scholarly journals Cell-cycle control of cell polarity in yeast

2018 ◽  
Vol 218 (1) ◽  
pp. 171-189 ◽  
Author(s):  
Kyle D. Moran ◽  
Hui Kang ◽  
Ana V. Araujo ◽  
Trevin R. Zyla ◽  
Koji Saito ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Polarity ◽  
Mammalian Cells ◽  
Feedback Loop ◽  
Cell Cycle Control ◽  
Yeast Saccharomyces Cerevisiae ◽  
Positive Feedback Loop ◽  
Cyclin Dependent Kinases ◽  
Daughter Cells ◽  
Rho Family

In many cells, morphogenetic events are coordinated with the cell cycle by cyclin-dependent kinases (CDKs). For example, many mammalian cells display extended morphologies during interphase but round up into more spherical shapes during mitosis (high CDK activity) and constrict a furrow during cytokinesis (low CDK activity). In the budding yeast Saccharomyces cerevisiae, bud formation reproducibly initiates near the G1/S transition and requires activation of CDKs at a point called “start” in G1. Previous work suggested that CDKs acted by controlling the ability of cells to polarize Cdc42, a conserved Rho-family GTPase that regulates cell polarity and the actin cytoskeleton in many systems. However, we report that yeast daughter cells can polarize Cdc42 before CDK activation at start. This polarization operates via a positive feedback loop mediated by the Cdc42 effector Ste20. We further identify a major and novel locus of CDK action downstream of Cdc42 polarization, affecting the ability of several other Cdc42 effectors to localize to the polarity site.

scholarly journals Cyclin-Dependent Kinases and CTD Phosphatases in Cell Cycle Transcriptional Control: Conservation across Eukaryotic Kingdoms and Uniqueness to Plants

Cells ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 279
Author(s):  
Zhi-Liang Zheng
Keyword(s):  
Cell Cycle ◽  
Rna Polymerase Ii ◽  
Large Scale ◽  
Transcriptional Control ◽  
Cell Cycle Control ◽  
Yeast Saccharomyces Cerevisiae ◽  
Pol Ii ◽  
Precise Control ◽  
Cyclin Dependent Kinases ◽  
Entire Cell

Cell cycle control is vital for cell proliferation in all eukaryotic organisms. The entire cell cycle can be conceptually separated into four distinct phases, Gap 1 (G1), DNA synthesis (S), G2, and mitosis (M), which progress sequentially. The precise control of transcription, in particular, at the G1 to S and G2 to M transitions, is crucial for the synthesis of many phase-specific proteins, to ensure orderly progression throughout the cell cycle. This mini-review highlights highly conserved transcriptional regulators that are shared in budding yeast (Saccharomyces cerevisiae), Arabidopsis thaliana model plant, and humans, which have been separated for more than a billion years of evolution. These include structurally and/or functionally conserved regulators cyclin-dependent kinases (CDKs), RNA polymerase II C-terminal domain (CTD) phosphatases, and the classical versus shortcut models of Pol II transcriptional control. A few of CDKs and CTD phosphatases counteract to control the Pol II CTD Ser phosphorylation codes and are considered critical regulators of Pol II transcriptional process from initiation to elongation and termination. The functions of plant-unique CDKs and CTD phosphatases in relation to cell division are also briefly summarized. Future studies towards testing a cooperative transcriptional mechanism, which is proposed here and involves sequence-specific transcription factors and the shortcut model of Pol II CTD code modulation, across the three eukaryotic kingdoms will reveal how individual organisms achieve the most productive, large-scale transcription of phase-specific genes required for orderly progression throughout the entire cell cycle.

scholarly journals CDKs family -a glimpse into the past and present: from cell cycle control to current biological functions

2020 ◽  
Vol 5 (1) ◽  
pp. 1-9
Author(s):  
Muzna Shah ◽  
Muhammad Fazal Hussain Qureshi ◽  
Danish Mohammad ◽  
Mahira Lakhani ◽  
Tabinda Urooj ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Mammalian Cells ◽  
Cell Cycle Progression ◽  
Cell Cycle Control ◽  
Cell Renewal ◽  
Catalytic Subunits ◽  
Cyclin Dependent Kinases ◽  
Stem Cell Renewal ◽  
Cyclin Protein ◽  
Cycle Regulation

Cyclin-dependent kinases (CDKs) are the catalytic subunits or protein kinases characterized by separate subunit “cyclin” that are essential for their enzymatic activity. CDKs play important roles in the control of cell cycle progression, cell division, neuronal function, epigenetic regulation, metabolism, stem cell renewal and transcription. However, they can accomplish some of these tasks independently, without binding with cyclin protein or kinase activity. Thus, so far, twenty different CDKs and cyclins have been reported in mammalian cells. The evolutionary expansion of the CDK family in mammals led to the division of CDKs into three cell-cycle-related subfamilies (Cdk1, Cdk4 and Cdk5) and five transcriptional subfamilies (Cdk7, Cdk8, Cdk9, Cdk11 and Cdk20). In this review, we summarizes that how CDKs are traditionally involve their latest revelations, their functional diversity beyond cell cycle regulation and their impact on development of disease in mammals.  

