Download or read book Nutrient Regulation of Cell Growth and Cell Proliferation in Saccharomyces Cerevisiae written by Matthew Grant Slattery and published by . This book was released on 2008 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Control of Cell Division by Nutrients and ER Stress Signaling in Saccharomyces Cerevisiae written by Jinbai Guo and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Cell cycle progression of Saccharomyces cerevisiae cells was monitored in continuous cultures limited for glucose or nitrogen. The G1 cell cycle phase, before initiation of DNA replication, did not exclusively expand when growth rate decreased. Especially during nitrogen limitation, non-G1 phases expanded almost as much as G1. In addition, cell size remained constant as a function of growth rate. These results contrast with current views that growth requirements are met before initiation of DNA replication, and suggest that distinct nutrient limitations differentially impinge on cell cycle progression. Therefore, multiple mechanisms are hypothesized to regulate the coordination of cell growth and cell division. Genetic interactions were identified between the dose-dependent cell-cycle regulator 2 (DCR2) phosphatase and genes involving in secretion/unfolded protein response pathway, including IRE1, through a genome-wide dominant negative genetic approach. Accumulation of unfolded proteins in the endoplasmic reticulum triggers the unfolded protein response (UPR). How the UPR is downregulated is not well understood. Inositol requirement 1 (IRE1) is an endoplasmic reticulum transmembrane UPR sensor in Saccharomyces cerevisiae. When the UPR is triggered, Ire1p is autophosphorylated, on Ser 840 and Ser 841, inducing the cytosolic endonuclease activity of Ire1p, thereby initiating the splicing and translational de-repression of HAC1 mRNA. Homologous to Atf/Creb1 (Hac1p) activates UPR transcription. We found that that Dcr2p phosphatase functionally and physically interacts with Ire1p. Overexpression of DCR2, but not of a catalytically inactive DCR2 allele, significantly delays HAC1 splicing and sensitizes cells to the UPR. Furthermore, Dcr2p physically interacts in vivo with Ire1p-S840E, S841E, which mimics phosphorylated Ire1p, and Dcr2p dephosphorylates Ire1p in vitro. Our results are consistent with de-phosphorylation of Ire1p being a mechanism for antagonizing UPR signaling.
Download or read book Cell Growth written by Michael N. Hall and published by CSHL Press. This book was released on 2004 with total page 668 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent breakthroughs in the field of cell growth, particularly in the control of cell size, are reviewed by experts in the three major divisions of the field: growth of individual cells, growth of organs, and regulation of cell growth in the contexts of development and cell division. This book is an introductory overview of the field and should be adaptable as a textbook.
Download or read book Life in the Midst of Scarcity Adaptations to Nutrient Availability in Saccharomyces Cerevisiae written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Cells of all living organisms contain complex signal transduction networks to ensure that a wide range of physiological properties are properly adapted to the environmental conditions. The fundamental concepts and individual building blocks of these signalling networks are generally well-conserved from yeast to man; yet, the central role that growth factors and hormones play in the regulation of signalling cascades in higher eukaryotes is executed by nutrients in yeast. Several nutrient-controlled pathways, which regulate cell growth and proliferation, metabolism and stress resistance, have been defined in yeast. These pathways are integrated into a signalling network, which ensures that yeast cells enter a quiescent, resting phase (G0) to survive periods of nutrient scarceness and that they rapidly resume growth and cell proliferation when nutrient conditions become favourable again. A series of well-conserved nutrient-sensory protein kinases perform key roles in this signalling network: i.e. Snf1, PKA, Tor1 and Tor2, Sch9 and Pho85- ho80. In this review, we provide a comprehensive overview on the current understanding of the signalling processes mediated via these kinases with a particular focus on how these individual pathways converge to signalling networks that ultimately ensure the dynamic translation of extracellular nutrient signals into appropriate physiological responses.
Download or read book Systematic Analysis of Cell Size Control in the Budding Yeast Saccharomyces Cerevisiae written by Michael Alexander Cook and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Molecular Biology of the Cell written by and published by . This book was released on 2002 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Quantitative Analysis of Nutrient responsive Signal Transduction Pathways in Saccharomyces Cerevisiae written by Jonathan M. Raser and published by . This book was released on 2005 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: Organisms and their component cells exist in a dynamic and unpredictable environment. Many of these environmental changes are potentially harmful or lethal. It is therefore unsurprising that cells are capable of adaptation to many of these potentially harmful environmental conditions. This adaptation requires both the ability to gather information about the environment, and the ability to convert the information gathered into the appropriate cellular response. Cells have developed specific signal transduction pathways that respond to a specific environmental stimulus and effect a specific, corresponding cellular response. Such signal transduction pathways are quantitative, in that cells do not simply display binary information processing but are capable of more subtle interpretation of different magnitudes of a particular stimulus. In particular, many signaling pathways enable adaptation to changing levels of environmental nutrients by control of cellular gene expression. We employed the single-cell eukaryote Saccharomyces cerevisiae as a model to study several facets of nutrient-responsive signal transduction in a quantitative manner. In the following text, we present our study of the sources of heterogeneity in gene expression in a population of genetically identical cells. In addition, we review recent advances in understanding of heterogeneity or noise in gene expression. Also, we present work characterizing the zinc-responsive signaling pathway in a quantitative manner, and studies uncovering the presence of positive feedback in the phosphate-responsive (PHO) signaling pathway.
