Genetic Analysis of the Kinetochore DASH Complex Reveals an Antagonistic Relationship with the Ras/Protein Kinase A Pathway and a Novel Subunit Required for Ask1 Association

Li, Jumei; Li, Yumei; Elledge, Stephen J.

doi:10.1128/mcb.25.2.767-778.2005

Cited by 31 publications

(30 citation statements)

References 53 publications

(63 reference statements)

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“…In budding yeast this complex consists of 10 essential subunits, including Dam1 (Cheeseman et al, 2001(Cheeseman et al, , 2002Janke et al, 2002;Li et al, 2002Li et al, , 2005. Loss of DASH complex function results in unequal sister chromatid segregation.…”

Section: Introductionmentioning

confidence: 99%

Sister Kinetochore Recapture in Fission Yeast Occurs by Two Distinct Mechanisms, Both Requiring Dam1 and Klp2

Gachet

Reyes

Courthéoux

et al. 2008

MBoC

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In eukaryotic cells, proper formation of the spindle is necessary for successful cell division. We have studied chromosome recapture in the fission yeast Schizosaccharomyces pombe. We show by live cell analysis that lost kinetochores interact laterally with intranuclear microtubules (INMs) and that both microtubule depolymerization (end-on pulling) and minus-end-directed movement (microtubule sliding) contribute to chromosome retrieval to the spindle pole body (SPB). We find that the minus-end-directed motor Klp2 colocalizes with the kinetochore during its transport to the SPB and contributes to the effectiveness of retrieval by affecting both end-on pulling and lateral sliding. Furthermore, we provide in vivo evidence that Dam1, a component of the DASH complex, also colocalizes with the kinetochore during its transport and is essential for its retrieval by either of these mechanisms. Finally, we find that the position of the unattached kinetochore correlates with the size and orientation of the INMs, suggesting that chromosome recapture may not be a random process.

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Section: Introductionmentioning

confidence: 99%

Sister Kinetochore Recapture in Fission Yeast Occurs by Two Distinct Mechanisms, Both Requiring Dam1 and Klp2

Gachet

Reyes

Courthéoux

et al. 2008

MBoC

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“…Three of these genes were previously uncharacterized-YLR099W-A, YNL024C-A, and YNL138W-A-while the remaining five sORFs were previously shown to be essential, which we confirmed in the gene-deletion strain background. These sORFs are required for functions such as kinetochore or spindle integrity (Cheeseman et al 2002;Li et al 2005), ER to golgi transport (Heidtman et al 2005), and pseudouridine biosynthesis (Henras et al 1998). Combined with the results from Version 1.0, 21 of the sORFs are essential, representing ∼8% of sORFs analyzed.…”

Section: Identification Of Essential Sorfsmentioning

confidence: 99%

Functional genomics of genes with small open reading frames (sORFs) in S. cerevisiae

et al. 2006

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Genes with small open reading frames (sORFs; <100 amino acids) represent an untapped source of important biology. sORFs largely escaped analysis because they were difficult to predict computationally and less likely to be targeted by genetic screens. Thus, the substantial number of sORFs and their potential importance have only recently become clear. To investigate sORF function, we undertook the first functional studies of sORFs in any system, using the model eukaryote Saccharomyces cerevisiae. Based on independent experimental approaches and computational analyses, evidence exists for 299 sORFs in the S. cerevisiae genome, representing ∼5% of the annotated ORFs. We determined that a similar percentage of sORFs are annotated in other eukaryotes, including humans, and 184 of the S. cerevisiae sORFs exhibit similarity with ORFs in other organisms. To investigate sORF function, we constructed a collection of gene-deletion mutants of 140 newly identified sORFs, each of which contains a strain-specific "molecular barcode," bringing the total number of sORF deletion strains to 247. Phenotypic analyses of the new gene-deletion strains identified 22 sORFs required for haploid growth, growth at high temperature, growth in the presence of a nonfermentable carbon source, or growth in the presence of DNA damage and replication-arrest agents. We provide a collection of sORF deletion strains that can be integrated into the existing deletion collection as a resource for the yeast community for elucidating gene function. Moreover, our analyses of the S. cerevisiae sORFs establish that sORFs are conserved across eukaryotes and have important biological functions.

