Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Regulation of cyclin-dependent kinase activity during mitotic exit and maintenance of genome stability by p21, p27, and p107.

ABSTRACT: To study the regulation of cyclin-dependent kinase (CDK) activity during mitotic exit in mammalian cells, we constructed murine cell lines that constitutively express a stabilized mutant of cyclin A (cyclin A47). Even though cyclin A47 was expressed throughout mitosis and in G1 cells, its associated CDK activity was inactivated after the transition from metaphase to anaphase. Cyclin A47 associated with both p21 and p27 during mitotic exit, implicating these proteins in CDK inactivation. However, cyclin A47 was fully inhibited during the M-to-G1 transition in p21(-/-) p27(-/-) fibroblasts. Also, the CDKs associated with cyclin A47 were not inactivated by phosphorylation at tyrosines. The protein responsible for CDK inactivation during mitotic exit in p21/p27 null cells was the Rb family member, p107. p107 bound to cyclin A47 when p21 and p27 were absent, and cyclin A47-CDK activity was not inactivated during the M-to-G1 transition in p21(-/-) p27(-/-) p107(-/-) null fibroblasts. Enforced expression of cyclin A in cells lacking all three CDK inhibitors induced rapid tetraploidization, indicative of mitotic failure/endoreduplication. We concluded that cyclin proteolysis and CDK inhibitors constitute redundant pathways that control cyclin A-CDK activity during mitotic exit in mammalian cells and that loss of these pathways can cause genetic instability.

SUBMITTER: Chibazakura T

PROVIDER: S-EPMC384770 | biostudies-other | 2004 Mar

REPOSITORIES: biostudies-other

ACCESS DATA

Json Xml

Similar Datasets

Mutual regulation of cyclin-dependent kinase and the mitotic exit network.

Project description:The mitotic exit network (MEN) is a spindle pole body (SPB)-associated, GTPase-driven signaling cascade that controls mitotic exit. The inhibitory Bfa1-Bub2 GTPase-activating protein (GAP) only associates with the daughter SPB (dSPB), raising the question as to how the MEN is regulated on the mother SPB (mSPB). Here, we show mutual regulation of cyclin-dependent kinase 1 (Cdk1) and the MEN. In early anaphase Cdk1 becomes recruited to the mSPB depending on the activity of the MEN kinase Cdc15. Conversely, Cdk1 negatively regulates binding of Cdc15 to the mSPB. In addition, Cdk1 phosphorylates the Mob1 protein to inhibit the activity of Dbf2-Mob1 kinase that regulates Cdc14 phosphatase. Our data revise the understanding of the spatial regulation of the MEN. Although MEN activity in the daughter cells is controlled by Bfa1-Bub2, Cdk1 inhibits MEN activity at the mSPB. Consistent with this model, only triple mutants that lack BUB2 and the Cdk1 phosphorylation sites in Mob1 and Cdc15 show mitotic exit defects.

| S-EPMC2819678 | biostudies-literature

Transmission distortion by loss of p21 or p27 cyclin-dependent kinase inhibitors following competitive spermatogonial transplantation.

Project description:Spermatogonial stem cells (SSCs) undergo self-renewal division to support spermatogenesis. Although several positive regulators of SSC self-renewal have been identified, little is known about the mechanisms that negatively regulate SSCs. Here we developed a novel transplantation assay for SSCs and demonstrate that p21 and p27 cyclin-dependent kinase inhibitors play critical roles in SSC self-renewal and differentiation. Overexpression of p21 or p27 abrogated proliferation of cultured SSCs in vitro, and their expression levels were downregulated by exogenous self-renewal signals. In contrast, no apparent defects were found in p21 or p27-deficient SSCs by spermatogonial transplantation. However, competitive spermatogonial transplantation with WT SSCs revealed that the loss of either gene causes distortion of germline transmission: p21-deficiency facilitated mutant offspring production, whereas germline transmission was limited by p27-deficiency. Serial transplantation also showed that the loss of p27, but not p21, decreases secondary colony formation, suggesting that appropriate amounts of p27 are necessary for sustaining SSC self-renewal. Thus, p21 and p27 cyclin-dependent kinase inhibitors play critical roles in germline transmission by regulating the balance between SSC self-renewal and differentiation, and competitive spermatogonial transplantation technique will be useful for analyzing subtle defects in spermatogenesis that are not evident by traditional spermatogonial transplantation.

| S-EPMC2851975 | biostudies-literature

Analysis of the mitotic exit control system using locked levels of stable mitotic cyclin.

