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Campos ACS, Araújo TM, Moraes L, Corrêa dos Santos RA, Goldman GH, Riano-Pachon DM, Oliveira JVDC, Squina FM, Castro IDM, Trópia MJM, da Cunha AC, Rosse IC, Brandão RL. Selected cachaça yeast strains share a genomic profile related to traits relevant to industrial fermentation processes. Appl Environ Microbiol 2024; 90:e0175923. [PMID: 38112453 PMCID: PMC10807443 DOI: 10.1128/aem.01759-23] [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: 10/04/2023] [Accepted: 11/01/2023] [Indexed: 12/21/2023] Open
Abstract
The isolation and selection of yeast strains to improve the quality of the cachaça-Brazilian Spirit-have been studied in our research group. Our strategy considers Saccharomyces cerevisiae as the predominant species involved in sugarcane juice fermentation and the presence of different stressors (osmolarity, temperature, ethanol content, and competition with other microorganisms). It also considers producing balanced concentrations of volatile compounds (higher alcohols and acetate and/or ethyl esters), flocculation capacity, and ethanol production. Since the genetic bases behind these traits of interest are not fully established, the whole genome sequencing of 11 different Saccharomyces cerevisiae strains isolated and selected from different places was analyzed to identify the presence of a specific genetic variation common to cachaça yeast strains. We have identified 20,128 single-nucleotide variants shared by all genomes. Of these shared variants, 37 were new variants (being six missenses), and 4,451 were identified as missenses. We performed a detailed functional annotation (using enrichment analysis, protein-protein interaction network analysis, and database and in-depth literature searches) of these new and missense variants. Many genes carrying these variations were involved in the phenotypes of flocculation, tolerance to fermentative stresses, and production of volatile compounds and ethanol. These results demonstrate the existence of a genetic profile shared by the 11 strains under study that could be associated with the applied selective strategy. Thus, this study points out genes and variants that may be used as molecular markers for selecting strains well suited to the fermentation process, including genetic improvement by genome editing, ultimately producing high-quality beverages and adding value.IMPORTANCEThis work demonstrates the existence of new genetic markers related to different phenotypes used to select yeast strains and mutations in genes directly involved in producing flavoring compounds and ethanol, and others related to flocculation and stress resistance.
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Affiliation(s)
- Anna Clara Silva Campos
- Laboratório de Biologia Celular e Molecular, Departamento de Farmácia, Escola de Farmácia, Ouro Preto, Brazil
| | - Thalita Macedo Araújo
- Laboratório de Biologia Celular e Molecular, Departamento de Farmácia, Escola de Farmácia, Ouro Preto, Brazil
- Área de Ciências Biológicas, Instituto Federal de Minas Gerais, Campus Ouro Preto, Ouro Preto, Minas Gerais, Brazil
| | - Lauro Moraes
- Laboratório Multiusuário de Bioinformática, Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, Brazil
| | - Renato Augusto Corrêa dos Santos
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto (FCFRP), Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
- Laboratório de Biologia Computacional, Evolutiva e de Sistemas, Centro de Energia Nuclear na Agricultura, Universidade de São Paulo, Piracicaba, São Paulo, Brazil
| | - Gustavo Henrique Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto (FCFRP), Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Diego Maurício Riano-Pachon
- Laboratório de Biologia Computacional, Evolutiva e de Sistemas, Centro de Energia Nuclear na Agricultura, Universidade de São Paulo, Piracicaba, São Paulo, Brazil
| | | | | | - Ieso de Miranda Castro
- Laboratório de Biologia Celular e Molecular, Departamento de Farmácia, Escola de Farmácia, Ouro Preto, Brazil
| | - Maria José Magalhães Trópia
- Laboratório de Biologia Celular e Molecular, Departamento de Farmácia, Escola de Farmácia, Ouro Preto, Brazil
| | - Aureliano Claret da Cunha
- Laboratório de Biologia Celular e Molecular, Departamento de Farmácia, Escola de Farmácia, Ouro Preto, Brazil
- Laboratório de Engenharia de Alimentos, Departamento de Alimentos, Escola de Nutrição, Salvador, Brazil
| | - Izinara C. Rosse
- Laboratório de Biologia Celular e Molecular, Departamento de Farmácia, Escola de Farmácia, Ouro Preto, Brazil
- Laboratório Multiusuário de Bioinformática, Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, Brazil
| | - Rogelio Lopes Brandão
- Laboratório de Biologia Celular e Molecular, Departamento de Farmácia, Escola de Farmácia, Ouro Preto, Brazil
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Hall D. MIL-CELL: a tool for multi-scale simulation of yeast replication and prion transmission. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2023; 52:673-704. [PMID: 37670150 PMCID: PMC10682183 DOI: 10.1007/s00249-023-01679-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 08/08/2023] [Accepted: 08/14/2023] [Indexed: 09/07/2023]
Abstract
The single-celled baker's yeast, Saccharomyces cerevisiae, can sustain a number of amyloid-based prions, the three most prominent examples being [URE3], [PSI+], and [PIN+]. In the laboratory, haploid S. cerevisiae cells of a single mating type can acquire an amyloid prion in one of two ways (i) spontaneous nucleation of the prion within the yeast cell, and (ii) receipt via mother-to-daughter transmission during the cell division cycle. Similarly, prions can be lost due to (i) dissolution of the prion amyloid by its breakage into non-amyloid monomeric units, or (ii) preferential donation/retention of prions between the mother and daughter during cell division. Here we present a computational tool (Monitoring Induction and Loss of prions in Cells; MIL-CELL) for modelling these four general processes using a multiscale approach describing both spatial and kinetic aspects of the yeast life cycle and the amyloid-prion behavior. We describe the workings of the model, assumptions upon which it is based and some interesting simulation results pertaining to the wave-like spread of the epigenetic prion elements through the yeast population. MIL-CELL is provided as a stand-alone GUI executable program for free download with the paper. MIL-CELL is equipped with a relational database allowing all simulated properties to be searched, collated and graphed. Its ability to incorporate variation in heritable properties means MIL-CELL is also capable of simulating loss of the isogenic nature of a cell population over time. The capability to monitor both chronological and reproductive age also makes MIL-CELL potentially useful in studies of cell aging.
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Affiliation(s)
- Damien Hall
- WPI Nano Life Science Institute, Kanazawa University, Kakumamachi, Kanazawa, Ishikawa, 920-1164, Japan.
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3
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Abstract
Fungi exhibit an enormous variety of morphologies, including yeast colonies, hyphal mycelia, and elaborate fruiting bodies. This diversity arises through a combination of polar growth, cell division, and cell fusion. Because fungal cells are nonmotile and surrounded by a protective cell wall that is essential for cell integrity, potential fusion partners must grow toward each other until they touch and then degrade the intervening cell walls without impacting cell integrity. Here, we review recent progress on understanding how fungi overcome these challenges. Extracellular chemoattractants, including small peptide pheromones, mediate communication between potential fusion partners, promoting the local activation of core cell polarity regulators to orient polar growth and cell wall degradation. However, in crowded environments, pheromone gradients can be complex and potentially confusing, raising the question of how cells can effectively find their partners. Recent findings suggest that the cell polarity circuit exhibits searching behavior that can respond to pheromone cues through a remarkably flexible and effective strategy called exploratory polarization.
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Willaert RG, Kayacan Y, Devreese B. The Flo Adhesin Family. Pathogens 2021; 10:pathogens10111397. [PMID: 34832553 PMCID: PMC8621652 DOI: 10.3390/pathogens10111397] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 10/11/2021] [Accepted: 10/25/2021] [Indexed: 12/14/2022] Open
Abstract
The first step in the infection of fungal pathogens in humans is the adhesion of the pathogen to host tissue cells or abiotic surfaces such as catheters and implants. One of the main players involved in this are the expressed cell wall adhesins. Here, we review the Flo adhesin family and their involvement in the adhesion of these yeasts during human infections. Firstly, we redefined the Flo adhesin family based on the domain architectures that are present in the Flo adhesins and their functions, and set up a new classification of Flo adhesins. Next, the structure, function, and adhesion mechanisms of the Flo adhesins whose structure has been solved are discussed in detail. Finally, we identified from Pfam database datamining yeasts that could express Flo adhesins and are encountered in human infections and their adhesin architectures. These yeasts are discussed in relation to their adhesion characteristics and involvement in infections.
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Affiliation(s)
- Ronnie G. Willaert
- Research Group Structural Biology Brussels (SBB), Vrije Universiteit Brussel (VUB), 1050 Brussels, Belgium;
- Alliance Research Group VUB-UGent NanoMicrobiology (NAMI), 1050 Brussels, Belgium;
- International Joint Research Group VUB-EPFL NanoBiotechnology & NanoMedicine (NANO), Vrije Universiteit Brussel (VUB), 1050 Brussels, Belgium
- Correspondence: ; Tel.: +32-2629-1846
| | - Yeseren Kayacan
- Research Group Structural Biology Brussels (SBB), Vrije Universiteit Brussel (VUB), 1050 Brussels, Belgium;
- Alliance Research Group VUB-UGent NanoMicrobiology (NAMI), 1050 Brussels, Belgium;
- International Joint Research Group VUB-EPFL NanoBiotechnology & NanoMedicine (NANO), Vrije Universiteit Brussel (VUB), 1050 Brussels, Belgium
- Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Bart Devreese
- Alliance Research Group VUB-UGent NanoMicrobiology (NAMI), 1050 Brussels, Belgium;
- International Joint Research Group VUB-EPFL NanoBiotechnology & NanoMedicine (NANO), Vrije Universiteit Brussel (VUB), 1050 Brussels, Belgium
- Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
- Laboratory for Microbiology, Gent University (UGent), 9000 Gent, Belgium
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Mathelié-Guinlet M, Viela F, Dehullu J, Filimonava S, Rauceo JM, Lipke PN, Dufrêne YF. Single-cell fluidic force microscopy reveals stress-dependent molecular interactions in yeast mating. Commun Biol 2021; 4:33. [PMID: 33397995 PMCID: PMC7782832 DOI: 10.1038/s42003-020-01498-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 11/13/2020] [Indexed: 11/09/2022] Open
Abstract
Sexual agglutinins of the budding yeast Saccharomyces cerevisiae are proteins mediating cell aggregation during mating. Complementary agglutinins expressed by cells of opposite mating types "a" and "α" bind together to promote agglutination and facilitate fusion of haploid cells. By means of an innovative single-cell manipulation assay combining fluidic force microscopy with force spectroscopy, we unravel the strength of single specific bonds between a- and α-agglutinins (~100 pN) which require pheromone induction. Prolonged cell-cell contact strongly increases adhesion between mating cells, likely resulting from an increased expression of agglutinins. In addition, we highlight the critical role of disulfide bonds of the a-agglutinin and of histidine residue H273 of α-agglutinin. Most interestingly, we find that mechanical tension enhances the interaction strength, pointing to a model where physical stress induces conformational changes in the agglutinins, from a weak-binding folded state, to a strong-binding extended state. Our single-cell technology shows promises for understanding and controlling the complex mechanism of yeast sexuality.
