ◽

Vol 21 (3) ◽

pp. 709

Author(s):

Javier Manzano-López ◽

Fernando Monje-Casas

Keyword(s):

Cell Cycle ◽

Cell Cycle Progression ◽

Current Knowledge ◽

Cell Cycle Control ◽

Multiple Roles ◽

Special Focus ◽

Cyclin Dependent Kinase ◽

Yeast Saccharomyces Cerevisiae ◽

Cycle Progression

The Cdc14 phosphatase is a key regulator of mitosis in the budding yeast Saccharomyces cerevisiae. Cdc14 was initially described as playing an essential role in the control of cell cycle progression by promoting mitotic exit on the basis of its capacity to counteract the activity of the cyclin-dependent kinase Cdc28/Cdk1. A compiling body of evidence, however, has later demonstrated that this phosphatase plays other multiple roles in the regulation of mitosis at different cell cycle stages. Here, we summarize our current knowledge about the pivotal role of Cdc14 in cell cycle control, with a special focus in the most recently uncovered functions of the phosphatase.

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Multiple Myeloma Cells Survival and Proliferation Rely on High Levels and Activity of the Serine-Threonine Kinase CK2.

Blood ◽

10.1182/blood.v104.11.643.643 ◽

2004 ◽

Vol 104 (11) ◽

pp. 643-643 ◽

Cited By ~ 1

Author(s):

Francesco A. Piazza ◽

Maria Ruzzene ◽

Giovanni Di Maira ◽

Enrico Brunetta ◽

Luca Bonanni ◽

...

Keyword(s):

Cell Cycle ◽

Cell Cycle Progression ◽

Transcriptional Activity ◽

Kinase Activity ◽

Serine Threonine Kinase ◽

Cycle Progression ◽

Threonine Kinase ◽

Protein Levels ◽

Tnf Α ◽

Ck2 Inhibitors

Abstract Survival and proliferation of Multiple Myeloma plasma cells (MMPCs) depend on the activation of signaling pathways through the interaction with the surrounding bone marrow microenvironment. CK2 is a ubiquitous cellular serine-threonine kinase, whose involvement in oncogenic transformation, apoptosis and cell cycle progression has recently become matter of intense research. Due to its connection with signaling molecules pivotal for plasma cell (PCs) survival, such as those implicated in the TNF-α/NF-κB, IGF1/PI3K/AKT and Wnt/β-catenin pathways, CK2 is likely to play a central role in MM biology. We investigated CK2 function in MMPCs survival and cell cycle progression, in the modulation of the sensitivity to chemotherapeutics and in the regulation of the I-κB/NF-κB dependent pathway. We first analysed the CK2 protein levels and specific kinase activity in MMPCs. Different cell lines and highly purified CD138+ PCs from 5 patients were used. We observed higher protein levels of the CK2 catalytic subunit αin the neoplastic MMPCs than in controls (resting peripheral blood and splenic B lymphocytes). Moreover, also the total CK2-dependent kinase activity was found significantly increased in MMPCs. We also assessed the levels and pattern of total protein phosphorylation by radioactive phosphate incorporation assay. We found that MMPCs share a similar pattern of phoshorylated proteins. The degree of phosphorylation of some of these proteins was significantly reduced in the presence of specific CK2 inhibitors. Next, using a panel of highly specific CK2 inhibitors, we studied the effects of hampering CK2 function in MMPCs. A dose-dependent cytotoxic effect was observed after the treatment with such compounds that was associated with the activation of both the extrinsic and intrinsic caspase-dependent pathways, the release from mitochondria of cytochrome c and smac/diablo and cell cycle arrest in G2-M. A possible role for CK2 inhibition in sensitising MMPCs to melphalan-induced apoptosis was also investigated. Indeed, CK2 blockade lowered the threshold of sensitivity of MMPCs to the cytotoxic effect of melphalan. We then looked at the consequences of CK2 blockade on the NF-κB dependent signaling cascade. Basal and TNF-α-dependent I-κB-αdegradation, as well as NF-κB transcriptional activity upon TNF-αstimulation, were partially impaired by CK2 blockade in MMPCs. Finally, we detected association between the endogenous αcatalytic subunit of CK2 and the NF-κB p50/p105 member by confocal microscopy and co-immunoprecipitation. Altogether, our data suggest a pivotal role for CK2 in controlling survival, proliferation and sensitivity to chemotherapeutics of MMPCs and implicate this kinase in the regulation of the NF-κB pathway in MM through the modulation of I-κB protein levels and NF-κB transcriptional activity. This latter effect is possibly exerted through physical association of CK2 with NF-κB transcription factors. Our findings also suggest that CK2 inhibition could be exploited as a novel therapeutic approach for MM.

