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1. Saccharomyces cerevisiae CellWall Remodeling in the Absence of Knr4 and Kre6 Revealed by Nano-FourierTransform Infrared Spectroscopy

Author

Bakir, Gorkem, Dahms, Tanya ES, Martin-Yken, Helene, Bechtel, Hans A, and Gough, Kathleen M

Subjects
Biochemistry and Cell Biology, Biological Sciences, beta-Glucans, Cell Wall, Chitin, Glucans, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Spectroscopy, Fourier Transform Infrared, ATR, Cell wall integrity, attenuated total reflection, chitin, far-field infrared spectroscopy, glucan, knr4Δ, kre6Δ, mannan, synchrotron infrared nanospectroscopy, Analytical Chemistry, Physical Chemistry (incl. Structural), Mechanical Engineering
Abstract

The cell wall integrity (CWI) signaling pathway regulates yeast cell wall biosynthesis, cell division, and responses to external stress. The cell wall, comprised of a dense network of chitin, β-1,3- and β-1,6- glucans, and mannoproteins, is very thin,

Published
2024

7. Yeast-Based Biosensors: Current Applications and New Developments

Author

Martin-yken, Helene and Martin-yken, Helene

Abstract

Biosensors are regarded as a powerful tool to detect and monitor environmental contaminants, toxins, and, more generally, organic or chemical markers of potential threats to human health. They are basically composed of a sensor part made up of either live cells or biological active molecules coupled to a transducer/reporter technological element. Whole-cells biosensors may be based on animal tissues, bacteria, or eukaryotic microorganisms such as yeasts and microalgae. Although very resistant to adverse environmental conditions, yeasts can sense and respond to a wide variety of stimuli. As eukaryotes, they also constitute excellent cellular models to detect chemicals and organic contaminants that are harmful to animals. For these reasons, combined with their ease of culture and genetic modification, yeasts have been commonly used as biological elements of biosensors since the 1970s. This review aims first at giving a survey on the different types of yeast-based biosensors developed for the environmental and medical domains. We then present the technological developments currently undertaken by academic and corporate scientists to further drive yeasts biosensors into a new era where the biological element is optimized in a tailor-made fashion by in silico design and where the output signals can be recorded or followed on a smartphone.

Published
2020
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11. Development of new biosensors to detect ciguatoxins

Author

Yken, Helene, Derick, Sylvain, Gironde, Camille, Darius, Hélène Taiana, Furger, Christophe, Laurent, Dominique, François, Jean-Marie, Chinain, Mireille, ProdInra, Archive Ouverte, Priority environmental contaminants in seafood: safety assessment, impact and public perception - 311820 - INCOMING, Laboratoire d'Ingénierie des Systèmes Biologiques et des Procédés (LISBP), Institut National de la Recherche Agronomique (INRA)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées (INSA)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Équipe Micro et nanosystèmes HyperFréquences Fluidiques (LAAS-MH2F), Laboratoire d'analyse et d'architecture des systèmes (LAAS), Université Toulouse Capitole (UT Capitole), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées (INSA)-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse Capitole (UT Capitole), Université Fédérale Toulouse Midi-Pyrénées, LED Engineering Development, Institut Louis Malardé [Papeete] (ILM), Institut de Recherche pour le Développement (IRD), Pharmacochimie et Biologie pour le Développement (PHARMA-DEV), Institut de Recherche pour le Développement (IRD)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), 'OcéaSafe', PEPs CNRS, 2016., European Project: 311820, Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), LAAS-2I, Institut National Polytechnique (Toulouse) (Toulouse INP), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse 1 Capitole (UT1)-Université Toulouse - Jean Jaurès (UT2J)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse 1 Capitole (UT1)-Université Toulouse - Jean Jaurès (UT2J), Méiose et reproduction : génétique moléculaire, physiologie, pathologies, applications (MRGMPPA), Institut National de la Recherche Agronomique (INRA)-Université Paris-Sud - Paris 11 (UP11)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Institut de Recherche pour le Développement (IRD [Polynésie]), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National de la Recherche Agronomique (INRA), Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Institut de Recherche pour le Développement (IRD), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT), Institut de Recherche pour le Développement (IRD)-Institut de Chimie de Toulouse (ICT), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), and Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3)