scholarly journals Conserved Mitotic Phosphorylation of a Proteasome Subunit Regulates Cell Proliferation

Cells ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 3075
Author(s):  
Jinyuan Duan ◽  
Wenzhu Li ◽  
Xin Shu ◽  
Bing Yang ◽  
Xiangwei He ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Mammalian Cells ◽  
Cell Cycle Control ◽  
Growth Defect ◽  
Proteasome Subunit ◽  
Cyclin Dependent Kinases ◽  
Physiological Processes ◽  
Mitotic Phosphorylation ◽  
Mutant Cells

Reversible phosphorylation has emerged as an important mechanism for regulating proteasome function in various physiological processes. Essentially all proteasome phosphorylations characterized thus far occur on proteasome holoenzyme or subcomplexes to regulate substrate degradation. Here, we report a highly conserved phosphorylation that only exists on the unassembled α5 subunit of the proteasome. The modified residue, α5-Ser16, is within a SP motif typically recognized by cyclin-dependent kinases (CDKs). Using a phospho-specific antibody generated against this site, we found that α5-S16 phosphorylation is mitosis-specific in both yeast and mammalian cells. Blocking this site with a S16A mutation caused growth defect and G2/M arrest of the cell cycle. α5-S16 phosphorylation depends on CDK1 activity and is highly abundant in some but not all mitotic cells. Immunoprecipitation and mass spectrometry (IP-MS) studies identified numerous proteins that could interact with phosphorylated α5, including PLK1, a key regulator of mitosis. α5–PLK1 interaction increased upon mitosis and could be facilitated by S16 phosphorylation. CDK1 activation downstream of PLK1 activity was delayed in S16A mutant cells, suggesting an important role of α5-S16 phosphorylation in regulating PLK1 and mitosis. These data have revealed an unappreciated function of “exo-proteasome” phosphorylation of a proteasome subunit and may bring new insights to our understanding of cell cycle control.

scholarly journals Interaction between a Ras and a Rho GTPase Couples Selection of a Growth Site to the Development of Cell Polarity in Yeast

2003 ◽  
Vol 14 (12) ◽  
pp. 4958-4970 ◽  
Author(s):  
Keith G. Kozminski ◽  
Laure Beven ◽  
Elizabeth Angerman ◽  
Amy Hin Yan Tong ◽  
Charles Boone ◽  
...  
Keyword(s):  
Cell Polarity ◽  
Rho Gtpase ◽  
Cell Cortex ◽  
Nucleotide Exchange ◽  
Yeast Saccharomyces Cerevisiae ◽  
Growth Site ◽  
Ras Family ◽  
Rho Family ◽  
Polarity Establishment ◽  
Selection Of

Polarized cell growth requires the coupling of a defined spatial site on the cell cortex to the apparatus that directs the establishment of cell polarity. In the budding yeast Saccharomyces cerevisiae, the Ras-family GTPase Rsr1p/Bud1p and its regulators select the proper site for bud emergence on the cell cortex. The Rho-family GTPase Cdc42p and its associated proteins then establish an axis of polarized growth by triggering an asymmetric organization of the actin cytoskeleton and secretory apparatus at the selected bud site. We explored whether a direct linkage exists between the Rsr1p/Bud1p and Cdc42p GTPases. Here we show specific genetic interactions between RSR1/BUD1 and particular cdc42 mutants defective in polarity establishment. We also show that Cdc42p coimmunoprecipitated with Rsr1p/Bud1p from yeast extracts. In vitro studies indicated a direct interaction between Rsr1p/Bud1p and Cdc42p, which was enhanced by Cdc24p, a guanine nucleotide exchange factor for Cdc42p. Our findings suggest that Cdc42p interacts directly with Rsr1p/Bud1p in vivo, providing a novel mechanism by which direct contact between a Ras-family GTPase and a Rho-family GTPase links the selection of a growth site to polarity establishment.

Calcium and cell cycle control

Development ◽  
1990 ◽  
Vol 108 (4) ◽  
pp. 525-542 ◽  
Author(s):  
M. Whitaker ◽  
R. Patel
Keyword(s):  
Cell Cycle ◽  
Sea Urchin ◽  
Mammalian Cells ◽  
Cell Cycle Regulation ◽  
Sea Urchins ◽  
Cell Cycle Control ◽  
Control Point ◽  
Control Cell ◽  
Free Calcium ◽  
Cycle Regulation

The cell division cycle of the early sea urchin embryo is basic. Nonetheless, it has control points in common with the yeast and mammalian cell cycles, at START, mitosis ENTRY and mitosis EXIT. Progression through each control point in sea urchins is triggered by transient increases in intracellular free calcium. The Cai transients control cell cycle progression by translational and post-translational regulation of the cell cycle control proteins pp34 and cyclin. The START Cai transient leads to phosphorylation of pp34 and cyclin synthesis. The mitosis ENTRY Cai transient triggers cyclin phosphorylation. The motosis EXIT transient causes destruction of phosphorylated cyclin. We compare cell cycle regulation by calcium in sea urchin embryos to cell cycle regulation in other eggs and oocytes and in mammalian cells.

scholarly journals Cell cycle phases in the unequal mother/daughter cell cycles of Saccharomyces cerevisiae.

