scholarly journals Acetylation of the SUN protein Mps3 by Eco1 regulates its function in nuclear organization

2012 ◽  
Vol 23 (13) ◽  
pp. 2546-2559 ◽  
Author(s):  
Suman Ghosh ◽  
Jennifer M. Gardner ◽  
Christine J. Smoyer ◽  
Jennifer M. Friederichs ◽  
Jay R. Unruh ◽  
...  
Keyword(s):  
Nuclear Membrane ◽  
Sister Chromatid ◽  
Transmembrane Domain ◽  
Nuclear Organization ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Sister Chromatid Cohesion ◽  
Chromatid Cohesion

The Saccharomyces cerevisiae SUN-domain protein Mps3 is required for duplication of the yeast centrosome-equivalent organelle, the spindle pole body (SPB), and it is involved in multiple aspects of nuclear organization, including telomere tethering and gene silencing at the nuclear membrane, establishment of sister chromatid cohesion, and repair of certain types of persistent DNA double-stranded breaks. How these diverse SUN protein functions are regulated is unknown. Here we show that the Mps3 N-terminus is a substrate for the acetyltransferase Eco1/Ctf7 in vitro and in vivo and map the sites of acetylation to three lysine residues adjacent to the Mps3 transmembrane domain. Mutation of these residues shows that acetylation is not essential for growth, SPB duplication, or distribution in the nuclear membrane. However, analysis of nonacetylatable mps3 mutants shows that this modification is required for accurate sister chromatid cohesion and for chromosome recruitment to the nuclear membrane. Acetylation of Mps3 by Eco1 is one of the few regulatory mechanisms known to control nuclear organization.

scholarly journals The acetyltransferase activity of San stabilizes the mitotic cohesin at the centromeres in a shugoshin-independent manner

2007 ◽  
Vol 177 (4) ◽  
pp. 587-597 ◽  
Author(s):  
Fajian Hou ◽  
Chih-Wen Chu ◽  
Xiangduo Kong ◽  
Kyoko Yokomori ◽  
Hui Zou
Keyword(s):  
Cell Cycle ◽  
Sister Chromatid ◽  
Sister Chromatid Cohesion ◽  
Independent Manner ◽  
Acetyltransferase Activity ◽  
Chromatid Cohesion ◽  
Interphase Cells ◽  
Gain Access

Proper sister chromatid cohesion is critical for maintaining genetic stability. San is a putative acetyltransferase that is important for sister chromatid cohesion in Drosophila melanogaster, but not in budding yeast. We showed that San is critical for sister chromatid cohesion in HeLa cells, suggesting that this mechanism may be conserved in metazoans. Furthermore, although a small fraction of San interacts with the NatA complex, San appears to mediate cohesion independently. San exhibits acetyltransferase activity in vitro, and its activity is required for sister chromatid cohesion in vivo. In the absence of San, Sgo1 localizes correctly throughout the cell cycle. However, cohesin is no longer detected at the mitotic centromeres. Furthermore, San localizes to the cytoplasm in interphase cells; thus, it may not gain access to chromosomes until mitosis. Moreover, in San-depleted cells, further depletion of Plk1 rescues the cohesion along the chromosome arms, but not at the centromeres. Collectively, San may be specifically required for the maintenance of the centromeric cohesion in mitosis.

scholarly journals A Potential Role for Human Cohesin in Mitotic Spindle Aster Assembly

2001 ◽  
Vol 276 (50) ◽  
pp. 47575-47582 ◽  
Author(s):  
Heather C. Gregson ◽  
John A. Schmiesing ◽  
Jong-Soo Kim ◽  
Toshiki Kobayashi ◽  
Sharleen Zhou ◽  
...  
Keyword(s):  
Sister Chromatid ◽  
Mitotic Spindle ◽  
Potential Role ◽  
Metaphase Plate ◽  
Spindle Pole ◽  
Sister Chromatid Cohesion ◽  
Cycle Arrest ◽  
Spindle Poles ◽  
Chromatid Cohesion

The cohesin multiprotein complex containing SMC1, SMC3, Scc3 (SA), and Scc1 (Rad21) is required for sister chromatid cohesion in eukaryotes. Although metazoan cohesin associates with chromosomes and was shown to function in the establishment of sister chromatid cohesion during interphase, the majority of cohesin was found to be off chromosomes and reside in the cytoplasm in metaphase. Despite its dissociation from chromosomes, however, microinjection of an antibody against human SMC1 led to disorganization of the metaphase plate and cell cycle arrest, indicating that human cohesin still plays an important role in metaphase. To address the mitotic function of human cohesin, the subcellular localization of cohesin components was reexamined in human cells. Interestingly, we found that cohesin localizes to the spindle poles during mitosis and interacts with NuMA, a spindle pole-associated factor required for mitotic spindle organization. The interaction with NuMA persists during interphase. Similar to NuMA, a significant amount of cohesin was found to associate with the nuclear matrix. Furthermore, in the absence of cohesin, mitotic spindle asters failed to formin vitro. Our results raise the intriguing possibility that in addition to its well demonstrated function in sister chromatid cohesion, cohesin may be involved in spindle assembly during mitosis.