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Affiliation(s)
- Marion Mathelié-Guinlet
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte L7.07.07, 1348, Louvain-la-Neuve, Belgium
| | - Felipe Viela
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte L7.07.07, 1348, Louvain-la-Neuve, Belgium
| | - Jérôme Dehullu
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte L7.07.07, 1348, Louvain-la-Neuve, Belgium
| | - Sviatlana Filimonava
- Department of Sciences, John Jay College of the City University of New York, New York, NY, 10019, USA
| | - Jason M Rauceo
- Department of Sciences, John Jay College of the City University of New York, New York, NY, 10019, USA
| | - Peter N Lipke
- Biology Department, Brooklyn College of the City University of New York, 2900 Bedford Avenue, Brooklyn, NY, 11210, USA.
| | - Yves F Dufrêne
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte L7.07.07, 1348, Louvain-la-Neuve, Belgium.
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6
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Ye M, Ye Y, Du Z, Chen G. Cell-surface engineering of yeasts for whole-cell biocatalysts. Bioprocess Biosyst Eng 2021; 44:1003-1019. [PMID: 33389168 DOI: 10.1007/s00449-020-02484-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 11/16/2020] [Indexed: 01/23/2023]
Abstract
Due to the unique advantages comparing with traditional free enzymes and chemical catalysis, whole-cell biocatalysts have been widely used to catalyze reactions effectively, simply and environment friendly. Cell-surface display technology provides a novel and effective approach for improved whole-cell biocatalysts expressing heterologous enzymes on the cell surface. They can overcome the substrate transport limitation of the intracellular expression and provide the enzymes with enhanced properties. Among all the host surface-displaying microorganisms, yeast is ideally suitable for constructing whole cell-surface-displaying biocatalyst, because of the large cell size, the generally regarded as safe (GRAS) status, and the perfect post-translational processing of secreted proteins. Yeast cell-surface display system has been a promising and powerful method for development of novel and improved engineered biocatalysts. In this review, the characterization and principles of yeast cell-surface display and the applications of yeast cell-surface display in engineered whole-cell biocatalysts as well as the improvement of the enzyme efficiency are summarized and discussed.
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Affiliation(s)
- Mengqi Ye
- Marine College, Shandong University, Weihai, 264209, China
| | - Yuqi Ye
- Marine College, Shandong University, Weihai, 264209, China
| | - Zongjun Du
- Marine College, Shandong University, Weihai, 264209, China
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, China
| | - Guanjun Chen
- Marine College, Shandong University, Weihai, 264209, China.
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, China.
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7
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Willaert RG. Adhesins of Yeasts: Protein Structure and Interactions. J Fungi (Basel) 2018; 4:jof4040119. [PMID: 30373267 PMCID: PMC6308950 DOI: 10.3390/jof4040119] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 10/23/2018] [Accepted: 10/24/2018] [Indexed: 12/14/2022] Open
Abstract
The ability of yeast cells to adhere to other cells or substrates is crucial for many yeasts. The budding yeast Saccharomyces cerevisiae can switch from a unicellular lifestyle to a multicellular one. A crucial step in multicellular lifestyle adaptation is self-recognition, self-interaction, and adhesion to abiotic surfaces. Infectious yeast diseases such as candidiasis are initiated by the adhesion of the yeast cells to host cells. Adhesion is accomplished by adhesin proteins that are attached to the cell wall and stick out to interact with other cells or substrates. Protein structures give detailed insights into the molecular mechanism of adhesin-ligand interaction. Currently, only the structures of a very limited number of N-terminal adhesion domains of adhesins have been solved. Therefore, this review focuses on these adhesin protein families. The protein architectures, protein structures, and ligand interactions of the flocculation protein family of S. cerevisiae; the epithelial adhesion family of C. glabrata; and the agglutinin-like sequence protein family of C. albicans are reviewed and discussed.
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Affiliation(s)
- Ronnie G Willaert
- Alliance Research Group VUB-UGent NanoMicrobiology (NAMI), IJRG VUB-EPFL NanoBiotechnology & NanoMedicine (NANO), Research Group Structural Biology Brussels, Vrije Universiteit Brussel, 1050 Brussels, Belgium.
- Department Bioscience Engineering, University Antwerp, 2020 Antwerp, Belgium.
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Tang H, Wang J, Wang S, Shen Y, Petranovic D, Hou J, Bao X. Efficient yeast surface-display of novel complex synthetic cellulosomes. Microb Cell Fact 2018; 17:122. [PMID: 30086751 PMCID: PMC6081942 DOI: 10.1186/s12934-018-0971-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 08/01/2018] [Indexed: 11/12/2022] Open
Abstract
Background The self-assembly of cellulosomes on the surface of yeast is a promising strategy for consolidated bioprocessing to convert cellulose into ethanol in one step. Results In this study, we developed a novel synthetic cellulosome that anchors to the endogenous yeast cell wall protein a-agglutinin through disulfide bonds. A synthetic scaffoldin ScafAGA3 was constructed using the repeated N-terminus of Aga1p and displayed on the yeast cell surface. Secreted cellulases were then fused with Aga2p to assemble the cellulosome. The display efficiency of the synthetic scaffoldin and the assembly efficiency of each enzyme were much higher than those of the most frequently constructed cellulosome using scaffoldin ScafCipA3 from Clostridium thermocellum. A complex cellulosome with two scaffoldins was also constructed using interactions between the displayed anchoring scaffoldin ScafAGA3 and scaffoldin I ScafCipA3 through disulfide bonds, and the assembly of secreted cellulases to ScafCipA3. The newly designed cellulosomes enabled yeast to directly ferment cellulose into ethanol. Conclusions This is the first report on the development of complex multiple-component assembly system through disulfide bonds. This strategy could facilitate the construction of yeast cell factories to express synergistic enzymes for use in biotechnology. Electronic supplementary material The online version of this article (10.1186/s12934-018-0971-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hongting Tang
- State Key Laboratory of Microbial Technology, Shandong University, Binhai Road 72, Jimo, Qingdao, 266237, People's Republic of China
| | - Jiajing Wang
- State Key Laboratory of Microbial Technology, Shandong University, Binhai Road 72, Jimo, Qingdao, 266237, People's Republic of China
| | - Shenghuan Wang
- State Key Laboratory of Microbial Technology, Shandong University, Binhai Road 72, Jimo, Qingdao, 266237, People's Republic of China
| | - Yu Shen
- State Key Laboratory of Microbial Technology, Shandong University, Binhai Road 72, Jimo, Qingdao, 266237, People's Republic of China
| | - Dina Petranovic
- Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivagen 10, 41296, Gothenburg, Sweden
| | - Jin Hou
- State Key Laboratory of Microbial Technology, Shandong University, Binhai Road 72, Jimo, Qingdao, 266237, People's Republic of China.
| | - Xiaoming Bao
- State Key Laboratory of Microbial Technology, Shandong University, Binhai Road 72, Jimo, Qingdao, 266237, People's Republic of China. .,Shandong Provincial Key Laboratory of Microbial Engineering, Qi Lu University of Technology, Jinan, 250353, People's Republic of China.
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High-throughput characterization of protein-protein interactions by reprogramming yeast mating. Proc Natl Acad Sci U S A 2017; 114:12166-12171. [PMID: 29087945 DOI: 10.1073/pnas.1705867114] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
High-throughput methods for screening protein-protein interactions enable the rapid characterization of engineered binding proteins and interaction networks. While existing approaches are powerful, none allow quantitative library-on-library characterization of protein interactions in a modifiable extracellular environment. Here, we show that sexual agglutination of Saccharomyces cerevisiae can be reprogrammed to link interaction strength with mating efficiency using synthetic agglutination (SynAg). Validation of SynAg with 89 previously characterized interactions shows a log-linear relationship between mating efficiency and protein binding strength for interactions with Kds ranging from below 500 pM to above 300 μM. Using induced chromosomal translocation to pair barcodes representing binding proteins, thousands of distinct interactions can be screened in a single pot. We demonstrate the ability to characterize protein interaction networks in a modifiable environment by introducing a soluble peptide that selectively disrupts a subset of interactions in a representative network by up to 800-fold. SynAg enables the high-throughput, quantitative characterization of protein-protein interaction networks in a fully defined extracellular environment at a library-on-library scale.
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Lim S, Glasgow JE, Interrante MF, Storm EM, Cochran JR. Dual display of proteins on the yeast cell surface simplifies quantification of binding interactions and enzymatic bioconjugation reactions. Biotechnol J 2017; 12:10.1002/biot.201600696. [PMID: 28299901 PMCID: PMC5708543 DOI: 10.1002/biot.201600696] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 03/14/2017] [Accepted: 03/15/2017] [Indexed: 11/12/2022]
Abstract
Yeast surface display, a well-established technology for protein analysis and engineering, involves expressing a protein of interest as a genetic fusion to either the N- or C-terminus of the yeast Aga2p mating protein. Historically, yeast-displayed protein variants are flanked by peptide epitope tags that enable flow cytometric measurement of construct expression using fluorescent primary or secondary antibodies. Here, we built upon this technology to develop a new yeast display strategy that comprises fusion of two different proteins to Aga2p, one to the N-terminus and one to the C-terminus. This approach allows an antibody fragment, ligand, or receptor to be directly coupled to expression of a fluorescent protein readout, eliminating the need for antibody-staining of epitope tags to quantify yeast protein expression levels. We show that this system simplifies quantification of protein-protein binding interactions measured on the yeast cell surface. Moreover, we show that this system facilitates co-expression of a bioconjugation enzyme and its corresponding peptide substrate on the same Aga2p construct, enabling enzyme expression and catalytic activity to be measured on the surface of yeast.
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Affiliation(s)
- Sungwon Lim
- Dept. of Bioengineering, Schools of Engineering and Medicine, Stanford University, Stanford, CA, USA
| | - Jeff E. Glasgow
- Dept. of Bioengineering, Schools of Engineering and Medicine, Stanford University, Stanford, CA, USA
- Joint Initiative for Metrology in Biology, Stanford, CA, USA
- Genome-scale Measurements Group, National Institute of Standards and Technology, Stanford, CA, USA
| | | | - Erica M. Storm
- School of Medicine, Stanford University, Stanford, CA, USA
| | - Jennifer R. Cochran
- Dept. of Bioengineering, Schools of Engineering and Medicine, Stanford University, Stanford, CA, USA
- Dept. of Chemical Engineering, School of Engineering, Stanford University, Stanford, CA, USA
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11
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Establishment of insect cell lines expressing green fluorescent protein on cell surface based on AcMNPV GP64 membrane fusion characteristic. Cytotechnology 2017; 69:775-783. [PMID: 28365799 DOI: 10.1007/s10616-017-0086-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 03/17/2017] [Indexed: 12/16/2022] Open
Abstract
Displaying a protein on the surface of cells has been provided a very successful strategy to function research of exogenous proteins. Based on the membrane fusion characteristic of Autographa californica multiple nucleopolyhedrovirus envelope protein GP64, we amplified and cloned N-terminal signal peptide and C-terminal transmembrane domain as well as cytoplasmic tail domain of gp64 gene into vector pIZ/V5-His with multi-cloning sites to construct the cell surface expression vector pIZ/V5-gp64. To verify that the vector can be used to express proteins on the membrane of insect cells, a recombinant plasmid pIZ/V5-gp64-GFP was constructed by introducing the PCR amplified green fluorescent protein (GFP) gene and transfected into insect cell lines Sf9 and H5. The transected cells were screened with zeocin and cell cloning. PCR verification results showed that the GFP gene was successfully integrated into these cells. Green fluorescence in Sf9-GFP and H5-GFP cells was observed by using confocal laser scanning microscopy and immunofluorescence detection indicated that GFP protein was located on the cell membrane. Western blot results showed that a fusion protein GP64-GFP of about 40 kDa was expressed on the membrane of Sf9-GFP and H5-GFP cells. The expression system constructed in this paper can be used for localization and continuous expression of exogenous proteins on insect cell membrane.
