Saccharomyces cerevisiae
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA319343 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR3418380.fastq.gz | Fastqsanger.gz | |||
| SRR3418381.fastq.gz | Fastqsanger.gz | |||
| SRR3418379.fastq.gz | Fastqsanger.gz |
Items per page: 5 1 - 3 of 3 |
Similar Datasets
Project description:Cryptococcus neoformans is an opportunistic, human fungal pathogen which undergoes fascinating switches in cell cycle control and ploidy when it encounters stressful environments such as the human lung. Here we carry out a mechanistic analysis of the spindle checkpoint which regulates the metaphase to anaphase transition, focusing on Mps1 kinase and the downstream checkpoint components Mad1 and Mad2. We demonstrate that Cryptococcus mad1D or mad2D strains are unable to respond to microtubule perturbations, continuing to re-bud and divide, and die as a consequence. Fluorescent tagging of Chromosome 3, using a lacO array and mNeonGreen-lacI fusion protein, demonstrates that mad mutants are unable to maintain sister-chromatid cohesion in the absence of microtubule polymers. Thus, the classic checkpoint functions of the SAC are conserved in Cryptococcus. In interphase, GFP-Mad1 is enriched at the nuclear periphery, and it is recruited to unattached kinetochores in mitosis. Purification of GFP-Mad1 followed by mass spectrometric analysis of associated proteins show that it forms a complex with Mad2 and that it interacts with other checkpoint signalling components (Bub1) and effectors (Cdc20 and APC/C sub-units) in mitosis. We also demonstrate that overexpression of Mps1 kinase is sufficient to arrest Cryptococcus cells in mitosis, and show that this arrest is dependent on both Mad1 and Mad2. We find that a C-terminal fragment of Mad1 is an effective in vitro substrate for Mps1 kinase and map several Mad1 phosphorylation sites. Some sites are highly conserved within the C-terminal Mad1 structure and we demonstrate that mutation of threonine 667 (T667A) leads to loss of checkpoint signalling and abrogation of the GAL-MPS1 arrest. Thus Mps1-dependent phosphorylation of C-terminal Mad1 residues is a critical step in Cryptococcus spindle checkpoint signalling. We conclude that CnMps1 protein kinase, Mad1 and Mad2 proteins have all conserved their important, spindle checkpoint signalling roles helping ensure high fidelity chromosome segregation.
2024-05-27 | PXD052327 | Pride
Project description:Analysis of the transcriptional response to aneuploidy in mouse epidermis. In this study we measured the transcriptional response to aneuploidy by aboragting the spindle checkpoint in mouse epidermis. We found that, whereas spindle checkpoint inactivation in the epidermis is tolerated, but results in metabolic deranged cells, SAC abrogation kills bulge stem cells Mad2; K14-Cre mice were sacrificed at indicated timepoints and epidermis was separated from dermis using overnight trypsin. RNA was isolated and expression patterns were compared between K14-Cre; Mad2f/f and Cfre negative animals for all timepoints.
2013-01-22 | E-GEOD-42698 | biostudies-arrayexpress
Project description:Most human tumors have abnormal numbers of chromosomes, a condition known as aneuploidy. The mitotic checkpoint is an important mechanism that prevents aneuploidy through restraining the activity of the anaphase-promoting complex (APC). USP44 was identified as a key regulator of APC activation that maintains the association of MAD2 with the APC co-activator Cdc20. However, the physiological importance of USP44 and its impact on cancer biology are unknown. Here, we show that USP44 is required to prevent tumors in mice and is frequently down-regulated in human lung cancer. USP44 inhibits chromosome segregation errors independently of its role in the mitotic checkpoint by regulating proper centrosome separation, positioning, and mitotic spindle geometry, functions that require direct binding to the centriole protein, centrin. These data reveal a new role for the ubiquitin system in mitotic spindle regulation and underscore the importance of USP44 in the pathogenesis of human cancer. Study included 100 non-neoplastic (N) lung samples, and 69, 12, and 13 stage I, II, and II lung adenocarcinoma (AD) frozen tissues, respectively. Expression levels of Usp44 in different stages of AD was compared against N.
