scholarly journals Kinetic Analysis of a Molecular Model of the Budding Yeast Cell Cycle

2000 ◽  
Vol 11 (1) ◽  
pp. 369-391 ◽  
Author(s):  
Katherine C. Chen ◽  
Attila Csikasz-Nagy ◽  
Bela Gyorffy ◽  
John Val ◽  
Bela Novak ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Budding Yeast ◽  
Molecular Model ◽  
Cell Cycle Control ◽  
Yeast Saccharomyces Cerevisiae ◽  
Bud Emergence ◽  
Molecular Events ◽  
Eukaryotic Organism ◽  
Molecular Machinery ◽  
Time Courses

The molecular machinery of cell cycle control is known in more detail for budding yeast, Saccharomyces cerevisiae, than for any other eukaryotic organism. In recent years, many elegant experiments on budding yeast have dissected the roles of cyclin molecules (Cln1–3 and Clb1–6) in coordinating the events of DNA synthesis, bud emergence, spindle formation, nuclear division, and cell separation. These experimental clues suggest a mechanism for the principal molecular interactions controlling cyclin synthesis and degradation. Using standard techniques of biochemical kinetics, we convert the mechanism into a set of differential equations, which describe the time courses of three major classes of cyclin-dependent kinase activities. Model in hand, we examine the molecular events controlling “Start” (the commitment step to a new round of chromosome replication, bud formation, and mitosis) and “Finish” (the transition from metaphase to anaphase, when sister chromatids are pulled apart and the bud separates from the mother cell) in wild-type cells and 50 mutants. The model accounts for many details of the physiology, biochemistry, and genetics of cell cycle control in budding yeast.

scholarly journals Mitotic exit kinase Dbf2 directly phosphorylates chitin synthase Chs2 to regulate cytokinesis in budding yeast

2012 ◽  
Vol 23 (13) ◽  
pp. 2445-2456 ◽  
Author(s):  
Younghoon Oh ◽  
Kuang-Jung Chang ◽  
Peter Orlean ◽  
Carsten Wloka ◽  
Raymond Deshaies ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Budding Yeast ◽  
Cell Cycle Control ◽  
Mitotic Exit ◽  
Chitin Synthase ◽  
Chitin Synthesis ◽  
Yeast Saccharomyces Cerevisiae ◽  
Ecm Remodeling ◽  
Division Site ◽  
Primary Septum

How cell cycle machinery regulates extracellular matrix (ECM) remodeling during cytokinesis remains poorly understood. In the budding yeast Saccharomyces cerevisiae, the primary septum (PS), a functional equivalent of animal ECM, is synthesized during cytokinesis by the chitin synthase Chs2. Here, we report that Dbf2, a conserved mitotic exit kinase, localizes to the division site after Chs2 and directly phosphorylates Chs2 on several residues, including Ser-217. Both phosphodeficient (chs2‑S217A) and phosphomimic (chs2‑S217D) mutations cause defects in cytokinesis, suggesting that dynamic phosphorylation–dephosphorylation of Ser-217 is critical for Chs2 function. It is striking that Chs2‑S217A constricts asymmetrically with the actomyosin ring (AMR), whereas Chs2-S217D displays little or no constriction and remains highly mobile at the division site. These data suggest that Chs2 phosphorylation by Dbf2 triggers its dissociation from the AMR during the late stage of cytokinesis. Of interest, both chs2‑S217A and chs2‑S217D mutants are robustly suppressed by increased dosage of Cyk3, a cytokinesis protein that displays Dbf2‑dependent localization and also stimulates Chs2‑mediated chitin synthesis. Thus Dbf2 regulates PS formation through at least two independent pathways: direct phosphorylation and Cyk3‑mediated activation of Chs2. Our study establishes a mechanism for direct cell cycle control of ECM remodeling during cytokinesis.

scholarly journals Systems Level Modeling of the Cell Cycle Using Budding Yeast

2007 ◽  
Vol 3 ◽  
pp. 117693510700300 ◽  
Author(s):  
B.P. Ingalls ◽  
B.P. Duncker ◽  
D.R. Kim ◽  
B.J. McConkey
Keyword(s):  
Cell Cycle ◽  
Budding Yeast ◽  
Human Cancer ◽  
Quality Data ◽  
Cell Cycle Gene ◽  
Mathematical Framework ◽  
Gene Transcript ◽  
Proteomics Data ◽  
Yeast Saccharomyces Cerevisiae ◽  
Protein Levels