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12
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Banderas A, Koltai M, Anders A, Sourjik V. Sensory input attenuation allows predictive sexual response in yeast. Nat Commun 2016; 7:12590. [PMID: 27557894 PMCID: PMC5007329 DOI: 10.1038/ncomms12590] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 07/14/2016] [Indexed: 12/22/2022] Open
Abstract
Animals are known to adjust their sexual behaviour depending on mate competition. Here we report similar regulation for mating behaviour in a sexual unicellular eukaryote, the budding yeast Saccharomyces cerevisiae. We demonstrate that pheromone-based communication between the two mating types, coupled to input attenuation by recipient cells, enables yeast to robustly monitor relative mate abundance (sex ratio) within a mixed population and to adjust their commitment to sexual reproduction in proportion to their estimated chances of successful mating. The mechanism of sex-ratio sensing relies on the diffusible peptidase Bar1, which is known to degrade the pheromone signal produced by mating partners. We further show that such a response to sexual competition within a population can optimize the fitness trade-off between the costs and benefits of mating response induction. Our study thus provides an adaptive explanation for the known molecular mechanism of pheromone degradation in yeast. Cells of the yeast Saccharomyces cerevisiae can mate with other cells of opposite mating type. Here, the authors show that the combination of a pheromone and a pheromone-degrading enzyme allows yeast cells to monitor relative mate abundance within a population and adjust their commitment to sexual reproduction.
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Affiliation(s)
- Alvaro Banderas
- Max Planck Institute for Terrestrial Microbiology &LOEWE Research Center for Synthetic Microbiology (SYNMIKRO), Karl-von-Frisch-Str. 16, D-35037 Marburg, Germany.,Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
| | - Mihaly Koltai
- Max Planck Institute for Terrestrial Microbiology &LOEWE Research Center for Synthetic Microbiology (SYNMIKRO), Karl-von-Frisch-Str. 16, D-35037 Marburg, Germany
| | - Alexander Anders
- Max Planck Institute for Terrestrial Microbiology &LOEWE Research Center for Synthetic Microbiology (SYNMIKRO), Karl-von-Frisch-Str. 16, D-35037 Marburg, Germany
| | - Victor Sourjik
- Max Planck Institute for Terrestrial Microbiology &LOEWE Research Center for Synthetic Microbiology (SYNMIKRO), Karl-von-Frisch-Str. 16, D-35037 Marburg, Germany
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A model for cell wall dissolution in mating yeast cells: polarized secretion and restricted diffusion of cell wall remodeling enzymes induces local dissolution. PLoS One 2014; 9:e109780. [PMID: 25329559 PMCID: PMC4199604 DOI: 10.1371/journal.pone.0109780] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 09/02/2014] [Indexed: 01/24/2023] Open
Abstract
Mating of the budding yeast, Saccharomyces cerevisiae, occurs when two haploid cells of opposite mating types signal using reciprocal pheromones and receptors, grow towards each other, and fuse to form a single diploid cell. To fuse, both cells dissolve their cell walls at the point of contact. This event must be carefully controlled because the osmotic pressure differential between the cytoplasm and extracellular environment causes cells with unprotected plasma membranes to lyse. If the cell wall-degrading enzymes diffuse through the cell wall, their concentration would rise when two cells touched each other, such as when two pheromone-stimulated cells adhere to each other via mating agglutinins. At the surfaces that touch, the enzymes must diffuse laterally through the wall before they can escape into the medium, increasing the time the enzymes spend in the cell wall, and thus raising their concentration at the point of attachment and restricting cell wall dissolution to points where cells touch each other. We tested this hypothesis by studying pheromone treated cells confined between two solid, impermeable surfaces. This confinement increases the frequency of pheromone-induced cell death, and this effect is diminished by reducing the osmotic pressure difference across the cell wall or by deleting putative cell wall glucanases and other genes necessary for efficient cell wall fusion. Our results support the model that pheromone-induced cell death is the result of a contact-driven increase in the local concentration of cell wall remodeling enzymes and suggest that this process plays an important role in regulating cell wall dissolution and fusion in mating cells.
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Jones SK, Hirakawa MP, Bennett RJ. Sexual biofilm formation in Candida tropicalis opaque cells. Mol Microbiol 2014; 92:383-98. [PMID: 24612417 DOI: 10.1111/mmi.12565] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/21/2014] [Indexed: 12/14/2022]
Abstract
Candida albicans and Candida tropicalis are opportunistic fungal pathogens that can transition between white and opaque phenotypic states. White and opaque cells differ both morphologically and in their responses to environmental signals. In C. albicans, opaque cells respond to sexual pheromones by undergoing conjugation, while white cells are induced by pheromones to form sexual biofilms. Here, we show that sexual biofilm formation also occurs in C. tropicalis but, unlike C. albicans, biofilms are formed exclusively by opaque cells. C. tropicalis biofilm formation was dependent on the pheromone receptors Ste2 and Ste3, confirming the role of pheromone signalling in sexual biofilm development. Structural analysis of C. tropicalis sexual biofilms revealed stratified communities consisting of a basal layer of yeast cells and an upper layer of filamentous cells, together with an extracellular matrix. Transcriptional profiling showed that genes involved in pheromone signalling and conjugation were upregulated in sexual biofilms. Furthermore, FGR23, which encodes an agglutinin-like protein, was found to enhance both mating and sexual biofilm formation. Together, these studies reveal that C. tropicalis opaque cells form sexual biofilms with a complex architecture, and suggest a conserved role for sexual agglutinins in mediating mating, cell cohesion and biofilm formation.
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Affiliation(s)
- Stephen K Jones
- Department of Microbiology and Immunology, Brown University, Providence, RI, 02912, USA
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Abstract
We tell of a journey that led to discovery of amyloids formed by yeast cell adhesins and their importance in biofilms and host immunity. We begin with the identification of the adhesin functional amyloid-forming sequences that mediate fiber formation in vitro. Atomic force microscopy and confocal microscopy show 2-dimensional amyloid "nanodomains" on the surface of cells that are activated for adhesion. These nanodomains are arrays of adhesin molecules that bind multivalent ligands with high avidity. Nanodomains form when adhesin molecules are stretched in the AFM or under laminar flow. Treatment with antiamyloid perturbants or mutation of the amyloid sequence prevents adhesion nanodomain formation and activation. We are now discovering biological consequences. Adhesin nanodomains promote formation and maintenance of biofilms, which are microbial communities. Also, in abscesses within candidiasis patients, we find adhesin amyloids on the surface of the fungi. In both human infection and a Caenorhabditis elegans infection model, the presence of fungal surface amyloids elicits anti-inflammatory responses. Thus, this is a story of how fungal adhesins respond to extension forces through formation of cell surface amyloid nanodomains, with key consequences for biofilm formation and host responses.
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Hirschmann WD, Westendorf H, Mayer A, Cannarozzi G, Cramer P, Jansen RP. Scp160p is required for translational efficiency of codon-optimized mRNAs in yeast. Nucleic Acids Res 2014; 42:4043-55. [PMID: 24445806 PMCID: PMC3973333 DOI: 10.1093/nar/gkt1392] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The budding yeast multi-K homology domain RNA-binding protein Scp160p binds to >1000 messenger RNAs (mRNAs) and polyribosomes, and its mammalian homolog vigilin binds transfer RNAs (tRNAs) and translation elongation factor EF1alpha. Despite its implication in translation, studies on Scp160p's molecular function are lacking to date. We applied translational profiling approaches and demonstrate that the association of a specific subset of mRNAs with ribosomes or heavy polysomes depends on Scp160p. Interaction of Scp160p with these mRNAs requires the conserved K homology domains 13 and 14. Transfer RNA pairing index analysis of Scp160p target mRNAs indicates a high degree of consecutive use of iso-decoding codons. As shown for one target mRNA encoding the glycoprotein Pry3p, Scp160p depletion results in translational downregulation but increased association with polysomes, suggesting that it is required for efficient translation elongation. Depletion of Scp160p also decreased the relative abundance of ribosome-associated tRNAs whose codons show low potential for autocorrelation on mRNAs. Conversely, tRNAs with highly autocorrelated codons in mRNAs are less impaired. Our data indicate that Scp160p might increase the efficiency of tRNA recharge, or prevent diffusion of discharged tRNAs, both of which were also proposed to be the likely basis for the translational fitness effect of tRNA pairing.
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Affiliation(s)
- Wolf D Hirschmann
- Interfaculty Institute for Biochemistry, Universität Tübingen, Hoppe-Seyler-Strasse 4, D-72076 Tübingen, Germany, Gene Center Munich and Department of Biochemistry, LMU München, Feodor-Lynen-Str. 25, D-81377 Munich, Germany, Institute of Plant Sciences, University of Bern, Altenbergrain 21, CH-3013 Bern, Switzerland and Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, D-37077 Göttingen, Germany
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Huberman LB, Murray AW. Genetically engineered transvestites reveal novel mating genes in budding yeast. Genetics 2013; 195:1277-90. [PMID: 24121774 PMCID: PMC3832273 DOI: 10.1534/genetics.113.155846] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2013] [Accepted: 09/30/2013] [Indexed: 01/19/2023] Open
Abstract
Haploid budding yeast has two mating types, defined by the alleles of the MAT locus, MATa and MATα. Two haploid cells of opposite mating types mate by signaling to each other using reciprocal pheromones and receptors, polarizing and growing toward each other, and eventually fusing to form a single diploid cell. The pheromones and receptors are necessary and sufficient to define a mating type, but other mating-type-specific proteins make mating more efficient. We examined the role of these proteins by genetically engineering "transvestite" cells that swap the pheromone, pheromone receptor, and pheromone processing factors of one mating type for another. These cells mate with each other, but their mating is inefficient. By characterizing their mating defects and examining their transcriptomes, we found Afb1 (a-factor barrier), a novel MATα-specific protein that interferes with a-factor, the pheromone secreted by MATa cells. Strong pheromone secretion is essential for efficient mating, and the weak mating of transvestites can be improved by boosting their pheromone production. Synthetic biology can characterize the factors that control efficiency in biological processes. In yeast, selection for increased mating efficiency is likely to have continually boosted pheromone levels and the ability to discriminate between partners who make more and less pheromone. This discrimination comes at a cost: weak mating in situations where all potential partners make less pheromone.