1984 ◽  
Vol 4 (11) ◽  
pp. 2529-2531 ◽  
Author(s):  
B J Brewer ◽  
E Chlebowicz-Sledziewska ◽  
W L Fangman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Cycle Phase ◽  
Cell Cycle Time ◽  
Yeast Saccharomyces Cerevisiae ◽  
Cell Cycles ◽  
Daughter Cells ◽  
Mother And Daughter ◽  
Cell Cycle Phases ◽  
Mother Cells

During cell division in the yeast Saccharomyces cerevisiae mother cells produce buds (daughter cells) which are smaller and have longer cell cycles. We performed experiments to compare the lengths of cell cycle phases in mothers and daughters. As anticipated from earlier indirect observations, the longer cell cycle time of daughter cells is accounted for by a longer G1 interval. The S-phase and the G2-phase are of the same duration in mother and daughter cells. An analysis of five isogenic strains shows that cell cycle phase lengths are independent of cell ploidy and mating type.

scholarly journals Cytoskeleton and cell cycle control during meiotic maturation of the mouse oocyte: integrating time and space

Reproduction ◽  
2005 ◽  
Vol 130 (6) ◽  
pp. 801-811 ◽  
Author(s):  
Stephane Brunet ◽  
Bernard Maro
Keyword(s):  
Cell Cycle ◽  
Intermediate Phase ◽  
Current Knowledge ◽  
Cell Cycle Control ◽  
Meiotic Maturation ◽  
Time And Space ◽  
Daughter Cells ◽  
Large Oocyte ◽  
Polar Bodies ◽  
Cytostatic Factor

During meiotic maturation of mammalian oocytes, two successive divisions occur without an intermediate phase of DNA replication, so that haploid gametes are produced. Moreover, these two divisions are asymmetric, to ensure that most of the maternal stores are retained within the oocyte. This leads to the formation of daughter cells with different sizes: the large oocyte and the small polar bodies. All these events are dependent upon the dynamic changes in the organization of the oocyte cytoskeleton (microtubules and microfilaments) and are highly regulated in time and space. We review here the current knowledge of the interplay between the cytoskeleton and the cell cycle machinery in mouse oocytes, with an emphasis on the two major activities that control meiotic maturation in vertebrates, MPF (Maturation promoting factor) and CSF (Cytostatic factor).

scholarly journals Cell cycle analysis of the activity, subcellular localization, and subunit composition of human CAK (CDK-activating kinase).

1994 ◽  
Vol 127 (2) ◽  
pp. 467-478 ◽  
Author(s):  
J P Tassan ◽  
S J Schultz ◽  
J Bartek ◽  
E A Nigg
Keyword(s):  
Cell Cycle ◽  
Somatic Cell ◽  
Cell Cycle Control ◽  
Gel Filtration ◽  
Multiprotein Complex ◽  
Cyclin Dependent Kinases ◽  
Critical Residue ◽  
Cdk Activating Kinase

The activity of cyclin-dependent kinases (cdks) depends on the phosphorylation of a residue corresponding to threonine 161 in human p34cdc2. One enzyme responsible for phosphorylating this critical residue has recently been purified from Xenopus and starfish. It was termed CAK (for cdk-activating kinase), and it was shown to contain p40MO15 as its catalytic subunit. In view of the cardinal role of cdks in cell cycle control, it is important to learn if and how CAK activity is regulated during the somatic cell cycle. Here, we report a molecular characterization of a human p40MO15 homologue and its associated CAK activity. We have cloned and sequenced a cDNA coding for human p40MO15, and raised specific polyclonal and monoclonal antibodies against the corresponding protein expressed in Escherichia coli. These tools were then used to demonstrate that p40MO15 protein expression and CAK activity are constant throughout the somatic cell cycle. Gel filtration suggests that active CAK is a multiprotein complex, and immunoprecipitation experiments identify two polypeptides of 34 and 32 kD as likely complex partners of p40MO15. The association of the three proteins is near stoichiometric and invariant throughout the cell cycle. Immunocytochemistry and biochemical enucleation experiments both demonstrate that p40MO15 is nuclear at all stages of the cell cycle (except for mitosis, when the protein redistributes throughout the cell), although the p34cdc2/cyclin B complex, one of the major purported substrates of CAK, occurs in the cytoplasm until shortly before mitosis. The absence of obvious changes in CAK activity in exponentially growing cells constitutes a surprise. It suggests that the phosphorylation state of threonine 161 in p34cdc2 (and the corresponding residue in other cdks) may be regulated primarily by the availability of the cdk/cyclin substrates, and by phosphatase(s).

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