Regulation of cytokinesis by the Elm1 protein kinase in Saccharomyces cerevisiae

2000 ◽  
Vol 113 (8) ◽  
pp. 1435-1445 ◽  
Author(s):  
N. Bouquin ◽  
Y. Barral ◽  
R. Courbeyrette ◽  
M. Blondel ◽  
M. Snyder ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Cell Division ◽  
Protein Kinase ◽  
Protein Kinases ◽  
Hyphal Growth ◽  
Negative Regulator ◽  
Bud Emergence ◽  
Bud Neck ◽  
Morphological Defects

A Saccharomyces cerevisiae mutant unable to grow in a cdc28-1N background was isolated and shown to be affected in the ELM1 gene. Elm1 is a protein kinase, thought to be a negative regulator of pseudo-hyphal growth. We show that Cdc11, one of the septins, is delocalised in the mutant, indicating that septin localisation is partly controlled by Elm1. Moreover, we show that cytokinesis is delayed in an elm1delta mutant. Elm1 levels peak at the end of the cell cycle and Elm1 is localised at the bud neck in a septin-dependent fashion from bud emergence until the completion of anaphase, at about the time of cell division. Genetic and biochemical evidence suggest that Elm1 and the three other septin-localised protein kinases, Hsl1, Gin4 and Kcc4, work in parallel pathways to regulate septin behaviour and cytokinesis. In addition, the elm1delta;) morphological defects can be suppressed by deletion of the SWE1 gene, but not the cytokinesis defect nor the septin mislocalisation. Our results indicate that cytokinesis in budding yeast is regulated by Elm1.

scholarly journals Fungal septins: one ring to rule it all?

2009 ◽  
Vol 4 (3) ◽  
pp. 274-289 ◽  
Author(s):  
Alberto González-Novo ◽  
Carlos Vázquez de Aldana ◽  
Javier Jiménez
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Hyphal Growth ◽  
Diffusion Barriers ◽  
Ashbya Gossypii ◽  
Molecular Architecture ◽  
Gtp Binding ◽  
Bud Neck ◽  
Living Organisms ◽  
Order Structures

AbstractSeptins are a conserved family of GTP-binding proteins found in living organisms ranging from yeasts to mammals. They are able to polymerize and form hetero-oligomers that assemble into higher-order structures whose detailed molecular architecture has recently been described in different organisms. In Saccharomyces cerevisiae, septins exert numerous functions throughout the cell cycle, serving as scaffolds for many different proteins or as diffusion barriers at the bud neck. In other fungi, septins are required for the proper completion of diverse functions such as polarized growth or pathogenesis. Recent results from several fungi have revealed important differences in septin organization and regulation as compared with S. cerevisiae, especially during Candida albicans hyphal growth and in Ashbya gossypii. Here we focus on these recent findings, their relevance in the biology of these eukaryotes and in consequence the “renaissance” of the study of septin structures in cells showing a different kind of morphological behaviour.

scholarly journals A novel mammalian protein, p55CDC, present in dividing cells is associated with protein kinase activity and has homology to the Saccharomyces cerevisiae cell division cycle proteins Cdc20 and Cdc4.

1994 ◽  
Vol 14 (5) ◽  
pp. 3350-3363 ◽  
Author(s):  
J Weinstein ◽  
F W Jacobsen ◽  
J Hsu-Chen ◽  
T Wu ◽  
L G Baum
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Cell Division ◽  
Protein Kinase ◽  
Mammalian Cells ◽  
Kinase Activity ◽  
Yeast Cells ◽  
Protein Kinase Activity ◽  
Growing Cell ◽  
Dividing Cells