Proteins involved in the regulation of the cell cycle are highly conserved across all eukaryotes, and so a relatively simple eukaryote such as yeast can provide insight into a variety of cell cycle perturbations including those that occur in human cancer. To date, the budding yeast Saccharomyces cerevisiae has provided the largest amount of experimental and modeling data on the progression of the cell cycle, making it a logical choice for in-depth studies of this process. Moreover, the advent of methods for collection of high-throughput genome, transcriptome, and proteome data has provided a means to collect and precisely quantify simultaneous cell cycle gene transcript and protein levels, permitting modeling of the cell cycle on the systems level. With the appropriate mathematical framework and sufficient and accurate data on cell cycle components, it should be possible to create a model of the cell cycle that not only effectively describes its operation, but can also predict responses to perturbations such as variation in protein levels and responses to external stimuli including targeted inhibition by drugs. In this review, we summarize existing data on the yeast cell cycle, proteomics technologies for quantifying cell cycle proteins, and the mathematical frameworks that can integrate this data into representative and effective models. Systems level modeling of the cell cycle will require the integration of high-quality data with the appropriate mathematical framework, which can currently be attained through the combination of dynamic modeling based on proteomics data and using yeast as a model organism.

scholarly journals Far3 and Five Interacting Proteins Prevent Premature Recovery from Pheromone Arrest in the Budding Yeast Saccharomyces cerevisiae

2003 ◽  
Vol 23 (5) ◽  
pp. 1750-1763 ◽  
Author(s):  
Hilary A. Kemp ◽  
George F. Sprague,
Keyword(s):  
Cell Cycle ◽  
Budding Yeast ◽  
Open Reading Frames ◽  
Velocity Sedimentation ◽  
Interacting Proteins ◽  
Yeast Saccharomyces Cerevisiae ◽  
Cycle Arrest ◽  
Mutant Cells ◽  
Two Hybrid ◽  
Reading Frames

ABSTRACT In budding yeast, diffusible mating pheromones initiate a signaling pathway that culminates in several responses, including cell cycle arrest. Only a handful of genes required for the interface between pheromone response and the cell cycle have been identified, among them FAR1 and FAR3; of these, only FAR1 has been extensively characterized. In an effort to learn about the mechanism by which Far3 acts, we used the two-hybrid method to identify interacting proteins. We identified five previously uncharacterized open reading frames, dubbed FAR7, FAR8, FAR9, FAR10, and FAR11, that cause a far3-like pheromone arrest defect when disrupted. Using two-hybrid and coimmunoprecipitation analysis, we found that all six Far proteins interact with each other. Moreover, velocity sedimentation experiments suggest that Far3 and Far7 to Far11 form a complex. The phenotype of a sextuple far3far7-far11 mutant is no more severe than any single mutant. Thus, FAR3 and FAR7 to FAR11 all participate in the same pathway leading to G1 arrest. These mutants initially arrest in response to pheromone but resume budding after 10 h. Under these conditions, wild-type cells fail to resume budding even after several days whereas far1 mutant cells resume budding within 1 h. We conclude that the FAR3-dependent arrest pathway is functionally distinct from that which employs FAR1.

scholarly journals Quantitative Characterization of a Mitotic Cyclin Threshold Regulating Exit from Mitosis

2005 ◽  
Vol 16 (5) ◽  
pp. 2129-2138 ◽  
Author(s):  
Frederick R. Cross ◽  
Lea Schroeder ◽  
Martin Kruse ◽  
Katherine C. Chen
Keyword(s):  
Cell Cycle ◽  
Budding Yeast ◽  
Cell Cycle Control ◽  
Predictive Ability ◽  
Eukaryotic Cell ◽  
Model Predictions ◽  
Mitotic Cyclin ◽  
Constitutive Overexpression

Regulation of cyclin abundance is central to eukaryotic cell cycle control. Strong overexpression of mitotic cyclins is known to lock the system in mitosis, but the quantitative behavior of the control system as this threshold is approached has only been characterized in the in vitro Xenopus extract system. Here, we quantitate the threshold for mitotic block in budding yeast caused by constitutive overexpression of the mitotic cyclin Clb2. Near this threshold, the system displays marked loss of robustness, in that loss or even heterozygosity for some regulators becomes deleterious or lethal, even though complete loss of these regulators is tolerated at normal cyclin expression levels. Recently, we presented a quantitative kinetic model of the budding yeast cell cycle. Here, we use this model to generate biochemical predictions for Clb2 levels, asynchronous as well as through the cell cycle, as the Clb2 overexpression threshold is approached. The model predictions compare well with biochemical data, even though no data of this type were available during model generation. The loss of robustness of the Clb2 overexpressing system is also predicted by the model. These results provide strong confirmation of the model's predictive ability.

scholarly journals Specific Inhibition of Elm1 Kinase Activity Reveals Functions Required for Early G1 Events

2003 ◽  
Vol 23 (17) ◽  
pp. 6327-6337 ◽  
Author(s):  
Aparna Sreenivasan ◽  
Anthony C. Bishop ◽  
Kevan M. Shokat ◽  
Douglas R. Kellogg
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Cell Growth ◽  
Kinase Activity ◽  
Budding Yeast ◽  
Specific Inhibition ◽  
Bud Emergence ◽  
Wee1 Kinase ◽  
Yeast Homolog

