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Liu JJ, Hou YK, Wang X, Zhou XT, Yin JY, Nie SP. Recent advances in the biosynthesis of fungal glucan structural diversity. Carbohydr Polym 2024; 329:121782. [PMID: 38286552 DOI: 10.1016/j.carbpol.2024.121782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 12/31/2023] [Accepted: 01/02/2024] [Indexed: 01/31/2024]
Abstract
Glucans are the most abundant class of macromolecule polymers in fungi, which are commonly found in Ascomycota and Basidiomycota. Fungal glucans are not only essential for cell integrity and function but also crucial for the immense industrial interest in high value applications. They present a variety of structural characteristics at the nanoscale due to the high regulation of genes and the involvement of stochastic processes in synthesis. However, although recent findings have demonstrated the genes of glucans synthesis are relatively conserved across diverse fungi, the formation and organization of diverse glucan structures is still unclear in fungi. Here, we summarize the structural features of fungal glucans and the recent developments in the mechanisms of glucans biosynthesis. Furthermore, we propose the engineering strategies of targeted glucan synthesis and point out the remaining challenges in the synthetic process. Understanding the synthesis process of diverse glucans is necessary for tailoring high value glucan towards specific applications. This engineering strategy contributes to enable the sustainable and efficient production of glucan diversity.
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Affiliation(s)
- Jin-Jin Liu
- State Key Laboratory of Food Science and Resources, China-Canada Joint Lab of Food Science and Technology (Nanchang), Nanchang University, Nanchang, Jiangxi Province 330047, China
| | - Yu-Ke Hou
- State Key Laboratory of Food Science and Resources, China-Canada Joint Lab of Food Science and Technology (Nanchang), Nanchang University, Nanchang, Jiangxi Province 330047, China
| | - Xin Wang
- State Key Laboratory of Food Science and Resources, China-Canada Joint Lab of Food Science and Technology (Nanchang), Nanchang University, Nanchang, Jiangxi Province 330047, China
| | - Xing-Tao Zhou
- State Key Laboratory of Food Science and Resources, China-Canada Joint Lab of Food Science and Technology (Nanchang), Nanchang University, Nanchang, Jiangxi Province 330047, China
| | - Jun-Yi Yin
- State Key Laboratory of Food Science and Resources, China-Canada Joint Lab of Food Science and Technology (Nanchang), Nanchang University, Nanchang, Jiangxi Province 330047, China.
| | - Shao-Ping Nie
- State Key Laboratory of Food Science and Resources, China-Canada Joint Lab of Food Science and Technology (Nanchang), Nanchang University, Nanchang, Jiangxi Province 330047, China; Food Laboratory of Zhongyuan, Luo he 462300, Henan, China.
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2
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Bakir G, Dahms TES, Martin-Yken H, Bechtel HA, Gough KM. Saccharomyces cerevisiae CellWall Remodeling in the Absence of Knr4 and Kre6 Revealed by Nano-FourierTransform Infrared Spectroscopy. APPLIED SPECTROSCOPY 2024; 78:355-364. [PMID: 38378014 PMCID: PMC10935619 DOI: 10.1177/00037028231213658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 09/17/2023] [Indexed: 02/22/2024]
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, <100 nm. Alterations in cell wall composition may activate the CWI pathway. Saccharomyces cerevisiae, a model yeast, was used to study the role of individual wall components in altering the structure and biophysical properties of the yeast cell wall. Near-field Fourier transform infrared spectroscopy (nano-FT-IR) was used for the first direct, spectrochemical identification of cell wall composition in a background (wild-type) strain and two deletion mutants from the yeast knock-out collection: kre6Δ and knr4Δ. Killer toxin resistant 6 (Kre6) is an integral membrane protein required for biosynthesis of β-1,6-glucan, while Knr4 is a cell signaling protein involved in the control of cell wall biosynthesis, in particular, biosynthesis and deposition of chitin. Complementary spectral data were obtained with far-field (FF)-FT-IR, in transmission, and with attenuated total reflectance (ATR) spectromicroscopy with 3-10 μm wavelength-dependent spatial resolution. The FF-FT-IR spectra of cells and spectra of isolated cell wall components showed that components of the cell body dominated transmission spectra and were still evident in ATR spectra. In contrast, the nano-FT-IR at ∼25 nm spatial resolution could be used to characterize the yeast wall chemical structure. Our results show that the β-1,6-glucan content is decreased in kre6Δ, while all glucan content is decreased in the knr4Δ cell wall. The latter may be thinner than in wild type, since not only are mannan and chitin detectable by nano-FT-IR, but also lipid membranes and protein, indicative of cell interior.
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Affiliation(s)
- Gorkem Bakir
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Tanya E. S. Dahms
- Department of Chemistry and Biochemistry, University of Regina, Regina, Saskatchewan, Canada
| | - Helene Martin-Yken
- TBI, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
- LAAS–CNRS, Université de Toulouse, Toulouse, France
| | - Hans A. Bechtel
- Advanced Light Source Division, Lawrence Berkeley National Lab, Berkeley, California, USA
| | - Kathleen M. Gough
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada
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3
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Oliveira LT, Marcos CM, Cabral AKLF, Medina-Alarcón KP, Pires RH, Fusco-Almeida AM, Mendes-Giannini MJS. Paracoccidioides spp.: the structural characterization of extracellular matrix, expression of glucan synthesis and associated genes and adhesins during biofilm formation. Front Microbiol 2024; 15:1354140. [PMID: 38516014 PMCID: PMC10955377 DOI: 10.3389/fmicb.2024.1354140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 02/19/2024] [Indexed: 03/23/2024] Open
Abstract
The genus Paracoccidioides includes Paracoccidioides lutzii and the Paracoccidioides brasiliensis complex, which comprises four phylogenetic species. A key feature distinguishing planktonic growth from biofilm is the presence of a 3D extracellular matrix (ECM). Therefore, in this study, we analyzed biofilm formation in different species of Paracoccidioides yeast phase, characterized the structural elements of the matrix of P. brasiliensis (Pb18), P. lutzii (Pl01 and 8334) and P. restrepiensis (339 and 192) and evaluated the expression of glucan genes, according to the stage of biofilm evolution for P. brasiliensis. The strains were cultivated in planktonic and biofilm form for 24-144 h. The fungi biomass and metabolic activity were determined by crystal violet and tetrazolium salt reduction (XTT) tests and colony-forming unit (CFU) by plating. The biofilm structure was designed using scanning electron microscopy and confocal laser scanning microscopy techniques. The extracellular matrix of P. brasiliensis and P. lutzii biofilms was extracted by sonication, and polysaccharides, proteins, and extracellular DNA (eDNA) were quantified. The RNA was extracted with the Trizol® reagent and quantified; then, the cDNA was synthesized to analyze the enolase expression, 14-3-3, FKS1, AGS1, GEL3, and KRE6 genes by real-time PCR. All strains of Paracoccidioides studied form a biofilm with more significant metabolic activity and biomass values in 144 h. The extracellular matrix of P. brasiliensis and P. lutzii had a higher content of polysaccharides in their composition, followed by proteins and eDNA in smaller quantities. The P. brasiliensis biofilm kinetics of formation showed greater expression of genes related to glucan's synthesis and its delivery to the external environment in addition adhesins during the biofilm's adhesion, initiation, and maturation. The GEL3 and enolase genes increased in expression within 24 h and during the biofilm maturation period, there was an increase in 14-3-3, AGS1, and FKS1. Furthermore, at 144 h, there was a decrease in KRE6 expression and an increase in GEL3. This study highlights the potential for biofilm formation for three species of Paracoccidioides and the main components of the extracellular matrix that can contribute to a better understanding of biofilm organization.