scholarly journals The Spindle Pole Body Assembly Component Mps3p/Nep98p Functions in Sister Chromatid Cohesion

2004 ◽  
Vol 279 (47) ◽  
pp. 49542-49550 ◽  
Author(s):  
Lisa M. Antoniacci ◽  
Margaret A. Kenna ◽  
Peter Uetz ◽  
Stanley Fields ◽  
Robert V. Skibbens
Keyword(s):  
Sister Chromatid ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Sister Chromatid Cohesion ◽  
Pole Body ◽  
Chromatid Cohesion ◽  
Assembly Component

scholarly journals LEM2 recruits CHMP7 for ESCRT-mediated nuclear envelope closure in fission yeast and human cells

2017 ◽  
Vol 114 (11) ◽  
pp. E2166-E2175 ◽  
Author(s):  
Mingyu Gu ◽  
Dollie LaJoie ◽  
Opal S. Chen ◽  
Alexander von Appen ◽  
Mark S. Ladinsky ◽  
...  
Keyword(s):  
Nuclear Envelope ◽  
Fission Yeast ◽  
Nuclear Membrane ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Human Cells ◽  
Nuclear Pore ◽  
Nuclear Pore Complexes ◽  
Loss Of Function

Endosomal sorting complexes required for transport III (ESCRT-III) proteins have been implicated in sealing the nuclear envelope in mammals, spindle pole body dynamics in fission yeast, and surveillance of defective nuclear pore complexes in budding yeast. Here, we report that Lem2p (LEM2), a member of the LEM (Lap2-Emerin-Man1) family of inner nuclear membrane proteins, and the ESCRT-II/ESCRT-III hybrid protein Cmp7p (CHMP7), work together to recruit additional ESCRT-III proteins to holes in the nuclear membrane. InSchizosaccharomyces pombe, deletion of the ATPasevps4leads to severe defects in nuclear morphology and integrity. These phenotypes are suppressed by loss-of-function mutations that arise spontaneously inlem2orcmp7, implying that these proteins may function upstream in the same pathway. Building on these genetic interactions, we explored the role of LEM2 during nuclear envelope reformation in human cells. We found that CHMP7 and LEM2 enrich at the same region of the chromatin disk periphery during this window of cell division and that CHMP7 can bind directly to the C-terminal domain of LEM2 in vitro. We further found that, during nuclear envelope formation, recruitment of the ESCRT factors CHMP7, CHMP2A, and IST1/CHMP8 all depend on LEM2 in human cells. We conclude that Lem2p/LEM2 is a conserved nuclear site-specific adaptor that recruits Cmp7p/CHMP7 and downstream ESCRT factors to the nuclear envelope.

scholarly journals Two Human Orthologues of Eco1/Ctf7 Acetyltransferases Are Both Required for Proper Sister-Chromatid Cohesion

2005 ◽  
Vol 16 (8) ◽  
pp. 3908-3918 ◽  
Author(s):  
Fajian Hou ◽  
Hui Zou
Keyword(s):  
Sister Chromatid ◽  
Cell Cycle Regulation ◽  
Sister Chromatid Cohesion ◽  
Genetic Studies ◽  
Conserved Domain ◽  
Chromatid Cohesion ◽  
The Difference ◽  
Cycle Regulation ◽  
Acetyltransferase Domain

Genetic studies in yeast and Drosophila have uncovered a conserved acetyltransferase involved in sister-chromatid cohesion. Here, we described the two human orthologues, previously named EFO1/ESCO1 and EFO2/ESCO2. Similar to their yeast (Eco1/Ctf7 and Eso1) and fly (deco) counterparts, both proteins feature a conserved C-terminal domain consisting of a H2C2 zinc finger motif and an acetyltransferase domain that is able to catalyze autoacetylation reaction in vitro. However, no similarity can be detected outside of the conserved domain. RNA interference depletion experiment revealed that EFO1/ESCO1 and EFO2/ESCO2 were not redundant and that both were required for proper sister-chromatid cohesion. The difference between EFO1 and EFO2 also is reflected in their cell cycle regulation. In mitosis, EFO1 is phosphorylated, whereas EFO2 is degraded. Furthermore, both proteins associate with chromosomes, and the chromosome binding depends on the diverse N-terminal domains. We propose that EFO1 and EFO2 are targeted to different chromosome structures to help establish or maintain sister-chromatid cohesion.