Subjects
[SDV.BIO]Life Sciences [q-bio]/Biotechnology, [SPI.GPROC] Engineering Sciences [physics]/Chemical and Process Engineering, [SDV]Life Sciences [q-bio], [SDE.MCG]Environmental Sciences/Global Changes, sensory neuron, Biotechnologies, yeast, brewer s, Ciguatoxins, intoxication, saccharomyces cerevisiae, [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering, 14. Life underwater, biosenseur, Génie des procédés, micro-algue, CIguatera, biosensors, [SDV.BIO] Life Sciences [q-bio]/Biotechnology, poisoning, Detection, Process Engineering, environment, marine toxins, [SDV.TOX]Life Sciences [q-bio]/Toxicology, [SDE]Environmental Sciences, fruit de mer, neurone sensoriel, [SDV.AEN]Life Sciences [q-bio]/Food and Nutrition
Abstract

International audience; Ciguatoxins are lipid-soluble polyether compounds produced by dinoflagellates from the genus Gambierdiscus spp.. Ciguatoxins are mostly found in tropical and subtropical zones; however, within the last decade, they have been identified in fishes caught in European waters, notably in Madeira (1) and Canary Islands (2), while Gambierdiscus spp. have also been found both in the NE Atlantic Ocean (3) and in the Mediterranean Sea (4). These toxins bind to Voltage Gated Sodium Channels at the surface of human sensory neurons where they remain, causing Ciguatera Fish Poisoning with a variety of gastrointestinal, cardiovascular and neurological symptoms (paresthesia, ataxia, cold allodynia), including persistent neurological effects. Ciguatera is the major cause of food poisonings by seafood worldwide, with an estimated 50 000 to 500 000 victims per year. However, there is so far no simple and quick way of detecting these toxins in contaminated samples. Currently, only heavy and expensive laboratory methods are available to detect them: LC-MS/MS, receptor-binding assays by competition with radiolabeled compounds, and neuroblastoma cell-based assays performed on mammalian neurons (5). We have started to engineer biosensors based on the detection of a transcriptional signal in the yeast model Saccharomyces cerevisiae. This unicellular eukaryotic model is well-known and easy to genetically modify, grows fast and presents a very good conservation of signaling pathways with higher eukaryotes. We present a series of genetically modified yeast strains which allow us to follow the activation of specific signaling pathways responding linearly to ciguatoxin exposure. This pre-exploratory project received a seed-funding by CNRS (PEPs project, Océasafe). References : 1 Otero et al., Anal. Chem. 2010, 82, 6032 2 Nuñez et al., 2012. Euro Surveill. 17, 20188 3 Fraga et Rodriguez, 2014 Protist 165, 839 4 Aligizaki et Nikolaidis, 2008. J. Biol. Res. Thessalon 9, 75. 5 Caillaud et al., 2010 Mar. Drugs. 8, 1838

Published
2017
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12. Stress, Drug Resistance, Adhesion: the dark side of the wall

Author

Yken, Helene, Formosa-Dague, Cécile, Schiavone, Marion, Dague, Etienne, Laboratoire d'Ingénierie des Systèmes Biologiques et des Procédés (LISBP), Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National de la Recherche Agronomique (INRA), Équipe Ingénierie pour les sciences du vivant (LAAS-ELIA), Laboratoire d'analyse et d'architecture des systèmes (LAAS), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse 1 Capitole (UT1)-Université Toulouse - Jean Jaurès (UT2J)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse 1 Capitole (UT1)-Université Toulouse - Jean Jaurès (UT2J), Institut National de la Recherche Agronomique (INRA)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées, Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université Toulouse Capitole (UT Capitole), and Université de Toulouse (UT)

Subjects
réaction au stress, drug resistance, [SDV.BIO]Life Sciences [q-bio]/Biotechnology, yeasts, drogue, brewer s, yeast, adhesion, stress, architecture moléculaire, narcotics, élasticité, cell wall, saccharomyces cerevisiae, elasticity, candida albicans, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, paroi cellulaire, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2016

14. Combining Atomic Force Microscopy and genetics to investigate the role of Knr4 in Saccharomyces cerevisiae sensitivity to K9 Killer toxin

