The Composition, Functions, and Regulation of the Budding Yeast Kinetochore

Biggins, Sue

doi:10.1534/genetics.112.145276

Cited by 181 publications

(265 citation statements)

References 387 publications

(686 reference statements)

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“…Kinetochores maintain a grip on dynamic microtubules that are constantly growing and shortening, and they also ensure that each chromatid is properly attached to microtubules emanating from only one pole. These attachments must be strong enough to withstand the mechanical tension associated with bipolar chromosome alignment, and yet they must be quickly released in response to signals that detect improper attachments (1,2). Each kinetochore is a macromolecular structure composed of 40 different types of proteins assembled into repeating subcomplexes that span from the centromeric DNA to the microtubule (2).…”

mentioning

confidence: 99%

“…These attachments must be strong enough to withstand the mechanical tension associated with bipolar chromosome alignment, and yet they must be quickly released in response to signals that detect improper attachments (1,2). Each kinetochore is a macromolecular structure composed of 40 different types of proteins assembled into repeating subcomplexes that span from the centromeric DNA to the microtubule (2). There is an intrinsic hierarchy, with few DNA-binding elements expanding out to multiple microtubule attachment complexes (3,4).…”

mentioning

confidence: 99%

“…Previous work has characterized the individual and combined activities of the outer microtubule-binding kinetochore complexes (1,2). How central kinetochore complexes contribute to establishing and maintaining microtubule attachment is less clear.…”

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confidence: 99%

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Regulation of outer kinetochore Ndc80 complex-based microtubule attachments by the central kinetochore Mis12/MIND complex

Kudalkar

Scarborough

Umbreit

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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Multiple protein subcomplexes of the kinetochore cooperate as a cohesive molecular unit that forms load-bearing microtubule attachments that drive mitotic chromosome movements. There is intriguing evidence suggesting that central kinetochore components influence kinetochore-microtubule attachment, but the mechanism remains unclear. Here, we find that the conserved Mis12/MIND (Mtw1, Nsl1, Nnf1, Dsn1) and Ndc80 (Ndc80, Nuf2, Spc24, Spc25) complexes are connected by an extensive network of contacts, each essential for viability in cells, and collectively able to withstand substantial tensile load. Using a single-molecule approach, we demonstrate that an individual MIND complex enhances the microtubulebinding affinity of a single Ndc80 complex by fourfold. MIND itself does not bind microtubules. Instead, MIND binds Ndc80 complex far from the microtubule-binding domain and confers increased microtubule interaction of the complex. In addition, MIND activation is redundant with the effects of a mutation in Ndc80 that might alter its ability to adopt a folded conformation. Together, our results suggest a previously unidentified mechanism for regulating microtubule binding of an outer kinetochore component by a central kinetochore complex.

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Regulation of outer kinetochore Ndc80 complex-based microtubule attachments by the central kinetochore Mis12/MIND complex

Kudalkar

Scarborough

Umbreit

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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“…The kinetochore attaches chromosomes to the spindle microtubules to drive accurate chromosome segregation. The kinetochore consists of at least 60 unique gene products present in multiple copies that stretch from the specialized H3 histone subunit (Cse4, CENP-A in mammals) to the microtubule binding proteins of the Dam1 complex (9). Kinetochores normally assemble hierarchically from the centromere-bound proteins (10).…”

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confidence: 99%

“…We used growth as a readout for kinetochore defects and any protein-protein interactions that affect growth we termed "synthetic physical interactions" or SPIs. We chose to study the kinetochore protein Mtw1, which is a conserved member of the MIND (Mis12) complex of the KMN (KNL1-Mis12-Ndc80) network of mid-/outer-kinetochore proteins (9). The SPI method identified proteins that, when bound to the kinetochore component Mtw1, cause a growth defect.…”

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confidence: 99%

Synthetic physical interactions map kinetochore regulators and regions sensitive to constitutive Cdc14 localization

Ólafsson

Thorpe

2015

Proc. Natl. Acad. Sci. U.S.A.