Download or read book Multiple Nutrient Sensing Kinases Converge to Phosphorylate an Element of Cdc34 that Increases Saccharomyces Cerevisiae Lifespan written by and published by . This book was released on 2009 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: Growth and division are tightly coordinated with available nutrient conditions. Cells of the budding yeast, Saccharomyces cerevisiae, grow to a larger size prior to budding and DNA replication when preferred carbon sources such as glucose, as opposed to less preferred sources like ethanol and acetate, are available. A culture's doubling time is also significantly reduced when the available carbon and nitrogen sources are more favorable. These physiological phenomena are well documented but the precise molecular mechanisms relaying nutrient conditions to the growth and division machinery are not well defined. I demonstrate here that Cdc34, the ubiquitin conjugating enzyme that promotes S phase entry, is phosphorylated upon a highly conserved serine residue which is part of a motif that defines the family of Cdc34/Ubc7 ubiquitin conjugating enzymes. This phosphorylation is regulated by multiple, nutrient sensing kinases including Protein Kinase A, Sch9 and TOR. Furthermore, this phosphorylation event is regulated through the cell cycle with the sole induction occurring in the G1 phase which is when nutrients are sensed and cells commit to another round of division. This phosphorylation likely activates Cdc34 and in turn propagates a signal to the cell division cycle machinery that nutrient conditions are favorable for commitment to a new round of division. This phosphorylation is critical for normal cell cycle progression but must be carefully controlled when cells are deprived of nutrients. Crippling the activity of Protein Kinase A, SCH9 or TOR increases the proportion of cells that survive stationary phase conditions, which because of the metabolic conditions that must be maintained and the similarity to post-mitotic mammalian cells, is referred to as a yeast culture's chronological lifespan. Yeast cells expressing Cdc34 mutants that are no longer subject to this regulation by phosphorylation have a reduced chronological lifespan. A precise molecular mechanism describing the change in Cdc34 activity after phosphorylation of this serine residue is discussed.
Download or read book The Biology of the Cell Cycle written by J. M. Mitchison and published by CUP Archive. This book was released on 1971-11-30 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Systematic Identification of Regulators of Cell Cycle Commitment and a Dynamic Transcriptional Network that Communicates Growth Potential to Ribosome Synthesis and Critical Cell Size in Budding Yeast microform written by Paul Conrad Jorgensen and published by Library and Archives Canada = Bibliothèque et Archives Canada. This book was released on 2004 with total page 778 pages. Available in PDF, EPUB and Kindle. Book excerpt: Size homeostasis requires that proliferating cells co-ordinate their growth and division. In Saccharomyces cerevisiae, this co-ordination occurs in late G1 phase at the point of commitment to cell division termed Start; traversal through Start requires that cells have grown to a critical cell size. The cell size threshold is flexible and is set higher in rich nutrient conditions and in proportion to ploidy. Despite its importance, Start remains poorly understood, in large part because the cell size phenotype has been refractory to conventional genetics. The recent construction of & sim;6000 yeast strains deleted for every predicted open reading frame allowed me to systematically identify genes whose deletion confers abnormally small or large cell size. These screens identified 40 potential Start regulators, including Whi5, the long postulated but previously unidentified target of Cln3-Cdc28 kinase at Start. The smallest deletion strains carried disruptions in SFP1 or SCH9. SFP1 encodes a zinc-finger transcription factor while SCH9 encodes a protein kinase, but neither gene product had been well characterised. Numerous experiments demonstrated that although Sfp1 and Sch9 are important for cell growth, they are also bona fide Start repressors. Remarkably, both Sfp1 and Sch9 activated the RP and Ribi regulons, two expansive transcriptional programmes whose expression is rate-limiting for ribosome production. This finding meshed nicely with the cell size screens, as my shortlist of potential Start repressors included 15 ribosome biogenesis factors. I elaborated a control network including Sfp1, Sch9, and the transcription factors Rgm1, Fhl1, and Ifh1 at RP promoters. Sfp1 and Sch9 are controlled by nutrient status at the level of nuclear localisation and abundance, respectively, and appear to tailor a cell's ribosome production to its growth potential. Overall, my data argues that the rate of ribosome biogenesis, dictated by nutrients via Sfp1 and Sch9, modulates the critical cell size threshold at Start by a mechanism that is independent of the known upstream regulators Cln3, Bck2, and Whi5. My work has allowed for a more complete molecular characterisation of Start, elucidated a dynamic transcriptional control network for the RP and Ribi regulons, and illuminated connections between ribosome biogenesis and Start.