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“…Despite the presence of improper attachments that should activate the spindle checkpoint, cells with impaired Ipl1/Aurora B function proceed through the cell cycle (3,10,19,26,40). Ipl1 is thought to promote proper chromosome segregation, in part, by phosphorylating components of the Dam1/DASH/DDD complex, an essential regulator of kinetochore-microtubule interactions and microtubule function (15,16,34,35,43,44,48,59,73).…”

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confidence: 99%

Glc7/Protein Phosphatase 1 Regulatory Subunits Can Oppose the Ipl1/Aurora Protein Kinase by Redistributing Glc7

Pinsky

Kotwaliwale

Tatsutani

et al. 2006

Molecular and Cellular Biology

103

112

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Faithful chromosome segregation depends on the opposing activities of the budding yeast Glc7/PP1 protein phosphatase and Ipl1/Aurora protein kinase. We explored the relationship between Glc7 and Ipl1 and found that the phosphorylation of the Ipl1 substrate, Dam1, was altered by decreased Glc7 activity, whereas Ipl1 levels, localization, and kinase activity were not. These data strongly suggest that Glc7 ensures accurate chromosome segregation by dephosphorylating Ipl1 targets rather than regulating the Ipl1 kinase. To identify potential Glc7 and Ipl1 substrates, we isolated ipl1-321 dosage suppressors. Seven genes (SDS22, BUD14, GIP3, GIP4, SOL1, SOL2, and PEX31) encode newly identified ipl1 dosage suppressors, and all 10 suppressors encode proteins that physically interact with Glc7. The overexpression of the Gip3 and Gip4 suppressors altered Glc7 localization, indicating they are previously unidentified Glc7 regulatory subunits. In addition, the overexpression of Gip3 and Gip4 from the galactose promoter restored Dam1 phosphorylation in ipl1-321 mutant cells and caused wild-type cells to arrest in metaphase with unsegregated chromosomes, suggesting that Gip3 and Gip4 overexpression impairs Glc7's mitotic functions. We therefore propose that the overexpression of Glc7 regulatory subunits can titrate Glc7 away from relevant Ipl1 targets and thereby suppress ipl1-321 cells by restoring the balance of phosphatase/kinase activity.The accurate partitioning of the genome during mitosis requires the precise regulation of the connection between chromosomes and the mitotic spindle. This fundamental interaction is mediated by the kinetochore, a specialized protein complex that assembles on centromeric DNA and facilitates the capture of dynamic spindle microtubules that arise from opposite poles (for reviews, see references 5, 13, and 17). Bipolar attachments promote accurate chromosome segregation by ensuring that the spindle forces on the replicated chromosomes (sister chromatids) are directed toward opposite sides of the cell. Once all chromosomes make proper bipolar attachments, the cell transitions to anaphase where sister chromatids are pulled to opposite poles. Failure to achieve bipolar attachments results in chromosome missegregation, and this aneuploid state predisposes multicellular organisms to the development of a variety of diseases. To prevent the premature segregation of improperly attached chromosomes, the spindle checkpoint monitors kinetochore-microtubule interactions and delays the metaphase to anaphase transition until bipolar attachments are achieved (for a review, see reference 42).An important regulator of both kinetochore attachment and the spindle checkpoint is the conserved Ipl1/Aurora B protein kinase, a component of the chromosomal passenger complex that localizes to kinetochores, spindles, and the spindle midzone and midbody (for reviews, see references 25 and 69).

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Genetic Analysis of the Kinetochore DASH Complex Reveals an Antagonistic Relationship with the Ras/Protein Kinase A Pathway and a Novel Subunit Required for Ask1 Association

Cited by 31 publications

References 53 publications

Sister Kinetochore Recapture in Fission Yeast Occurs by Two Distinct Mechanisms, Both Requiring Dam1 and Klp2

Sister Kinetochore Recapture in Fission Yeast Occurs by Two Distinct Mechanisms, Both Requiring Dam1 and Klp2

Functional genomics of genes with small open reading frames (sORFs) in S. cerevisiae

Glc7/Protein Phosphatase 1 Regulatory Subunits Can Oppose the Ipl1/Aurora Protein Kinase by Redistributing Glc7

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