Cell cycle control of spindle pole body duplication and splitting by Sfi1 and Cdc31 in fission yeast

2015 ◽  
Vol 128 (8) ◽  
pp. 1481-1493 ◽  
Author(s):  
I. B. Bouhlel ◽  
M. Ohta ◽  
A. Mayeux ◽  
N. Bordes ◽  
F. Dingli ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Fission Yeast ◽  
Cell Cycle Control ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Pole Body

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.

scholarly journals The S. pombe mitotic regulator Cut12 promotes spindle pole body activation and integration into the nuclear envelope

2009 ◽  
Vol 185 (5) ◽  
pp. 875-888 ◽  
Author(s):  
Victor A. Tallada ◽  
Kenji Tanaka ◽  
Mitsuhiro Yanagida ◽  
Iain M. Hagan
Keyword(s):  
Cell Cycle ◽  
Nuclear Envelope ◽  
Cell Cycle Control ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Loss Of Function ◽  
Pole Body ◽  
Cytoplasmic Structure ◽  
Monopolar Spindle ◽  
Nuclear Component

The fission yeast spindle pole body (SPB) comprises a cytoplasmic structure that is separated from an ill-defined nuclear component by the nuclear envelope. Upon mitotic commitment, the nuclear envelope separating these domains disperses as the two SPBs integrate into a hole that forms in the nuclear envelope. The SPB component Cut12 is linked to cell cycle control, as dominant cut12.s11 mutations suppress the mitotic commitment defect of cdc25.22 cells and elevated Cdc25 levels suppress the monopolar spindle phenotype of cut12.1 loss of function mutations. We show that the cut12.1 monopolar phenotype arises from a failure to activate and integrate the new SPB into the nuclear envelope. The activation of the old SPB was frequently delayed, and its integration into the nuclear envelope was defective, resulting in leakage of the nucleoplasm into the cytoplasm through large gaps in the nuclear envelope. We propose that these activation/integration defects arise from a local deficiency in mitosis-promoting factor activation at the new SPB.

Evidence for cell cycle-specific, spindle pole body-mediated, nuclear positioning in the fission yeast Schizosaccharomyces pombe

1997 ◽  
Vol 110 (16) ◽  
pp. 1851-1866 ◽  
Author(s):  
I. Hagan ◽  
M. Yanagida
Keyword(s):  
Cell Cycle ◽  
Fission Yeast ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Nuclear Positioning ◽  
Central Location ◽  
Pole Body ◽  
Spindle Pole Bodies ◽  
A Cell ◽  
Multiple Spindle

Specific changes in spatial order occur during cell cycle progression in fission yeast. Growth of the rod-shaped cells is highly regulated and undergoes a cell cycle and size-regulated switch from monopolar to bipolar tip extension. During both phases of growth, the interphase nucleus is maintained in a central location. Following the separation of the genome to the cell tips in mitosis, the two nuclei migrate back towards the cell equator before stopping in two new positions that will become the middle of the two new cells. Here we use simultaneous labeling of microtubules, chromatin and spindle pole bodies in wild-type and cdc mutants, to show that nuclear positioning is achieved by regulation of spindle pole body-mediated nuclear migration. We show that the number and location of nuclear positioning signals is regulated in a cell cycle-specific manner and that spindle pole body-mediated forces are likely to be responsible for maintaining correct nuclear position once the nuclei have reached the appropriate position in the cell. Accentuating the movement of the nuclei back towards the cell equator after mitosis by artificially increasing cell length shows that the spindle pole body leads the nucleus during this migration. When multiple spindle pole bodies are associated with the same or different nuclei they all go to the same point indicating that the different spindle pole bodies are responding to the same positional cue. In a septation-defective mutant cell, which contains four nuclei, the spindle pole bodies on the four different nuclei initially group as two pairs in regions that would become the middle of the new cells, were the cell able to divide. In the subsequent interphase, the nuclei aggregate as a group of four in the centre of the cell. The presence of two or three clusters of spindle pole bodies in larger cells with eight nuclei suggests that the mechanisms specifying the normally central location for multiple nuclei may be unable to operate properly as the cells get larger. Perturbation of microtubules with the microtubule poison thiabendazole prevents the spindle pole body clustering in septation mutants, demonstrating that nuclear positioning requires a functional microtubule cytoskeleton.

scholarly journals Measuring Affinities of Fission Yeast Spindle Pole Body Proteins in Live Cells across the Cell Cycle

2013 ◽  
Vol 105 (6) ◽  
pp. 1324-1335 ◽  
Author(s):  
Chad D. McCormick ◽  
Matthew S. Akamatsu ◽  
Shih-Chieh Ti ◽  
Thomas D. Pollard
Keyword(s):  
Cell Cycle ◽  
Fission Yeast ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Live Cells ◽  
Pole Body

Distinct nuclear and spindle pole body populations of cyclin–cdc2 in fission yeast

Nature ◽  
1990 ◽  
Vol 347 (6294) ◽  
pp. 680-682 ◽  
Author(s):  
Caroline E. Alfa ◽  
Bernard Ducommun ◽  
David Beach ◽  
Jeremy S. Hyams
Keyword(s):  
Fission Yeast ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Pole Body

Asymmetry of the spindle pole bodies and spg1p GAP segregation during mitosis in fission yeast

1999 ◽  
Vol 112 (14) ◽  
pp. 2313-2321 ◽  
Author(s):  
L. Cerutti ◽  
V. Simanis
Keyword(s):  
Cell Cycle ◽  
Fission Yeast ◽  
Spindle Pole Body ◽  
Mitotic Cell ◽  
Spindle Pole ◽  
The Other ◽  
Septum Formation ◽  
Spindle Pole Bodies ◽  
Interphase Cells ◽  
Early Mitosis

In the fission yeast Schizosaccharomyces pombe, the onset of septum formation is induced by a signal transduction network involving several protein kinases and a GTPase switch. One of the roles of the spg1p GTPase is to localise the cdc7p protein kinase to the poles of the mitotic spindle, from where the onset of septation is thought to be signalled at the end of mitosis. Immunofluorescence studies have shown that cdc7p is located on both spindle pole bodies early in mitosis, but only on one during the later stages of anaphase. This is mediated by inactivation of spg1p on one pole before the other. The GAP for spg1p is a complex of two proteins, cdc16p and byr4p. Localisation of cdc16p and byr4p by indirect immunofluorescence during the mitotic cell cycle showed that both proteins are present on the spindle pole body in interphase cells. During mitosis, byr4p is seen first on both poles of the spindle, then on only one. This occurs prior to cdc7p becoming asymmetric. In contrast, the signal due to cdc16p decreases to a low level during early mitosis, before being seen strongly on the same pole as byr4p. Double staining indicates that this is the opposite pole to that which retains cdc7p in late anaphase. Examination of the effect of inactivating cdc16p at various stages of the cell cycle suggests that cdc16p, together with cdc2p plays a role in restraining septum formation during interphase. The asymmetric inactivation of spg1p is mediated by recruitment of the cdc16p-byr4p GAP to one of the poles of the spindle before the other, and the asymmetry of the spindle pole bodies may be established early during mitosis. Moreover, the spindle pole bodies appear to be non-equivalent even after division has been completed.

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.

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.

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