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The Interplay Between Microrna-223 and E2F1 Regulates Cell Cycle Control During Granulopoiesis.

Blood ◽

10.1182/blood.v114.22.255.255 ◽

2009 ◽

Vol 114 (22) ◽

pp. 255-255

Author(s):

John Anto Pulikkan ◽

Viola Dengler ◽

Philomina Sona Peramangalam ◽

Abdul A. Peer Zada ◽

Carsten Müller tidow ◽

...

Keyword(s):

Cell Cycle ◽

Chromatin Immunoprecipitation ◽

Cell Cycle Progression ◽

Conflicts Of Interest ◽

Myeloid Cells ◽

Granulocytic Differentiation ◽

Cycle Progression ◽

Protein Levels ◽

Cell Cycle Inhibition

Abstract Abstract 255 Transcription factor CCAAT enhancer binding protein α (C/EBPα) functions as a master regulator of granulocyte development by co-ordinating cell cycle inhibition and differentiation. Recent findings demonstrate that deregulation of C/EBPα is a critical step in the development of acute myeloid leukemia (AML). Inhibition of E2F1, the key regulator of cell cycle progression by C/EBPα is essential for granulopoiesis and disruption of this function of C/EBPα leads to leukemia. The mechanism with which C/EBPα inhibits E2F1 in granulopoiesis is poorly understood. Recent advances in our understanding about microRNAs suggest that these molecules have profound impact in gene expression programmes. Also, deregulation of microRNAs has been shown as a hall mark of many cancers including leukemia. microRNA-223 (miR-223) is upregulated by C/EBPα during granulopoiesis. The pivotal role of miR-223 in granulopoiesis is shown by the finding that mice deficient for miR-223 display defects in granulopoiesis. In this study, we explored the role of miR-223 in the cell cycle inhibition function of C/EBPα. Computational analysis by using programmes such as Target Scan suggests that E2F1 is a putative target of miR-223. Luciferase assays using 3'UTR of E2F1 suggest E2F1 is a potential target of miR-223. Western blot analysis using bone marrow cells isolated from miR-223 null mice shows accumulation of E2F1 protein levels. Interestingly, E2F1 protein levels were downregulated during miR-223 overexpression in myeloid cells. Analysis of miR-223 by quantitative Real-Time RT-PCR in AML patient samples shows that miR-223 is downregulated in different subtypes of AML. Proliferation assays, cell cycle analysis and BrdU assays show that miR-223 functions as an inhibitor of myeloid cell cycle progression. Several studies have reported the ability of E2F1 to block granulocytic differentiation. We next analysed whether E2F1 is inhibiting myeloid differentiation through miR-223. Promoter assays show that E2F1 inhibits the miR-223 promoter activity. By using Chromatin immunoprecipitation assays, we found that E2F1 binds to miR-223 promoter in leukemia derived cell lines and this binding is reversed during granulocytic differentiation. We also observed that E2F1 is bound to the miR-223 promoter in blast cells isolated from AML patients as analysed by chromatin immunoprecipitation assays. In addition, we show that overexpression of E2F1 leads to down regulation of miR-223 levels in myeloid cells. All these data suggest that E2F1 functions as a transcriptional repressor of the miR-223 gene. Taken together, our data suggest that granulopoiesis is regulated by the interplay between miR-223 and E2F1 and deregulation of this interplay may lead to the development of AML. Overexpression of miR-223 could be a potential strategy in the treatment of AML patients in which E2F1 inhibition by C/EBPα is deregulated. Disclosures: No relevant conflicts of interest to declare.

