Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Small changes in phospho-occupancy at the kinetochore-microtubule interface drive mitotic fidelity

ABSTRACT: Kinetochore protein phosphorylation promotes the correction of erroneous microtubule attachments to ensure faithful chromosome segregation during cell division. Determining how phosphorylation executes error correction requires an understanding of whether kinetochore substrates are completely (i.e. all-or-none) or only fractionally phosphorylated. Using quantitative mass spectrometry (MS), we measured phospho-occupancy on the conserved kinetochore protein Hec1 (NDC80) that directly binds microtubules. None of the positions measured exceeded ~50% phospho-occupancy, and the cumulative phospho-occupancy changed by only ~20% in response to changes in microtubule attachment status. The narrow dynamic range of phospho-occupancy is maintained, in part, by ongoing phosphatase activity. Further, both Cdk1-Cyclin B1 and Aurora kinases phosphorylate Hec1 to enhance error correction in response to different types of microtubule attachment errors. The low inherent phospho-occupancy promotes microtubule attachment to kinetochores while the high sensitivity of kinetochore-microtubule attachments to small changes in phospho-occupancy drives error correction and ensures high mitotic fidelity.

INSTRUMENT(S): Orbitrap Fusion, Q Exactive Plus

ORGANISM(S): Homo Sapiens (ncbitaxon:9606)

SUBMITTER: Scott Gerber

PROVIDER: MSV000089738 | MassIVE | Mon Jun 27 11:59:00 BST 2022

SECONDARY ACCESSION(S): PXD034945

REPOSITORIES: MassIVE

ACCESS DATA

Json Xml

Dataset's files

Source:

			Action	DRS
		Other

Items per page:

1 - 1 of 1

Similar Datasets

A Siz1/Siz2-mediated SUMOylation programme inactivates the shugoshin-associated phosphatase-kinase network to stabilize sister kinetochore biorientation

Project description:The accurate segregation of chromosomes during mitosis relies on the attachment of sister chromatids to microtubules from opposite poles, called biorientation. Sister chromatid cohesion resists microtubule forces, generating tension which provides the signal that biorientation has occurred. How tension silences the surveillance pathways that prevent cell cycle progression and correct erroneous kinetochore-microtubule attachments remains unclear. Here we identify SUMOylation as a mechanism that promotes anaphase onset upon biorientation. SUMO ligases modify the tension-sensing pericentromere-localized chromatin protein, shugoshin, to stabilize bioriented sister kinetochore-microtubule attachments. In the absence of SUMOylation, Aurora B kinase removal from kinetochores is delayed. Shugoshin SUMOylation prevents its binding to protein phosphatase 2A (PP2A) and release of this interaction is important for stabilizing sister kinetochore biorientation. We propose that SUMOylation modulates the kinase-phosphatase network within pericentromeres to inactivate the error correction machinery, thereby allowing anaphase entry in response to biorientation.

2021-03-25 | PXD019287 | Pride

CX-MS of Phospho-regulated Bim1/EB1 interactions trigger Dam1c ring assembly at the budding yeast outer kinetochore

Project description:Kinetochores form the link between chromosomes and microtubules of the mitotic spindle. The heterodecameric Dam1 complex (Dam1c) is a major component of the S. cerevisiae outer kinetochore, assembling into 3 MDa-sized microtubule-embracing rings, but how ring assembly is specifically initiated at kinetochores remains to be understood. Here, we describe a molecular pathway that provides local control of ring assembly during the establishment of sister kinetochore bi-orientation. We show that Dam1c and the general microtubule plus-end-associated protein (+TIP) Bim1/EB1 form a stable complex depending on a conserved motif in the Duo1 subunit of Dam1c. EM analyses reveal that Bim1 crosslinks protrusion domains of adjacent Dam1c heterodecamers and promotes the formation of oligomers with defined curvature. Disruption of the Dam1c-Bim1 interaction impairs kinetochore localization of Dam1c in metaphase and delays mitosis. Phosphorylation promotes Dam1c-Bim1 binding by relieving an intramolecular inhibition of the Dam1 C-terminus. In addition, Bim1 recruits Bik1/CLIP-170 to Dam1c and induces formation of full rings even in the absence of microtubules. Our data help to explain how new kinetochore end-on attachments are formed during the process of attachment error correction.

2021-06-28 | PXD026935 | Pride

Shugoshin biases chromosomes for biorientation through condensin recruitment to the pericentromere

Project description:To protect against aneuploidy, chromosomes must attach to microtubules from opposite poles (“biorientation”) prior to their segregation during mitosis. Biorientation relies on the correction of erroneous attachments by the aurora B kinase, which destabilizes kinetochore-microtubule attachments that lack tension. Incorrect attachments are also avoided because sister kinetochores are intrinsically biased towards capture by microtubules from opposite poles. Here we show that shugoshin acts as a pericentromeric adaptor that plays dual roles in biorientation in budding yeast. Shugoshin maintains the aurora B kinase at kinetochores that lack tension, thereby engaging the error correction machinery. Shugoshin also recruits the chromosome-organising complex, condensin, to the pericentromere. Pericentromeric condensin biases sister kinetochores towards capture by microtubules from opposite poles. Overall, shugoshin integrates a bias to sister kinetochore capture with error correction to enable chromosome biorientation. Our findings uncover the molecular basis of the bias to sister kinetochore capture and expose shugoshin as a pericentromeric hub controlling chromosome biorientation.