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Affiliation(s)
- Lariane Teodoro Oliveira
- Department of Clinical Analysis, School of Pharmaceutical Sciences, São Paulo State University (UNESP), Araraquara, Brazil
| | - Caroline Maria Marcos
- Department of Clinical Analysis, School of Pharmaceutical Sciences, São Paulo State University (UNESP), Araraquara, Brazil
| | - Ana Karla Lima Freire Cabral
- Department of Clinical Analysis, School of Pharmaceutical Sciences, São Paulo State University (UNESP), Araraquara, Brazil
- Laboratory of Medical Mycology, School of Pharmaceutical Sciences, Federal University of Amazonas-UFAM, Manaus, Brazil
| | - Kaila Petronila Medina-Alarcón
- Department of Clinical Analysis, School of Pharmaceutical Sciences, São Paulo State University (UNESP), Araraquara, Brazil
| | - Regina Helena Pires
- Laboratory of Mycology and Environmental Diagnosis, University of Franca, Franca, Brazil
| | - Ana Marisa Fusco-Almeida
- Department of Clinical Analysis, School of Pharmaceutical Sciences, São Paulo State University (UNESP), Araraquara, Brazil
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4
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Kshirsagar R, Munhoven A, Tran Nguyen TM, Ehrenhofer-Murray AE. A role for β-1,6- and β-1,3-glucans in kinetochore function in Saccharomyces cerevisiae. Genetics 2024; 226:iyad195. [PMID: 37950911 DOI: 10.1093/genetics/iyad195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 10/30/2023] [Accepted: 11/01/2023] [Indexed: 11/13/2023] Open
Abstract
Chromosome segregation is crucial for the faithful inheritance of DNA to the daughter cells after DNA replication. For this, the kinetochore, a megadalton protein complex, assembles on centromeric chromatin containing the histone H3 variant CENP-A, and provides a physical connection to the microtubules. Here, we report an unanticipated role for enzymes required for β-1,6- and β-1,3-glucan biosynthesis in regulating kinetochore function in Saccharomyces cerevisiae. These carbohydrates are the major constituents of the yeast cell wall. We found that the deletion of KRE6, which encodes a glycosylhydrolase/ transglycosidase required for β-1,6-glucan synthesis, suppressed the centromeric defect of mutations in components of the kinetochore, foremost the NDC80 components Spc24, Spc25, the MIND component Nsl1, and Okp1, a constitutive centromere-associated network protein. Similarly, the absence of Fks1, a β-1,3-glucan synthase, and Kre11/Trs65, a TRAPPII component, suppressed a mutation in SPC25. Genetic analysis indicates that the reduction of intracellular β-1,6- and β-1,3-glucans, rather than the cell wall glucan content, regulates kinetochore function. Furthermore, we found a physical interaction between Kre6 and CENP-A/Cse4 in yeast, suggesting a potential function for Kre6 in glycosylating CENP-A/Cse4 or another kinetochore protein. This work shows a moonlighting function for selected cell wall synthesis proteins in regulating kinetochore assembly, which may provide a mechanism to connect the nutritional status of the cell to cell-cycle progression and chromosome segregation.
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Affiliation(s)
- Rucha Kshirsagar
- Institut für Biologie, Humboldt-Universität zu Berlin, Philippstr. 13, Rhoda-Erdmann-Haus, 10099 Berlin, Germany
| | - Arno Munhoven
- Institut für Biologie, Humboldt-Universität zu Berlin, Philippstr. 13, Rhoda-Erdmann-Haus, 10099 Berlin, Germany
| | - Tra My Tran Nguyen
- Institut für Biologie, Humboldt-Universität zu Berlin, Philippstr. 13, Rhoda-Erdmann-Haus, 10099 Berlin, Germany
| | - Ann E Ehrenhofer-Murray
- Institut für Biologie, Humboldt-Universität zu Berlin, Philippstr. 13, Rhoda-Erdmann-Haus, 10099 Berlin, Germany
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5
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Yammine M, Bray F, Flament S, Picavet A, Lacroix JM, Poilpré E, Mouly I, Rolando C. Reliable Approach for Pure Yeast Cell Wall Protein Isolation from Saccharomyces cerevisiae Yeast Cells. ACS OMEGA 2022; 7:29702-29713. [PMID: 36061670 PMCID: PMC9435031 DOI: 10.1021/acsomega.2c02176] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Saccharomyces cerevisiae yeast is a fungus presenting a peripheral organelle called the cell wall. The cell wall protects the yeast cell from stress and provides means for communication with the surrounding environment. It has a complex molecular structure, composed of an internal part of cross-linked polysaccharides and an external part of mannoproteins. These latter are very interesting owing to their functional properties, dependent on their molecular features with massive mannosylations. Therefore, the molecular characterization of mannoproteins is a must relying on the optimal isolation and preparation of the cell wall fraction. Multiple methods are well reported for yeast cell wall isolation. The most applied one consists of yeast cell lysis by mechanical disruption. However, applying this classical approach to S288C yeast cells showed considerable contamination with noncell wall proteins, mainly comprising mitochondrial proteins. Herein, we tried to further purify the yeast cell wall preparation by two means: ultracentrifugation and Triton X-100 addition. While the first strategy showed limited outcomes in mitochondrial protein removal, the second strategy showed optimal results when Triton X-100 was added at 5%, allowing the identification of more mannoproteins and significantly enriching their amounts. This promising method could be reliably implemented on the lab scale for identification of mannoproteins and molecular characterization and industrial processes for "pure" cell wall isolation.
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Affiliation(s)
- Marie Yammine
- Univ.
