scholarly journals Intrinsic and Cyclin-dependent Kinase-dependent Control of Spindle Pole Body Duplication in Budding Yeast

2008 ◽  
Vol 19 (8) ◽  
pp. 3243-3253 ◽  
Author(s):  
Laura A. Simmons Kovacs ◽  
Christine L. Nelson ◽  
Steven B. Haase
Keyword(s):  
Cell Cycle ◽  
Budding Yeast ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Cyclin Dependent Kinase ◽  
Multipolar Spindle ◽  
Cyclin Dependent Kinases ◽  
Pole Body ◽  
Intrinsic Mechanism ◽  
Mitotic Cyclin

Centrosome duplication must be tightly controlled so that duplication occurs only once each cell cycle. Accumulation of multiple centrosomes can result in the assembly of a multipolar spindle and lead to chromosome mis-segregation and genomic instability. In metazoans, a centrosome-intrinsic mechanism prevents reduplication until centriole disengagement. Mitotic cyclin/cyclin-dependent kinases (CDKs) prevent reduplication of the budding yeast centrosome, called a spindle pole body (SPB), in late S-phase and G2/M, but the mechanism remains unclear. How SPB reduplication is prevented early in the cell cycle is also not understood. Here we show that, similar to metazoans, an SPB-intrinsic mechanism prevents reduplication early in the cell cycle. We also show that mitotic cyclins can inhibit SPB duplication when expressed before satellite assembly in early G1, but not later in G1, after the satellite had assembled. Moreover, electron microscopy revealed that SPBs do not assemble a satellite in cells expressing Clb2 in early G1. Finally, we demonstrate that Clb2 must localize to the cytoplasm in order to inhibit SPB duplication, suggesting the possibility for direct CDK inhibition of satellite components. These two mechanisms, intrinsic and extrinsic control by CDK, evoke two-step system that prevents SPB reduplication throughout the cell cycle.

scholarly journals Cdk1 promotes cytokinesis in fission yeast through activation of the septation initiation network

2014 ◽  
Vol 25 (15) ◽  
pp. 2250-2259 ◽  
Author(s):  
Nicole Rachfall ◽  
Alyssa E. Johnson ◽  
Sapna Mehta ◽  
Jun-Song Chen ◽  
Kathleen L. Gould
Keyword(s):  
Cell Cycle ◽  
Spindle Pole Body ◽  
Complete Removal ◽  
Spindle Pole ◽  
Cyclin Dependent Kinase ◽  
Gtpase Activating Protein ◽  
Pole Body ◽  
Kinase Cascade ◽  
Septation Initiation Network ◽  
Cycle Dependent

In Schizosaccharomyces pombe, late mitotic events are coordinated with cytokinesis by the septation initiation network (SIN), an essential spindle pole body (SPB)–associated kinase cascade, which controls the formation, maintenance, and constriction of the cytokinetic ring. It is not fully understood how SIN initiation is temporally regulated, but it depends on the activation of the GTPase Spg1, which is inhibited during interphase by the essential bipartite GTPase-activating protein Byr4-Cdc16. Cells are particularly sensitive to the modulation of Byr4, which undergoes cell cycle–dependent phosphorylation presumed to regulate its function. Polo-like kinase, which promotes SIN activation, is partially responsible for Byr4 phosphorylation. Here we show that Byr4 is also controlled by cyclin-dependent kinase (Cdk1)–mediated phosphorylation. A Cdk1 nonphosphorylatable Byr4 phosphomutant displays severe cell division defects, including the formation of elongated, multinucleate cells, failure to maintain the cytokinetic ring, and compromised SPB association of the SIN kinase Cdc7. Our analyses show that Cdk1-mediated phosphoregulation of Byr4 facilitates complete removal of Byr4 from metaphase SPBs in concert with Plo1, revealing an unexpected role for Cdk1 in promoting cytokinesis through activation of the SIN pathway.

scholarly journals Regulation of spindle pole body assembly and cytokinesis by the centrin-binding protein Sfi1 in fission yeast

2014 ◽  
Vol 25 (18) ◽  
pp. 2735-2749 ◽  
Author(s):  
I-Ju Lee ◽  
Ning Wang ◽  
Wen Hu ◽  
Kersey Schott ◽  
Jürg Bähler ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Fission Yeast ◽  
Budding Yeast ◽  
Binding Protein ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Centrosome Duplication ◽  
Pole Body ◽  
The Individual