Project description:Cyclin-dependent kinase (Cdk) both promotes mitotic entry (spindle assembly and anaphase) and inhibits mitotic exit (spindle disassembly and cytokinesis), leading to an elegant quantitative hypothesis that a single cyclin oscillation can function as a ratchet to order these events. This ratchet is at the core of a published ODE model for the yeast cell cycle. However, the ratchet model requires appropriate cyclin dose-response thresholds. Here, we test the inhibition of mitotic exit in budding yeast using graded levels of stable mitotic cyclin (Clb2). In opposition to the ratchet model, stable levels of Clb2 introduced dose-dependent delays, rather than hard thresholds, that varied by mitotic exit event. The ensuing cell cycle was highly abnormal, suggesting a novel reason for cyclin degradation. Cdc14 phosphatase antagonizes Clb2-Cdk, and Cdc14 is released from inhibitory nucleolar sequestration independently of stable Clb2. Thus, Cdc14/Clb2 balance may be the appropriate variable for mitotic regulation. Although our results are inconsistent with the aforementioned ODE model, revision of the model to allow Cdc14/Clb2 balance to control mitotic exit corrects these discrepancies, providing theoretical support for our conclusions.

| S-EPMC2795472 | biostudies-literature

The Down syndrome-related protein kinase DYRK1A phosphorylates p27(Kip1) and Cyclin D1 and induces cell cycle exit and neuronal differentiation.

Project description:A fundamental question in neurobiology is how the balance between proliferation and differentiation of neuronal precursors is maintained to ensure that the proper number of brain neurons is generated. Substantial evidence implicates DYRK1A (dual specificity tyrosine-phosphorylation-regulated kinase 1A) as a candidate gene responsible for altered neuronal development and brain abnormalities in Down syndrome. Recent findings support the hypothesis that DYRK1A is involved in cell cycle control. Nonetheless, how DYRK1A contributes to neuronal cell cycle regulation and thereby affects neurogenesis remains poorly understood. In the present study we have investigated the mechanisms by which DYRK1A affects cell cycle regulation and neuronal differentiation in a human cell model, mouse neurons, and mouse brain. Dependent on its kinase activity and correlated with the dosage of overexpression, DYRK1A blocked proliferation of SH-SY5Y neuroblastoma cells within 24 h and arrested the cells in G₁ phase. Sustained overexpression of DYRK1A induced G₀ cell cycle exit and neuronal differentiation. Furthermore, we provide evidence that DYRK1A modulated protein stability of cell cycle-regulatory proteins. DYRK1A reduced cellular Cyclin D1 levels by phosphorylation on Thr286, which is known to induce proteasomal degradation. In addition, DYRK1A phosphorylated p27(Kip1) on Ser10, resulting in protein stabilization. Inhibition of DYRK1A kinase activity reduced p27(Kip1) Ser10 phosphorylation in cultured hippocampal neurons and in embryonic mouse brain. In aggregate, these results suggest a novel mechanism by which overexpression of DYRK1A may promote premature neuronal differentiation and contribute to altered brain development in Down syndrome.

| S-EPMC4111700 | biostudies-literature

FGFR1 signaling stimulates proliferation of human mesenchymal stem cells by inhibiting the cyclin-dependent kinase inhibitors p21(Waf1) and p27(Kip1).

Project description:Signaling through fibroblast growth factor receptor one (FGFR1) is a known inducer of proliferation in both embryonic and human adult mesenchymal stem cells (hMSCs) and positively regulates maintenance of stem cell viability. Leveraging the mitogenic potential of FGF2/FGFR1 signaling in stem cells for therapeutic applications necessitates a mechanistic understanding of how this receptor stimulates cell cycle progression. Using small interfering RNA (siRNA) depletion, antibody-inhibition, and small molecule inhibition, we establish that FGFR1 activity is rate limiting for self-renewal of hMSCs. We show that FGFR1 promotes stem cell proliferation through multiple mechanisms that unite to antagonize cyclin-dependent kinase (CDK) inhibitors. FGFR1 not only stimulates c-Myc to suppress transcription of the CDK inhibitors p21(Waf1) and p27(Kip1), thus promoting cell cycle progression but also increases the activity of protein kinase B (AKT) and the level of S-phase kinase-associated protein 2 (Skp2), resulting in the nuclear exclusion and reduction of p21(Waf1). The in vivo importance of FGFR1 signaling for the control of proliferation in mesenchymal progenitor populations is underscored by defects in ventral mesoderm formation during development upon inhibition of its signaling. Collectively, these studies demonstrate that FGFR1 signaling mediates the continuation of MSC growth and establishes a receptor target for enhancing the expansion of mesenchymal progenitors while maintaining their multilineage potential.

| S-EPMC8553008 | biostudies-literature

The cyclin-dependent kinase inhibitor p21 is regulated by RNA-binding protein PCBP4 via mRNA stability.

Project description:RNA-binding proteins (RBPs) play a major role in many post-transcriptional processes, including mRNA stability, alternative splicing and translation. PCBP4, also called MCG10, is an RBP belonging to the poly(C)-binding protein family and a target of p53 tumor suppressor. Ectopic expression of PCBP4 induces cell-cycle arrest in G₂ and apoptosis. To identify RNA targets regulated by PCBP4 and further decipher its function, we generated multiple cell lines in which PCBP4 is either inducibly over-expressed or knocked down. We found that PCBP4 expression decreases cyclin-dependent kinase inhibitor p21 induction in response to DNA damage. We also provided evidence that PCBP4 regulates p21 expression independently of p53. In addition, we showed that a deficiency in PCBP4 enhances p21 induction upon DNA damage. To validate PCBP4 regulation of p21, we made PCBP4-deficient mice and showed that p21 expression is markedly increased in PCBP4-deficient primary mouse embryo fibroblasts compared to that in wild-type counterparts. Finally, we uncovered that PCBP4 binds to the 3'-UTR of p21 transcript in vitro and in vivo to regulate p21 mRNA stability. Taken together, we revealed that PCBP4 regulates both basal and stress-induced p21 expression through binding p21 3'-UTR and modulating p21 mRNA stability.

| S-EPMC3017617 | biostudies-literature

Functional and spatial regulation of mitotic centromere-associated kinesin by cyclin-dependent kinase 1.

