scholarly journals SPC72: a spindle pole component required for spindle orientation in the yeast Saccharomyces cerevisiae

1998 ◽  
Vol 111 (18) ◽  
pp. 2809-2818 ◽  
Author(s):  
S. Soues ◽  
I.R. Adams
Keyword(s):  
Cell Cycle ◽  
Spindle Pole Body ◽  
Coiled Coil ◽  
Spindle Pole ◽  
Spindle Orientation ◽  
Yeast Saccharomyces Cerevisiae ◽  
Spindle Positioning ◽  
Pole Body ◽  
Per Se ◽  
Pole Component

The monoclonal antibody 78H6 recognises an 85 kDa component of the yeast spindle pole body. Here we identify and characterise this component as Spc72p, the product of YAL047C. The sequence of SPC72 contains potential coiled-coil domains; its overexpression induced formation of large polymers that were strictly localised at the outer plaque and at the bridge of the spindle pole body. Immunoelectron microscopy confirmed that Spc72p was a component of these polymers. SPC72 was found to be non-essential for cell growth, but its deletion resulted in abnormal spindle positioning, aberrant nuclear migration and defective mating capability. Precisely, deletion of SPC72 resulted in a decreased number of astral microtubules: early in the cell cycle only few were detectable, and these were unattached to the spindle pole body in small-budded cells. Later in the cell cycle few, if any, remained, and they were unable to align the spindle properly. We conclude that Spc72p is not absolutely required for nucleation per se, but is needed for normal abundance and stability of astral microtubules.

scholarly journals Spc98p Directs the Yeast γ-Tubulin Complex into the Nucleus and Is Subject to Cell Cycle-dependent Phosphorylation on the Nuclear Side of the Spindle Pole Body

1998 ◽  
Vol 9 (4) ◽  
pp. 775-793 ◽  
Author(s):  
Gislene Pereira ◽  
Michael Knop ◽  
Elmar Schiebel
Keyword(s):  
Cell Cycle ◽  
Spindle Pole Body ◽  
Mitotic Checkpoint ◽  
Spindle Pole ◽  
Nuclear Localization Sequence ◽  
Checkpoint Control ◽  
Yeast Saccharomyces Cerevisiae ◽  
Pole Body ◽  
Cycle Dependent ◽  
Cytoplasmic Side

In the yeast Saccharomyces cerevisiae, microtubules are organized by the spindle pole body (SPB), which is embedded in the nuclear envelope. Microtubule organization requires the γ-tubulin complex containing the γ-tubulin Tub4p, Spc98p, and Spc97p. The Tub4p complex is associated with cytoplasmic and nuclear substructures of the SPB, which organize the cytoplasmic and nuclear microtubules. Here we present evidence that the Tub4p complex assembles in the cytoplasm and then either binds to the cytoplasmic side of the SPB or is imported into the nucleus followed by binding to the nuclear side of the SPB. Nuclear import of the Tub4p complex is mediated by the essential nuclear localization sequence of Spc98p. Our studies also indicate that Spc98p in the Tub4p complex is phosphorylated at the nuclear, but not at the cytoplasmic, side of the SPB. This phosphorylation is cell cycle dependent and occurs after SPB duplication and nucleation of microtubules by the new SPB and therefore may have a role in mitotic spindle function. In addition, activation of the mitotic checkpoint stimulates Spc98p phosphorylation. The kinase Mps1p, which functions in SPB duplication and mitotic checkpoint control, seems to be involved in Spc98p phosphorylation. Our results also suggest that the nuclear and cytoplasmic Tub4p complexes are regulated differently.

scholarly journals Nuf2, a spindle pole body-associated protein required for nuclear division in yeast.