Centrosomes play critical roles in the cell division cycle and ciliogenesis. Sfi1 is a centrin-binding protein conserved from yeast to humans. Budding yeast Sfi1 is essential for the initiation of spindle pole body (SPB; yeast centrosome) duplication. However, the recruitment and partitioning of Sfi1 to centrosomal structures have never been fully investigated in any organism, and the presumed importance of the conserved tryptophans in the internal repeats of Sfi1 remains untested. Here we report that in fission yeast, instead of doubling abruptly at the initiation of SPB duplication and remaining at a constant level thereafter, Sfi1 is gradually recruited to SPBs throughout the cell cycle. Like an sfi1Δ mutant, a Trp-to-Arg mutant (sfi1-M46) forms monopolar spindles and exhibits mitosis and cytokinesis defects. Sfi1-M46 protein associates preferentially with one of the two daughter SPBs during mitosis, resulting in a failure of new SPB assembly in the SPB receiving insufficient Sfi1. Although all five conserved tryptophans tested are involved in Sfi1 partitioning, the importance of the individual repeats in Sfi1 differs. In summary, our results reveal a link between the conserved tryptophans and Sfi1 partitioning and suggest a revision of the model for SPB assembly.

The Budding Yeast Cdc15 Localizes to the Spindle Pole Body in a Cell-Cycle-Dependent Manner

1999 ◽  
Vol 2 (3) ◽  
pp. 178-184 ◽  
Author(s):  
R. Cenamor ◽  
J. Jiménez ◽  
V.J. Cid ◽  
C. Nombela ◽  
M. Sánchez
Keyword(s):  
Cell Cycle ◽  
Budding Yeast ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Dependent Manner ◽  
Pole Body ◽  
A Cell ◽  
Cycle Dependent

scholarly journals Docking to a Basic Helix Promotes Specific Phosphorylation by G1-Cdk1

2021 ◽  
Vol 22 (17) ◽  
pp. 9514
Author(s):  
Ilona Faustova ◽  
Kaidi Möll ◽  
Ervin Valk ◽  
Mart Loog ◽  
Mihkel Örd
Keyword(s):  
Cell Cycle ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Specific Substrate ◽  
Cyclin Dependent Kinase ◽  
Short Linear Motifs ◽  
G1 Cyclins ◽  
Pole Body ◽  
Linear Motifs ◽  
Essential Function

Cyclins are the activators of cyclin-dependent kinase (CDK) complex, but they also act as docking scaffolds for different short linear motifs (SLiMs) in CDK substrates and inhibitors. According to the unified model of CDK function, the cell cycle is coordinated by CDK both via general CDK activity thresholds and cyclin-specific substrate docking. Recently, it was found that the G1-cyclins of S. cerevisiae have a specific function in promoting polarization and growth of the buds, making the G1 cyclins essential for cell survival. Thus, while a uniform CDK specificity of a single cyclin can be sufficient to drive the cell cycle in some cells, such as in fission yeast, cyclin specificity can be essential in other organisms. However, the known G1-CDK specific LP docking motif, was not responsible for this essential function, indicating that G1-CDKs use yet other unknown docking mechanisms. Here we report a discovery of a G1 cyclin-specific (Cln1,2) lysine-arginine-rich helical docking motif (the K/R motif) in G1-CDK targets involved in the mating pathway (Ste7), transcription (Xbp1), bud morphogenesis (Bud2) and spindle pole body (Spc29, Spc42, Spc110, Sli15) function of S. cerevisiae. We also show that the docking efficiency of K/R motif can be regulated by basophilic kinases such as protein kinase A. Our results further widen the list of cyclin specificity mechanisms and may explain the recently demonstrated unique essential function of G1 cyclins in budding yeast.

scholarly journals Duplication of the Yeast Spindle Pole Body Once per Cell Cycle

2016 ◽  
Vol 36 (9) ◽  
pp. 1324-1331 ◽  
Author(s):  
Diana Rüthnick ◽  
Elmar Schiebel
Keyword(s):  
Cell Cycle ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Cyclin Dependent Kinase ◽  
Content Type ◽  
Anaphase Onset ◽  
Pole Body ◽  
Essential Components ◽  
Functional Equivalent ◽  
Early Mitosis

The yeast spindle pole body (SPB) is the functional equivalent of the mammalian centrosome. Centrosomes and SPBs duplicate exactly once per cell cycle by mechanisms that use the mother structure as a platform for the assembly of the daughter. The conserved Sfi1 and centrin proteins are essential components of the SPB duplication process. Sfi1 is an elongated molecule that has, in its center, 20 to 23 binding sites for the Ca2+-binding protein centrin. In the yeastSaccharomyces cerevisiae, all Sfi1 N termini are in contact with the mother SPB whereas the free C termini are distal to it. During S phase and early mitosis, cyclin-dependent kinase 1 (Cdk1) phosphorylation of mainly serine residues in the Sfi1 C termini blocks the initiation of SPB duplication (“off” state). Upon anaphase onset, the phosphatase Cdc14 dephosphorylates Sfi1 (“on” state) to promote antiparallel and shifted incorporation of cytoplasmic Sfi1 molecules into the half-bridge layer, which thereby elongates into the bridge. The Sfi1 C termini of the two Sfi1 layers localize in the bridge center, whereas the N termini of the newly assembled Sfi1 molecules are distal to the mother SPB. These free Sfi1 N termini then assemble the new SPB in G1phase. Recruitment of Sfi1 molecules into the anaphase SPB and bridge formation were also observed inSchizosaccharomyces pombe, suggesting that the Sfi1 bridge cycle is conserved between the two organisms. Thus, restricting SPB duplication to one event per cell cycle requires only an oscillation between Cdk1 kinase and Cdc14 phosphatase activities. This clockwork regulates the “on”/“off” state of the Sfi1-centrin receiver.