Lille, CNRS, USR 3290, MSAP, Miniaturisation pour la Synthèse,
l’Analyse et la Protéomique, F-59000 Lille, France
- Lesaffre
international, Research and Development department, 77 rue de Menin, F-59520 Marquette-lez-Lille, France
| | - Fabrice Bray
- Univ.
Lille, CNRS, USR 3290, MSAP, Miniaturisation pour la Synthèse,
l’Analyse et la Protéomique, F-59000 Lille, France
| | - Stéphanie Flament
- Univ.
Lille, CNRS, USR 3290, MSAP, Miniaturisation pour la Synthèse,
l’Analyse et la Protéomique, F-59000 Lille, France
| | - Antoine Picavet
- Lesaffre
international, Research and Development department, 77 rue de Menin, F-59520 Marquette-lez-Lille, France
| | - Jean-Marie Lacroix
- Univ.
Lille, CNRS, UMR 8765, UGSF, Unité de Glycobiologie Structurale
et Fonctionnelle, F-59000 Lille, France
| | - Emmanuel Poilpré
- Lesaffre
international, Research and Development department, 77 rue de Menin, F-59520 Marquette-lez-Lille, France
| | - Isabelle Mouly
- Lesaffre
international, Research and Development department, 77 rue de Menin, F-59520 Marquette-lez-Lille, France
| | - Christian Rolando
- Univ.
Lille, CNRS, USR 3290, MSAP, Miniaturisation pour la Synthèse,
l’Analyse et la Protéomique, F-59000 Lille, France
- Shrieking
sixties, 1-3 Allée
Lavoisier, F-59650 Villeneuve-d’Ascq, France
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6
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CRISPR/Cas9 disruption of glucan synthase in Nannochloropsis gaditana attenuates accumulation of β-1,3-glucose oligomers. ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102385] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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7
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Chen X, Wang Y, He CY, Wang GL, Zhang GC, Wang CL, Wang DH, Zou X, Wei GY. Improved production of β-glucan by a T-DNA-based mutant of Aureobasidium pullulans. Appl Microbiol Biotechnol 2021; 105:6887-6898. [PMID: 34448899 DOI: 10.1007/s00253-021-11538-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 08/16/2021] [Accepted: 08/21/2021] [Indexed: 11/26/2022]
Abstract
To improve β-1,3-1,6-D-glucan (β-glucan) production by Aureobasidium pullulans, an Agrobacterium tumefaciens-mediated transformation method was developed to screen a mutant A. pullulans CGMCC 19650. Based on thermal asymmetric-interlaced PCR detection, DNA sequencing, BLAST analysis, and quantitative real-time PCR assay, the T-DNA was identified to be inserted in the coding region of mal31 gene, which encodes a sugar transporter involved in pullulan biosynthesis in the mutant. The maximal biomass and β-glucan production under batch fermentation were significantly increased by 47.6% and 78.6%, respectively, while pullulan production was decreased by 41.7% in the mutant, as compared to the parental strain A. pullulans CCTCC M 2012259. Analysis of the physiological mechanism of these changes revealed that mal31 gene disruption increased the transcriptional levels of pgm2, ugp, fks1, and kre6 genes; increased the amounts of key enzymes associated with UDPG and β-glucan biosynthesis; and improved intracellular UDPG contents and energy supply, all of which favored β-glucan production. However, the T-DNA insertion decreased the transcriptional levels of ags2 genes, and reduced the biosynthetic capability to form pullulan, resulting in the decrease in pullulan production. This study not only provides an effective approach for improved β-glucan production by A. pullulans, but also presents an accurate and useful gene for metabolic engineering of the producer for efficient polysaccharide production. KEY POINTS: • A mutant A. pullulans CGMCC 19650 was screened by using the ATMT method. • The mal31 gene encoding a sugar transporter was disrupted in the mutant. • β-Glucan produced by the mutant was significantly improved.
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Affiliation(s)
- Xing Chen
- School of Biology and Basic Medical Sciences, Soochow University, 199# Ren'ai Road, Suzhou, 215123, People's Republic of China
| | - Ying Wang
- School of Biology and Basic Medical Sciences, Soochow University, 199# Ren'ai Road, Suzhou, 215123, People's Republic of China
| | - Chao-Yong He
- School of Biology and Basic Medical Sciences, Soochow University, 199# Ren'ai Road, Suzhou, 215123, People's Republic of China
| | - Guo-Liang Wang
- School of Biology and Basic Medical Sciences, Soochow University, 199# Ren'ai Road, Suzhou, 215123, People's Republic of China
| | - Gao-Chuan Zhang
- School of Biology and Basic Medical Sciences, Soochow University, 199# Ren'ai Road, Suzhou, 215123, People's Republic of China
| | - Chong-Long Wang
- School of Biology and Basic Medical Sciences, Soochow University, 199# Ren'ai Road, Suzhou, 215123, People's Republic of China
| | - Da-Hui Wang
- School of Biology and Basic Medical Sciences, Soochow University, 199# Ren'ai Road, Suzhou, 215123, People's Republic of China
| | - Xiang Zou
- College of Pharmaceutical Sciences, Southwest University, 2# TianSheng Road, Beibei, Chongqing, 400715, People's Republic of China.
| | - Gong-Yuan Wei
- School of Biology and Basic Medical Sciences, Soochow University, 199# Ren'ai Road, Suzhou, 215123, People's Republic of China.
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Wang ZA, Li LX, Doering TL. Unraveling synthesis of the cryptococcal cell wall and capsule. Glycobiology 2019; 28:719-730. [PMID: 29648596 DOI: 10.1093/glycob/cwy030] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 03/28/2018] [Indexed: 11/15/2022] Open
Abstract
Fungal pathogens cause devastating infections in millions of individuals each year, representing a huge but underappreciated burden on human health. One of these, the opportunistic fungus Cryptococcus neoformans, kills hundreds of thousands of patients annually, disproportionately affecting people in resource-limited areas. This yeast is distinguished from other pathogenic fungi by a polysaccharide capsule that is displayed on the cell surface. The capsule consists of two complex polysaccharide polymers: a mannan substituted with xylose and glucuronic acid, and a galactan with galactomannan side chains that bear variable amounts of glucuronic acid and xylose. The cell wall, with which the capsule is associated, is a matrix of alpha and beta glucans, chitin, chitosan, and mannoproteins. In this review, we focus on synthesis of the wall and capsule, both of which are critical for the ability of this microbe to cause disease and are distinct from structures found in either model yeasts or the mammals afflicted by this infection. Significant research effort over the last few decades has been applied to defining the synthetic machinery of these two structures, including nucleotide sugar metabolism and transport, glycosyltransferase activities, polysaccharide export, and assembly and association of structural elements. Discoveries in this area have elucidated fundamental biology and may lead to novel targets for antifungal therapy. In this review, we summarize the progress made in this challenging and fascinating area, and outline future research questions.