A novel protein, p55CDC, has been identified in cycling mammalian cells. This transcript is readily detectable in all exponentially growing cell lines but disappears when cells are chemically induced to fall out of the cell cycle and differentiate. The p55CDC protein appears to be essential for cell division, since transfection of antisense p55CDC cDNA into CHO cells resulted in isolation of only those cells which exhibited a compensatory increase in p55CDC transcripts in the sense orientation. Immunoprecipitation of p55CDC yielded protein complexes with kinase activity which fluctuated during the cell cycle. Since p55CDC does not have the conserved protein kinase domains, this activity must be due to one or more of the associated proteins in the immune complex. The highest levels of protein kinase activity were seen with alpha-casein and myelin basic protein as substrates and demonstrated a pattern of activity distinct from that described for the known cyclin-dependent cell division kinases. The p55CDC protein was also phosphorylated in dividing cells. The amino acid sequence of p55CDC contains seven repeats homologous to the beta subunit of G proteins, and the highest degree of homology in these repeats was found with the Saccharomyces cerevisiae Cdc20 and Cdc4 proteins, which have been proposed to be involved in the formation of a functional bipolar mitotic spindle in yeast cells. The G beta repeat has been postulated to mediate protein-protein interactions and, in p55CDC, may modulate its association with a unique cell cycle protein kinase. These findings suggest that p55CDC is a component of the mammalian cell cycle mechanism.

scholarly journals Roles of Hsl1p and Hsl7p in Swe1p Degradation: beyond Septin Tethering

2012 ◽  
Vol 11 (12) ◽  
pp. 1496-1502 ◽  
Author(s):  
Kindra King ◽  
Michelle Jin ◽  
Daniel Lew
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Cell Division ◽  
Nuclear Division ◽  
Cell Division Cycle ◽  
Cyclin Dependent Kinase ◽  
Bud Formation ◽  
Content Type ◽  
Cell Cycle Delay ◽  
Bud Neck

ABSTRACT The morphogenesis checkpoint in Saccharomyces cerevisiae couples bud formation to the cell division cycle by delaying nuclear division until cells have successfully constructed a bud. The cell cycle delay is due to the mitosis-inhibitory kinase Swe1p, which phosphorylates the cyclin-dependent kinase Cdc28p. In unperturbed cells, Swe1p is degraded via a mechanism thought to involve its tethering to a cortical scaffold of septin proteins at the mother-bud neck. In cells that experience stresses that delay bud formation, Swe1p is stabilized, accumulates, and promotes a G 2 delay. The tethering of Swe1p to the neck requires two regulators, called Hsl1p and Hsl7p. Hsl1p interacts with septins, and Hsl7p interacts with Swe1p; tethering occurs when Hsl1p interacts with Hsl7p. Here we created a version of Swe1p that is artificially tethered to the neck by fusion to a septin so that Swe1p no longer requires Hsl1p or Hsl7p for its localization to the neck. We show that the interaction between Hsl1p and Hsl7p, required for normal Swe1p degradation, is no longer needed for septin-Swe1p degradation, supporting the idea that the Hsl1p-Hsl7p interaction serves mainly to tether Swe1p to the neck. However, both Hsl1p and Hsl7p are still required for Swe1p degradation, implying that these proteins play additional roles beyond localizing Swe1p to the neck.

A novel mammalian protein, p55CDC, present in dividing cells is associated with protein kinase activity and has homology to the Saccharomyces cerevisiae cell division cycle proteins Cdc20 and Cdc4

1994 ◽  
Vol 14 (5) ◽  
pp. 3350-3363
Author(s):  
J Weinstein ◽  
F W Jacobsen ◽  
J Hsu-Chen ◽  
T Wu ◽  
L G Baum
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Cell Division ◽  
Protein Kinase ◽  
Mammalian Cells ◽  
Kinase Activity ◽  
Yeast Cells ◽  
Protein Kinase Activity ◽  
Growing Cell ◽  
Dividing Cells