scholarly journals Budding yeast relies on G1 cyclin specificity to couple cell cycle progression with morphogenetic development

2021 ◽  
Vol 7 (23) ◽  
pp. eabg0007
Author(s):  
Deniz Pirincci Ercan ◽  
Florine Chrétien ◽  
Probir Chakravarty ◽  
Helen R. Flynn ◽  
Ambrosius P. Snijders ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Budding Yeast ◽  
Quantitative Model ◽  
Cyclin Dependent Kinase ◽  
Cycle Progression ◽  
Model Cell ◽  
Mitotic Cyclin ◽  
Substrate Phosphorylation ◽  
The Cost

Two models have been put forward for cyclin-dependent kinase (Cdk) control of the cell cycle. In the qualitative model, cell cycle events are ordered by distinct substrate specificities of successive cyclin waves. Alternatively, in the quantitative model, the gradual rise of Cdk activity from G1 phase to mitosis leads to ordered substrate phosphorylation at sequential thresholds. Here, we study the relative contributions of qualitative and quantitative Cdk control in Saccharomyces cerevisiae. All S phase and mitotic cyclins can be replaced by a single mitotic cyclin, albeit at the cost of reduced fitness. A single cyclin can also replace all G1 cyclins to support ordered cell cycle progression, fulfilling key predictions of the quantitative model. However, single-cyclin cells fail to polarize or grow buds and thus cannot survive. Our results suggest that budding yeast has become dependent on G1 cyclin specificity to couple cell cycle progression to essential morphogenetic events.

scholarly journals Studies concerning the temporal and genetic control of cell polarity in Saccharomyces cerevisiae.

1991 ◽  
Vol 114 (3) ◽  
pp. 515-532 ◽  
Author(s):  
M Snyder ◽  
S Gehrung ◽  
B D Page
Keyword(s):  
Cell Cycle ◽  
Cell Polarity ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Yeast Cells ◽  
Cell Cycle Distribution ◽  
Restrictive Temperature ◽  
Microtubule Bundle ◽  
Pole Body ◽  
Capture Site

The establishment of cell polarity was examined in the budding yeast, S. cerevisiae. The distribution of a polarized protein, the SPA2 protein, was followed throughout the yeast cell cycle using synchronized cells and cdc mutants. The SPA2 protein localizes to a patch at the presumptive bud site of G1 cells. Later it concentrates at the bud tip in budded cells. At cytokinesis, the SPA2 protein is at the neck between the mother and daughter cells. Analysis of unbudded haploid cells has suggested a series of events that occurs during G1. The SPA2 patch is established very early in G1, while the spindle pole body residues on the distal side of the nucleus. Later, microtubules emanating from the spindle pole body intersect the SPA2 crescent, and the nucleus probably rotates towards the SPA2 patch. By middle G1, most cells contain the SPB on the side of the nucleus proximal to the SPA2 patch, and a long extranuclear microtubule bundle intersects this patch. We suggest that a microtubule capture site exists in the SPA2 staining region that stabilizes the long microtubule bundle; this capture site may be responsible for rotation of the nucleus. Cells containing a polarized distribution of the SPA2 protein also possess a polarized distribution of actin spots in the same region, although the actin staining is much more diffuse. Moreover, cdc4 mutants, which form multiple buds at the restrictive temperature, exhibit simultaneous staining of the SPA2 protein and actin spots in a subset of the bud tips. spa2 mutants contain a polarized distribution of actin spots, and act1-1 and act1-2 mutants often contain a polarized distribution of the SPA2 protein suggesting that the SPA2 protein is not required for localization of the actin spots and the actin spots are not required for localization of the SPA2 protein. cdc24 mutants, which fail to form buds at the restrictive temperature, fail to exhibit polarized localization of the SPA2 protein and actin spots, indicating that the CDC24 protein is directly or indirectly responsible for controlling the polarity of these proteins. Based on the cell cycle distribution of the SPA2 protein, a "cytokinesis tag" model is proposed to explain the mechanism of the non-random positioning of bud sites in haploid yeast cells.

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