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Affiliation(s)
- Lori B. Huberman
- Molecular and Cellular Biology and Faculty of Arts and Sciences Center for Systems Biology, Harvard University, Cambridge, Massachusetts 02138
| | - Andrew W. Murray
- Molecular and Cellular Biology and Faculty of Arts and Sciences Center for Systems Biology, Harvard University, Cambridge, Massachusetts 02138
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Hwp1 and related adhesins contribute to both mating and biofilm formation in Candida albicans. EUKARYOTIC CELL 2009; 8:1909-13. [PMID: 19837954 DOI: 10.1128/ec.00245-09] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Candida albicans Hwp1, Hwp2, and Rbt1 are related cell wall proteins expressed during the programs of sexual differentiation and filamentous growth. In this study, we compare strains lacking either single factors or a combination of these genes, and we demonstrate distinct but overlapping roles in mating and biofilm formation.
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Conserved WCPL and CX4C domains mediate several mating adhesin interactions in Saccharomyces cerevisiae. Genetics 2009; 182:173-89. [PMID: 19299340 DOI: 10.1534/genetics.108.100073] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Several adhesins are induced by pheromones during mating in Saccharomyces cerevisiae, including Aga1p, Aga2p, Sag1p (Agalpha1p), and Fig2p. These four proteins all participate in or influence a well-studied agglutinin interaction mediated by Aga1p-Aga2p complexes and Sag1p; however, they also play redundant and essential roles in mating via an unknown mechanism. Aga1p and Fig2p both contain repeated, conserved WCPL and CX(4)C domains. This study was directed toward understanding the mechanism underlying the collective requirement of agglutinins and Fig2p for mating. Apart from the well-known agglutinin interaction between Aga2p and Sag1p, three more pairs of interactions in cells of opposite mating type were revealed by this study, including bilateral heterotypic interactions between Aga1p and Fig2p and a homotypic interaction between Fig2p and Fig2p. These four pairs of adhesin interactions are collectively required for maximum mating efficiency and normal zygote morphogenesis. GPI-less, epitope-tagged forms of Aga1p and Fig2p can be co-immunoprecipitated from the culture medium of mating cells in a manner dependent on the WCPL and CX(4)C domains in the R1 repeat of Aga1p. Using site-directed mutagenesis, the conserved residues in Aga1p that interact with Fig2p were identified. Aga1p is involved in two distinct adhesive functions that are independent of each other, which raises the possibility for combinatorial interactions of this protein with its different adhesion receptors, Sag1 and Fig2p, a property of many higher eukaryotic adhesins.
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20
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Fichtner L, Schulze F, Braus GH. Differential Flo8p-dependent regulation of FLO1 and FLO11 for cell-cell and cell-substrate adherence of S. cerevisiae S288c. Mol Microbiol 2008; 66:1276-89. [PMID: 18001350 PMCID: PMC2780560 DOI: 10.1111/j.1365-2958.2007.06014.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Cell–cell and cell–surface adherence represents initial steps in forming multicellular aggregates or in establishing cell–surface interactions. The commonly used Saccharomyces cerevisiae laboratory strain S288c carries a flo8 mutation, and is only able to express the flocculin-encoding genes FLO1 and FLO11, when FLO8 is restored. We show here that the two flocculin genes exhibit differences in regulation to execute distinct functions under various environmental conditions. In contrast to the laboratory strain Σ1278b, haploids of the S288c genetic background require FLO1 for cell–cell and cell–substrate adhesion, whereas FLO11 is required for pseudohyphae formation of diploids. In contrast to FLO11, FLO1 repression requires the Sin4p mediator tail component, but is independent of the repressor Sfl1p. FLO1 regulation also differs from FLO11, because it requires neither the KSS1 MAP kinase cascade nor the pathways which lead to the transcription factors Gcn4p or Msn1p. The protein kinase A pathway and the transcription factors Flo8p and Mss11p are the major regulators for FLO1 expression. Therefore, S. cerevisiae is prepared to simultaneously express two genes of its otherwise silenced FLO reservoir resulting in an appropriate cellular surface for different environments.
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Affiliation(s)
- Lars Fichtner
- Institut für Mikrobiologie und Genetik, DFG Research Center for Molecular Physiology of the Brain (CMPB), Georg-August Universität Göttingen, Grisebachstr. 8, D-37077 Göttingen, Germany
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21
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Dranginis AM, Rauceo JM, Coronado JE, Lipke PN. A biochemical guide to yeast adhesins: glycoproteins for social and antisocial occasions. Microbiol Mol Biol Rev 2007; 71:282-94. [PMID: 17554046 PMCID: PMC1899881 DOI: 10.1128/mmbr.00037-06] [Citation(s) in RCA: 219] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Fungi are nonmotile eukaryotes that rely on their adhesins for selective interaction with the environment and with other fungal cells. Glycosylphosphatidylinositol (GPI)-cross-linked adhesins have essential roles in mating, colony morphology, host-pathogen interactions, and biofilm formation. We review the structure and binding properties of cell wall-bound adhesins of ascomycetous yeasts and relate them to their effects on cellular interactions, with particular emphasis on the agglutinins and flocculins of Saccharomyces and the Als proteins of Candida. These glycoproteins share common structural motifs tailored to surface activity and biological function. After being secreted to the outer face of the plasma membrane, they are covalently anchored in the wall through modified GPI anchors, with their binding domains elevated beyond the wall surface on highly glycosylated extended stalks. N-terminal globular domains bind peptide or sugar ligands, with between millimolar and nanomolar affinities. These affinities and the high density of adhesins and ligands at the cell surface determine microscopic and macroscopic characteristics of cell-cell associations. Central domains often include Thr-rich tandemly repeated sequences that are highly glycosylated. These domains potentiate cell-to-cell binding, but the molecular mechanism of such an association is not yet clear. These repeats also mediate recombination between repeats and between genes. The high levels of recombination and epigenetic regulation are sources of variation which enable the population to continually exploit new niches and resources.
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Affiliation(s)
- Anne M Dranginis
- Department of Biological Science, St John's University, Queens, New York, USA
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22
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Huang G, Zhang M, Erdman SE. Posttranslational modifications required for cell surface localization and function of the fungal adhesin Aga1p. EUKARYOTIC CELL 2004; 2:1099-114. [PMID: 14555493 PMCID: PMC219368 DOI: 10.1128/ec.2.5.1099-1114.2003] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Adherence of fungal cells to host substrates and each other affects their access to nutrients, sexual conjugation, and survival in hosts. Adhesins are cell surface proteins that mediate these different cell adhesion interactions. In this study, we examine the in vivo functional requirements for specific posttranslational modifications to these proteins, including glycophosphatidylinositol (GPI) anchor addition and O-linked glycosylation. The processing of some fungal GPI anchors, creating links to cell wall beta-1,6 glucans, is postulated to facilitate postsecretory traffic of proteins to cell wall domains conducive to their functions. By studying the yeast sexual adhesin subunit Aga1p, we found that deletion of its signal sequence for GPI addition eliminated its activity, while deletions of different internal domains had various effects on function. Substitution of the Aga1p GPI signal domain with those of other GPI-anchored proteins, a single transmembrane domain, or a cysteine capable of forming a disulfide all produced functional adhesins. A portion of the cellular pool of Aga1p was determined to be cell wall resident. Aga1p and the alpha-agglutinin Agalpha1p were shown to be under glycosylated in cells lacking the protein mannosyltransferase genes PMT1 and PMT2, with phenotypes manifested only in MATalpha cells for single mutants but in both cell types when both genes are absent. We conclude that posttranslational modifications to Aga1p are necessary for its biogenesis and activity. Our studies also suggest that in addition to GPI-glucan linkages, other cell surface anchorage mechanisms, such as transmembrane domains or disulfides, may be employed by fungal species to localize adhesins.
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Affiliation(s)
- Guohong Huang
- Department of Biology, Syracuse University, Syracuse, New York 13244, USA.
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23
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Braus GH, Grundmann O, Brückner S, Mösch HU. Amino acid starvation and Gcn4p regulate adhesive growth and FLO11 gene expression in Saccharomyces cerevisiae. Mol Biol Cell 2003; 14:4272-84. [PMID: 14517335 PMCID: PMC207018 DOI: 10.1091/mbc.e03-01-0042] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2003] [Revised: 05/22/2003] [Accepted: 05/27/2003] [Indexed: 11/11/2022] Open
Abstract
In baker's yeast Saccharomyces cerevisiae, cell-cell and cell-surface adhesion are required for haploid invasive growth and diploid pseudohyphal development. These morphogenetic events are induced by starvation for glucose or nitrogen and require the cell surface protein Flo11p. We show that amino acid starvation is a nutritional signal that activates adhesive growth and expression of FLO11 in both haploid and diploid strains in the presence of glucose and ammonium, known suppressors of adhesion. Starvation-induced adhesive growth requires Flo11p and is under control of Gcn2p and Gcn4p, elements of the general amino acid control system. Tpk2p and Flo8p, elements of the cAMP pathway, are also required for activation but not Ste12p and Tec1p, known targets of the mitogen-activated protein kinase cascade. Promoter analysis of FLO11 identifies one upstream activation sequence (UASR) and one repression site (URS) that confer regulation by amino acid starvation. Gcn4p is not required for regulation of the UASR by amino acid starvation, but seems to be indirectly required to overcome the negative effects of the URS on FLO11 transcription. In addition, Gcn4p controls expression of FLO11 by affecting two basal upstream activation sequences (UASB). In summary, our study suggests that amino acid starvation is a nutritional signal that triggers a Gcn4p-controlled signaling pathway, which relieves repression of FLO11 gene expression and induces adhesive growth.
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Affiliation(s)
- Gerhard H Braus
- Institute for Microbiology and Genetics, Georg-August-University, D-37077 Göttingen, Germany.
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Zhang N, Harrex AL, Holland BR, Fenton LE, Cannon RD, Schmid J. Sixty alleles of the ALS7 open reading frame in Candida albicans: ALS7 is a hypermutable contingency locus. Genome Res 2003; 13:2005-17. [PMID: 12952872 PMCID: PMC403672 DOI: 10.1101/gr.1024903] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2002] [Accepted: 06/30/2003] [Indexed: 12/22/2022]
Abstract
The ALS (agglutinin-like sequence) gene family encodes proteins that play a role in adherence of the yeast Candida albicans to endothelial and epithelial cells. The proteins are proposed as virulence factors for this important fungal pathogen of humans. We analyzed 66 C. albicans strains, representing a worldwide collection of 266 infection-causing isolates, and discovered 60 alleles of the ALS7 open reading frame (ORF). Differences between alleles were largely caused by rearrangements of repeat elements in the so-called tandem repeat domain (21 different types occurred) and the VASES region (19 different types). C. albicans is diploid, and combinations of ALS7 alleles generated 49 different genotypes. ALS7 expression was detected in samples isolated directly from five oral candidosis patients. ORFs in the opposite direction contained within the ALS7 ORF were also transcribed in all strains tested. Isolates representing a more pathogenic general-purpose genotype (GPG) cluster of strains tended to have more tandem repeats than other strains. Two types of VASES regions were largely exclusive to GPG strains; the remaining types were largely exclusive to noncluster strains. Our results provide evidence that ALS7 is a hypermutable contingency locus and important for the success of C. albicans as an opportunistic pathogen of humans.