Project description:Mitotic centromere-associated kinesin (MCAK) plays an essential role in spindle formation and in correction of improper microtubule-kinetochore attachments. The localization and activity of MCAK at the centromere/kinetochore are controlled by Aurora B kinase. However, MCAK is also abundant in the cytosol and at centrosomes during mitosis, and its regulatory mechanism at these sites is unknown. We show here that cyclin-dependent kinase 1 (Cdk1) phosphorylates T537 in the core domain of MCAK and attenuates its microtubule-destabilizing activity in vitro and in vivo. Phosphorylation of MCAK by Cdk1 promotes the release of MCAK from centrosomes and is required for proper spindle formation. Interfering with the regulation of MCAK by Cdk1 causes dramatic defects in spindle formation and in chromosome positioning. This is the first study demonstrating that Cdk1 regulates the localization and activity of MCAK in mitosis by directly phosphorylating the catalytic core domain of MCAK.

| S-EPMC2876524 | biostudies-literature

Cell cycle regulation by the intrinsically disordered proteins p21 and p27.

Project description:Today, it is widely accepted that proteins that lack highly defined globular three-dimensional structures, termed IDPs (intrinsically disordered proteins), play key roles in myriad biological processes. Our understanding of how intrinsic disorder mediates biological function is, however, incomplete. In the present paper, we review disorder-mediated cell cycle regulation by two intrinsically disordered proteins, p21 and p27. A structural adaptation mechanism involving a stretchable dynamic linker helix allows p21 to promiscuously recognize the various Cdk (cyclin-dependent kinase)-cyclin complexes that regulate cell division. Disorder within p27 mediates transmission of an N-terminal tyrosine phosphorylation signal to a C-terminal threonine phosphorylation, constituting a signalling conduit. These mechanisms are mediated by folding upon binding p21/p27's regulatory targets. However, residual disorder within the bound state contributes critically to these functional mechanisms. Our studies provide insights into how intrinsic protein disorder mediates regulatory processes and opportunities for designing drugs that target cancer-associated IDPs.

| S-EPMC7065656 | biostudies-literature

Cdc7p-Dbf4p regulates mitotic exit by inhibiting Polo kinase.

Project description:Cdc7p-Dbf4p is a conserved protein kinase required for the initiation of DNA replication. The Dbf4p regulatory subunit binds Cdc7p and is essential for Cdc7p kinase activation, however, the N-terminal third of Dbf4p is dispensable for its essential replication activities. Here, we define a short N-terminal Dbf4p region that targets Cdc7p-Dbf4p kinase to Cdc5p, the single Polo kinase in budding yeast that regulates mitotic progression and cytokinesis. Dbf4p mediates an interaction with the Polo substrate-binding domain to inhibit its essential role during mitosis. Although Dbf4p does not inhibit Polo kinase activity, it nonetheless inhibits Polo-mediated activation of the mitotic exit network (MEN), presumably by altering Polo substrate targeting. In addition, although dbf4 mutants defective for interaction with Polo transit S-phase normally, they aberrantly segregate chromosomes following nuclear misorientation. Therefore, Cdc7p-Dbf4p prevents inappropriate exit from mitosis by inhibiting Polo kinase and functions in the spindle position checkpoint.

| S-EPMC2682205 | biostudies-literature

Ordered dephosphorylation initiated by the selective proteolysis of cyclin B drives mitotic exit.

Project description:APC/C-mediated proteolysis of cyclin B and securin promotes anaphase entry, inactivating CDK1 and permitting chromosome segregation, respectively. Reduction of CDK1 activity relieves inhibition of the CDK1-counteracting phosphatases PP1 and PP2A-B55, allowing wide-spread dephosphorylation of substrates. Meanwhile, continued APC/C activity promotes proteolysis of other mitotic regulators. Together, these activities orchestrate a complex series of events during mitotic exit. However, the relative importance of regulated proteolysis and dephosphorylation in dictating the order and timing of these events remains unclear. Using high temporal-resolution proteomics, we compare the relative extent of proteolysis and protein dephosphorylation. This reveals highly-selective rapid proteolysis of cyclin B, securin and geminin at the metaphase-anaphase transition, followed by slow proteolysis of other substrates. Dephosphorylation requires APC/C-dependent destruction of cyclin B and was resolved into PP1-dependent categories with unique sequence motifs. We conclude that dephosphorylation initiated by selective proteolysis of cyclin B drives the bulk of changes observed during mitotic exit.

| S-EPMC7529458 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data