Download or read book Coordination of Growth and Division in Saccharomyces Cerevisiae by the G1 Cyclin CLN3 written by David Dean Markwardt and published by . This book was released on 2000 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Systems Biology written by Lilia Alberghina and published by Springer Science & Business Media. This book was released on 2007-10-04 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: For life to be understood and disease to become manageable, the wealth of postgenomic data now needs to be made dynamic. This development requires systems biology, integrating computational models for cells and organisms in health and disease; quantitative experiments (high-throughput, genome-wide, living cell, in silico); and new concepts and principles concerning interactions. This book defines the new field of systems biology and discusses the most efficient experimental and computational strategies. The benefits for industry, such as the new network-based drug-target design validation, and testing, are also presented.
Download or read book Coordination of Growth and Cell Division by the TORC1 Nutrient Signaling Pathway in Saccharomyces Cerevisiae written by Marta Moreno Torres and published by . This book was released on 2016 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Ras PKA Pathway Controls Transcription of Genes Involved in Stationary Phase Entry in Saccharomyces Cerevisiae written by Ya-Wen Chang and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Upon nutrient deprivation, Saccharomyces cerevisiae cells arrest division and enter into a specialized resting state, known as stationary phase. The entry into this resting state is regulated, in part, by the Ras/PKA (cAMP-dependent protein kinase) signaling pathway. We are interested in understanding the mechanisms regulating stationary phase biology in S. cerevisiae, with an ultimate goal of defining the targets of PKA that are responsible for this growth control. To this end, we have identified a collection of mutants that exhibited a defective transcriptional response to nutrient limitation and failed to enter into a normal stationary phase. These rye mutants were isolated on the basis of defects in the regulation of YGP1 expression. We found that the levels of YGP1 were significantly elevated in the rye mutants during the log phase of growth. The rye defects were not specific to this YGP1 expression defect because these mutants also exhibited multiple defects in stationary phase properties, including an inability to survive periods of prolonged starvation and a failure to tolerate a mild heat shock. These data indicated that the RYE genes may encode important regulators of yeast cell growth. Interestingly, three of these RYE genes encoded the Srb proteins, Srb9p, Srb10p, and Srb11p. These Srb proteins are components of the Srb complex associated with the RNA polymerase II holoenzyme. We found that specific transcription defects associated with these srb mutations were suppressed by RAS2val19, a hyperactive allele of RAS2. However, increased Ras signaling was not able to correct the expression defects associated with an srb9 null mutant, suggesting that the Srb9 protein is essential for the Ras suppression. Moreover, there are two potential PKA consensus sites in Srb9p. Our results showed that the suppression of the srb9 defects required the presence of these two PKA sites. In addition, we have found that Srb9p was phosphorylated by PKA in vitro and in vivo. In all, our results suggest that Srb9p is a substrate for PKA, and that this phosphorylation of Srb9p modulates the in vivo activity of the Srb complex to regulate transcription of a subset of genes involved in stationary phase entry.
Download or read book The Cell Cycle written by David Owen Morgan and published by New Science Press. This book was released on 2007 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Cell Cycle: Principles of Control provides an engaging insight into the process of cell division, bringing to the student a much-needed synthesis of a subject entering a period of unprecedented growth as an understanding of the molecular mechanisms underlying cell division are revealed.
Download or read book Cellular Quiescence written by H. Daniel Lacorazza and published by Humana Press. This book was released on 2017-10-18 with total page 303 pages. Available in PDF, EPUB and Kindle. Book excerpt: This detailed volume explores methods and protocols that aim to increase our understanding of how cells enter a quiescent state during homeostasis and how cells exit quiescence and re-enter differentiating cell divisions to restore damaged tissues, essential for developing new approaches in regenerative medicine in the future. The chapters in this book were designed to address cellular quiescence in prokaryote and eukaryote organisms, detection of quiescence (Hoechst/pyronin Y, FUCCI, CFSE, BrdU, H2B-GFP, CyTOF), quiescence in stem cells (skin, intestinal, neuronal, hematopoietic), genomic regulation (gene expression, transcription factors, lncRNA, RNA methylation), as well as analysis of the heterogeneity of quiescence by computer modeling. Written for the highly successful Methods in Molecular Biology series, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Authoritative and practical, Cellular Quiescence: Methods and Protocols offers a broad view of basic and cutting-edge technology to inspire research in this emerging field of cell biology.
Download or read book The Plant Cell Cycle written by Dirk Inzé and published by Springer Science & Business Media. This book was released on 2011-06-27 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years, the study of the plant cell cycle has become of major interest, not only to scientists working on cell division sensu strictu , but also to scientists dealing with plant hormones, development and environmental effects on growth. The book The Plant Cell Cycle is a very timely contribution to this exploding field. Outstanding contributors reviewed, not only knowledge on the most important classes of cell cycle regulators, but also summarized the various processes in which cell cycle control plays a pivotal role. The central role of the cell cycle makes this book an absolute must for plant molecular biologists.