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Affiliation(s)
- Ningxin Zhang
- Institute of Molecular BioSciences, Massey University, Palmerston North, New Zealand
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25
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Woo PCY, Chong KTK, Leung ASP, Wong SSY, Lau SKP, Yuen KY. AFLMP1 encodes an antigenic cel wall protein in Aspergillus flavus. J Clin Microbiol 2003; 41:845-50. [PMID: 12574298 PMCID: PMC149704 DOI: 10.1128/jcm.41.2.845-850.2003] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have previously reported the cloning and characterization of the MP1 gene in Penicillium marneffei and the AFMP1 gene in Aspergillus fumigatus and their use for serodiagnosis of penicilliosis and aspergilloma and invasive aspergillosis, respectively. In this study, we describe the cloning of the AFLMP1 gene, which encodes the homologous antigenic cell wall protein in Aspergillus flavus, the most common Aspergillus species associated with human disease in our locality and in other Asian countries and the second most common Aspergillus species associated with human disease in Western countries. AFLMP1 codes for a protein, Aflmp1p, of 273 amino acid residues, with a few sequence features that are present in Mp1p and Afmp1p, the homologous antigenic cell wall proteins in P. marneffei and A. fumigatus, respectively, as well as several other cell wall proteins of Saccharomyces cerevisiae and Candida albicans. It contains a serine- and threonine-rich region for O glycosylation, a signal peptide, and a putative glycosylphosphatidylinositol attachment signal sequence. Specific anti-Aflmp1p antibody was generated with recombinant Aflmp1p protein purified from Escherichia coli to allow further characterization of Aflmp1p. Indirect immunofluorescence analysis indicated that Aflmp1p is present on the surface of the hyphae of A. flavus. Finally, it was observed that patients with aspergilloma and invasive aspergillosis due to A. flavus develop a specific antibody response against Aflmp1p. This suggested that the recombinant protein and its antibody may be useful for serodiagnosis in patients with aspergilloma or invasive aspergillosis, and the protein may represent a good cell surface target for host humoral immunity.
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Affiliation(s)
- Patrick C Y Woo
- Department of Microbiology, The University of Hong Kong, Queen Mary Hospital, Hong Kong
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Monteoliva L, Matas ML, Gil C, Nombela C, Pla J. Large-scale identification of putative exported proteins in Candida albicans by genetic selection. EUKARYOTIC CELL 2002; 1:514-25. [PMID: 12456000 PMCID: PMC117995 DOI: 10.1128/ec.1.4.514-525.2002] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In all living organisms, secreted proteins play essential roles in different processes. Of special interest is the construction of the fungal cell wall, since this structure is absent from mammalian cells. The identification of the proteins involved in its biogenesis is therefore a primary goal in antifungal research. To perform a systematic identification of such proteins in Candida albicans, we carried out a genetic screening in which in-frame fusions with an intracellular allele of invertase gene SUC2 of Saccharomyces cerevisiae can be used to select and identify putatively exported proteins in the heterologous host S. cerevisiae. Eighty-three clones were selected, including 11 previously identified genes from C. albicans as well as 41 C. albicans genes that encode proteins homologous to already described proteins from related organisms. They include enzymes involved in cell wall synthesis and protein secretion. We also found membrane receptors and transporters presumably related to the interaction of C. albicans with the environment as well as extracellular enzymes and proteins involved in different morphological transitions. In addition, 11 C. albicans open reading frames (ORFs) identified in this screening encode proteins homologous to unknown or putative proteins, while 5 ORFs encode novel secreted proteins without known homologues in other organisms. This screening procedure therefore not only identifies a set of targets of interest in antifungal research but also provides new clues for understanding the topological locations of many proteins involved in processes relevant to the pathogenicity of this microorganism.
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Affiliation(s)
- L Monteoliva
- Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid, E-28040 Madrid, Spain
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27
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Sheehan D, Meade G, Foley VM, Dowd CA. Structure, function and evolution of glutathione transferases: implications for classification of non-mammalian members of an ancient enzyme superfamily. Biochem J 2001; 360:1-16. [PMID: 11695986 PMCID: PMC1222196 DOI: 10.1042/0264-6021:3600001] [Citation(s) in RCA: 702] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The glutathione transferases (GSTs; also known as glutathione S-transferases) are major phase II detoxification enzymes found mainly in the cytosol. In addition to their role in catalysing the conjugation of electrophilic substrates to glutathione (GSH), these enzymes also carry out a range of other functions. They have peroxidase and isomerase activities, they can inhibit the Jun N-terminal kinase (thus protecting cells against H(2)O(2)-induced cell death), and they are able to bind non-catalytically a wide range of endogenous and exogenous ligands. Cytosolic GSTs of mammals have been particularly well characterized, and were originally classified into Alpha, Mu, Pi and Theta classes on the basis of a combination of criteria such as substrate/inhibitor specificity, primary and tertiary structure similarities and immunological identity. Non-mammalian GSTs have been much less well characterized, but have provided a disproportionately large number of three-dimensional structures, thus extending our structure-function knowledge of the superfamily as a whole. Moreover, several novel classes identified in non-mammalian species have been subsequently identified in mammals, sometimes carrying out functions not previously associated with GSTs. These studies have revealed that the GSTs comprise a widespread and highly versatile superfamily which show similarities to non-GST stress-related proteins. Independent classification systems have arisen for groups of organisms such as plants and insects. This review surveys the classification of GSTs in non-mammalian sources, such as bacteria, fungi, plants, insects and helminths, and attempts to relate them to the more mainstream classification system for mammalian enzymes. The implications of this classification with regard to the evolution of GSTs are discussed.
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Affiliation(s)
- D Sheehan
- Department of Biochemistry, University College Cork, Lee Maltings, Prospect Row, Mardyke, Cork, Ireland.
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Yuen KY, Chan CM, Chan KM, Woo PC, Che XY, Leung AS, Cao L. Characterization of AFMP1: a novel target for serodiagnosis of aspergillosis. J Clin Microbiol 2001; 39:3830-7. [PMID: 11682494 PMCID: PMC88451 DOI: 10.1128/jcm.39.11.3830-3837.2001] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We cloned the AFMP1 gene, which encodes the first antigenic cell wall galactomannoprotein in Aspergillus fumigatus. AFMP1 codes for a protein, Afmp1p, of 284 amino acid residues, with a few sequence features that are present in Mp1p, the antigenic cell wall mannoprotein in Penicillium marneffei that we described previously, as well as several other cell wall proteins of Saccharomyces cerevisiae and Candida albicans. It contains a serine- and threonine-rich region for O glycosylation, a signal peptide, and a putative glycosylphosphatidyl inositol attachment signal sequence. Specific anti-Afmp1p antibody was generated with recombinant Afmp1p protein purified from Escherichia coli to allow further characterization of Afmp1p. Afmp1p has a high affinity for Galanthus nivalis agglutinin, a characteristic indicative of a mannoprotein. Furthermore, it was recognized by a rat monoclonal antibody against the galactofuran side chain of galactomannan, indicating that it is a galactomannoprotein. Ultrastructural analysis by immunogold staining indicated that Afmp1p is present in the cell walls of the hyphae and conidia of A. fumigatus. Finally, it was observed that patients with aspergilloma and invasive aspergillosis due to A. fumigatus develop a specific antibody response against Afmp1p. This suggested that the recombinant protein and its antibody may be useful for serodiagnosis in patients with aspergilloma or invasive aspergillosis, and the protein may represent a good cell surface target for host humoral immunity.
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Affiliation(s)
- K Y Yuen
- Department of Microbiology, The University of Hong Kong, Queen Mary Hospital, Hong Kong.
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Zhao H, Shen ZM, Kahn PC, Lipke PN. Interaction of alpha-agglutinin and a-agglutinin, Saccharomyces cerevisiae sexual cell adhesion molecules. J Bacteriol 2001; 183:2874-80. [PMID: 11292808 PMCID: PMC99505 DOI: 10.1128/jb.183.9.2874-2880.2001] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
alpha-Agglutinin and a-agglutinin are complementary cell adhesion glycoproteins active during mating in the yeast Saccharomyces cerevisiae. They bind with high affinity and high specificity: cells of opposite mating types are irreversibly bound by a few pairs of agglutinins. Equilibrium and surface plasmon resonance kinetic analyses showed that the purified binding region of alpha-agglutinin interacted similarly with purified a-agglutinin and with a-agglutinin expressed on cell surfaces. At 20 degrees C, the K(D) for the interaction was 2 x 10(-9) to 5 x 10(-9) M. This high affinity was a result of a very low dissociation rate ( approximately 2.6 x 10(-4) s(-1)) coupled with a low association rate (= 5 x 10(4) M(-1) s(-1)). Circular-dichroism spectroscopy showed that binding of the proteins was accompanied by measurable changes in secondary structure. Furthermore, when binding was assessed at 10 degrees C, the association kinetics were sigmoidal, with a very low initial rate. An induced-fit model of binding with substantial apposition of hydrophobic surfaces on the two ligands can explain the observed affinity, kinetics, and specificity and the conformational effects of the binding reaction.
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Affiliation(s)
- H Zhao
- Department of Biological Sciences and the Institute for Biomolecular Structure and Function, Hunter College of the City University of New York, New York, 10021, USA
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Abramova N, Sertil O, Mehta S, Lowry CV. Reciprocal regulation of anaerobic and aerobic cell wall mannoprotein gene expression in Saccharomyces cerevisiae. J Bacteriol 2001; 183:2881-7. [PMID: 11292809 PMCID: PMC99506 DOI: 10.1128/jb.183.9.2881-2887.2001] [Citation(s) in RCA: 119] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The DAN/TIR genes encode nine cell wall mannoproteins in Saccharomyces cerevisiae which are expressed during anaerobiosis (DAN1, DAN2, DAN3, DAN4, TIR1, TIR2, TIR3, TIR4, and TIP1). Most are expressed within an hour of an anaerobic shift, but DAN2 and DAN3 are expressed after about 3 h. At the same time, CWP1 and CWP2, the genes encoding the major mannoproteins, are down-regulated, suggesting that there is a programmed remodeling of the cell wall in which Cwp1 and Cwp2 are replaced by nine anaerobic counterparts. TIP1, TIR1, TIR2, and TIR4 are also induced during cold shock. Correspondingly, CWP1 is down-regulated during cold shock. As reported elsewhere, Mox4 is a heme-inhibited activator, and Mot3 is a heme-induced repressor of the DAN/TIR genes (but not of TIP1). We show that CWP2 (but not CWP1) is controlled by the same factors, but in reverse fashion-primarily by Mot3 (which can function as either an activator or repressor) but also by Mox4, accounting for the reciprocal regulation of the two groups of genes. Disruptions of TIR1, TIR3, or TIR4 prevent anaerobic growth, indicating that each protein is essential for anaerobic adaptation. The Dan/Tir and Cwp proteins are homologous, with the greatest similarities shown within three subgroups: the Dan proteins, the Tip and Tir proteins, and, more distantly, the Cwp proteins. The clustering of homology corresponds to differences in expression: the Tip and Tir proteins are expressed during hypoxia and cold shock, the Dan proteins are more stringently repressed by oxygen and insensitive to cold shock, and the Cwp proteins are oppositely regulated by oxygen and temperature.