Author

Yken, Helene, Liu, Ran, Formosa-Dague, Cécile, Schiavone, Marion, DAGUE, Etienne, François, Jean-Marie, Timmers Dagkessamanskaya, Adilya, Laboratoire d'Ingénierie des Systèmes Biologiques et des Procédés (LISBP), Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National de la Recherche Agronomique (INRA), Équipe NanoBioSystèmes (LAAS-NBS), Laboratoire d'analyse et d'architecture des systèmes (LAAS), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse 1 Capitole (UT1)-Université Toulouse - Jean Jaurès (UT2J)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse 1 Capitole (UT1)-Université Toulouse - Jean Jaurès (UT2J), Institut National de la Recherche Agronomique (INRA)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse 1 Capitole (UT1), and Université Fédérale Toulouse Midi-Pyrénées

Subjects
[SDV.OT]Life Sciences [q-bio]/Other [q-bio.OT]
Abstract

International audience; K9 killer toxin is a small peptide secreted by the yeaststrong cytocidal activity against sensitive yeast strains, includingformation of pores at the surface of the cells, and more specifically at places where cell wall synthesis is the most active,tip of growing buds or mating projections. Yeast cells treated withese pores. In the yeast S. cerevisiae, KNR4 protein localizes at the sites of polarized growth (bud tips, shmoo tips), which are also thesites where the toxin forms pores in the cell wall. Mutants defective inanalyzed for the first time the biophysical effects of K9 on the yeast cell wall using Atomic Force Microscopy (AFM),technology that allows measuring the nanomechanicalwe measured the effects of K9 toxin on the nanomechanical properties of the cell wall ofdeleted for KNR4 gene, at the short (2 h) and long term (20 h).type cells already after 2 hours and only visible inprotein in the cells sensitivity towards the toxin.which is required for its correct cellular localization at the bud tip during cell cycle, is essential for the toxin Kaddition, a series of deletion mutants from the YKO collection in which the Knr4 cellular localization is also lost display asensitivity to the K9 toxin. Taken together, these results shed light on the importance of theintensive cell wall growth for the wild-type cells sensitivity to K9 killer toxin.

Published
2015

15. Evidence for a Role for the Plasma Membrane in the Nanomechanical Properties of the Cell Wall as Revealed by an Atomic Force Microscopy Study of the Response of Saccharomyces cerevisiae to Ethanol Stress

Author

Schiavone, Marion, primary, Formosa-Dague, Cécile, additional, Elsztein, Carolina, additional, Teste, Marie-Ange, additional, Martin-Yken, Helene, additional, De Morais, Marcos A., additional, Dague, Etienne, additional, and François, Jean M., additional

Published
2016
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21. Structure-function analysis of Knr4/Smi1, a newly member of intrinsically disordered proteins family, indispensable in the absence of a functional PKC1-SLT2 pathway in Saccharomyces cerevisiae.

Author

Durand, Fabien, Dagkessamanskaia, Adilia, Martin-Yken, Helene, Graille, Marc, Van Tilbeurgh, Herman, Uversky, Vladimir N., and François, Jean M.

Abstract

The coordination between cell wall synthesis and cell growth in the yeast Saccharomyces cerevisiae implicates the PKC1-dependent MAP kinase pathway. KNR4, encoding a 505 amino acid long protein, participates in this coordination, since it displays synthetic lethality with all the members of the PKC1 pathway and shows physical interaction with Slt2/Mpk1. The recent finding that KNR4 interacts genetically or physically with more than 100 partners implicated in different cellular processes raised the question of how these interactions may occur and their physiological significance. This called for an in-depth structure-function analysis of the Knr4 protein, which is reported in the present paper. Computational analysis supported by biochemical and biophysical data characterize Knr4 as a newly identified member of the growing family of intrinsically disordered proteins. Despite disordered regions that are located at the N- and C-termini and are probably responsible for fine regulatory function; this protein contains a structured central core (amino acid residues 80-340) that is able to restore wild-type phenotypes of knr4Δ mutant in stress conditions. However, this fragment was unable to complement synthetic lethality between knr4 mutations and deletions of genes encoding protein kinases of the PKC1-dependent pathway. For these crucial events to occur, the presence of the N-terminal part of Knr4 protein is indispensable. Moreover, we demonstrate that this protein is essential for cell viability in the absence of a functional Pkc1-Slt2 pathway, since the lethality caused by KNR4 deletion in such a genetic background could not be compensated by overexpression of any gene from yeast genomic libraries. Copyright © 2008 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Published
2008
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23. <TOGGLE>Saccharomyces cerevisiae YCRO17c/CWH43</TOGGLE> encodes a putative sensor/transporter protein upstream of the <TOGGLE>BCK2</TOGGLE> branch of the PKC1-dependent cell wall integrity pathway

