A common molecular mechanism underlies the role of Mps1 in chromosome biorientation and the spindle assembly checkpoint
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA604761 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR11015505.fastq.gz | Fastqsanger.gz | |||
| SRR11015506.fastq.gz | Fastqsanger.gz | |||
| SRR11015507.fastq.gz | Fastqsanger.gz | |||
| SRR11015508.fastq.gz | Fastqsanger.gz | |||
| SRR11015509.fastq.gz | Fastqsanger.gz |
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Project description:The conserved Mps1 kinase corrects improper kinetochore-microtubule attachments, thereby ensuring chromosome biorientation. Yet, its critical targets in this process remain elusive. Mps1 is also involved in the spindle assembly checkpoint (SAC), the surveillance mechanism halting chromosome segregation until biorientation is attained. Its role in SAC activation is antagonized by the PP1 phosphatase and involves phosphorylation of Knl1/Spc105, which recruits Bub1 to kinetochores to promote assembly of SAC effector complexes. A crucial question is whether error correction and SAC activation are part of a single device or separable pathways. Here we characterise a novel yeast mutant, mps1-3, defective in chromosome biorientation and SAC activation. Through an unbiased screen for suppressors, we found that mutations lowering PP1 levels at Spc105 or forced association of Bub1 with Spc105 reinstate both chromosome biorientation and SAC signalling in mps1-3 cells. Our data strongly argue that Mps1-dependent phosphorylation of the Knl1/Spc105 kinetochore scaffold is critical for Mps1 function in both chromosome biorientation and SAC activation, thus supporting the idea that a common sensory apparatus simultaneously elicits error correction and SAC signalling.
2020-02-05 | GSE144741 | GEO
Project description:Checkpoint kinase 2 (CHK2) plays an important role in safeguarding the mitotic progression, specifically the spindle assembly, though the mechanism of regulation remains poorly understood. Here, we identified a novel mitotic phosphorylation site on CHK2 Tyr156, and its responsible kinase JAK2. Expression of a phospho-deficient mutant CHK2 Y156F or treatment with JAK2 inhibitor IV compromised mitotic spindle assembly, leading to genome instability. In contrast, a phospho-mimicking mutant CHK2 Y156E restored mitotic normalcy in JAK2-inhibited cells. Mechanistically, we show that this phosphorylation is required for CHK2 interaction with and phosphorylation of the spindle assembly checkpoint (SAC) kinase Mps1, and failure of which results in impaired Mps1 kinetochore localization and defective SAC. Concordantly, analysis of clinical cancer datasets revealed that deletion of JAK2 is associated with increased genome alteration; and alteration in CHEK2 and JAK2 is linked to preferential deletion or amplification of cancer-related genes. Thus, our findings not only reveal a novel JAK2-CHK2 signaling axis that maintains genome integrity through SAC but also highlight the potential impact on genomic stability with clinical JAK2 inhibition.
2024-10-16 | PXD056821 | Pride
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:Kinetochores are multiprotein assemblies that bind chromosomes to the spindle during mitosis. Despite conserved roles, repertoires of kinetochore proteins vary greatly across eukaryotes. In particular, most known components are not clearly detected in a group of parasites known as the Apicomplexa. Furthermore, flexibility in scale of amplification and an apparent incapability to delay cell cycle progression in response to spindle integrity has coined an idea these parasites divide in the absence of spindle checkpoints. In this study, we reunite divergent apicomplexan kinetochore components to a common eukaryotic set and additionally identify 9 kinetochore proteins that share little homology to known proteins. AKiTs are essential for chromosome segregation and show modes of division parallel to eukaryotic metaphase to anaphase transition and spindle assembly checkpoint signaling. These findings suggest conserved spindle assembly checkpoint signaling maintains fidelity during chromosome segregation in apicomplexan parasites.
2023-03-11 | PXD028595 | Pride
Project description:The Mps1 kinase corrects improper kinetochore-microtubule attachments, thereby ensuring chromosome biorientation. Yet, its critical phosphorylation targets in this process remain largely elusive. Mps1 also controls the spindle assembly checkpoint (SAC), which halts chromosome segregation until biorientation is attained. Its role in SAC activation is antagonised by the PP1 phosphatase and involves phosphorylation of the kinetochore scaffold Knl1/Spc105, which in turn recruits the Bub1 kinase to promote assembly of SAC effector complexes. A crucial question is whether error correction and SAC activation are part of a single or separable pathways. Here, we isolate and characterise a new yeast mutant, mps1-3, that is severely defective in chromosome biorientation and SAC signalling. Through an unbiased screen for extragenic suppressors, we found that mutations lowering PP1 levels at Spc105 or forced association of Bub1 with Spc105 reinstate both chromosome biorientation and SAC signalling in mps1-3 cells. Our data argue that a common mechanism based on Knl1/Spc105 phosphorylation is critical for Mps1 function in error correction and SAC signalling, thus supporting the idea that a single sensory apparatus simultaneously elicits both pathways.
| S-EPMC7271318 | biostudies-literature
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: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: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:Spindle assembly checkpoint (SAC) regulators such as the Mps1 kinase not only delay anaphase onset, but also correct improper chromosome-spindle linkages that would otherwise lead to missegregation and aneuploidy. However, the substrates and mechanisms involved in this pathway of error correction remain poorly understood. Using a chemically tuned kinetochore-targeting assay, we show that Mps1 destabilizes microtubule attachments (K-fibers) epistatically to Aurora B, the other major error-correcting kinase. Through chemical genetics and quantitative proteomics, we identify both known and novel sites of Mps1- regulated phosphorylation at the outer kinetochore. Modification of these substrates was sensitive to microtubule tension and counterbalanced by the PP2A-B56 phosphatase, a positive regulator of chromosome-spindle interactions. Consistently, Mps1 inhibition rescued K-fiber stability after depleting PP2A-B56. We also identify the hinge region of the W-shaped Ska complex as a key effector of Mps1 at the kinetochore-microtubule interface, as mutations that mimic constitutive phosphorylation strongly destabilized K-fibers in vivo and inhibited the Ska complex’s conversion from lattice diffusion to end-coupled microtubule binding in vitro. Together these results provide new insights into how Mps1 modulates the microtubule-binding properties of the kinetochore to promote the selective stabilization of bipolar attachments and error-free chromosome segregation.
2018-10-24 | PXD006135 | Pride