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Affiliation(s)
- N Abramova
- Center for Immunology and Microbial Disease, Albany Medical College, New York 12208, USA
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31
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Zou W, Ueda M, Tanaka A. Genetically controlled self-aggregation of cell-surface-engineered yeast responding to glucose concentration. Appl Environ Microbiol 2001; 67:2083-7. [PMID: 11319085 PMCID: PMC92840 DOI: 10.1128/aem.67.5.2083-2087.2001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We constructed an arming (cell-surface-engineered) yeast displaying two types of agglutinin (modified a-agglutinin and alpha-agglutinin) on the cell surface, with agglutination being independent of both mating type and pheromones. The modified a-agglutinin was artificially prepared by the fusion of the genes encoding Aga1p and Aga2p. The modified a-agglutinin could induce agglutination of cells displaying Agalpha1p (alpha-agglutinin). The upstream region of the isocitrate lyase gene of Candida tropicalis (UPR-ICL), active at a low glucose concentration, was used as the promoter to express the modified a-agglutinin- and alpha-agglutinin-encoding genes. The arming yeast displaying both agglutinins agglutinated and sedimented in response to decreased glucose concentration. When the glucose concentration was high, the arming yeast grew normally. In the late log phase, when the glucose concentration became very low, agglutination occurred suddenly and drastically and yeast cells sedimented completely. Sedimentation was confirmed by weighing the aggregated cells after filtration of the broth. Strains in which aggregation can be genetically controlled can be used in industrial processes in which the separation of yeast cells from the supernatant is necessary.
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Affiliation(s)
- W Zou
- Laboratory of Applied Biological Chemistry, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan
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Guo B, Styles CA, Feng Q, Fink GR. A Saccharomyces gene family involved in invasive growth, cell-cell adhesion, and mating. Proc Natl Acad Sci U S A 2000; 97:12158-63. [PMID: 11027318 PMCID: PMC17311 DOI: 10.1073/pnas.220420397] [Citation(s) in RCA: 299] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The cell wall of bakers' yeast contains a family of glycosyl-phosphatidylinositol (GPI)-linked glycoproteins of domain structure similar to the adhesins of pathogenic fungi. In wild-type cells each of these proteins has a unique function in different developmental processes (mating, invasive growth, cell-cell adhesion, or filamentation). What unifies these developmental events is adhesion, either to an inert substrate or to a cell. Although they differ in their specificities, many of these proteins can substitute for each other when overexpressed. For example, Flo11p is required during vegetative growth for haploid invasion and diploid filamentation, whereas Fig2p is required for mating. When overexpressed, Flo11p and Fig2p can function in mating, invasion, filamentation, and flocculation. The ability of Flo11p to supply Fig2p function in mating depends on its intracellular localization to the mating projection, where Fig2p normally functions in the adhesion of mating cells. Our data show that even distant family members retain the ability to carry out disparate functions if localized and expressed appropriately.
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Affiliation(s)
- B Guo
- Whitehead Institute for Biomedical Research/Massachusetts Institute of Technology, Nine Cambridge Center, Cambridge, MA 02142, USA
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33
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Sharkey LL, McNemar MD, Saporito-Irwin SM, Sypherd PS, Fonzi WA. HWP1 functions in the morphological development of Candida albicans downstream of EFG1, TUP1, and RBF1. J Bacteriol 1999; 181:5273-9. [PMID: 10464197 PMCID: PMC94032 DOI: 10.1128/jb.181.17.5273-5279.1999] [Citation(s) in RCA: 147] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The morphological plasticity of Candida albicans is an important determinant of pathogenicity, and nonfilamentous mutants are avirulent. HWP1, a hypha-specific gene, was identified in a genetic screen for developmentally regulated genes and encodes a cell surface protein of unknown function. Heterozygous and homozygous deletions of HWP1 resulted in a medium-conditional defect in hyphal development. HWP1 expression was blocked in a Deltaefg1 mutant, reduced in an Deltarbf1 mutant, and derepressed in a Deltatup1 mutant. Therefore, HWP1 functions downstream of the developmental regulators EFG1, TUP1, and RBF1. Mutation of CPH1 had no effect on HWP1 expression, suggesting that the positive regulators of hyphal development, CPH1 and EFG1, are components of separate pathways with different target genes. The expression of a second developmentally regulated gene, ECE1, was similarly regulated by EFG1. Since ECE1 is not required for hyphal development, the regulatory role of EFG1 apparently extends beyond the control of cell shape determinants. However, expression of ECE1 was not influenced by TUP1, suggesting that there may be some specificity in the regulation of morphogenic elements during hyphal development.
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Affiliation(s)
- L L Sharkey
- Department of Microbiology and Immunology, Georgetown University, Washington, D.C. 20007, USA
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Hamada K, Terashima H, Arisawa M, Yabuki N, Kitada K. Amino acid residues in the omega-minus region participate in cellular localization of yeast glycosylphosphatidylinositol-attached proteins. J Bacteriol 1999; 181:3886-9. [PMID: 10383953 PMCID: PMC93875 DOI: 10.1128/jb.181.13.3886-3889.1999] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The final destination of glycosylphosphatidylinositol (GPI)-attached proteins in Saccharomyces cerevisiae is the plasma membrane or the cell wall. Two kinds of signals have been proposed for their cellular localization: (i) the specific amino acid residues V, I, or L at the site 4 or 5 amino acids upstream of the GPI attachment site (the omega site) and Y or N at the site 2 amino acids upstream of the omega site for cell wall localization and (ii) dibasic residues in the region upstream of the omega site (the omega-minus region) for plasma membrane localization. The relationships between these amino acid residues and efficiencies of cell wall incorporation were examined by constructing fusion reporter proteins from open reading frames encoding putative GPI-attached proteins. The levels of incorporation were high in the constructs containing the specific amino acid residues and quite low in those containing two basic amino acid residues in the omega-minus region. With constructs that contained neither specific residues nor two basic residues, levels of incorporation were moderate. These correlations clearly suggest that GPI-attached proteins have two different signals which act positively or negatively in cell wall incorporation for their cellular localization.
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Affiliation(s)
- K Hamada
- Department of Mycology, Nippon Roche Research Center, Kamakura, Kanagawa 247-8530, Japan
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Jackson RJ, Hall DF, Kerr PJ. Myxoma virus encodes an alpha2,3-sialyltransferase that enhances virulence. J Virol 1999; 73:2376-84. [PMID: 9971821 PMCID: PMC104483 DOI: 10.1128/jvi.73.3.2376-2384.1999] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/1998] [Accepted: 12/08/1998] [Indexed: 11/20/2022] Open
Abstract
A 4.7-kb region of DNA sequence contained at the right end of the myxoma virus EcoRI-G2 fragment located 24 kb from the right end of the 163-kb genome has been determined. This region of the myxoma virus genome encodes homologs of the vaccinia virus genes A51R, A52R, A55R, A56R, and B1R; the myxoma virus gene equivalents have been given the prefix M. The MA55 gene encodes a protein belonging to the kelch family of actin-binding proteins, while the MA56 gene encodes a member of the immunoglobulin superfamily related to a variety of cellular receptors and adhesion molecules. A novel myxoma virus early gene, MST3N, is a member of the eukaryotic sialyltransferase gene family located between genes MA51 and MA52. Detergent lysates prepared from myxoma virus-infected cell cultures contained a virally encoded sialyltransferase activity that catalyzed the transfer of sialic acid (Sia) from CMP-Sia to an asialofetuin glycoprotein acceptor. Analysis of the in vitro-sialylated glycoprotein acceptor by digestion with N-glycosidase F and by lectin binding suggested that the MST3N gene encodes an enzyme with Galbeta1,3(4)GlcNAc alpha2,3-sialyltransferase specificity for the N-linked oligosaccharide of glycoprotein. Lectin binding assays demonstrated that alpha2,3-sialyltransferase activity is expressed by several known leporipoxviruses that naturally infect Sylvilagus rabbits. The sialyltransferase is nonessential for myxoma virus replication in cell culture; however, disruption of the MST3N gene caused attenuation in vivo. The possible implications of the myxoma virus-expressed sialyltransferase in terms of the host's defenses against infection are discussed.
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Affiliation(s)
- R J Jackson
- Vertebrate Biocontrol CRC, CSIRO Wildlife and Ecology, Canberra, Australia.
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36
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Chaffin WL, López-Ribot JL, Casanova M, Gozalbo D, Martínez JP. Cell wall and secreted proteins of Candida albicans: identification, function, and expression. Microbiol Mol Biol Rev 1998; 62:130-80. [PMID: 9529890 PMCID: PMC98909 DOI: 10.1128/mmbr.62.1.130-180.1998] [Citation(s) in RCA: 505] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The cell wall is essential to nearly every aspect of the biology and pathogenicity of Candida albicans. Although it was initially considered an almost inert cellular structure that protected the protoplast against osmotic offense, more recent studies have demonstrated that it is a dynamic organelle. The major components of the cell wall are glucan and chitin, which are associated with structural rigidity, and mannoproteins. The protein component, including both mannoprotein and nonmannoproteins, comprises some 40 or more moieties. Wall proteins may differ in their expression, secretion, or topological location within the wall structure. Proteins may be modified by glycosylation (primarily addition of mannose residues), phosphorylation, and ubiquitination. Among the secreted enzymes are those that are postulated to have substrates within the cell wall and those that find substrates in the extracellular environment. Cell wall proteins have been implicated in adhesion to host tissues and ligands. Fibrinogen, complement fragments, and several extracellular matrix components are among the host proteins bound by cell wall proteins. Proteins related to the hsp70 and hsp90 families of conserved stress proteins and some glycolytic enzyme proteins are also found in the cell wall, apparently as bona fide components. In addition, the expression of some proteins is associated with the morphological growth form of the fungus and may play a role in morphogenesis. Finally, surface mannoproteins are strong immunogens that trigger and modulate the host immune response during candidiasis.
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Affiliation(s)
- W L Chaffin
- Department of Microbiology and Immunology, Texas Tech University Health Sciences Center, Lubbock 79430, USA.
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37
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Cao L, Chan CM, Lee C, Wong SS, Yuen KY. MP1 encodes an abundant and highly antigenic cell wall mannoprotein in the pathogenic fungus Penicillium marneffei. Infect Immun 1998; 66:966-73. [PMID: 9488383 PMCID: PMC108003 DOI: 10.1128/iai.66.3.966-973.1998] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
We cloned the MP1 gene, which encodes an abundant antigenic cell wall mannoprotein from the dimorphic pathogenic fungus Penicillium marneffei. MP1 is a unique gene without homologs in sequence databases. It codes for a protein, Mp1p, of 462 amino acid residues, with a few sequence features that are present in several cell wall proteins of Saccharomyces cerevisiae and Candida albicans. It contains two putative N glycosylation sites, a serine- and threonine-rich region for O glycosylation, a signal peptide, and a putative glycosylphosphatidylinositol attachment signal sequence. Specific anti-Mp1p antibody was generated with recombinant Mp1p protein purified from Escherichia coli to allow further characterization of Mp1p. Western blot analysis with anti-Mp1p antibody revealed that Mp1p has predominant bands with molecular masses of 58 and 90 kDa and that it belongs to a group of cell wall proteins that can be readily removed from yeast cell surfaces by glucanase digestion. In addition, Mp1p is an abundant yeast glycoprotein and has high affinity for concanavalin A, a characteristic indicative of a mannoprotein. Furthermore, ultrastructural analysis with immunogold staining indicated that Mp1p is present in the cell walls of the yeast, hyphae, and conidia of P. marneffei. Finally, it was observed that infected patients develop a specific antibody response against Mp1p, suggesting that this protein represents a good cell surface target for host humoral immunity.