Author

Martin-Yken, Helene, Dagkessamanskaia, Adilia, Groot, Piet De, Ram, Arthur, Klis, Frans, and François, Jean

Abstract

The Saccharomyces cerevisiae cwh43-2 mutant, originally isolated for its Calcofluor white hypersensitivity, displays several cell wall defects similar to mutants in the PKC1–MPK1 pathway, including a growth defect and increased release of β-1,6-glucan and β-glucosylated proteins into the growth medium at increased temperatures. The cloning of CWH43 showed that it corresponds to YCR017c and encodes a protein with 14–16 transmembrane segments containing several putative phosphorylation and glycosylation sites. The N-terminal part of the amino acid sequence of Cwh43p shows 40% similarity with the mammalian FRAG1, a membrane protein that activates the fibroblast growth factor receptor of rat osteosarcoma (FGFR2-ROS) and with protein sequences of four uncharacterized ORFs from Caenorhabditis elegans and one from Drosophila melanogaster. The C-terminus of Cwh43p shows low similarities with a xylose permease of Bacillus megaterium and with putative sugar transporter from D. melanogaster, and has 52% similarity with a protein sequence from a Schizosaccharomyces pombe cDNA. A Cwh43–GFP fusion protein suggested a plasma membrane localization, although localization to the internal structure of the cells could not be excluded, and it concentrates to the bud tip of small budded cells and to the neck of dividing cells. Deletion of CWH43 resulted in cell wall defects less pronounced than those of the cwh43-2 mutant. This allele-specific phenotype appears to be due to a G–R substitution at position 57 in a highly conserved region of the protein. Genetic analysis places CWH43 upstream of the BCK2 branch of the PKC1 signalling pathway, since cwh43 mutations were synthetic lethal with pkc1 deletion, whereas the cwh43 defects could be rescued by overexpression of BCK2 and not by high-copy-number expression of genes encoding downstream proteins of the PKC1 pathway However, unlike BCK2, whose disruption in a cln3 mutant resulted in growth arrest in G1, no growth defect was observed in a double cwh43 cln3 mutants. Taken together, it is proposed that CWH43 encodes a protein with putative sensor and transporter domains acting in parallel to the main PKC1-dependent cell wall integrity pathway, and that this gene has evolved into two distinct genes in higher eukaryotes. Copyright © 2001 John Wiley & Sons, Ltd.

Published
2001

24. Saccharomyces cerevisiae YCRO17c/CWH43encodes a putative sensor/transporter protein upstream of the BCK2branch of the PKC1‐dependent cell wall integrity pathway

Author

Martin‐Yken, Helene, Dagkessamanskaia, Adilia, De Groot, Piet, Ram, Arthur, Klis, Frans, and François, Jean

Abstract

The Saccharomyces cerevisiae cwh43‐2mutant, originally isolated for its Calcofluor white hypersensitivity, displays several cell wall defects similar to mutants in the PKC1–MPK1 pathway, including a growth defect and increased release of β‐1,6‐glucan and β‐glucosylated proteins into the growth medium at increased temperatures. The cloning of CWH43showed that it corresponds to YCR017c and encodes a protein with 14–16 transmembrane segments containing several putative phosphorylation and glycosylation sites. The N‐terminal part of the amino acid sequence of Cwh43p shows 40% similarity with the mammalian FRAG1, a membrane protein that activates the fibroblast growth factor receptor of rat osteosarcoma (FGFR2‐ROS) and with protein sequences of four uncharacterized ORFs from Caenorhabditis elegansand one from Drosophila melanogaster. The C‐terminus of Cwh43p shows low similarities with a xylose permease of Bacillus megateriumand with putative sugar transporter from D. melanogaster, and has 52% similarity with a protein sequence from a Schizosaccharomyces pombecDNA. A Cwh43–GFP fusion protein suggested a plasma membrane localization, although localization to the internal structure of the cells could not be excluded, and it concentrates to the bud tip of small budded cells and to the neck of dividing cells. Deletion of CWH43resulted in cell wall defects less pronounced than those of the cwh43‐2mutant. This allele‐specific phenotype appears to be due to a G–R substitution at position 57 in a highly conserved region of the protein. Genetic analysis places CWH43upstream of the BCK2branch of the PKC1 signalling pathway, since cwh43mutations were synthetic lethal with pkc1deletion, whereas the cwh43defects could be rescued by overexpression of BCK2and not by high‐copy‐number expression of genes encoding downstream proteins of the PKC1pathway However, unlike BCK2, whose disruption in a cln3mutant resulted in growth arrest in G1, no growth defect was observed in a double cwh43 cln3mutants. Taken together, it is proposed that CWH43encodes a protein with putative sensor and transporter domains acting in parallel to the main PKC1‐dependent cell wall integrity pathway, and that this gene has evolved into two distinct genes in higher eukaryotes. Copyright © 2001 John Wiley & Sons, Ltd.