scholarly journals The yeast protein kinase Mps1p is required for assembly of the integral spindle pole body component Spc42p

2002 ◽  
Vol 156 (3) ◽  
pp. 453-465 ◽  
Author(s):  
Andrea R. Castillo ◽  
Janet B. Meehl ◽  
Garry Morgan ◽  
Amy Schutz-Geschwender ◽  
Mark Winey
Keyword(s):  
Protein Kinase ◽  
Spindle Pole Body ◽  
Spindle Checkpoint ◽  
Spindle Pole ◽  
Physical Interaction ◽  
Gene Encoding ◽  
Pole Body ◽  
Conditional Allele

Saccharomyces cerevisiae MPS1 encodes an essential protein kinase that has roles in spindle pole body (SPB) duplication and the spindle checkpoint. Previously characterized MPS1 mutants fail in both functions, leading to aberrant DNA segregation with lethal consequences. Here, we report the identification of a unique conditional allele, mps1–8, that is defective in SPB duplication but not the spindle checkpoint. The mutations in mps1-8 are in the noncatalytic region of MPS1, and analysis of the mutant protein indicates that Mps1-8p has wild-type kinase activity in vitro. A screen for dosage suppressors of the mps1-8 conditional growth phenotype identified the gene encoding the integral SPB component SPC42. Additional analysis revealed that mps1-8 exhibits synthetic growth defects when combined with certain mutant alleles of SPC42. An epitope-tagged version of Mps1p (Mps1p-myc) localizes to SPBs and kinetochores by immunofluorescence microscopy and immuno-EM analysis. This is consistent with the physical interaction we detect between Mps1p and Spc42p by coimmunoprecipitation. Spc42p is a substrate for Mps1p phosphorylation in vitro, and Spc42p phosphorylation is dependent on Mps1p in vivo. Finally, Spc42p assembly is abnormal in a mps1-1 mutant strain. We conclude that Mps1p regulates assembly of the integral SPB component Spc42p during SPB duplication.

scholarly journals The microtubule polymerase Stu2 promotes oligomerization of the γ-TuSC for cytoplasmic microtubule nucleation

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Judith Gunzelmann ◽  
Diana Rüthnick ◽  
Tien-chen Lin ◽  
Wanlu Zhang ◽  
Annett Neuner ◽  
...  
Keyword(s):  
Budding Yeast ◽  
Spindle Pole Body ◽  
Family Members ◽  
Spindle Pole ◽  
Microtubule Nucleation ◽  
Cytoplasmic Microtubule ◽  
Pole Body ◽  
Cytoplasmic Microtubules

Stu2/XMAP215/ZYG-9/Dis1/Alp14/Msps/ch-TOG family members in association with with γ-tubulin complexes nucleate microtubules, but we know little about the interplay of these nucleation factors. Here, we show that the budding yeast Stu2 in complex with the γ-tubulin receptor Spc72 nucleates microtubules in vitro without the small γ-tubulin complex (γ-TuSC). Upon γ-TuSC addition, Stu2 facilitates Spc72–γ-TuSC interaction by binding to Spc72 and γ-TuSC. Stu2 together with Spc72–γ-TuSC increases microtubule nucleation in a process that is dependent on the TOG domains of Stu2. Importantly, these activities are also important for microtubule nucleation in vivo. Stu2 stabilizes Spc72–γ-TuSC at the minus end of cytoplasmic microtubules (cMTs) and an in vivo assay indicates that cMT nucleation requires the TOG domains of Stu2. Upon γ-tubulin depletion, we observed efficient cMT nucleation away from the spindle pole body (SPB), which was dependent on Stu2. Thus, γ-TuSC restricts cMT assembly to the SPB whereas Stu2 nucleates cMTs together with γ-TuSC and stabilizes γ-TuSC at the cMT minus end.

scholarly journals ATP dependent DNA transport within cohesin: Scc2 clamps DNA on top of engaged heads while Scc3 promotes entrapment within the SMC-kleisin ring

2020 ◽  
Author(s):  
James E Collier ◽  
Byung-Gil Lee ◽  
Maurici B Roig ◽  
Stanislav Yatskevich ◽  
Naomi J Petela ◽  
...  
Keyword(s):  
Sister Chromatid ◽  
Atp Hydrolysis ◽  
Sister Chromatid Cohesion ◽  
S Phase ◽  
Coiled Coils ◽  
Rigorous Proof ◽  
Dna Loops ◽  
Dna Transport ◽  
Chromatid Cohesion