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Affiliation(s)
- Zhuo A Wang
- Department of Molecular Microbiology, Washington University School of Medicine, 660 South Euclid Avenue, Saint Louis, MO, USA
| | - Lucy X Li
- Department of Molecular Microbiology, Washington University School of Medicine, 660 South Euclid Avenue, Saint Louis, MO, USA
| | - Tamara L Doering
- Department of Molecular Microbiology, Washington University School of Medicine, 660 South Euclid Avenue, Saint Louis, MO, USA
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9
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Han Q, Wang N, Yao G, Mu C, Wang Y, Sang J. Blocking β-1,6-glucan synthesis by deleting KRE6 and SKN1 attenuates the virulence of Candida albicans. Mol Microbiol 2019; 111:604-620. [PMID: 30507002 DOI: 10.1111/mmi.14176] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/26/2018] [Indexed: 12/24/2022]
Abstract
β-1,6-glucan is an important component of the fungal cell wall. The β-1,6-glucan synthase gene KRE6 was thought to be essential in the fungal pathogen Candida albicans because it could not be deleted in previous efforts. Also, the role of its homolog SKN1 was unclear because its deletion caused no defects. Here, we report the construction and characterization of kre6Δ/Δ, skn1Δ/Δ and kre6Δ/Δ skn1Δ/Δ mutants in C. albicans. While deleting KRE6 or SKN1 had no obvious phenotypic consequence, deleting both caused slow growth, cell separation failure, cell wall abnormalities, diminished hyphal growth, poor biofilm formation and loss of virulence in mice. Furthermore, the GPI-linked cell surface proteins Hwp1 and the invasin Als3 or Ssa1 were not detected in kre6Δ/Δ skn1Δ/Δ mutant. In GMM medium, RT-qPCR and western blotting revealed a constitutive expression of KRE6 and growth conditions-associated activation of SKN1. Like many hypha-specific genes, SKN1 is repressed by Nrg1, but its activation does not involve the transcription factor Efg1. Dysregulation of SKN1 reduces C. albicans ability to damage epithelial and endothelial cells and attenuates its virulence. Given the vital role of β-1,6-glucan synthesis in C. albicans physiology and virulence, Kre6 and Skn1 are worthy targets for developing antifungal agents.
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Affiliation(s)
- Qi Han
- Key Laboratory of Cell Proliferation and Regulation Biology, College of Life Sciences, Beijing Normal University, Beijing, China
| | - Na Wang
- Key Laboratory of Cell Proliferation and Regulation Biology, College of Life Sciences, Beijing Normal University, Beijing, China
| | - Guangyin Yao
- Key Laboratory of Cell Proliferation and Regulation Biology, College of Life Sciences, Beijing Normal University, Beijing, China
| | - Chunhua Mu
- Key Laboratory of Cell Proliferation and Regulation Biology, College of Life Sciences, Beijing Normal University, Beijing, China
| | - Yue Wang
- Agency for Science, Technology and Research, Institute of Molecular and Cell Biology, Singapore, Singapore.,Depatment of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Jianli Sang
- Key Laboratory of Cell Proliferation and Regulation Biology, College of Life Sciences, Beijing Normal University, Beijing, China
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10
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Castells-Ballester J, Zatorska E, Meurer M, Neubert P, Metschies A, Knop M, Strahl S. Monitoring Protein Dynamics in Protein O-Mannosyltransferase Mutants In Vivo by Tandem Fluorescent Protein Timers. Molecules 2018; 23:E2622. [PMID: 30322079 PMCID: PMC6222916 DOI: 10.3390/molecules23102622] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 10/05/2018] [Accepted: 10/09/2018] [Indexed: 12/27/2022] Open
Abstract
For proteins entering the secretory pathway, a major factor contributing to maturation and homeostasis is glycosylation. One relevant type of protein glycosylation is O-mannosylation, which is essential and evolutionarily-conserved in fungi, animals, and humans. Our recent proteome-wide study in the eukaryotic model organism Saccharomyces cerevisiae revealed that more than 26% of all proteins entering the secretory pathway receive O-mannosyl glycans. In a first attempt to understand the impact of O-mannosylation on these proteins, we took advantage of a tandem fluorescent timer (tFT) reporter to monitor different aspects of protein dynamics. We analyzed tFT-reporter fusions of 137 unique O-mannosylated proteins, mainly of the secretory pathway and the plasma membrane, in mutants lacking the major protein O-mannosyltransferases Pmt1, Pmt2, or Pmt4. In these three pmtΔ mutants, a total of 39 individual proteins were clearly affected, and Pmt-specific substrate proteins could be identified. We observed that O-mannosylation may cause both enhanced and diminished protein abundance and/or stability when compromised, and verified our findings on the examples of Axl2-tFT and Kre6-tFT fusion proteins. The identified target proteins are a valuable resource towards unraveling the multiple functions of O-mannosylation at the molecular level.
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Affiliation(s)
| | - Ewa Zatorska
- Centre for Organismal Studies (COS), Heidelberg University, 69120 Heidelberg, Germany.
| | - Matthias Meurer
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, Heidelberg University, 69120 Heidelberg, Germany.
| | - Patrick Neubert
- Centre for Organismal Studies (COS), Heidelberg University, 69120 Heidelberg, Germany.
| | - Anke Metschies
- Centre for Organismal Studies (COS), Heidelberg University, 69120 Heidelberg, Germany.
| | - Michael Knop
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, Heidelberg University, 69120 Heidelberg, Germany.
- Deutsches Krebsforschungszentrum (DKFZ), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany.
| | - Sabine Strahl
- Centre for Organismal Studies (COS), Heidelberg University, 69120 Heidelberg, Germany.