Published
2001
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25. Interaction of Knr4 protein, a protein involved in cell wall synthesis, with tyrosine tRNA synthetase encoded by TYS1in Saccharomyces cerevisiae

Author

Dagkessamanskaia, Adilia, Martin‐Yken, Helene, Basmaji, Fadi, Briza, Peter, and Francois, Jean

Abstract

The Knr4 protein, known to be involved in the regulation of cell wall assembly in Saccharomyces cerevisiae, strongly interacts with the tyrosine tRNA synthetase protein encoded by TYS1as demonstrated by the genetic two‐hybrid system and a biochemical pull‐down experiment using GST–Tys1p fusion. Data reported here raise the possibility that this physical interaction between these proteins is required for dityrosine formation during the sporulation process. In addition, it is shown that the efficiency of spores formation was drastically reduced in diploid cells homozygous for the disruption of KNR4or for a temperature‐sensitive mutation of TYS1, although this effect could be independent of their protein interaction. Altogether, these data provide novel functions of Knr4p and Tys1p to those that were known before.

Published
2001
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26. Interaction of Knr4 protein, a protein involved in cell wall synthesis, with tyrosine tRNA synthetase encoded by TYS1 in Saccharomyces cerevisiae

Author

Dagkessamanskaia, Adilia, Martin-Yken, Helene, Basmaji, Fadi, Briza, Peter, and Francois, Jean

Abstract

The Knr4 protein, known to be involved in the regulation of cell wall assembly in Saccharomyces cerevisiae, strongly interacts with the tyrosine tRNA synthetase protein encoded by TYS1 as demonstrated by the genetic two-hybrid system and a biochemical pull-down experiment using GST–Tys1p fusion. Data reported here raise the possibility that this physical interaction between these proteins is required for dityrosine formation during the sporulation process. In addition, it is shown that the efficiency of spores formation was drastically reduced in diploid cells homozygous for the disruption of KNR4 or for a temperature-sensitive mutation of TYS1, although this effect could be independent of their protein interaction. Altogether, these data provide novel functions of Knr4p and Tys1p to those that were known before.

Published
2001
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27. Combining atomic force microscopy and genetics to investigate the role of KNR4 inSaccharomyces Cerevisiae sensitivity to K9 killer toxin

Author

Ran Liu, Cécile Formosa-Dague, Adilia Dagkessamanskaia, Etienne Dague, Jean Marie François, Hélène Martin-Yken, Laboratoire d'Ingénierie des Systèmes Biologiques et des Procédés (LISBP), Institut National de la Recherche Agronomique (INRA)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Équipe NanoBioSystèmes (LAAS-NBS), Laboratoire d'analyse et d'architecture des systèmes (LAAS), Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT), Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National de la Recherche Agronomique (INRA), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse 1 Capitole (UT1)-Université Toulouse - Jean Jaurès (UT2J)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse 1 Capitole (UT1)-Université Toulouse - Jean Jaurès (UT2J), Yken, Helene, Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse 1 Capitole (UT1), and Université Fédérale Toulouse Midi-Pyrénées

Subjects
[SDV.MP]Life Sciences [q-bio]/Microbiology and Parasitology, MESH: K9 killer toxin, Saccharomyces cerevisiae, KNR4 gene deletion, Atomic Force Microscopy, Autre (Sciences du Vivant)
Abstract