1994 ◽  
Vol 125 (4) ◽  
pp. 853-866 ◽  
Author(s):  
M A Osborne ◽  
G Schlenstedt ◽  
T Jinks ◽  
P A Silver
Keyword(s):  
Nuclear Division ◽  
Spindle Pole Body ◽  
Coiled Coil ◽  
Temperature Shift ◽  
Spindle Pole ◽  
Temperature Sensitive ◽  
Yeast Saccharomyces Cerevisiae ◽  
Culture Cells ◽  
Pole Body ◽  
Associated Proteins

The NUF2 gene of the yeast Saccharomyces cerevisiae encodes an essential 53-kd protein with a high content of potential coiled-coil structure similar to myosin. Nuf2 is associated with the spindle pole body (SPB) as determined by coimmunofluorescence with known SPB proteins. Nuf2 appears to be localized to the intranuclear region and is a candidate for a protein involved in SPB separation. The nuclear association of Nuf2 can be disrupted, in part, by 1 M salt but not by the detergent Triton X-100. All Nuf2 can be removed from nuclei by 8 M urea extraction. In this regard, Nuf2 is similar to other SPB-associated proteins including Nufl/SPC110, also a coiled-coil protein. Temperature-sensitive alleles of NUF2 were generated within the coiled-coil region of Nuf2 and such NUF2 mutant cells rapidly arrest after temperature shift with a single undivided or partially divided nucleus in the bud neck, a shortened mitotic spindle and their DNA fully replicated. In sum, Nuf2 is a protein associated with the SPB that is critical for nuclear division. Anti-Nuf2 antibodies also recognize a mammalian 73-kd protein and display centrosome staining of mammalian tissue culture cells suggesting the presence of a protein with similar function.

scholarly journals The Role of Actin in Spindle Orientation Changes during the Saccharomyces cerevisiae Cell Cycle

1999 ◽  
Vol 146 (5) ◽  
pp. 1019-1032 ◽  
Author(s):  
Chandra L. Theesfeld ◽  
Javier E. Irazoqui ◽  
Kerry Bloom ◽  
Daniel J. Lew
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Spindle Orientation ◽  
Cortical Actin ◽  
Yeast Saccharomyces Cerevisiae ◽  
Daughter Cells ◽  
M Phase ◽  
Actin Cables

In the budding yeast Saccharomyces cerevisiae, the mitotic spindle must align along the mother-bud axis to accurately partition the sister chromatids into daughter cells. Previous studies showed that spindle orientation required both astral microtubules and the actin cytoskeleton. We now report that maintenance of correct spindle orientation does not depend on F-actin during G2/M phase of the cell cycle. Depolymerization of F-actin using Latrunculin-A did not perturb spindle orientation after this stage. Even an early step in spindle orientation, the migration of the spindle pole body (SPB), became actin-independent if it was delayed until late in the cell cycle. Early in the cell cycle, both SPB migration and spindle orientation were very sensitive to perturbation of F-actin. Selective disruption of actin cables using a conditional tropomyosin double-mutant also led to de- fects in spindle orientation, even though cortical actin patches were still polarized. This suggests that actin cables are important for either guiding astral microtubules into the bud or anchoring them in the bud. In addition, F-actin was required early in the cell cycle for the development of the actin-independent spindle orientation capability later in the cell cycle. Finally, neither SPB migration nor the switch from actin-dependent to actin-independent spindle behavior required B-type cyclins.

scholarly journals Saccharomyces cerevisiae MPS2Encodes a Membrane Protein Localized at the Spindle Pole Body and the Nuclear Envelope

1999 ◽  
Vol 10 (7) ◽  
pp. 2393-2406 ◽  
Author(s):  
Marı́a de la Cruz Muñoz-Centeno ◽  
Susan McBratney ◽  
Antonio Monterrosa ◽  
Breck Byers ◽  
Carl Mann ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Membrane Protein ◽  
Nuclear Envelope ◽  
Fluorescent Protein ◽  
Spindle Pole Body ◽  
Coiled Coil ◽  
Spindle Pole ◽  
Yeast Saccharomyces Cerevisiae ◽  
Pole Body ◽  
Monopolar Spindle