A novel protein, p55CDC, has been identified in cycling mammalian cells. This transcript is readily detectable in all exponentially growing cell lines but disappears when cells are chemically induced to fall out of the cell cycle and differentiate. The p55CDC protein appears to be essential for cell division, since transfection of antisense p55CDC cDNA into CHO cells resulted in isolation of only those cells which exhibited a compensatory increase in p55CDC transcripts in the sense orientation. Immunoprecipitation of p55CDC yielded protein complexes with kinase activity which fluctuated during the cell cycle. Since p55CDC does not have the conserved protein kinase domains, this activity must be due to one or more of the associated proteins in the immune complex. The highest levels of protein kinase activity were seen with alpha-casein and myelin basic protein as substrates and demonstrated a pattern of activity distinct from that described for the known cyclin-dependent cell division kinases. The p55CDC protein was also phosphorylated in dividing cells. The amino acid sequence of p55CDC contains seven repeats homologous to the beta subunit of G proteins, and the highest degree of homology in these repeats was found with the Saccharomyces cerevisiae Cdc20 and Cdc4 proteins, which have been proposed to be involved in the formation of a functional bipolar mitotic spindle in yeast cells. The G beta repeat has been postulated to mediate protein-protein interactions and, in p55CDC, may modulate its association with a unique cell cycle protein kinase. These findings suggest that p55CDC is a component of the mammalian cell cycle mechanism.

Histone H3 transcription in Saccharomyces cerevisiae is controlled by multiple cell cycle activation sites and a constitutive negative regulatory element

1992 ◽  
Vol 12 (12) ◽  
pp. 5455-5463 ◽  
Author(s):  
K B Freeman ◽  
L R Karns ◽  
K A Lutz ◽  
M M Smith
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Cell Division ◽  
Transcriptional Activation ◽  
Regulatory Element ◽  
Histone H3 ◽  
Regulatory Elements ◽  
Cell Division Cycle ◽  
Cell Cycle Activation ◽  
Multiple Cell

The promoters of the Saccharomyces cerevisiae histone H3 and H4 genes were examined for cis-acting DNA sequence elements regulating transcription and cell division cycle control. Deletion and linker disruption mutations identified two classes of regulatory elements: multiple cell cycle activation (CCA) sites and a negative regulatory site (NRS). Duplicate 19-bp CCA sites are present in both the copy I and copy II histone H3-H4 promoters arranged as inverted repeats separated by 45 and 68 bp. The CCA sites are both necessary and sufficient to activate transcription under cell division cycle control. A single CCA site provides cell cycle control but is a weak transcriptional activator, while an inverted repeat comprising two CCA sites provides both strong transcriptional activation and cell division cycle control. The NRS was identified in the copy I histone H3-H4 promoter. Deletion or disruption of the NRS increased the level of the histone H3 promoter activity but did not alter the cell division cycle periodicity of transcription. When the CCA sites were deleted from the histone promoter, the NRS element was unable to confer cell division cycle control on the remaining basal level of transcription. When the NRS element was inserted into the promoter of a foreign reporter gene, transcription was constitutively repressed and did not acquire cell cycle regulation.

MKK1 and MKK2, which encode Saccharomyces cerevisiae mitogen-activated protein kinase-kinase homologs, function in the pathway mediated by protein kinase C

1993 ◽  
Vol 13 (5) ◽  
pp. 3076-3083
Author(s):  
K Irie ◽  
M Takase ◽  
K S Lee ◽  
D E Levin ◽  
H Araki ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Map Kinase ◽  
Protein Kinases ◽  
Cell Lysis ◽  
Yeast Cells ◽  
Temperature Sensitive ◽  
Kinase C ◽  
Mitogen Activated Protein

The PKC1 gene of Saccharomyces cerevisiae encodes a homolog of mammalian protein kinase C that is required for normal growth and division of yeast cells. We report here the isolation of the yeast MKK1 and MKK2 (for mitogen-activated protein [MAP] kinase-kinase) genes which, when overexpressed, suppress the cell lysis defect of a temperature-sensitive pkc1 mutant. The MKK genes encode protein kinases most similar to the STE7 product of S. cerevisiae, the byr1 product of Schizosaccharomyces pombe, and vertebrate MAP kinase-kinases. Deletion of either MKK gene alone did not cause any apparent phenotypic defects, but deletion of both MKK1 and MKK2 resulted in a temperature-sensitive cell lysis defect that was suppressed by osmotic stabilizers. This phenotypic defect is similar to that associated with deletion of the BCK1 gene, which is thought to function in the pathway mediated by PCK1. The BCK1 gene also encodes a predicted protein kinase. Overexpression of MKK1 suppressed the growth defect caused by deletion of BCK1, whereas an activated allele of BCK1 (BCK1-20) did not suppress the defect of the mkk1 mkk2 double disruption. Furthermore, overexpression of MPK1, which encodes a protein kinase closely related to vertebrate MAP kinases, suppressed the defect of the mkk1 mkk2 double mutant. These results suggest that MKK1 and MKK2 function in a signal transduction pathway involving the protein kinases encoded by PKC1, BCK1, and MPK1. Genetic epistasis experiments indicated that the site of action for MKK1 and MKK2 is between BCK1 and MPK1.