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11
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Uchiyama H, Iwai A, Dohra H, Ohnishi T, Kato T, Park EY. The effects of gene disruption of Kre6-like proteins on the phenotype of β-glucan-producing Aureobasidium pullulans. Appl Microbiol Biotechnol 2018; 102:4467-4475. [PMID: 29600492 DOI: 10.1007/s00253-018-8947-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 03/09/2018] [Accepted: 03/14/2018] [Indexed: 11/27/2022]
Abstract
Killer toxin resistant 6 (Kre6) and its paralog, suppressor of Kre null 1 (Skn1), are thought to be involved in the biosynthesis of cell wall β-(1 → 6)-D-glucan in baker's yeast, Saccharomyces cerevisiae. The Δkre6Δskn1 mutant of S. cerevisiae and other fungi shows severe growth defects due to the failure to synthesize normal cell walls. In this study, two homologs of Kre6, namely, K6LP1 (Kre6-like protein 1) and K6LP2 (Kre6-like protein 2), were identified in Aureobasidium pullulans M-2 by draft genome analysis. The Δk6lp1, Δk6lp2, and Δk6lp1Δk6lp2 mutants were generated in order to confirm the functions of the Kre6-like proteins in A. pullulans M-2. The cell morphologies of Δk6lp1 and Δk6lp1Δk6lp2 appeared to be different from those of wild type and Δk6lp2 in both their yeast and hyphal forms. The productivity of the extracellular polysaccharides, mainly composed of β-(1 → 3),(1 → 6)-D-glucan (β-glucan), of the mutants was 5.1-17.3% less than that of wild type, and the degree of branching in the extracellular β-glucan of mutants was 14.5-16.8% lower than that of wild type. This study showed that the gene disruption of Kre6-like proteins affected the cell morphology, the productivity of extracellular polysaccharides, and the structure of extracellular β-glucan, but it did not have a definite effect on the cell viability even in Δk6lp1Δk6lp2, unlike in the Δkre6Δskn1 of S. cerevisiae.
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Affiliation(s)
- Hirofumi Uchiyama
- Laboratory of Biotechnology, Integrated Bioscience Section, Graduate School of Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529, Japan
- Aureo-Science Co., Ltd., Nishi 12-2, Kita 21-jo, Kita-ku, Sapporo, Hokkaido, 001-0021, Japan
| | - Atsushi Iwai
- Aureo-Science Co., Ltd., Nishi 12-2, Kita 21-jo, Kita-ku, Sapporo, Hokkaido, 001-0021, Japan
| | - Hideo Dohra
- Instrumental Research Support Office, Research Institute of Green Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529, Japan
| | - Toshiyuki Ohnishi
- Laboratory of Organic Chemistry of Natural Products, Green Chemistry Research Division, Research Institute of Green Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529, Japan
| | - Tatsuya Kato
- Laboratory of Biotechnology, Integrated Bioscience Section, Graduate School of Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529, Japan
- Laboratory of Biotechnology, Green Chemistry Research Division, Research Institute of Green Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529, Japan
| | - Enoch Y Park
- Laboratory of Biotechnology, Integrated Bioscience Section, Graduate School of Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529, Japan.
- Laboratory of Biotechnology, Green Chemistry Research Division, Research Institute of Green Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529, Japan.
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Pan HP, Wang N, Tachikawa H, Nakanishi H, Gao XD. β-1,6-glucan synthesis-associated genes are required for proper spore wall formation in Saccharomyces cerevisiae. Yeast 2017; 34:431-446. [PMID: 28732129 DOI: 10.1002/yea.3244] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 06/16/2017] [Accepted: 07/16/2017] [Indexed: 01/30/2023] Open
Abstract
The yeast spore wall is an excellent model to study the assembly of an extracellular macromolecule structure. In the present study, mutants defective in β-1,6-glucan synthesis, including kre1∆, kre6∆, kre9∆ and big1∆, were sporulated to analyse the effect of β-1,6-glucan defects on the spore wall. Except for kre6∆, these mutant spores were sensitive to treatment with ether, suggesting that the mutations perturb the integrity of the spore wall. Morphologically, the mutant spores were indistinguishable from wild-type spores. They lacked significant sporulation defects partly because the chitosan layer, which covers the glucan layer, compensated for the damage. The proof for this model was obtained from the effect of the additional deletion of CHS3 that resulted in the absence of the chitosan layer. Among the double mutants, the most severe spore wall deficiency was observed in big1∆ spores. The majority of the big1∆chs3∆ mutants failed to form visible spores at a higher temperature. Given that the big1∆ mutation caused a failure to attach a GPI-anchored reporter, Cwp2-GFP, to the spore wall, β-1,6-glucan is involved in tethering of GPI-anchored proteins in the spore wall as well as in the vegetative cell wall. Thus, β-1,6-glucan is required for proper organization of the spore wall. Copyright © 2017 John Wiley & Sons, Ltd.
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Affiliation(s)
- Hua-Ping Pan
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Ning Wang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Hiroyuki Tachikawa
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan
| | - Hideki Nakanishi
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Xiao-Dong Gao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
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13
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Abstract
β-(1,3)-Glucan, the major fungal cell wall component, ramifies through β-(1,6)-glycosidic linkages, which facilitates its binding with other cell wall components contributing to proper cell wall assembly. Using Saccharomyces cerevisiae as a model, we developed a protocol to quantify β-(1,6)-branching on β-(1,3)-glucan. Permeabilized S. cerevisiae and radiolabeled substrate UDP-(14C)glucose allowed us to determine branching kinetics. A screening aimed at identifying deletion mutants with reduced branching among them revealed only two, the bgl2Δ and gas1Δ mutants, showing 15% and 70% reductions in the branching, respectively, compared to the wild-type strain. Interestingly, a recombinant Gas1p introduced β-(1,6)-branching on the β-(1,3)-oligomers following its β-(1,3)-elongase activity. Sequential elongation and branching activity of Gas1p occurred on linear β-(1,3)-oligomers as well as Bgl2p-catalyzed products [short β-(1,3)-oligomers linked by a linear β-(1,6)-linkage]. The double S. cerevisiae gas1Δ bgl2Δ mutant showed a drastically sick phenotype. An ScGas1p ortholog, Gel4p from Aspergillus fumigatus, also showed dual β-(1,3)-glucan elongating and branching activity. Both ScGas1p and A. fumigatus Gel4p sequences are endowed with a carbohydrate binding module (CBM), CBM43, which was required for the dual β-(1,3)-glucan elongating and branching activity. Our report unravels the β-(1,3)-glucan branching mechanism, a phenomenon occurring during construction of the cell wall which is essential for fungal life. The fungal cell wall is essential for growth, morphogenesis, protection, and survival. In spite of being essential, cell wall biogenesis, especially the core β-(1,3)-glucan ramification, is poorly understood; the ramified β-(1,3)-glucan interconnects other cell wall components. Once linear β-(1,3)-glucan is synthesized by plasma membrane-bound glucan synthase, the subsequent event is its branching event in the cell wall space. Using Saccharomyces cerevisiae as a model, we identified GH72 and GH17 family glycosyltransferases, Gas1p and Bgl2p, respectively, involved in the β-(1,3)-glucan branching. The sick phenotype of the double Scgas1Δ bgl2Δ mutant suggested that β-(1,3)-glucan branching is essential. In addition to ScGas1p, GH72 family ScGas2p and Aspergillus fumigatus Gel4p, having CBM43 in their sequences, showed dual β-(1,3)-glucan elongating and branching activity. Our report identifies the fungal cell wall β-(1,3)-glucan branching mechanism. The essentiality of β-(1,3)-glucan branching suggests that enzymes involved in the glucan branching could be exploited as antifungal targets.