2013-09-01 | E-GEOD-40791 | biostudies-arrayexpress
Project description:Gametes are produced via meiosis, a specialized cell division associated with frequent errors which cause birth defects and infertility. Uniquely in meiosis I, homologous chromosomes segregate to opposite poles, usually requiring their linkage by chiasmata, the products of crossover recombination1. The spindle checkpoint delays cell cycle progression until all chromosomes are properly attached to microtubules2 but the steps leading to the capture and alignment of chromosomes on the meiosis I spindle remain poorly understood. In budding yeast meiosis I, Mad2 and Mad3BUBR1 are equally important for spindle checkpoint delay, but biorientation of homologs on the meiosis I spindle requires Mad2, but not Mad3BUBR1 3,4. Here we show that Mad3BUBR1 promotes accurate meiosis I homolog segregation outside its canonical checkpoint role, independently of Mad2. We find that Mad3BUBR1 associates with the TOGL1 domain of Stu1CLASP, a conserved plus-end microtubule protein which is important for chromosome capture onto the spindle. Homologous chromosome pairs that are proficient in crossover formation, but which fail to biorient, rely on Mad3BUBR1-Stu1CLASP to ensure their efficient attachment to microtubules and segregation during meiosis I. Furthermore, we show that Mad3BUBR1-Stu1CLASP are essential to rescue the segregation of mini-chromosomes lacking crossovers. Our findings define a new pathway ensuring microtubule-dependent chromosome capture and demonstrate that spindle checkpoint proteins safeguard the fidelity of chromosome segregation both by actively promoting chromosome alignment and delaying cell cycle progression until this has occurred.
2024-07-18 | PXD048251 | Pride
Project description:During metaphase, in response to improper kinetochore-microtubule attachments, the spindle assembly checkpoint (SAC) activates the mitotic checkpoint complex (MCC) to inhibit the anaphase-promoting complex/cyclosome (APC/C). The Mad1-Mad2 complex provides a catalytic platform for MCC assembly. Mad1-bound Mad2 recruits open-Mad2 through asymmetric dimerization and Mad1 phosphorylation by Mps1 promotes conversion of Mad2 from an open (O-Mad2) to closed (C-Mad2) state, which binds Cdc20 to form the MCC. How Mad1 phosphorylation catalytically activates MCC formation is poorly understood. This study characterises Mad1 phosphorylation by Mps1 and provides structural and biochemical insights into a phosphorylation-specific Mad1-Cdc20 interaction, which allows for a tripartite assembly of Bub1-Mad1-Cdc20 on the C-terminal domain of Mad1. We also identify a folded state of Mad1-Mad2 complex, suggesting a model by which the Cdc20-Mad1 interaction brings the Cdc20 MIM motif near Mad2. The Cdc20 MIM motif is then entrapped by the Mad2 safety belt to form a stable complex, allowing spontaneous MCC assembly.
2023-03-11 | PXD031872 | Pride
Project description:Most human tumors have abnormal numbers of chromosomes, a condition known as aneuploidy. The mitotic checkpoint is an important mechanism that prevents aneuploidy through restraining the activity of the anaphase-promoting complex (APC). USP44 was identified as a key regulator of APC activation that maintains the association of MAD2 with the APC co-activator Cdc20. However, the physiological importance of USP44 and its impact on cancer biology are unknown. Here, we show that USP44 is required to prevent tumors in mice and is frequently down-regulated in human lung cancer. USP44 inhibits chromosome segregation errors independently of its role in the mitotic checkpoint by regulating proper centrosome separation, positioning, and mitotic spindle geometry, functions that require direct binding to the centriole protein, centrin. These data reveal a new role for the ubiquitin system in mitotic spindle regulation and underscore the importance of USP44 in the pathogenesis of human cancer.
