Spc24 interacts with Mps2 and is required for chromosome segregation, but is not implicated in spindle pole body duplication

Masson, Ivan Le; Saveanu, Cosmin; Chevalier, Anne; Namane, Abdelkader; Gobin, Renée; Fromont‐Racine, Micheline; Jacquier, Alain; Mann, Carl

doi:10.1046/j.1365-2958.2002.02844.x

Cited by 23 publications

(30 citation statements)

References 42 publications

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“…The budding yeast Ndc80 central kinetochore complex, which is composed of the four coiled-coil proteins, Ndc80, Nuf2, Spc24, and Spc25, is required for proper attachment of chromosomes to spindle MTs and activation of the spindle checkpoint in the presence of defects in attachment (Janke et al, 2001;Wigge and Kilmartin, 2001;Le Masson et al, 2002;Montpetit et al, 2005;Pinsky et al, 2006). It has recently been shown that the kinetochore has a role in maintaining a short (1.5-2 m) spindle when DNA replication is stalled by treatment of cells with HU (Bachant et al, 2005).…”

Section: Spc24 Is Required For Viability and For Preventing Spindle Ementioning

confidence: 99%

Spc24 and Stu2 Promote Spindle Integrity When DNA Replication Is Stalled

McQueen

Cuschieri²,

Vogel

et al. 2007

MBoC

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The kinetochore, a protein complex that links chromosomes to microtubules (MTs), is required to prevent spindle expansion during S phase in budding yeast, but the mechanism of how the kinetochore maintains integrity of the bipolar spindle before mitosis is not well understood. Here, we demonstrate that a mutation of Spc24, a component of the conserved Ndc80 kinetochore complex, causes lethality when cells are exposed to the DNA replication inhibitor hydroxyurea (HU) due to premature spindle expansion and segregation of incompletely replicated DNA. Overexpression of Stu1, a CLASP-related MT-associated protein or a truncated form of the XMAP215 orthologue Stu2 rescues spc24-9 HU lethality and prevents spindle expansion. Truncated Stu2 likely acts in a dominant-negative manner, because overexpression of full-length STU2 does not rescue spc24-9 HU lethality, and spindle expansion in spc24-9 HU-treated cells requires active Stu2. Stu1 and Stu2 localize to the kinetochore early in the cell cycle and Stu2 kinetochore localization depends on Spc24. We propose that mislocalization of Stu2 results in premature spindle expansion in S phase stalled spc24-9 mutants. Identifying factors that restrain spindle expansion upon inhibition of DNA replication is likely applicable to the mechanism by which spindle elongation is regulated during a normal cell cycle. INTRODUCTIONPreserving the integrity of the genome is a fundamental requirement for eukaryotic cell viability. DNA replication must be completed before segregation of the chromosomes to prevent the transmission of partially replicated chromosomes to daughter cells. In the budding yeast Saccharomyces cerevisiae, cells undergo a closed mitosis and the microtubule (MT) organizing centers, or spindle pole bodies (SPBs), are imbedded in the nuclear envelope. SPB duplication begins at the end of anaphase and spindle formation begins during S phase when duplicated SPBs separate from each other (Adams and Kilmartin, 1999;Jaspersen and Winey, 2004). Because chromosomes remain attached to kinetochore MTs throughout the cell cycle, spindle expansion must be restrained until all 16 chromosomes have duplicated and kinetochores on sister chromatids have formed bipolar MT attachments. When DNA replication is stalled by hydroxyurea (HU) treatment, cells arrest with a large bud, an undivided nucleus positioned at the mother-bud neck and a short bipolar spindle (Allen et al., 1994). Maintaining a short spindle is crucial for cell survival during HU-induced arrest, which activates the DNA replication checkpoint effectors Mec1 and Rad53 (Kolodner et al., 2002). When mec1 and rad53 mutants are treated with HU, the DNA replication checkpoint is not activated, and, as a result, replication forks are not stabilized, the spindle expands, and unequal division of incompletely replicated nuclear material occurs-all of these events contribute to cell lethality (Allen et al., 1994;Weinert et al., 1994;Lopes et al., 2001).In human cells, stalled replication forks activate the ataxia telangiectasia mutat...

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Section: Spc24 Is Required For Viability and For Preventing Spindle Ementioning

confidence: 99%

Spc24 and Stu2 Promote Spindle Integrity When DNA Replication Is Stalled

McQueen

Cuschieri²,

Vogel

et al. 2007

MBoC

View full text Add to dashboard Cite

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“…Strains were arrested in G 1 phase using the mating pheromone aF and then released to 37°and monitored over a period of 4 hr. Multiple spc24 Ts mutants have been created yet only one arrest phenotype has been published (Janke et al 2001;Wigge and Kilmartin 2001;Le Masson et al 2002). Unexpectedly, we found that all three of our spc24 alleles displayed different arrest profiles (Figure 1, A and B).…”