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Montoro AG, Bigliani G, Taubas JV. Transmembrane-domain shape is a novel endocytosis signal for single-spanning membrane proteins. J Cell Sci 2017; 130:3829-3838. [DOI: 10.1242/jcs.202937] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 09/27/2017] [Indexed: 02/03/2023] Open
Abstract
Endocytosis is crucial for all cells as it allows them to incorporate material from the extracellular space and control the availability of transmembrane proteins at the plasma membrane. In yeast, endocytosis followed by recycling to the plasma membrane results in a polarised distribution of membrane proteins by a kinetic mechanism. Here we report that increasing the volume of the residues that constitute the exoplasmic half of the transmembrane domain in the yeast SNARE Sso1, a type II membrane protein, results in its polarised distribution at the plasma membrane. Expression of this chimera in strains affected in either endocytosis or recycling revealed that this polarisation is achieved by endocytic cycling. A bioinformatics search of the Saccharomyces cerevisiae proteome identified several proteins with high-volume exoplasmic hemi-TMDs. Our experiments indicate that TMDs from these proteins can confer a polarised distribution to the Sso1 cytoplasmic domain, indicating that the shape of the TMD can act as a novel endocytosis and polarity signal in yeast. Additionally, a high-volume exoplasmic hemi-TMD can act as an endocytosis signal in a mammalian cell line.
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Affiliation(s)
- Ayelén González Montoro
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
- Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Current address: University of Osnabrück, Department of Biology/Chemistry, Biochemistry section, Barbarastrasse 13, 49076 Osnabrück, Germany
| | - Gonzalo Bigliani
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
- Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Javier Valdez Taubas
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina
- Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
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15
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Huang W, Río Bártulos C, Kroth PG. Diatom Vacuolar 1,6-β-Transglycosylases can Functionally Complement the Respective Yeast Mutants. J Eukaryot Microbiol 2016; 63:536-46. [DOI: 10.1111/jeu.12298] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 12/23/2015] [Accepted: 01/12/2016] [Indexed: 01/16/2023]
Affiliation(s)
- Weichao Huang
- Pflanzliche Ökophysiologie; Department of Biology; Universität Konstanz; 78457 Konstanz Germany
| | - Carolina Río Bártulos
- Pflanzliche Ökophysiologie; Department of Biology; Universität Konstanz; 78457 Konstanz Germany
| | - Peter G. Kroth
- Pflanzliche Ökophysiologie; Department of Biology; Universität Konstanz; 78457 Konstanz Germany
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16
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Phosphoregulatory protein 14-3-3 facilitates SAC1 transport from the endoplasmic reticulum. Proc Natl Acad Sci U S A 2015; 112:E3199-206. [PMID: 26056309 DOI: 10.1073/pnas.1509119112] [Citation(s) in RCA: 196] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Most secretory cargo proteins in eukaryotes are synthesized in the endoplasmic reticulum and actively exported in membrane-bound vesicles that are formed by the cytosolic coat protein complex II (COPII). COPII proteins are assisted by a variety of cargo-specific adaptor proteins required for the concentration and export of secretory proteins from the endoplasmic reticulum (ER). Adaptor proteins are key regulators of cargo export, and defects in their function may result in disease phenotypes in mammals. Here we report the role of 14-3-3 proteins as a cytosolic adaptor in mediating SAC1 transport in COPII-coated vesicles. Sac1 is a phosphatidyl inositol-4 phosphate (PI4P) lipid phosphatase that undergoes serum dependent translocation between the endoplasmic reticulum and Golgi complex and controls cellular PI4P lipid levels. We developed a cell-free COPII vesicle budding reaction to examine SAC1 exit from the ER that requires COPII and at least one additional cytosolic factor, the 14-3-3 protein. Recombinant 14-3-3 protein stimulates the packaging of SAC1 into COPII vesicles and the sorting subunit of COPII, Sec24, interacts with 14-3-3. We identified a minimal sorting motif of SAC1 that is important for 14-3-3 binding and which controls SAC1 export from the ER. This LS motif is part of a 7-aa stretch, RLSNTSP, which is similar to the consensus 14-3-3 binding sequence. Homology models, based on the SAC1 structure from yeast, predict this region to be in the exposed exterior of the protein. Our data suggest a model in which the 14-3-3 protein mediates SAC1 traffic from the ER through direct interaction with a sorting signal and COPII.
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17
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Yeast β-1,6-glucan is a primary target for the Saccharomyces cerevisiae K2 toxin. EUKARYOTIC CELL 2015; 14:406-14. [PMID: 25710965 DOI: 10.1128/ec.00287-14] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2014] [Accepted: 02/18/2015] [Indexed: 11/20/2022]
Abstract
Certain Saccharomyces cerevisiae strains secrete different killer proteins of double-stranded-RNA origin. These proteins confer a growth advantage to their host by increasing its survival. K2 toxin affects the target cell by binding to the cell surface, disrupting the plasma membrane integrity, and inducing ion leakage. In this study, we determined that K2 toxin saturates the yeast cell surface receptors in 10 min. The apparent amount of K2 toxin, bound to a single cell of wild type yeast under saturating conditions, was estimated to be 435 to 460 molecules. It was found that an increased level of β-1,6-glucan directly correlates with the number of toxin molecules bound, thereby impacting the morphology and determining the fate of the yeast cell. We observed that the binding of K2 toxin to the yeast surface receptors proceeds in a similar manner as in case of the related K1 killer protein. It was demonstrated that the externally supplied pustulan, a poly-β-1,6-glucan, but not the glucans bearing other linkage types (such as laminarin, chitin, and pullulan) efficiently inhibits the K2 toxin killing activity. In addition, the analysis of toxin binding to the intact cells and spheroplasts confirmed that majority of K2 protein molecules attach to the β-1,6-glucan, rather than the plasma membrane-localized receptors. Taken together, our results reveal that β-1,6-glucan is a primary target of K2 toxin and is important for the execution of its killing property.