ABSTRACT In budding yeast, the Elm1 kinase is required for coordination of cell growth and cell division at G2/M. Elm1 is also required for efficient cytokinesis and for regulation of Swe1, the budding yeast homolog of the Wee1 kinase. To further characterize Elm1 function, we engineered an ELM1 allele that can be rapidly and selectively inhibited in vivo. We found that inhibition of Elm1 kinase activity during G2 results in a phenotype similar to the phenotype caused by deletion of the ELM1 gene, as expected. However, inhibition of Elm1 kinase activity earlier in the cell cycle results in a prolonged G1 delay. The G1 requirement for Elm1 kinase activity occurs before bud emergence, polarization of the septins, and synthesis of G1 cyclins. Inhibition of Elm1 kinase activity during early G1 also causes defects in the organization of septins, and inhibition of Elm1 kinase activity in a strain lacking the redundant G1 cyclins CLN1 and CLN2 is lethal. These results demonstrate that the Elm1 kinase plays an important role in G1 events required for bud emergence and septin organization.

scholarly journals From START to FINISH: computational analysis of cell cycle control in budding yeast

2015 ◽  
Vol 1 (1) ◽  
Author(s):  
Pavel Kraikivski ◽  
Katherine C Chen ◽  
Teeraphan Laomettachit ◽  
T M Murali ◽  
John J Tyson
Keyword(s):  
Cell Cycle ◽  
Computational Analysis ◽  
Budding Yeast ◽  
Cell Cycle Control

scholarly journals Budding yeast Dma1 and Dma2 participate in regulation of Swe1 levels and localization

2011 ◽  
Vol 22 (13) ◽  
pp. 2185-2197 ◽  
Author(s):  
Erica Raspelli ◽  
Corinne Cassani ◽  
Giovanna Lucchini ◽  
Roberta Fraschini
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Budding Yeast ◽  
Cell Cycle Control ◽  
Replication Stress ◽  
Down Regulation ◽  
Evolutionarily Conserved ◽  
Dna Replication Stress ◽  
Morphogenesis Checkpoint ◽  
The One

Timely down-regulation of the evolutionarily conserved protein kinase Swe1 plays an important role in cell cycle control, as Swe1 can block nuclear division through inhibitory phosphorylation of the catalytic subunit of cyclin-dependent kinase. In particular, Swe1 degradation is important for budding yeast cell survival in case of DNA replication stress, whereas it is inhibited by the morphogenesis checkpoint in response to alterations in actin cytoskeleton or septin structure. We show that the lack of the Dma1 and Dma2 ubiquitin ligases, which moderately affects Swe1 localization and degradation during an unperturbed cell cycle with no apparent phenotypic effects, is toxic for cells that are partially defective in Swe1 down-regulation. Moreover, Swe1 is stabilized, restrained at the bud neck, and hyperphosphorylated in dma1Δ dma2Δ cells subjected to DNA replication stress, indicating that the mechanism stabilizing Swe1 under these conditions is different from the one triggered by the morphogenesis checkpoint. Finally, the Dma proteins are required for proper Swe1 ubiquitylation. Taken together, the data highlight a previously unknown role of these proteins in the complex regulation of Swe1 and suggest that they might contribute to control, directly or indirectly, Swe1 ubiquitylation.

scholarly journals A Monitor for Bud Emergence in the Yeast Morphogenesis Checkpoint

2003 ◽  
Vol 14 (8) ◽  
pp. 3280-3291 ◽  
Author(s):  
Chandra L. Theesfeld ◽  
Trevin R. Zyla ◽  
Elaine G.S. Bardes ◽  
Daniel J. Lew
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Actin Cytoskeleton ◽  
Budding Yeast ◽  
Bud Formation ◽  
Bud Emergence ◽  
Checkpoint Pathway ◽  
Morphogenesis Checkpoint ◽  
External Signals ◽  
Biochemical Signals

Cell cycle transitions are subject to regulation by both external signals and internal checkpoints that monitor satisfactory progression of key cell cycle events. In budding yeast, the morphogenesis checkpoint arrests the cell cycle in response to perturbations that affect the actin cytoskeleton and bud formation. Herein, we identify a step in this checkpoint pathway that seems to be directly responsive to bud emergence. Activation of the kinase Hsl1p is dependent upon its recruitment to a cortical domain organized by the septins, a family of conserved filament-forming proteins. Under conditions that delayed or blocked bud emergence, Hsl1p recruitment to the septin cortex still took place, but hyperphosphorylation of Hsl1p and recruitment of the Hsl1p-binding protein Hsl7p to the septin cortex only occurred after bud emergence. At this time, the septin cortex spread to form a collar between mother and bud, and Hsl1p and Hsl7p were restricted to the bud side of the septin collar. We discuss models for translating cellular geometry (in this case, the emergence of a bud) into biochemical signals regulating cell proliferation.

Sign in / Sign up

Export Citation Format

Share Document