SUMMARYIn addition to extruding DNA loops, cohesin entraps within its SMC-kleisin ring (S-K) individual DNAs during G1 and sister DNAs during S-phase. All three activities require related hook-shaped proteins called Scc2 and Scc3. Using thiol-specific crosslinking we provide rigorous proof of entrapment activity in vitro. Scc2 alone promotes entrapment of DNAs in the E-S and E-K compartments, between ATP-bound engaged heads and the SMC hinge and associated kleisin, respectively. This does not require ATP hydrolysis nor is it accompanied by entrapment within S-K rings, which is a slower process requiring Scc3. Cryo-EM reveals that DNAs transported into E-S/E-K compartments are “clamped” in a sub-compartment created by Scc2’s association with engaged heads whose coiled coils are folded around their elbow. We suggest that clamping may be a recurrent feature of cohesin complexes active in loop extrusion and that this conformation precedes the S-K entrapment required for sister chromatid cohesion.

scholarly journals Dynamic Localization of the Swe1 Regulator Hsl7 During theSaccharomyces cerevisiae Cell Cycle

2001 ◽  
Vol 12 (6) ◽  
pp. 1645-1669 ◽  
Author(s):  
Victor J. Cid ◽  
Mark J. Shulewitz ◽  
Kent L. McDonald ◽  
Jeremy Thorner
Keyword(s):  
Cell Cycle ◽  
Protein Kinase ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Fine Tuning ◽  
Dependent Manner ◽  
Binding Assays ◽  
Bud Neck

In Saccharomyces cerevisiae, entry into mitosis requires activation of the cyclin-dependent kinase Cdc28 in its cyclin B (Clb)-associated form. Clb-bound Cdc28 is susceptible to inhibitory tyrosine phosphorylation by Swe1 protein kinase. Swe1 is itself negatively regulated by Hsl1, a Nim1-related protein kinase, and by Hsl7, a presumptive protein-arginine methyltransferase. In vivo all three proteins localize to the bud neck in a septin-dependent manner, consistent with our previous proposal that formation of Hsl1-Hsl7-Swe1 complexes constitutes a checkpoint that monitors septin assembly. We show here that Hsl7 is phosphorylated by Hsl1 in immune-complex kinase assays and can physically associate in vitro with either Hsl1 or Swe1 in the absence of any other yeast proteins. With the use of both the two-hybrid method and in vitro binding assays, we found that Hsl7 contains distinct binding sites for Hsl1 and Swe1. A differential interaction trap approach was used to isolate four single-site substitution mutations in Hsl7, which cluster within a discrete region of its N-terminal domain, that are specifically defective in binding Hsl1. When expressed in hsl7Δ cells, each of these Hsl7 point mutants is unable to localize at the bud neck and cannot mediate down-regulation of Swe1, but retains other functions of Hsl7, including oligomerization and association with Swe1. GFP-fusions of these Hsl1-binding defective Hsl7 proteins localize as a bright perinuclear dot, but never localize to the bud neck; likewise, inhsl1Δ cells, a GFP-fusion to wild-type Hsl7 or native Hsl7 localizes to this dot. Cell synchronization studies showed that, normally, Hsl7 localizes to the dot, but only in cells in the G1 phase of the cell cycle. Immunofluorescence analysis and immunoelectron microscopy established that the dot corresponds to the outer plaque of the spindle pole body (SPB). These data demonstrate that association between Hsl1 and Hsl7 at the bud neck is required to alleviate Swe1-imposed G2-M delay. Hsl7 localization at the SPB during G1 may play some additional role in fine-tuning the coordination between nuclear and cortical events before mitosis.

scholarly journals Maternal Obesity Enhances Oocyte Chromosome Abnormalities Associated With Aging

2018 ◽  
Author(s):  
Yan Yun ◽  
Zijie Wei ◽  
Neil Hunter
Keyword(s):  
Sister Chromatid ◽  
Maternal Obesity ◽  
Sister Chromatid Cohesion ◽  
Chromosome Abnormalities ◽  
Obese Mice ◽  
Sister Chromatids ◽  
Chromatid Cohesion ◽  
Metaphase I

Obesity is increasing globally and maternal obesity has adverse effects on pregnancy outcomes and the long-term health of offspring. Maternal obesity has been associated with pregnancy failure through impaired oogenesis and embryogenesis. However, whether maternal obesity causes chromosome abnormalities in oocytes has remained unclear. Here we show that chromosome abnormalities are increased in the oocytes of obese mice and identify weakened sister-chromatid cohesion as the likely cause. Numbers of full-grown follicles retrieved from obese mice were the same as controls and the efficiency of in vitro oocyte maturation remained high. However, chromosome abnormalities presenting in both metaphase-I and metaphase-II were elevated, most prominently the premature separation of sister chromatids. Weakened sister-chromatid cohesion in oocytes from obese mice was manifested both as the terminalization of chiasmata in metaphase-I and as increased separation of sister centromeres in metaphase II. Obesity-associated abnormalities were elevated in older mice implying that maternal obesity exacerbates the deterioration of cohesion seen with advancing age.

Sign in / Sign up

Export Citation Format

Share Document