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Affiliation(s)
- L Cao
- Department of Microbiology, The University of Hong Kong.
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38
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Moukadiri I, Armero J, Abad A, Sentandreu R, Zueco J. Identification of a mannoprotein present in the inner layer of the cell wall of Saccharomyces cerevisiae. J Bacteriol 1997; 179:2154-62. [PMID: 9079899 PMCID: PMC178950 DOI: 10.1128/jb.179.7.2154-2162.1997] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Cell wall extracts from the double-mutant mnn1 mnn9 strain were used as the immunogen to obtain a monoclonal antibody (MAb), SAC A6, that recognizes a specific mannoprotein--which we have named Icwp--in the walls of cells of Saccharomyces cerevisiae. Icwp runs as a polydisperse band of over 180 kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of Zymolyase extracts of cell walls, although an analysis of the secretory pattern of the mannoprotein shows that at the level of secretory vesicles, it behaves like a discrete band of 140 kDa. Immunofluorescence analysis with the MAb showed that Icwp lies at the inner layer of the cell wall, being accessible to the antibody only after the outer layer of mannoproteins is disturbed by treatment with tunicamycin. The screening of a lambda gt11 expression library enabled us to identify the open reading frame (ORF) coding for Icwp. ICWP (EMBL accession number YLR391w, frame +3) codes for 238 amino acids, of which over 40% are serine or threonine, and contains a putative N-glycosylation site and a putative glycosylphosphatidylinositol attachment signal. Both disruption and overexpression of the ORF caused increased sensitivities to calcofluor white and Congo red, while the disruption caused an increased sensitivity to Zymolyase digestion, suggesting for Icwp a structural role in association with glucan.
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Affiliation(s)
- I Moukadiri
- Sección Departamental de Microbiología, Facultad de Farmacia, Universidad de Valencia, Burjassot, Spain
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39
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Lo WS, Dranginis AM. FLO11, a yeast gene related to the STA genes, encodes a novel cell surface flocculin. J Bacteriol 1996; 178:7144-51. [PMID: 8955395 PMCID: PMC178626 DOI: 10.1128/jb.178.24.7144-7151.1996] [Citation(s) in RCA: 166] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
We report the characterization of a gene encoding a novel flocculin related to the STA genes of yeast, which encode secreted glucoamylase. The STA genes comprise sequences that are homologous to the sporulation-specific glucoamylase SGA and to two other sequences, S2 and S1. We find that S2 and S1 are part of a single gene which we have named FLO11. The sequence of FLO11 reveals a 4,104-bp open reading frame on chromosome IX whose predicted product is similar in overall structure to the class of yeast serine/threonine-rich GPI-anchored cell wall proteins. An amino-terminal domain containing a signal sequence and a carboxy-terminal domain with homology to GPI (glycosyl-phosphatidyl-inositol) anchor-containing proteins are separated by a central domain containing a highly repeated threonine- and serine-rich sequence. Yeast cells that express FLO11 aggregate in the calcium-dependent process of flocculation. Flocculation is abolished when FLO11 is disrupted. The product of STA1 also is shown to have flocculating activity. When a green fluorescent protein fusion of FLO11 was expressed from the FLO11 promoter on a single-copy plasmid, fluorescence was observed in vivo at the periphery of cells. We propose that FLO11 encodes a flocculin because of its demonstrated role in flocculation, its structural similarity to other members of the FLO gene family, and the cell surface location of its product. FLO11 gene sequences are present in all yeast strains tested, including all standard laboratory strains, unlike the STA genes which are present only in the variant strain Saccharomyces cerevisiae var. diastaticus. FLO11 differs from all other yeast flocculins in that it is located near a centromere rather than a telomere, and its expression is regulated by mating type. Repression of FLO11-dependent flocculation in diploids is conferred by the mating-type repressor al/alpha2.
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Affiliation(s)
- W S Lo
- Department of Biological Sciences, St. John's University, Jamaica, New York 11439, USA
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40
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Bailey DA, Feldmann PJ, Bovey M, Gow NA, Brown AJ. The Candida albicans HYR1 gene, which is activated in response to hyphal development, belongs to a gene family encoding yeast cell wall proteins. J Bacteriol 1996; 178:5353-60. [PMID: 8808922 PMCID: PMC178351 DOI: 10.1128/jb.178.18.5353-5360.1996] [Citation(s) in RCA: 175] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
A hyphally regulated gene (HYR1) from the dimorphic human pathogenic fungus Candida albicans was isolated and characterized. Northern (RNA) analyses showed that the HYR1 mRNA was induced specifically in response to hyphal development when morphogenesis was stimulated by serum addition and temperature elevation, increases in both culture pH and temperature, or N-acetylglucosamine addition. The HYR1 gene sequence revealed a 937-codon open reading frame capable of encoding a protein with an N-terminal signal sequence, a C-terminal glycosylphosphatidylinositol-anchoring domain, 17 potential N glycosylation sites, and a large domain rich in serine and threonine (51% of 230 residues). These features are observed in many yeast cell wall proteins, but no homologs are present in the databases. In addition, Hyr1p contained a second domain rich in glycine, serine, and asparagine (79% of 239 residues). The HYR1 locus in C. albicans CAI4 was disrupted by "Ura-blasting," but the resulting homozygous delta hyr1/delta hyr1 null mutant displayed no obvious morphological phenotype. The growth rates for yeast cells and hyphae and the kinetics of germ tube formation in the null mutant were unaffected. Aberrant expression of HYR1 in yeast cells, when an ADH1-HYR1 fusion was used, did not stimulate hyphal formation in C. albicans or pseudohyphal growth in Saccharomyces cerevisiae. HYR1 appears to encode a nonessential component of the hyphal cell wall.
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Affiliation(s)
- D A Bailey
- Department of Molecular and Cell Biology, University of Aberdeen, United Kingdom
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41
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Weaver CH, Sheehan KC, Keath EJ. Localization of a yeast-phase-specific gene product to the cell wall in Histoplasma capsulatum. Infect Immun 1996; 64:3048-54. [PMID: 8757832 PMCID: PMC174186 DOI: 10.1128/iai.64.8.3048-3054.1996] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
A yeast-phase-specific gene, yps-3, has been identified in the virulent Histoplasma capsulatum strain, G217B. Although DNA sequencing of the genomic yps-3 gene from G217B failed to detect homologies with known proteins, the 5' end of a yps-3 cDNA contained a consensus signal sequence. A 519-bp fragment of the cDNA containing the translational stop codon was linker modified and inserted into the bacterial expression vector, pATH 1. Escherichia coli extracts containing the pATH 1 vector alone expressed a major 34-kDa TrpE polypeptide following induction with indoleacrylic acid, while the pATH 1/yps-3 construct produced a predominant 54-kDa TrpE/yps-3 fusion protein. Polyclonal rabbit sera directed against G217B reacted exclusively with the 54-kDa fusion protein in Western blots (immunoblots); serum samples from three patients with acute pulmonary or disseminated histoplasmosis were also positive. To localize the yps-3 protein within G217B, a monoclonal antibody (MAb 7.1) which recognized the yps-3 portion of the fusion protein was generated. A 17.4-kDa protein was detected with MAb 7.1 in Western blots prepared from cell wall fractions of G217B; cytoplasmic fractions were unreactive. No yps-3 antigen was detected in either fraction of the Downs strain, which fails to express the yps-3 gene. MAb 7.1 also detected a 17.4-kDa antigen in ethanol-precipitated culture supernatants derived from G217B. These findings localize the yps-3 gene product to the cell wall and culture supernatants, where the protein may influence the phase transition or the maintenance of the yeast state.
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Affiliation(s)
- C H Weaver
- Department of Biology, Saint Louis University, Missouri 63103, USA
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42
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Oehlen LJ, McKinney JD, Cross FR. Ste12 and Mcm1 regulate cell cycle-dependent transcription of FAR1. Mol Cell Biol 1996; 16:2830-7. [PMID: 8649392 PMCID: PMC231275 DOI: 10.1128/mcb.16.6.2830] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The transcripts of many genes involved in Saccharomyces cerevisiae mating were found to fluctuate during the cell cycle. In the absence of a functional Ste12 transcription factor, both the levels and the cell cycle pattern of expression of these genes were affected. FUS1 and AGA1 levels, which are maximally expressed only in G1-phase cells, were strongly reduced in ste12- cells. The cell cycle transcription pattern for FAR1 was changed in ste12- cells: the gene was still significantly expressed in G2/M, but transcript levels were strongly reduced in G1 phase, resulting in a lack of Far1 protein accumulation. G2/M transcription of FAR1 was dependent on the transcription factor Mcm1, and expression of a gene with Mcm1 fused to a strong transcriptional activation domain resulted in increased levels of FAR1 transcription. The pattern of cell cycle-regulated transcription of FAR1 could involve combinatorial control of Ste12 and Mcm1. Forced G1 expression of FAR1 from the GAL1 promoter resorted the ability to arrest in response to pheromone in ste12-cells. This indicates that transcription of FAR1 in the G1 phase is essential for accumulation of the protein and for pheromone-induced cell cycle arrest.
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Affiliation(s)
- L J Oehlen
- Rockefeller University, New York, New York 10021, USA
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43
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de Nobel H, Lipke PN, Kurjan J. Identification of a ligand-binding site in an immunoglobulin fold domain of the Saccharomyces cerevisiae adhesion protein alpha-agglutinin. Mol Biol Cell 1996; 7:143-53. [PMID: 8741846 PMCID: PMC278619 DOI: 10.1091/mbc.7.1.143] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The Saccharomyces cerevisiae adhesion protein alpha-agglutinin (Ag alpha 1p) is expressed by alpha cells and binds to the complementary a-agglutinin expressed by a cells. The N-terminal half of alpha-agglutinin is sufficient for ligand binding and has been proposed to contain an immunoglobulin (Ig) fold domain. Based on a structural homology model for this domain and a previously identified critical residue (His292), we made Ag alpha 1p mutations in three discontinuous patches of the domain that are predicted to be in close proximity to His292 in the model. Residues in each of the three patches were identified that are important for activity and therefore define a putative ligand binding site, whereas mutations in distant loops had no effect on activity. This putative binding site is on a different surface of the Ig fold than the defined binding sites of immunoglobulins and other members of the Ig superfamily. Comparison of protein interaction sites by structural and mutational analysis has indicated that the area of surface contact is larger than the functional binding site identified by mutagenesis. The putative alpha-agglutinin binding site is therefore likely to identify residues that contribute to the functional binding site within a larger area that contacts a-agglutinin.