2013-09-01 | GSE40791 | GEO
Project description:The spindle checkpoint is a mitotic surveillance system which ensures equal segregation of sister chromatids. It delays anaphase onset by inhibiting the action of the E3 ubiquitin ligase known as the anaphase promoting complex or cyclosome (APC/C). Mads/BubR1 is a key component of the mitotic checkpoint complex (MCC) which binds and inhibits the APC/C early in mitosis. Mps1Mph1 kinase is critical for checkpoint signalling and MCC-APC/C inhibition, yet few substrates have been identified. Here we identify Mad3 as a substrate of fission yeast Mps1Mph1 kinase. We map and mutate phosphorylation sites in Mad3, producing mutants that are targeted to kinetochores and assembled into MCC, yet display reduced APC/C binding and are unable to maintain checkpoint arrests. We chow biochemically that Mad3 phospho-mimics are potent APC/C inhibitors in vitro, demonstrating that Mad3p modification can directly influence Cdc20Slp1-APC/C activity. This genetic dissection of APC/C inhibition demonstrates that Mps1Mph1 kinase-dependant modification of Mad3 and Mad2 act in a concerted manner to maintain spindle checkpoint arrests.
2016-03-31 | PXD003806 | Pride
Project description:Ibrahim2008 - Mitotic Spindle Assembly Checkpoint - Dissociation variant
The Mitotic Spindle Assembly Checkpoint ((M)SAC) is an evolutionary conserved mechanism. This model incorporates the perspectives of three central control pathways, namely Mad1/Mad2 induced Cdc20 sequestering based on the Template Model, MCC formation, and APC inhibition. MCC:APC dissociation is described by two alternatives models, namely the "Dissociation" and the "Convey" model variants. Both these model are available in BioModels Database. This model corresponds to the "Dissociation" variant.
This model is described in the article:
In-silico modeling of the mitotic spindle assembly checkpoint.
Ibrahim B, Diekmann S, Schmitt E, Dittrich P
PLoS One. 2008 Feb 6;3(2):e1555.
Abstract:
BACKGROUND: The Mitotic Spindle Assembly Checkpoint ((M)SAC) is an evolutionary conserved mechanism that ensures the correct segregation of chromosomes by restraining cell cycle progression from entering anaphase until all chromosomes have made proper bipolar attachments to the mitotic spindle. Its malfunction can lead to cancer.
PRINCIPLE FINDINGS: We have constructed and validated for the human (M)SAC mechanism an in silico dynamical model, integrating 11 proteins and complexes. The model incorporates the perspectives of three central control pathways, namely Mad1/Mad2 induced Cdc20 sequestering based on the Template Model, MCC formation, and APC inhibition. Originating from the biochemical reactions for the underlying molecular processes, non-linear ordinary differential equations for the concentrations of 11 proteins and complexes of the (M)SAC are derived. Most of the kinetic constants are taken from literature, the remaining four unknown parameters are derived by an evolutionary optimization procedure for an objective function describing the dynamics of the APC:Cdc20 complex. MCC:APC dissociation is described by two alternatives, namely the "Dissociation" and the "Convey" model variants. The attachment of the kinetochore to microtubuli is simulated by a switching parameter silencing those reactions which are stopped by the attachment. For both, the Dissociation and the Convey variants, we compare two different scenarios concerning the microtubule attachment dependent control of the dissociation reaction. Our model is validated by simulation of ten perturbation experiments.
CONCLUSION: Only in the controlled case, our models show (M)SAC behaviour at meta- to anaphase transition in agreement with experimental observations. Our simulations revealed that for (M)SAC activation, Cdc20 is not fully sequestered; instead APC is inhibited by MCC binding.
This model describes the controlled dissociation variant of the mitotic spindle assembly checkpoint. If the tool you use has problems with events, you can uncomment the assignment rules for u and u_prime and comment out the list of events.
In accordance with the authors due to typos in the original publication some initial conditions and parameters were slightly changed in the model:
article
model
[O-Mad2]
1.5e-7 M
1.3e-7 M
[BubR1:Bub3]
1.30e-7 M
1.27e-7 M
k -4
0.01 M -1
s -1
0.02 M -1
s -1
k -5
0.1 M -1
s -1
0.2 M -1
s -1
This model is hosted on BioModels Database
and identified by: MODEL6655615431
.