Protein kinase cascades in meiotic and mitotic cell cycle control

1990 ◽  
Vol 68 (12) ◽  
pp. 1297-1330 ◽  
Author(s):  
Steven L. Pelech ◽  
Jasbinder S. Sanghera ◽  
Maleki Daya-Makin
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Protein Kinase ◽  
Tyrosine Kinases ◽  
Somatic Cells ◽  
Protein Tyrosine Kinases ◽  
Sea Star ◽  
Protein Tyrosine ◽  
Threonine Kinases ◽  
Cell Division Control

Eukaryotic cell cycle progression during meiosis and mitosis is extensively regulated by reversible protein phosphorylation. Many cell surface receptors for mitogens are ligand-stimulated protein-tyrosine kinases that control the activation of a network of cytoplasmic and nuclear protein-serine(threonine) kinases. Over 30 plasma membrane associated protein-tyrosine kinases are encoded by proto-oncogenes, i.e., genes that have the potential to facilitate cancer when disregulated. Proteins such as ribosomal protein S6, microtubule-associated protein-2, myelin basic protein, and casein have been used to detect intracellular protein-serine(threonine) kinases that are activated further downstream in growth factor signalling transduction cascades. Genetic analysis of yeast cell division control (cdc) mutants has revealed another 20 or so protein-serine(threonine) kinases. One of these, specified by the cdc-2 gene in Schizosaccharomyces pombe, has homologs that are stimulated during M phase in maturing sea star and frog oocytes and mammalian somatic cells. Furthermore, during meiotic maturation in these echinoderm and amphibian oocytes, this is followed by activation of many of the same protein-serine(threonine) kinases that are stimulated when quiescent mammalian somatic cells are prompted with mitogens to traverse from G0 to G1 phase. These findings imply that a similar protein kinase cascade may oversee progression at multiple points in the cell cycle.Key words: protein kinases, mitosis, meiosis, oncogenes, cell division control.

scholarly journals Dynamic Localization of Protein Phosphatase Type 1 in the Mitotic Cell Cycle of Saccharomyces cerevisiae

2000 ◽  
Vol 149 (1) ◽  
pp. 125-140 ◽  
Author(s):  
Andrew Bloecher ◽  
Kelly Tatchell
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Protein Phosphatase ◽  
Essential Gene ◽  
Mitotic Cell ◽  
Type I ◽  
Mitotic Cell Cycle ◽  
Dependent Manner ◽  
Bud Neck ◽  
Protein Phosphatase Type

Protein phosphatase type I (PP1), encoded by the single essential gene GLC7 in Saccharomyces cerevisiae, functions in diverse cellular processes. To identify in vivo subcellular location(s) where these processes take place, we used a functional green fluorescent protein (GFP)–Glc7p fusion protein. Time-lapse fluorescence microscopy revealed GFP–Glc7p localizes predominantly in the nucleus throughout the mitotic cell cycle, with the highest concentrations in the nucleolus. GFP–Glc7p was also observed in a ring at the bud neck, which was dependent upon functional septins. Supporting a role for Glc7p in bud site selection, a glc7-129 mutant displayed a random budding pattern. In α-factor treated cells, GFP–Glc7p was located at the base of mating projections, again in a septin-dependent manner. At the start of anaphase, GFP–Glc7p accumulated at the spindle pole bodies and remained there until cytokinesis. After anaphase, GFP–Glc7p became concentrated in a ring that colocalized with the actomyosin ring. A GFP–Glc7-129 fusion was defective in localizing to the bud neck and SPBs. Together, these results identify sites of Glc7p function and suggest Glc7p activity is regulated through dynamic changes in its location.