The MPS2 (monopolar spindle two) gene is one of several genes required for the proper execution of spindle pole body (SPB) duplication in the budding yeast Saccharomyces cerevisiae ( Winey et al., 1991 ). We report here that the MPS2 gene encodes an essential 44-kDa protein with two putative coiled-coil regions and a hydrophobic sequence. Although MPS2 is required for normal mitotic growth, some null strains can survive; these survivors exhibit slow growth and abnormal ploidy. The MPS2 protein was tagged with nine copies of the myc epitope, and biochemical fractionation experiments show that it is an integral membrane protein. Visualization of a green fluorescent protein (GFP) Mps2p fusion protein in living cells and indirect immunofluorescence microscopy of 9xmyc-Mps2p revealed a perinuclear localization with one or two brighter foci of staining corresponding to the SPB. Additionally, immunoelectron microscopy shows that GFP-Mps2p localizes to the SPB. Our analysis suggests that Mps2p is required as a component of the SPB for insertion of the nascent SPB into the nuclear envelope.

scholarly journals Mutational Analysis Reveals a Role for the C Terminus of the Proteasome Subunit Rpt4p in Spindle Pole Body Duplication inSaccharomyces cerevisiae

Genetics ◽  
2002 ◽  
Vol 162 (2) ◽  
pp. 705-720 ◽  
Author(s):  
Heather B McDonald ◽  
Astrid Hoes Helfant ◽  
Erin M Mahony ◽  
Shaun K Khosla ◽  
Loretta Goetsch
Keyword(s):  
Cell Cycle ◽  
Mutational Analysis ◽  
Genetic Interaction ◽  
Spindle Pole Body ◽  
Coiled Coil ◽  
Spindle Pole ◽  
Terminal Region ◽  
Wild Type ◽  
Pole Body ◽  
C Terminus

AbstractThe ubiquitin/proteasome pathway plays a key role in regulating cell cycle progression. Previously, we reported that a conditional mutation in the Saccharomyces cerevisiae gene RPT4/PCS1, which encodes one of six ATPases in the proteasome 19S cap complex/regulatory particle (RP), causes failure of spindle pole body (SPB) duplication. To improve our understanding of Rpt4p, we created 58 new mutations, 53 of which convert clustered, charged residues to alanine. Virtually all mutations that affect the N-terminal region, which contains a putative nuclear localization signal and coiled-coil motif, result in a wild-type phenotype. Nine mutations that affect the central ATPase domain and the C-terminal region confer recessive lethality. The two conditional mutations identified, rpt4-145 and rpt4-150, affect the C terminus. After shift to high temperature, these mutations generally cause cells to progress slowly through the first cell cycle and to arrest in the second cycle with large buds, a G2 content of DNA, and monopolar spindles, although this phenotype can vary depending on the medium. Additionally, we describe a genetic interaction between RPT4 and the naturally polymorphic gene SSD1, which in wild-type form modifies the rpt4-145 phenotype such that cells arrest in G2 of the first cycle with complete bipolar spindles.

scholarly journals Polo-like kinase Cdc5 regulates Spc72 recruitment to spindle pole body in the methylotrophic yeast Ogataea polymorpha

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Hiromi Maekawa ◽  
Annett Neuner ◽  
Diana Rüthnick ◽  
Elmar Schiebel ◽  
Gislene Pereira ◽  
...  
Keyword(s):  
Spindle Pole Body ◽  
Methylotrophic Yeast ◽  
Spindle Pole ◽  
Yeast Saccharomyces Cerevisiae ◽  
Spindle Positioning ◽  
Pole Body ◽  
Complex Receptor ◽  
Cytoplasmic Microtubules ◽  
Cytoplasmic Side ◽  
Ogataea Polymorpha