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18
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Schiavone M, Vax A, Formosa C, Martin-Yken H, Dague E, François JM. A combined chemical and enzymatic method to determine quantitatively the polysaccharide components in the cell wall of yeasts. FEMS Yeast Res 2014; 14:933-47. [PMID: 25041403 DOI: 10.1111/1567-1364.12182] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 07/02/2014] [Accepted: 07/03/2014] [Indexed: 12/19/2022] Open
Abstract
A reliable method to determine cell wall polysaccharides composition in yeast is presented, which combines acid and enzymatic hydrolysis. Sulphuric acid treatment is used to determine mannans, whereas specific hydrolytic enzymes are employed in a two sequential steps to quantify chitin and the proportion of β-(1,3) and β-(1,6)-glucan in the total β-glucan of the cell wall. In the first step, chitin and β-(1,3)-glucan were hydrolysed into their corresponding monomers N-acetylglucosamine and glucose, respectively, by the combined action of a chitinase from Streptomyces griseus and a pure preparation of endo/exo-β-(1,3)-glucanase from Trichoderma species. This step was followed by addition of recombinant endo-β-(1,6)-glucanase from Trichoderma harzianum with β-glucosidase from Aspergillus niger to hydrolyse the remaining β-glucan. This latter component corresponded to a highly branched β-(1,6)-glucan that contained about 75-80% of linear β-(1,6)-glucose linked units as deduced from periodate oxidation. We validated this novel method by showing that the content of β-(1,3), β-(1,6)-glucan or chitin was dramatically decreased in yeast mutants defective in the biosynthesis of these cell wall components. Moreover, we found that heat shock at 42 °C in Saccharomyces cerevisiae and treatment of this yeast species and Candida albicans with the antifungal drug caspofungin resulted in 2- to 3-fold increase of chitin and in a reduction of β-(1,3)-glucan accompanied by an increase of β-(1,6)-glucan, whereas ethanol stress had apparently no effect on yeast cell wall composition.
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Affiliation(s)
- Marion Schiavone
- INSA, UPS, INP, Université de Toulouse, Toulouse, France; UMR792 Ingénierie des Systèmes Biologiques et des Procédés, INRA, Toulouse, France; UMR5504, CNRS, Toulouse, France; Lallemand SAS, Blagnac, France
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Noda Y, Hara T, Ishii M, Yoda K. Distinct adaptor proteins assist exit of Kre2-family proteins from the yeast ER. Biol Open 2014; 3:209-24. [PMID: 24585773 PMCID: PMC4001239 DOI: 10.1242/bio.20146312] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Svp26 protein of S. cerevisiae is an ER- and Golgi-localized integral membrane protein with 4 potential membrane-spanning domains. It functions as an adaptor protein that facilitates the ER exit of Ktr3, a mannosyltransferase required for biosynthesis of O-linked oligosaccharides, and the ER exit of Mnn2 and Mnn5, mannosyltransferases, which participate in the biosynthesis of N-linked oligosaccharides. Ktr3 belongs to the Kre2 family, which consists of 9 members of type-II membrane proteins sharing sequence similarities. In this report, we examined all Kre2 family members and found that the Golgi localizations of two others, Kre2 and Ktr1, were dependent on Svp26 by immunofluorescence microscopy and cell fractionations in sucrose density gradients. We show that Svp26 functions in facilitating the ER exit of Kre2 and Ktr1 by an in vitro COPII budding assay. Golgi localization of Ktr4 was not dependent on Svp26. Screening null mutants of the genes encoding abundant COPII membrane proteins for those showing mislocalization of Ktr4 in the ER revealed that Erv41 and Erv46 are required for the correct Golgi localization of Ktr4. We provide biochemical evidence that the Erv41-Erv46 complex functions as an adaptor protein for ER exit of Ktr4. This is the first demonstration of the molecular function of this evolutionally conserved protein complex. The domain switching experiments show that the lumenal domain of Ktr4 is responsible for recognition by the Erv41-Erv46 complex. Thus, ER exit of Kre2-family proteins is dependent on distinct adaptor proteins and our results provide new insights into the traffic of Kre2-family mannosyltransferases.
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Affiliation(s)
- Yoichi Noda
- Department of Biotechnology, University of Tokyo, Yayoi, Bunkyo-Ku, Tokyo 113-8657, Japan
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20
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Zambuzzi-Carvalho PF, Tomazett PK, Santos SC, Ferri PH, Borges CL, Martins WS, de Almeida Soares CM, Pereira M. Transcriptional profile of Paracoccidioides induced by oenothein B, a potential antifungal agent from the Brazilian Cerrado plant Eugenia uniflora. BMC Microbiol 2013; 13:227. [PMID: 24119145 PMCID: PMC3852496 DOI: 10.1186/1471-2180-13-227] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 10/01/2013] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND The compound oenothein B (OenB), which is isolated from the leaves of Eugenia uniflora, a Brazilian Cerrado plant, interferes with Paracoccidioides yeast cell morphology and inhibits 1,3-β-D-glucan synthase (PbFKS1) transcript accumulation, which is involved in cell wall synthesis. In this work we examined the gene expression changes in Paracoccidioides yeast cells following OenB treatment in order to investigate the adaptive cellular responses to drug stress. RESULTS We constructed differential gene expression libraries using Representational Difference Analysis (RDA) of Paracoccidioides yeast cells treated with OenB for 90 and 180 min. Treatment for 90 min resulted in the identification of 463 up-regulated expressed sequences tags (ESTs) and 104 down-regulated ESTs. For the 180 min treatment 301 up-regulated ESTs and 143 down-regulated were identified. Genes involved in the cell wall biosynthesis, such as GLN1, KRE6 and FKS1, were found to be regulated by OenB. Infection experiments in macrophages corroborated the in vitro results. Fluorescence microscopy showed increased levels of chitin in cells treated with OenB. The carbohydrate polymer content of the cell wall of the fungus was also evaluated, and the results corroborated with the transcriptional data. Several other genes, such as those involved in a variety of important cellular processes (i.e., membrane maintenance, stress and virulence) were found to be up-regulated in response to OenB treatment. CONCLUSIONS The exposure of Paracoccidioides to OenB resulted in a complex altered gene expression profile. Some of the changes may represent specific adaptive responses to this compound in this important pathogenic fungus.