2014-01-08 | GSE53856 | GEO

Aurora A kinase phosphorylates Hec1 to regulate metaphase kinetochore-microtubule dynamics.

Project description:Precise regulation of kinetochore-microtubules is essential for successful chromosome segregation. Central to this regulation is Aurora B kinase, which phosphorylates kinetochore substrates to promote microtubule turnover. A critical target of Aurora B is the N-terminal “tail” domain of Hec1/NDC80, which is a component of the NDC80 complex, a force-transducing link between kinetochores and microtubules. While Aurora B is regarded as the “master regulator” of kinetochore-microtubule attachment, it is likely that other mitotic kinases contribute to Hec1phosphorylation. Here we show that Aurora A kinase phosphorylates the tail domain of Hec1 at Serine 69, a previously uncharacterized phosphorylation target site, and plays an important role in controlling kinetochore-microtubule attachment dynamics. Using phospho-specific antibodies, Hec1 phospho-deficient mutants, and kinase inhibitors, we demonstrate that Aurora A is required for the regulation of kinetochore-microtubule dynamics of metaphase chromosomes and identify Hec1 Serine 69 as a critical Aurora A substrate for this regulation. Additionally, we demonstrate that Aurora A kinase associates with INCENP during mitosis and that INCENP is competent to drive accumulation of the kinase to the centromere region of mitotic chromosomes. These findings reveal that both Aurora A and Aurora B contribute to kinetochore-microtubule attachment dynamics, and they uncover an unexpected role for Aurora A in mitosis.

2017-11-28 | PXD006892 | Pride

Mps1 regulates kinetochore-microtubule attachment stability via the Ska complex to ensure error-free chromosome segregation

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

Shugoshin biases chromosomes for biorientation through condensin recruitment to the pericentromere

2014-01-08 | E-GEOD-53856 | biostudies-arrayexpress

A common molecular mechanism underlies the role of Mps1 in chromosome biorientation and the spindle assembly checkpoint

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

Kinetochores read detyrosinated tubulin to sustain microtubule attachments

Project description:Post-translational cycles of α-tubulin detyrosination/tyrosination generate microtubule diversity, with broad physiological and clinical implications. However, the mechanistic understanding of how this microtubule diversity is decoded into specific cellular functions remains largely unknown. Here we show that the core microtubule-binding site at kinetochores ‘reads’ and responds to the α-tubulin detyrosination/tyrosination code. By combining CRISPR-Cas9 gene editing of enzymatic ‘writers’ of α-tubulin detyrosination/tyrosination in human cells, with biochemical purifications, mass spectrometry and super-resolution microscopy, we identified over a hundred proteins that preferentially associate with either detyrosinated or tyrosinated microtubules during mitosis. Among these, the conserved KNL-1/MIS12 complex/NDC80 complex (KMN) network at kinetochores showed a preference for tyrosinated microtubules. In addition to established roles in error correction and polar chromosome alignment, live-cell imaging uncovered a previously overlooked link between the α-tubulin detyrosination/tyrosination code and the formation of functional kinetochore-microtubule attachments, necessary for normal metaphase chromosome oscillations and timely spindle assembly checkpoint satisfaction. In vitro reconstitution experiments revealed that α-tubulin detyrosination specifically promotes Ndc80 diffusion along the microtubule lattice. We propose that the gradual accumulation of detyrosinated α-tubulin after initial microtubule capture at kinetochores facilitates the biased diffusion of core-binding proteins along the microtubule lattice, establishing a positive feedback loop that sustains kinetochore-microtubule attachments.

2024-10-03 | PXD047133 | Pride

Pcs1 and Mde4 are inner centromere proteins required to prevent merotelic kinetochore orientation

Project description:Chromosome segregation depends on proper attachment of sister kinetochores to microtubules. Merotelic kinetochore orientation is an error which occurs when a single kinetochore is attached to microtubules emanating form opposite poles. Mechanisms preventing or correcting the merotelic attachment must operate to avoid chromosome missegregation. Pcs1 has been implicated in preventing merotelic attachment in mitosis and meiosis II. We describe here the identification of Mde4 protein which forms a complex with the Pcs1. Both Mde4 and Pcs1 localize to the central core of the centromere. Similarly to the pcs1 mutant, in the absence of mde4 lagging chromosomes are frequently observed during mitosis and meiosis II . We provide the first evidence that the lagging chromosomes in pcs1 and mde4 mutants are due to merotelic kinetochore orientation. Keywords: ChIP-chip analysis ChIP-chip analysis: In all cases, hybridization data for ChIP fraction was compared with that of SUP (supernatant) fraction. Pombe whole chromosome array was used.

2010-06-10 | E-GEOD-5257 | biostudies-arrayexpress

Pcs1 and Mde4 are inner centromere proteins required to prevent merotelic kinetochore orientation

2007-06-18 | GSE5257 | GEO