Microtubule-entrained kinase activities associated with the cortical cytoskeleton during cytokinesis

1997 ◽  
Vol 110 (12) ◽  
pp. 1373-1386 ◽  
Author(s):  
G.R. Walker ◽  
C.B. Shuster ◽  
D.R. Burgess
Keyword(s):  
Cell Cycle ◽  
Protein Kinase ◽  
Protein Phosphorylation ◽  
Immunoblot Analysis ◽  
Negative Regulator ◽  
Mitogen Activated Protein Kinase ◽  
Mitotic Apparatus ◽  
Cortical Cytoskeleton

Research over the past few years has demonstrated the central role of protein phosphorylation in regulating mitosis and the cell cycle. However, little is known about how the mechanisms regulating the entry into mitosis contribute to the positional and temporal regulation of the actomyosin-based contractile ring formed during cytokinesis. Recent studies implicate p34cdc2 as a negative regulator of myosin II activity, suggesting a link between the mitotic cycle and cytokinesis. In an effort to study the relationship between protein phosphorylation and cytokinesis, we examined the in vivo and in vitro phosphorylation of actin-associated cortical cytoskeletal (CSK) proteins in an isolated model of the sea urchin egg cortex. Examination of cortices derived from eggs or zygotes labeled with 32P-orthophosphate reveals a number of cortex-associated phosphorylated proteins, including polypeptides of 20, 43 and 66 kDa. These three major phosphoproteins are also detected when isolated cortices are incubated with [32P]ATP in vitro, suggesting that the kinases that phosphorylate these substrates are also specifically associated with the cortex. The kinase activities in vivo and in vitro are stimulated by fertilization and display cell cycle-dependent activities. Gel autophosphorylation assays, kinase assays and immunoblot analysis reveal the presence of p34cdc2 as well as members of the mitogen-activated protein kinase family, whose activities in the CSK peak at cell division. Nocodazole, which inhibits microtubule formation and thus blocks cytokinesis, significantly delays the time of peak cortical protein phosphorylation as well as the peak in whole-cell histone H1 kinase activity. These results suggest that a key element regulating cortical contraction during cytokinesis is the timing of protein kinase activities associated with the cortical cytoskeleton that is in turn regulated by the mitotic apparatus.

scholarly journals Membrane localization of the kinase which phosphorylates p34cdc2 on threonine 14.

1994 ◽  
Vol 5 (3) ◽  
pp. 273-282 ◽  
Author(s):  
S Kornbluth ◽  
B Sebastian ◽  
T Hunter ◽  
J Newport
Keyword(s):  
Cell Cycle ◽  
Protein Kinase ◽  
Schizosaccharomyces Pombe ◽  
Protein Kinases ◽  
Membrane Fraction ◽  
Kinase Activity ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Dual Specificity ◽  
Detergent Extraction

The key regulator of entry into mitosis is the serine/threonine kinase p34cdc2. This kinase is regulated both by association with cyclins and by phosphorylation at several sites. Phosphorylation at Tyr 15 and Thr 14 are believed to inhibit the kinase activity of cdc2. In Schizosaccharomyces pombe, the wee1 (and possibly mik1) protein kinase catalyzes phosphorylation of Tyr 15. It is not clear whether these or other, as yet unidentified, protein kinases phosphorylate Thr 14. In this report we show, using extracts of Xenopus eggs, that the Thr 14-directed kinase is tightly membrane associated. Specifically, we have shown that a purified membrane fraction, in the absence of cytoplasm, can promote phosphorylation of cdc2 on both Thr 14 and Tyr 15. In contrast, the cytoplasm can phosphorylate cdc2 only on Tyr 15, suggesting the existence of at least two distinctly localized subpopulations of cdc2 Tyr 15-directed kinases. The membrane-associated Tyr 15 and Thr 14 kinase activities behaved similarly during salt or detergent extraction and were similarly regulated during the cell cycle and by the checkpoint machinery that delays mitosis while DNA is being replicated. This suggests the possibility that a dual-specificity membrane-associated protein kinase may catalyze phosphorylation of both Tyr 15 and Thr 14.

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