To cite BioModels Database, please use: BioModels Database: An enhanced, curated and annotated resource for published quantitative kinetic models
.
To the extent possible under law, all copyright and related or neighbouring rights to this encoded model have been dedicated to the public domain worldwide. Please refer to CC0 Public Domain Dedication
for more information.
2024-09-02 | BIOMD0000000186 | BioModels
Project description:Ibrahim2008 - Mitotic Spindle Assembly Checkpoint - Convey variant
The Mitotic Spindle Assembly Checkpoint ((M)SAC) is an evolutionary conserved mechanism. This model incorporates the perspectives of three central control pathways, namely Mad1/Mad2 induced Cdc20 sequestering based on the Template Model, MCC formation, and APC inhibition. MCC:APC dissociation is described by two alternatives models, namely the "Dissociation" and the "Convey" model variants. Both these model are available in BioModels Database. This model corresponds to the "Convey" variant.
This model is described in the article:
In-silico modeling of the mitotic spindle assembly checkpoint.
Ibrahim B, Diekmann S, Schmitt E, Dittrich P
PLoS One. 2008 Feb 6;3(2):e1555.
Abstract:
BACKGROUND: The Mitotic Spindle Assembly Checkpoint ((M)SAC) is an evolutionary conserved mechanism that ensures the correct segregation of chromosomes by restraining cell cycle progression from entering anaphase until all chromosomes have made proper bipolar attachments to the mitotic spindle. Its malfunction can lead to cancer.
PRINCIPLE FINDINGS: We have constructed and validated for the human (M)SAC mechanism an in silico dynamical model, integrating 11 proteins and complexes. The model incorporates the perspectives of three central control pathways, namely Mad1/Mad2 induced Cdc20 sequestering based on the Template Model, MCC formation, and APC inhibition. Originating from the biochemical reactions for the underlying molecular processes, non-linear ordinary differential equations for the concentrations of 11 proteins and complexes of the (M)SAC are derived. Most of the kinetic constants are taken from literature, the remaining four unknown parameters are derived by an evolutionary optimization procedure for an objective function describing the dynamics of the APC:Cdc20 complex. MCC:APC dissociation is described by two alternatives, namely the "Dissociation" and the "Convey" model variants. The attachment of the kinetochore to microtubuli is simulated by a switching parameter silencing those reactions which are stopped by the attachment. For both, the Dissociation and the Convey variants, we compare two different scenarios concerning the microtubule attachment dependent control of the dissociation reaction. Our model is validated by simulation of ten perturbation experiments.
CONCLUSION: Only in the controlled case, our models show (M)SAC behaviour at meta- to anaphase transition in agreement with experimental observations. Our simulations revealed that for (M)SAC activation, Cdc20 is not fully sequestered; instead APC is inhibited by MCC binding.
This model describes the controlled dissociation variant of the mitotic spindle assembly checkpoint. If the tool you use has problems with events, you can uncomment the assignment rules for u and u_prime and comment out the list of events.
In accordance with the authors due to typos in the original publication some initial conditions and parameters were slightly changed in the model:
article
model
[O-Mad2]
1.5e-7 M
1.3e-7 M
[BubR1:Bub3]
1.30e-7 M
1.27e-7 M
k -4
0.01 M -1
s -1
0.02 M -1
s -1
k -5
0.1 M -1
s -1
0.2 M -1
s -1
This model is hosted on BioModels Database
and identified by: MODEL6655578762
.
To cite BioModels Database, please use: BioModels Database: An enhanced, curated and annotated resource for published quantitative kinetic models
.
To the extent possible under law, all copyright and related or neighbouring rights to this encoded model have been dedicated to the public domain worldwide. Please refer to CC0 Public Domain Dedication
for more information.
2024-09-02 | BIOMD0000000187 | BioModels
Project description:Histone acetylation, not stoichiometry, regulates linker histone binding in S. cerevisiae
| PRJNA392237 | ENA