Section: Resultsmentioning

confidence: 70%

“…We decided to focus on one member of the Ndc80 complex, Spc24p, which has previously been shown to have a role in MT attachment and spindle checkpoint control, and one member of the outer kinetochore Dam1 complex, Spc34p, which is required for MT attachment, spindle stability, and prevention of monopolar attachment (Janke et al 2001(Janke et al , 2002Wigge and Kilmartin 2001;Le Masson et al 2002). We were concerned that genome-wide screening using only a single mutant of spc24 and spc34 might limit our results, depending on the nature of the mutation and the resulting defect in protein function.…”

Section: Resultsmentioning

confidence: 99%

“…Inner and central kinetochore complexes assemble in a hierarchical manner onto CEN DNA and serve as a link to the Dam1 outer kinetochore complex that encircles MTs (Biggins and Walczak 2003;McAinsh et al 2003;Miranda et al 2005;Westermann et al 2005). The Ndc80 complex is a highly conserved central kinetochore complex that is required for attachment of chromosomes to MTs (He et al 2001;Janke et al 2001;Wigge and Kilmartin 2001;Le Masson et al 2002). Studies in multiple eukaryotic systems have shown that the Ndc80 complex is required to localize spindle checkpoint proteins to the kinetochore and that cells carrying mutations in 1 Ndc80 complex components are defective in checkpoint signaling (Gillett et al 2004;Maiato et al 2004).…”

mentioning

confidence: 99%

“…Mps2p localizes to both the SPB and the NE and is required for SPB insertion into the NE (Winey et al 1991;MunozCenteno et al 1999). Interestingly, Mps2p interacts in vivo with Spc24p, a component of the Ndc80 complex, suggesting that the kinetochore may physically interact with components of the NE (Le Masson et al 2002). In support of a kinetochore-NE connection, CENs cluster near the SPB/NE in interphase and colocalize with SPBs during late anaphase (Goshima and Yanagida 2000;He et al 2000;Jin et al 2000;Pearson et al 2001).…”

mentioning

confidence: 99%

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Genome-Wide Synthetic Lethal Screens Identify an Interaction Between the Nuclear Envelope Protein, Apq12p, and the Kinetochore in Saccharomyces cerevisiae

et al. 2005

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The maintenance of genome stability is a fundamental requirement for normal cell cycle progression. The budding yeast Saccharomyces cerevisiae is an excellent model to study chromosome maintenance due to its well-defined centromere and kinetochore, the region of the chromosome and associated protein complex, respectively, that link chromosomes to microtubules. To identify genes that are linked to chromosome stability, we performed genome-wide synthetic lethal screens using a series of novel temperaturesensitive mutations in genes encoding a central and outer kinetochore protein. By performing the screens using different mutant alleles of each gene, we aimed to identify genetic interactions that revealed diverse pathways affecting chromosome stability. Our study, which is the first example of genome-wide synthetic lethal screening with multiple alleles of a single gene, demonstrates that functionally distinct mutants uncover different cellular processes required for chromosome maintenance. Two of our screens identified APQ12, which encodes a nuclear envelope protein that is required for proper nucleocytoplasmic transport of mRNA. We find that apq12 mutants are delayed in anaphase, rereplicate their DNA, and rebud prior to completion of cytokinesis, suggesting a defect in controlling mitotic progression. Our analysis reveals a novel relationship between nucleocytoplasmic transport and chromosome stability.

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Scaffolds, levers, rods and springs: diverse cellular functions of long coiled-coil proteins

Rose

Meier

2004

CMLS, Cell. Mol. Life Sci.

126

133

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Long alpha-helical coiled-coil proteins are involved in a variety of organizational and regulatory processes in eukaryotic cells. They provide cables and networks in the cyto- and nucleoskeleton, molecular scaffolds that organize membrane systems, motors, levers, rotating arms and possibly springs. A growing number of human diseases are found to be caused by mutations in long coiled-coil proteins. This review summarizes our current understanding of the multifaceted group of long coiled-coil proteins in the cytoskeleton, nucleus, Golgi and cell division apparatus. The biophysical features of coiled-coil domains provide first clues toward their contribution to the diverse protein functions and promise potential future applications in the area of nanotechnology. Combining the power of fully sequenced genomes and structure prediction algorithms, it is now possible to comprehensively summarize and compare the complete inventory of coiled-coil proteins of different organisms.

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Spc24 interacts with Mps2 and is required for chromosome segregation, but is not implicated in spindle pole body duplication

Cited by 23 publications

References 42 publications

Spc24 and Stu2 Promote Spindle Integrity When DNA Replication Is Stalled

Spc24 and Stu2 Promote Spindle Integrity When DNA Replication Is Stalled

Genome-Wide Synthetic Lethal Screens Identify an Interaction Between the Nuclear Envelope Protein, Apq12p, and the Kinetochore in Saccharomyces cerevisiae

Scaffolds, levers, rods and springs: diverse cellular functions of long coiled-coil proteins

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