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Affiliation(s)
- H de Nobel
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington 05405-0068, USA
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Benghezal M, Lipke PN, Conzelmann A. Identification of six complementation classes involved in the biosynthesis of glycosylphosphatidylinositol anchors in Saccharomyces cerevisiae. J Biophys Biochem Cytol 1995; 130:1333-44. [PMID: 7559756 PMCID: PMC2120569 DOI: 10.1083/jcb.130.6.1333] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Glycosylphosphatidylinositol (GPI)-anchored membrane proteins are synthesized by the posttranslational attachment of a preformed glycolipid to newly made glycoproteins. alpha-Agglutinin is a GPI-anchored glycoprotein that gets expressed at the cell surface of MAT alpha cells after induction with type a mating factor. Mutants affecting the biosynthesis of GPI anchors were obtained by selecting for the absence of alpha-agglutinin from the cell wall after induction with a-factor at 37 degrees C. 10 recessive mutants were grouped into 6 complementation classes, gpi4 to gpi9. Mutants are considered to be deficient in the biosynthesis of GPI anchors, since each mutant accumulates an abnormal, incomplete GPI glycolipid containing either zero, two, or four mannoses. One mutant accumulates a complete precursor glycolipid, suggesting that it might be deficient in the transfer of complete precursor lipids to proteins. When labeled with [2-3H]inositol, mutants accumulate reduced amounts of radiolabeled GPI-anchored proteins, and the export of the GPI-anchored Gas1p out of the ER is severely delayed in several mutant strains. On the other hand, invertase and acid phosphatase are secreted by all but one mutant. All mutants show an increased sensitivity to calcofluor white and hygromycin B. This suggests that GPI-anchored proteins are required for the integrity of the yeast cell wall.
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Affiliation(s)
- M Benghezal
- Institute of Biochemistry, University of Fribourg, Switzerland
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Wei YF, Chen BJ, Samson L. Suppression of Escherichia coli alkB mutants by Saccharomyces cerevisiae genes. J Bacteriol 1995; 177:5009-15. [PMID: 7665478 PMCID: PMC177278 DOI: 10.1128/jb.177.17.5009-5015.1995] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The alkB gene is one of a group of alkylation-inducible genes in Escherichia coli, and its product protects cells from SN2-type alkylating agents such as methyl methanesulfonate (MMS). However, the precise biochemical function of the AlkB protein remains unknown. Here, we describe the cloning, sequencing, and characterization of three Saccharomyces cerevisiae genes (YFW1, YFW12, and YFW16) that functionally complement E. coli alkB mutant cells. DNA sequence analysis showed that none of the three gene products have any amino acid sequence homology with the AlkB protein. The YFW1 and YFW12 proteins are highly serine and threonine rich, and YFW1 contains a stretch of 28 hydrophobic residues, indicating that it may be a membrane protein. The YFW16 gene turned out to be allelic with the S. cerevisiae STE11 gene. STE11 is a protein kinase known to be involved in pheromone signal transduction in S. cerevisiae; however, the kinase activity is not required for MMS resistance because mutant STE11 proteins lacking kinase activity could still complement E. coli alkB mutants. Despite the fact that YFW1, YFW12, and YFW16/STE11 each confer substantial MMS resistance upon E. coli alkB cells, S. cerevisiae null mutants for each gene were not MMS sensitive. Whether these three genes provide alkylation resistance in E. coli via an alkB-like mechanism remains to be determined, but protection appears to be specific for AlkB-deficient E. coli because none of the genes protect other alkylation-sensitive E. coli strains from killing by MMS.
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Affiliation(s)
- Y F Wei
- Department of Molecular and Cellular Toxicology, Harvard School of Public Health, Boston, Massachusetts, USA
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van der Vaart JM, Caro LH, Chapman JW, Klis FM, Verrips CT. Identification of three mannoproteins in the cell wall of Saccharomyces cerevisiae. J Bacteriol 1995; 177:3104-10. [PMID: 7768807 PMCID: PMC176999 DOI: 10.1128/jb.177.11.3104-3110.1995] [Citation(s) in RCA: 192] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Three glucanase-extractable cell wall proteins from Saccharomyces cerevisiae were purified, and their N-terminal amino acid sequences were determined. With this information, we were able to assign gene products to three known open reading frames (ORFs). The N-terminal sequence of a 55-kDa mannoprotein corresponded with the product of ORF YKL096w, which we named CWP1 (cell wall protein 1). A 80-kDa mannoprotein was identified as the product of the TIP1 gene, and a 180-kDa mannoprotein corresponded to the product of the ORF YKL444, which we named CWP2. CWP1, TIP1, and CWP2 encode proteins of 239, 210, and 92 amino acids, respectively. The C-terminal regions of these proteins all consist for more than 40% of serine/threonine and contain putative glycosylphosphatidylinositol attachment signals. Furthermore, Cwp1p and Tip1p were shown to carry a beta 1,6-glucose-containing side chain. The cwp2 deletion mutant displayed an increased sensitivity to Congo red, calcofluor white, and Zymolyase. Electron microscopic analysis of the cwp2 deletion mutant showed a strongly reduced electron-dense layer on the outside of the cell wall. These results indicate that Cwp2p is a major constituent of the cell wall and plays an important role in stabilizing the cell wall. Depletion of Cwp1p or Tip1p also caused increased sensitivities to Congo red and calcofluor white, but the effects were less pronounced than for cwp2 delta. All three cell wall proteins show a substantial homology with Srp1p, which also appears to be localized in the cell wall. We conclude that these four proteins are small structurally related cell wall proteins.
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Affiliation(s)
- J M van der Vaart
- Department of Molecular Cell Biology, University of Utrecht, The Netherlands
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Abstract
Saccharomyces cerevisiae alpha-agglutinin is a cell wall-anchored adhesion glycoprotein. The previously identified 140-kDa form, which contains a glycosyl-phosphatidylinositol (GPI) anchor (D. Wojciechowicz, C.-F. Lu, J. Kurjan, and P. N. Lipke, Mol. Cell. Biol. 13:2554-2563, 1993), and additional forms of 80, 150, 250 to 300, and > 300 kDa had the properties of intermediates in a transport and cell wall anchorage pathway. N glycosylation and additional modifications resulted in successive increases in size during transport. The 150- and 250- to 300-kDa forms were membrane associated and are likely to be intermediates between the 140-kDa form and a cell surface GPI-anchored form of > 300 kDa. A soluble form of > 300 kDa that lacked the GPI anchor had properties of a periplasmic intermediate between the plasma membrane form and the > 300-kDa cell wall-anchored form. These results constitute experimental support for the hypothesis that GPI anchors act to localize alpha-agglutinin to the plasma membrane and that cell wall anchorage involves release from the GPI anchor to produce a periplasmic intermediate followed by linkage to the cell wall.
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Lu CF, Kurjan J, Lipke PN. A pathway for cell wall anchorage of Saccharomyces cerevisiae alpha-agglutinin. Mol Cell Biol 1994; 14:4825-33. [PMID: 8007981 PMCID: PMC358855 DOI: 10.1128/mcb.14.7.4825-4833.1994] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Saccharomyces cerevisiae alpha-agglutinin is a cell wall-anchored adhesion glycoprotein. The previously identified 140-kDa form, which contains a glycosyl-phosphatidylinositol (GPI) anchor (D. Wojciechowicz, C.-F. Lu, J. Kurjan, and P. N. Lipke, Mol. Cell. Biol. 13:2554-2563, 1993), and additional forms of 80, 150, 250 to 300, and > 300 kDa had the properties of intermediates in a transport and cell wall anchorage pathway. N glycosylation and additional modifications resulted in successive increases in size during transport. The 150- and 250- to 300-kDa forms were membrane associated and are likely to be intermediates between the 140-kDa form and a cell surface GPI-anchored form of > 300 kDa. A soluble form of > 300 kDa that lacked the GPI anchor had properties of a periplasmic intermediate between the plasma membrane form and the > 300-kDa cell wall-anchored form. These results constitute experimental support for the hypothesis that GPI anchors act to localize alpha-agglutinin to the plasma membrane and that cell wall anchorage involves release from the GPI anchor to produce a periplasmic intermediate followed by linkage to the cell wall.
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Affiliation(s)
- C F Lu
- Department of Biological Sciences, Hunter College, City University of New York, New York 10021
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Cell surface anchorage and ligand-binding domains of the Saccharomyces cerevisiae cell adhesion protein alpha-agglutinin, a member of the immunoglobulin superfamily. Mol Cell Biol 1993. [PMID: 8455628 DOI: 10.1128/mcb.13.4.2554] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
alpha-Agglutinin is a cell adhesion glycoprotein expressed on the cell wall of Saccharomyces cerevisiae alpha cells. Binding of alpha-agglutinin to its ligand a-agglutinin, expressed by a cells, mediates cell-cell contact during mating. Analysis of truncations of the 650-amino-acid alpha-agglutinin structural gene AG alpha 1 delineated functional domains of alpha-agglutinin. Removal of the C-terminal hydrophobic sequence allowed efficient secretion of the protein and loss of cell surface attachment. This cell surface anchorage domain was necessary for linkage to a glycosyl phosphatidylinositol anchor. A construct expressing the N-terminal 350 amino acid residues retained full a-agglutinin-binding activity, localizing the binding domain to the N-terminal portion of alpha-agglutinin. A 278-residue N-terminal peptide was inactive; therefore, the binding domain includes residues between 278 and 350. The segment of alpha-agglutinin between amino acid residues 217 and 308 showed significant structural and sequence similarity to a consensus sequence for immunoglobulin superfamily variable-type domains. The similarity of the alpha-agglutinin-binding domain to mammalian cell adhesion proteins suggests that this structure is a highly conserved feature of adhesion proteins in diverse eukaryotes.
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Wojciechowicz D, Lu CF, Kurjan J, Lipke PN. Cell surface anchorage and ligand-binding domains of the Saccharomyces cerevisiae cell adhesion protein alpha-agglutinin, a member of the immunoglobulin superfamily. Mol Cell Biol 1993; 13:2554-63. [PMID: 8455628 PMCID: PMC359586 DOI: 10.1128/mcb.13.4.2554-2563.1993] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
alpha-Agglutinin is a cell adhesion glycoprotein expressed on the cell wall of Saccharomyces cerevisiae alpha cells. Binding of alpha-agglutinin to its ligand a-agglutinin, expressed by a cells, mediates cell-cell contact during mating. Analysis of truncations of the 650-amino-acid alpha-agglutinin structural gene AG alpha 1 delineated functional domains of alpha-agglutinin. Removal of the C-terminal hydrophobic sequence allowed efficient secretion of the protein and loss of cell surface attachment. This cell surface anchorage domain was necessary for linkage to a glycosyl phosphatidylinositol anchor. A construct expressing the N-terminal 350 amino acid residues retained full a-agglutinin-binding activity, localizing the binding domain to the N-terminal portion of alpha-agglutinin. A 278-residue N-terminal peptide was inactive; therefore, the binding domain includes residues between 278 and 350. The segment of alpha-agglutinin between amino acid residues 217 and 308 showed significant structural and sequence similarity to a consensus sequence for immunoglobulin superfamily variable-type domains. The similarity of the alpha-agglutinin-binding domain to mammalian cell adhesion proteins suggests that this structure is a highly conserved feature of adhesion proteins in diverse eukaryotes.
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Affiliation(s)
- D Wojciechowicz
- Department of Biological Sciences, Hunter College, City University of New York, New York 10021
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