International audience; K9 killer toxin is a small peptide secreted by the yeast Williopsis saturnus var: mrakii (previously known as Hansenula mrakii) with a strong cytocidal activity against sensitive yeast strains, including Saccharomyces cerevisiae. Treatment with this toxin results in the formation of pores at the surface of the cells, and more specifically at places where cell wall synthesis is the most active, namely at the tip of growing buds or mating projections. Yeast cells treated with K9 toxin then die by releasing cytoplasm and cellular materials from these pores. In the yeast S. cerevisiae, KNR4 protein localizes at the sites of polarized growth (bud tips, shmoo tips), which are also the sites where the toxin forms pores in the cell wall. Mutants defective in KNR4 gene are remarkably resistant to this toxin. In this study, we analyzed for the first time the biophysical effects of K9 on the yeast cell wall using Atomic Force Microscopy (AFM), a cutting edge technology that allows measuring the nanomechanical properties of living yeast cells, and their alterations by various drugs. To this end, we measured the effects of K9 toxin on the nanomechanical properties of the cell wall of S. cerevisiae wild-type cells and mutants deleted for KNR4 gene, at the short (2 h) and long term (20 h). Our results reveal an important cell wall remodeling occurring in wild- type cells already after 2 hours and only visible in knr4 mutant after 20 hours of treatment. Moreover, we investigated the role of Knr4 protein in the cells sensitivity towards the toxin. We were able to show that the presence of the N-terminal domain of Knr4 protein, which is required for its correct cellular localization at the bud tip during cell cycle, is essential for the toxin K9 wild-type sensitivity. In addition, a series of deletion mutants from the YKO collection in which the Knr4 cellular localization is also lost display a reduced sensitivity to the K9 toxin. Taken together, these results shed light on the importance of the proper localization of Knr4 protein at sites of intensive cell wall growth for the wild-type cells sensitivity to K9 killer toxin.

Published
2015

28. Cell Wall Remodeling Enzymes Modulate Fungal Cell Wall Elasticity and Osmotic Stress Resistance

Author

Louise A. Walker, Marion Schiavone, Alistair J. P. Brown, Hélène Martin-Yken, Iuliana V. Ene, Etienne Dague, Neil A. R. Gow, Keunsook K. Lee, Carol A. Munro, School of Medical Sciences, University of Aberdeen, Laboratoire d'Ingénierie des Systèmes Biologiques et des Procédés (LISBP), Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National de la Recherche Agronomique (INRA), Équipe NanoBioSystèmes (LAAS-NBS), Laboratoire d'analyse et d'architecture des systèmes (LAAS), Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées, UK Biotechnology and Biological Research Council (BB/F00513X/1, BB/K017365/1), the UK Medical Research Council (G0400284), the Wellcome Trust (080088, 088858/Z/09/Z 097377, 101873). ANR (AFMYST project ANR-11-JSV5-001-01 n° SD 30024331), ANR-11-JSV5-0001,AFMYST,Etude Biophysique, biochimique et biomoléculaire de la paroi des levures.(2011), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse 1 Capitole (UT1)-Université Toulouse - Jean Jaurès (UT2J)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse 1 Capitole (UT1)-Université Toulouse - Jean Jaurès (UT2J), School of Medical Sciences - Institute of Medical Sciences, Laboratoire d'Ingénierie des Systèmes Biologiques et des Procédés ( LISBP ), Institut National de la Recherche Agronomique ( INRA ) -Institut National des Sciences Appliquées - Toulouse ( INSA Toulouse ), Institut National des Sciences Appliquées ( INSA ) -Institut National des Sciences Appliquées ( INSA ) -Centre National de la Recherche Scientifique ( CNRS ), Équipe NanoBioSystèmes ( LAAS-NBS ), Laboratoire d'analyse et d'architecture des systèmes [Toulouse] ( LAAS ), Centre National de la Recherche Scientifique ( CNRS ) -Université Toulouse III - Paul Sabatier ( UPS ), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse ( INSA Toulouse ), Institut National des Sciences Appliquées ( INSA ) -Institut National des Sciences Appliquées ( INSA ) -Institut National Polytechnique [Toulouse] ( INP ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Toulouse III - Paul Sabatier ( UPS ), Institut National des Sciences Appliquées ( INSA ) -Institut National des Sciences Appliquées ( INSA ) -Institut National Polytechnique [Toulouse] ( INP ), Institut National Polytechnique [Toulouse] ( INP ) -Institut National des Sciences Appliquées - Toulouse ( INSA Toulouse ), Institut National des Sciences Appliquées ( INSA ) -Institut National des Sciences Appliquées ( INSA ) -Université Paul Sabatier - Toulouse 3 ( UPS ) -Centre National de la Recherche Scientifique ( CNRS ) -Institut National Polytechnique [Toulouse] ( INP ) -Institut National des Sciences Appliquées - Toulouse ( INSA Toulouse ), Institut National des Sciences Appliquées ( INSA ) -Institut National des Sciences Appliquées ( INSA ) -Université Paul Sabatier - Toulouse 3 ( UPS ) -Centre National de la Recherche Scientifique ( CNRS ), Martin-Yken, Helene, Brown, Alistair J. P., Institut National de la Recherche Agronomique (INRA)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université Toulouse Capitole (UT Capitole), and Université de Toulouse (UT)