Cytoplasmic microtubules (cMT) control mitotic spindle positioning in many organisms, and are therefore pivotal for successful cell division. Despite its importance, the temporal control of cMT formation remains poorly understood. Here we show that unlike the best-studied yeast Saccharomyces cerevisiae, position of pre-anaphase nucleus is not strongly biased toward bud neck in Ogataea polymorpha and the regulation of spindle positioning becomes active only shortly before anaphase. This is likely due to the unstable property of cMTs compared to those in S. cerevisiae. Furthermore, we show that cMT nucleation/anchoring is restricted at the level of recruitment of the γ-tubulin complex receptor, Spc72, to spindle pole body (SPB), which is regulated by the polo-like kinase Cdc5. Additionally, electron microscopy revealed that the cytoplasmic side of SPB is structurally different between G1 and anaphase. Thus, polo-like kinase dependent recruitment of γ-tubulin receptor to SPBs determines the timing of spindle orientation in O. polymorpha.

scholarly journals MPS1 and MPS2: novel yeast genes defining distinct steps of spindle pole body duplication.

1991 ◽  
Vol 114 (4) ◽  
pp. 745-754 ◽  
Author(s):  
M Winey ◽  
L Goetsch ◽  
P Baum ◽  
B Byers
Keyword(s):  
Cell Cycle ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Yeast Saccharomyces Cerevisiae ◽  
Pole Body ◽  
Bud Emergence ◽  
Monopolar Spindle ◽  
The Individual ◽  
Yeast Genes

It is crucial to the eucaryotic cell cycle that the centrosome undergo precise duplication to generate the two poles of the mitotic spindle. In the budding yeast Saccharomyces cerevisiae, centrosomal functions are provided by the spindle pole body (SPB), which is duplicated at the time of bud emergence in G1 of the cell cycle. Genetic control of this process has previously been revealed by the characterization of mutants in CDC31 and KAR1, which prevent SPB duplication and lead to formation of a monopolar spindle. Newly isolated mutations described here (mps1 and mps2, for monopolar spindle) similarly cause monopolar mitosis but their underlying effects on SPB duplication are unique. The MPS1 gene is found by electron microscopy to be essential for proper formation of the site at which the new SPB normally arises adjacent to the existing one. By contrast, a mutation in MPS2 permits duplication to proceed, but the newly formed SPB is structurally defective and unable to serve as a functional spindle pole. Distinct temporal requirements for the CDC31, MPS1, and MPS2 gene functions during the SPB duplication cycle further demonstrate the individual roles of these genes in the morphogenetic pathway.

scholarly journals Timely Septation Requires SNAD-dependent Spindle Pole Body Localization of the Septation Initiation Network Components in the Filamentous FungusAspergillus nidulans

2009 ◽  
Vol 20 (12) ◽  
pp. 2874-2884 ◽  
Author(s):  
Jung-Mi Kim ◽  
Cui Jing Tracy Zeng ◽  
Tania Nayak ◽  
Rongzhong Shao ◽  
An-Chi Huang ◽  
...  
Keyword(s):  
Spindle Pole Body ◽  
Coiled Coil ◽  
Spindle Pole ◽  
Scaffold Protein ◽  
Negative Regulators ◽  
Timely Manner ◽  
Division Site ◽  
Pole Body ◽  
Septation Initiation Network ◽  
Per Se

In the filamentous fungus Aspergillus nidulans, cytokinesis/septation is triggered by the septation initiation network (SIN), which first appears at the spindle pole body (SPB) during mitosis. The coiled-coil protein SNAD is associated with the SPB and is required for timely septation and conidiation. We have determined that SNAD acted as a scaffold protein that is required for the localization of the SIN proteins of SIDB and MOBA to the SPB. Another scaffold protein SEPK, whose localization at the SPB was dependent on SNAD, was also required for SIDB and MOBA localization to the SPB. In the absence of either SEPK or SNAD, SIDB/MOBA successfully localized to the septation site, indicating that their earlier localization at SPB was not essential for their later appearance at the division site. Unlike their functional counterparts in fission yeast, SEPK and SNAD were not required for vegetative growth but only for timely septation. Furthermore, down-regulation of negative regulators of the SIN suppressed the septation and conidiation phenotypes due to the loss of SNAD. Therefore, we conclude that SPB localization of SIN components is not essential for septation per se, but critical for septation to take place in a timely manner in A. nidulans.

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.

Sign in / Sign up

Export Citation Format

Share Document