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Functional Differentiation of SWI/SNF Remodelers in Transcription and Cell Cycle Control

Molecular and Cellular Biology ◽

10.1128/mcb.01257-06 ◽

2006 ◽

Vol 27 (2) ◽

pp. 651-661 ◽

Cited By ~ 91

Author(s):

Yuri M. Moshkin ◽

Lisette Mohrmann ◽

Wilfred F. J. van Ijcken ◽

C. Peter Verrijzer

Keyword(s):

Cell Cycle ◽

Cell Cycle Progression ◽

Target Genes ◽

Structural Integrity ◽

Function Analysis ◽

Cell Cycle Control ◽

Functional Differentiation ◽

Transcription Control ◽

Cycle Progression ◽

The Core

ABSTRACT Drosophila BAP and PBAP represent two evolutionarily conserved subclasses of SWI/SNF chromatin remodelers. The two complexes share the same core subunits, including the BRM ATPase, but differ in a few signature subunits: OSA defines BAP, whereas Polybromo (PB) and BAP170 specify PBAP. Here, we present a comprehensive structure-function analysis of BAP and PBAP. An RNA interference knockdown survey revealed that the core subunits BRM and MOR are critical for the structural integrity of both complexes. Whole-genome expression profiling suggested that the SWI/SNF core complex is largely dysfunctional in cells. Regulation of the majority of target genes required the signature subunit OSA, PB, or BAP170, suggesting that SWI/SNF remodelers function mostly as holoenzymes. BAP and PBAP execute similar, independent, or antagonistic functions in transcription control and appear to direct mostly distinct biological processes. BAP, but not PBAP, is required for cell cycle progression through mitosis. Because in yeast the PBAP-homologous complex, RSC, controls cell cycle progression, our finding reveals a functional switch during evolution. BAP mediates G2/M transition through direct regulation of string/cdc25. Its signature subunit, OSA, is required for directing BAP to the string/cdc25 promoter. Our results suggest that the core subunits play architectural and enzymatic roles but that the signature subunits determine most of the functional specificity of SWI/SNF holoenzymes in general gene control.

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Cell cycle control

Oxford Textbook of Oncology ◽

10.1093/med/9780199656103.003.0004 ◽

2016 ◽

pp. 31-41

Author(s):

Simon M. Carr ◽

Nicholas B. La Thangue

Keyword(s):

Cell Cycle ◽

Final Stage ◽

Cell Cycle Progression ◽

Cell Cycle Control ◽

Control Mechanisms ◽

Chromosomal Dna ◽

Cycle Progression ◽

M Phase ◽

Cellular Components ◽

Regulate Cell Cycle Progression

All cells arise by the division of existing cells in a highly regulated series of events known as the cell cycle. Whilst duplication of other cellular contents occurs throughout all stages of the cycle, chromosomal DNA is replicated only once at a stage known as S phase. Once this is complete, distribution of chromosomes and other cellular components occurs during the final stage of the cell cycle, known as M phase, or mitosis. The cell cycle is therefore regulated in a temporal fashion, so that entry into subsequent cell cycle stages only occurs once the previous stage has been completed. A number of signalling mechanisms monitor the integrity of cell cycle progression, and later cell cycle stages can be delayed if any errors need correction. This chapter gives an overview of the major control mechanisms that regulate cell cycle progression, and how these are circumvented during the onset of cancer.

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