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The location of proteins within eukaryotic cells is often critical for their function and relocation of proteins forms the mainstay of regulatory pathways. To assess the importance of protein location to cellular homeostasis, we have developed a methodology to systematically create binary physical interactions between a query protein and most other members of the proteome. This method allows us to rapidly assess which of the thousands of possible protein interactions modify a phenotype. As proof of principle we studied the kinetochore, a multiprotein assembly that links centromeres to the microtubules of the spindle during cell division. In budding yeast, the kinetochores from the 16 chromosomes cluster together to a single location within the nucleus. The many proteins that make up the kinetochore are regulated through ubiquitylation and phosphorylation. By systematically associating members of the proteome to the kinetochore, we determine which fusions affect its normal function. We identify a number of candidate kinetochore regulators, including the phosphatase Cdc14. We examine where within the kinetochore Cdc14 can act and show that the effect is limited to regions that correlate with known phosphorylation sites, demonstrating the importance of serine phospho-regulation for normal kinetochore homeostasis.T he relocation of proteins between cellular compartments underlies many regulatory pathways. For example, protein relocation underpins most cell-signaling pathways (1) and the establishment of cell polarity and asymmetric cell division both require highly specialized relocation of proteins within the cell (2). Furthermore, the aberrant localization of proteins underlies the pathology of a number of diseases (3). However, our understanding of the effect of relocalizing members of the proteome is limited to specific studies typically concerning individual proteins, and only a select few studies have globally monitored protein relocation (4, 5).One highly localized structure within the cell is the kinetochore, which in budding yeast forms a single megadalton complex (6-8). The kinetochore attaches chromosomes to the spindle microtubules to drive accurate chromosome segregation. The kinetochore consists of at least 60 unique gene products present in multiple copies that stretch from the specialized H3 histone subunit (Cse4, CENP-A in mammals) to the microtubule binding proteins of the Dam1 complex (9). Kinetochores normally assemble hierarchically from the centromere-bound proteins (10). Once assembled, the structural homeostasis of the kinetochore is regulated by proteins that are recruited to kinetochores. For example, the histone subunit Cse4 is tightly regulated by the E3 ubiquitin ligase Psh1, which is localized at centromeres. Psh1 prevents excessive Cse4 centromere loading via ubiquitylation-dependent degradation of Cse4 (and at noncentromeric regions) (11). Cse4 is also phosphorylated by Ipl1, likely to destabilize aberrant microtubule interactions and ensure correct sister chromosome biorientation (12...

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Kinetochore: Structure, Function and Evolution

Liu

2014

Encyclopedia of Life Sciences

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Duplicated eukaryotic chromosomes are segregated into daughter cells through cell division. Faithful chromosome segregation depends on kinetochores, which are specialized macromolecular structures built upon centromeric chromatin. The dynamic kinetochore structures connect chromosomes with spindle microtubules, power chromosome movement, and signal the activation and silencing of the spindle assembly checkpoint (SAC). Molecular analyses of the components and architecture of kinetochores have advanced rapidly in recent years. A human kinetochore contains approximately 200 proteins, many of which are evolutionarily conserved in other organisms. A histone H3 variant, CENP‐A and associated constitutive centromere proteins lay the foundation for kinetochore build‐up. Multiple kinetochore‐localised microtubule‐binding proteins including the Ndc80 complex help regulate chromosome movement. The SAC signalling originates from kinetochores and contributes to the fidelity of chromosome segregation. Many fascinating properties remain to be elucidated about the kinetochore as a fundamental machinery to maintain genomic stability. Key Concepts: Chromosome segregation in eukaryotic cells depends upon connecting spindle microtubules with special macromolecular structures on chromosomes called kinetochores. The centromere is the chromosomal locus where a kinetochore is built. Laying the foundation for kinetochore assembly at centromeres are CENP‐A (a histone H3 variant) containing nucleosomes and a group of CENP‐A associated proteins (termed constitutive centromere proteins). There are multiple microtubule motors and nonmotor microtubule‐binding proteins localised at kinetochores to coordinate chromosome movement. A 10 protein complex called KMN network is currently thought to provide the primary end‐on microtubule‐binding activity. The spindle assembly checkpoint (SAC) monitors the kinetochore–microtubule attachment and signals the delay of the metaphase‐to‐anaphase transition when defects are detected. Conformational change of MAD2 and assembly of the mitotic checkpoint complex (MCC) are the key events to activate the SAC. Comparative studies of similar and distinct kinetochore composition, structure and function in different species and during mitosis or meiosis have provided evolutionary perspectives on mechanisms regulating chromosome segregation.

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The Composition, Functions, and Regulation of the Budding Yeast Kinetochore

Cited by 181 publications

References 387 publications

Regulation of outer kinetochore Ndc80 complex-based microtubule attachments by the central kinetochore Mis12/MIND complex

Regulation of outer kinetochore Ndc80 complex-based microtubule attachments by the central kinetochore Mis12/MIND complex

Synthetic physical interactions map kinetochore regulators and regions sensitive to constitutive Cdc14 localization

Kinetochore: Structure, Function and Evolution

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