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Affiliation(s)
- Patrícia Fernanda Zambuzzi-Carvalho
- Departamento de Bioquímica e Biologia Molecular, Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, ICBII, Campus II, Universidade Federal de Goiás, C.P. 131, 74001-970 Goiânia, GO, Brazil
| | - Patrícia Kott Tomazett
- Departamento de Bioquímica e Biologia Molecular, Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, ICBII, Campus II, Universidade Federal de Goiás, C.P. 131, 74001-970 Goiânia, GO, Brazil
| | - Suzana Costa Santos
- Laboratório de Bioatividade Molecular, Instituto de Química, Universidade Federal de Goiás, Goiânia, GO, Brazil
| | - Pedro Henrique Ferri
- Laboratório de Bioatividade Molecular, Instituto de Química, Universidade Federal de Goiás, Goiânia, GO, Brazil
| | - Clayton Luiz Borges
- Departamento de Bioquímica e Biologia Molecular, Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, ICBII, Campus II, Universidade Federal de Goiás, C.P. 131, 74001-970 Goiânia, GO, Brazil
| | | | - Célia Maria de Almeida Soares
- Departamento de Bioquímica e Biologia Molecular, Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, ICBII, Campus II, Universidade Federal de Goiás, C.P. 131, 74001-970 Goiânia, GO, Brazil
| | - Maristela Pereira
- Departamento de Bioquímica e Biologia Molecular, Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, ICBII, Campus II, Universidade Federal de Goiás, C.P. 131, 74001-970 Goiânia, GO, Brazil
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Orlean P. Architecture and biosynthesis of the Saccharomyces cerevisiae cell wall. Genetics 2012; 192:775-818. [PMID: 23135325 PMCID: PMC3522159 DOI: 10.1534/genetics.112.144485] [Citation(s) in RCA: 296] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Accepted: 08/06/2012] [Indexed: 01/02/2023] Open
Abstract
The wall gives a Saccharomyces cerevisiae cell its osmotic integrity; defines cell shape during budding growth, mating, sporulation, and pseudohypha formation; and presents adhesive glycoproteins to other yeast cells. The wall consists of β1,3- and β1,6-glucans, a small amount of chitin, and many different proteins that may bear N- and O-linked glycans and a glycolipid anchor. These components become cross-linked in various ways to form higher-order complexes. Wall composition and degree of cross-linking vary during growth and development and change in response to cell wall stress. This article reviews wall biogenesis in vegetative cells, covering the structure of wall components and how they are cross-linked; the biosynthesis of N- and O-linked glycans, glycosylphosphatidylinositol membrane anchors, β1,3- and β1,6-linked glucans, and chitin; the reactions that cross-link wall components; and the possible functions of enzymatic and nonenzymatic cell wall proteins.
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Affiliation(s)
- Peter Orlean
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
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22
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Identification and functional characterization of Rca1, a transcription factor involved in both antifungal susceptibility and host response in Candida albicans. EUKARYOTIC CELL 2012; 11:916-31. [PMID: 22581526 DOI: 10.1128/ec.00134-12] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The identification of novel transcription factors associated with antifungal response may allow the discovery of fungus-specific targets for new therapeutic strategies. A collection of 241 Candida albicans transcriptional regulator mutants was screened for altered susceptibility to fluconazole, caspofungin, amphotericin B, and 5-fluorocytosine. Thirteen of these mutants not yet identified in terms of their role in antifungal response were further investigated, and the function of one of them, a mutant of orf19.6102 (RCA1), was characterized by transcriptome analysis. Strand-specific RNA sequencing and phenotypic tests assigned Rca1 as the regulator of hyphal formation through the cyclic AMP/protein kinase A (cAMP/PKA) signaling pathway and the transcription factor Efg1, but also probably through its interaction with a transcriptional repressor, most likely Tup1. The mechanisms responsible for the high level of resistance to caspofungin and fluconazole observed resulting from RCA1 deletion were investigated. From our observations, we propose that caspofungin resistance was the consequence of the deregulation of cell wall gene expression and that fluconazole resistance was linked to the modulation of the cAMP/PKA signaling pathway activity. In conclusion, our large-scale screening of a C. albicans transcription factor mutant collection allowed the identification of new effectors of the response to antifungals. The functional characterization of Rca1 assigned this transcription factor and its downstream targets as promising candidates for the development of new therapeutic strategies, as Rca1 influences host sensing, hyphal development, and antifungal response.
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23
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Genome-wide analysis of cell wall-related genes in Tuber melanosporum. Curr Genet 2012; 58:165-77. [PMID: 22481122 DOI: 10.1007/s00294-012-0374-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 03/15/2012] [Accepted: 03/20/2012] [Indexed: 10/28/2022]
Abstract
A genome-wide inventory of proteins involved in cell wall synthesis and remodeling has been obtained by taking advantage of the recently released genome sequence of the ectomycorrhizal Tuber melanosporum black truffle. Genes that encode cell wall biosynthetic enzymes, enzymes involved in cell wall polysaccharide synthesis or modification, GPI-anchored proteins and other cell wall proteins were identified in the black truffle genome. As a second step, array data were validated and the symbiotic stage was chosen as the main focus. Quantitative RT-PCR experiments were performed on 29 selected genes to verify their expression during ectomycorrhizal formation. The results confirmed the array data, and this suggests that cell wall-related genes are required for morphogenetic transition from mycelium growth to the ectomycorrhizal branched hyphae. Labeling experiments were also performed on T. melanosporum mycelium and ectomycorrhizae to localize cell wall components.
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Kurita T, Noda Y, Yoda K. Action of multiple endoplasmic reticulum chaperon-like proteins is required for proper folding and polarized localization of Kre6 protein essential in yeast cell wall β-1,6-glucan synthesis. J Biol Chem 2012; 287:17415-17424. [PMID: 22447934 DOI: 10.1074/jbc.m111.321018] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Saccharomyces cerevisiae Kre6 is a type II membrane protein essential for cell wall β-1,6-glucan synthesis. Recently we reported that the majority of Kre6 is in the endoplasmic reticulum (ER), but a significant portion of Kre6 is found in the plasma membrane of buds, and this polarized appearance of Kre6 is required for β-1,6-glucan synthesis. An essential membrane protein, Keg1, and ER chaperon Rot1 bind to Kre6. In this study we found that in mutant keg1-1 cells, accumulation of Kre6 at the buds is diminished, binding of Kre6 to Keg1 is decreased, and Kre6 becomes susceptible to ER-associated degradation (ERAD), which suggests Keg1 participates in folding and transport of Kre6. All mutants of the calnexin cycle member homologues (cwh41, rot2, kre5, and cne1) showed defects in β-1,6-glucan synthesis, although the calnexin chaperon system is considered not functional in yeast. We found synthetic defects between them and keg1-1, and Cne1 co-immunoprecipitated with Keg1 and Kre6. A stronger binding of Cne1 to Kre6 was detected when two glucosidases (Cwh41 and Rot2) that remove glucose on N-glycan were functional. Skn1, a Kre6 homologue, was not detected by immunofluorescence in the wild type yeast, but in kre6Δ cells it became detectable and behaved like Kre6. In conclusion, the action of multiple ER chaperon-like proteins is required for proper folding and localization of Kre6 and probably Skn1 to function in β-1,6-glucan synthesis.
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Affiliation(s)
- Tomokazu Kurita
- Department of Biotechnology, University of Tokyo, Yayoi, Bunkyo-Ku, Tokyo 113-8657, Japan
| | - Yoichi Noda
- Department of Biotechnology, University of Tokyo, Yayoi, Bunkyo-Ku, Tokyo 113-8657, Japan
| | - Koji Yoda
- Department of Biotechnology, University of Tokyo, Yayoi, Bunkyo-Ku, Tokyo 113-8657, Japan.
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