Subjects
MAPK/ERK pathway, Programmed cell death, Osmotic shock, Mycology, Biology, Cell morphology, Microbiology, Cell wall, 03 medical and health sciences, Cell Wall, Osmotic Pressure, Virology, Candida albicans, medicine, Lactic Acid, Protein kinase A, [ SDV.MP.MYC ] Life Sciences [q-bio]/Microbiology and Parasitology/Mycology, [SDV.MP.MYC]Life Sciences [q-bio]/Microbiology and Parasitology/Mycology, 030304 developmental biology, 0303 health sciences, Osmotic concentration, 030306 microbiology, Elasticity, QR1-502, Culture Media, Enzymes, Cell biology, Mycologie, Glucose, Biochemistry, Shock (circulatory), medicine.symptom, Research Article
Abstract

The fungal cell wall confers cell morphology and protection against environmental insults. For fungal pathogens, the cell wall is a key immunological modulator and an ideal therapeutic target. Yeast cell walls possess an inner matrix of interlinked β-glucan and chitin that is thought to provide tensile strength and rigidity. Yeast cells remodel their walls over time in response to environmental change, a process controlled by evolutionarily conserved stress (Hog1) and cell integrity (Mkc1, Cek1) signaling pathways. These mitogen-activated protein kinase (MAPK) pathways modulate cell wall gene expression, leading to the construction of a new, modified cell wall. We show that the cell wall is not rigid but elastic, displaying rapid structural realignments that impact survival following osmotic shock. Lactate-grown Candida albicans cells are more resistant to hyperosmotic shock than glucose-grown cells. We show that this elevated resistance is not dependent on Hog1 or Mkc1 signaling and that most cell death occurs within 10 min of osmotic shock. Sudden decreases in cell volume drive rapid increases in cell wall thickness. The elevated stress resistance of lactate-grown cells correlates with reduced cell wall elasticity, reflected in slower changes in cell volume following hyperosmotic shock. The cell wall elasticity of lactate-grown cells is increased by a triple mutation that inactivates the Crh family of cell wall cross-linking enzymes, leading to increased sensitivity to hyperosmotic shock. Overexpressing Crh family members in glucose-grown cells reduces cell wall elasticity, providing partial protection against hyperosmotic shock. These changes correlate with structural realignment of the cell wall and with the ability of cells to withstand osmotic shock., IMPORTANCE The C. albicans cell wall is the first line of defense against external insults, the site of immune recognition by the host, and an attractive target for antifungal therapy. Its tensile strength is conferred by a network of cell wall polysaccharides, which are remodeled in response to growth conditions and environmental stress. However, little is known about how cell wall elasticity is regulated and how it affects adaptation to stresses such as sudden changes in osmolarity. We show that elasticity is critical for survival under conditions of osmotic shock, before stress signaling pathways have time to induce gene expression and drive glycerol accumulation. Critical cell wall remodeling enzymes control cell wall flexibility, and its regulation is strongly dependent on host nutritional inputs. We also demonstrate an entirely new level of cell wall dynamism, where significant architectural changes and structural realignment occur within seconds of an osmotic shock.

Published
2015
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