scholarly journals Molecular Basis for Strain Variation in the Saccharomyces cerevisiae Adhesin Flo11p

mSphere ◽  
2016 ◽  
Vol 1 (4) ◽  
Author(s):  
Subit Barua ◽  
Li Li ◽  
Peter N. Lipke ◽  
Anne M. Dranginis
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Surface ◽  
Molecular Basis ◽  
Phenotypic Variability ◽  
Surface Hydrophobicity ◽  
Strain Variation ◽  
Content Type ◽  
Amino Terminal ◽  
Important Means ◽  
Domain Peptide

ABSTRACT As a nonmotile organism, Saccharomyces cerevisiae employs the cell surface flocculin Flo11/Muc1 as an important means of adapting to environmental change. However, there is a great deal of strain variation in the expression of Flo11-dependent phenotypes, including flocculation. In this study, we investigated the molecular basis of this strain-specific phenotypic variability. Our data indicate that strain-specific differences in the level of flocculation result from significant sequence differences in the FLO11 alleles and do not depend on quantitative differences in FLO11 expression or on surface hydrophobicity. We further have shown that beads coated with amino-terminal domain peptide bind preferentially to homologous cells. These data show that variability in the structure of the Flo11 adhesion domain may thus be an important determinant of membership in microbial communities and hence may drive selection and evolution. FLO11 encodes a yeast cell wall flocculin that mediates a variety of adhesive phenotypes in Saccharomyces cerevisiae. Flo11p is implicated in many developmental processes, including flocculation, formation of pseudohyphae, agar invasion, and formation of microbial mats and biofilms. However, Flo11p mediates different processes in different yeast strains. To investigate the mechanisms by which FLO11 determines these differences in colony morphology, flocculation, and invasion, we studied gene structure, function, and expression levels. Nonflocculent Saccharomyces cerevisiae Σ1278b cells exhibited significantly higher FLO11 mRNA expression, especially in the stationary phase, than highly flocculent S. cerevisiae var. diastaticus. The two strains varied in cell surface hydrophobicity, and Flo11p contributed significantly to surface hydrophobicity in S. cerevisiae var. diastaticus but not in strain Σ1278b. Sequencing of the FLO11 gene in S. cerevisiae var. diastaticus revealed strain-specific differences, including a 15-amino-acid insertion in the adhesion domain. Flo11p adhesion domains from strain Σ1278b and S. cerevisiae var. diastaticus were expressed and used to coat magnetic beads. The adhesion domain from each strain bound preferentially to homologous cells, and the preferences were independent of the cells in which the adhesion domains were produced. These results are consistent with the idea that strain-specific variations in the amino acid sequences in the adhesion domains cause different Flo11p flocculation activities. The results also imply that strain-specific differences in expression levels, posttranslational modifications, and allelic differences outside the adhesion domains have little effect on flocculation. IMPORTANCE As a nonmotile organism, Saccharomyces cerevisiae employs the cell surface flocculin Flo11/Muc1 as an important means of adapting to environmental change. However, there is a great deal of strain variation in the expression of Flo11-dependent phenotypes, including flocculation. In this study, we investigated the molecular basis of this strain-specific phenotypic variability. Our data indicate that strain-specific differences in the level of flocculation result from significant sequence differences in the FLO11 alleles and do not depend on quantitative differences in FLO11 expression or on surface hydrophobicity. We further have shown that beads coated with amino-terminal domain peptide bind preferentially to homologous cells. These data show that variability in the structure of the Flo11 adhesion domain may thus be an important determinant of membership in microbial communities and hence may drive selection and evolution.

scholarly journals Acquisition of the Ability To Assimilate Mannitol by Saccharomyces cerevisiae through Dysfunction of the General Corepressor Tup1-Cyc8

2014 ◽  
Vol 81 (1) ◽  
pp. 9-16 ◽  
Author(s):  
Moeko Chujo ◽  
Shiori Yoshida ◽  
Anri Ota ◽  
Kousaku Murata ◽  
Shigeyuki Kawai
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Molecular Basis ◽  
Mutant Allele ◽  
Wild Type ◽  
Growth Data ◽  
Content Type ◽  
Corepressor Complex ◽  
Marine Biomass ◽  
Prolonged Culture ◽  
Genes Encoding

ABSTRACTSaccharomyces cerevisiaenormally cannot assimilate mannitol, a promising brown macroalgal carbon source for bioethanol production. The molecular basis of this inability remains unknown. We found that cells capable of assimilating mannitol arose spontaneously from wild-typeS. cerevisiaeduring prolonged culture in mannitol-containing medium. Based on microarray data, complementation analysis, and cell growth data, we demonstrated that acquisition of mannitol-assimilating ability was due to spontaneous mutations in the genes encoding Tup1 or Cyc8, which constitute a general corepressor complex that regulates many kinds of genes. We also showed that anS. cerevisiaestrain carrying a mutant allele ofCYC8exhibited superior salt tolerance relative to other ethanologenic microorganisms; this characteristic would be highly beneficial for the production of bioethanol from marine biomass. Thus, we succeeded in conferring the ability to assimilate mannitol onS. cerevisiaethrough dysfunction of Tup1-Cyc8, facilitating production of ethanol from mannitol.

scholarly journals Variation in Cell Surface Hydrophobicity among Cryptococcus neoformans Strains Influences Interactions with Amoebas

mSphere ◽  
2020 ◽  
Vol 5 (2) ◽  
Author(s):  
Raghav Vij ◽  
Carina Danchik ◽  
Conor Crawford ◽  
Quigly Dragotakes ◽  
Arturo Casadevall
Keyword(s):  
Cell Surface ◽  
Cryptococcus Neoformans ◽  
Cell Surface Hydrophobicity ◽  
Surface Hydrophobicity ◽  
Natural Soil ◽  
Order Structure ◽  
Hydroxyl Groups ◽  
Biophysical Properties ◽  
Content Type ◽  
Biophysical Parameter

ABSTRACT Cryptococcus neoformans and Cryptococcus gattii are pathogenic fungi that cause significant morbidity and mortality. Cell surface hydrophobicity (CSH) is a biophysical parameter that influences the adhesion of fungal cells or spores to biotic and abiotic surfaces. C. neoformans is encased by polysaccharide capsule that is highly hydrophilic and is a critical determinant of virulence. In this study, we report large differences in the CSH of some C. neoformans and C. gattii strains. The capsular polysaccharides of C. neoformans strains differ in repeating motifs and therefore vary in the number of hydroxyl groups, which, along with higher-order structure of the capsule, may contribute to the variation in hydrophobicity that we observed. We found that cell wall composition, in the context of chitin-chitosan content, does not influence CSH. For C. neoformans, CSH correlated with phagocytosis by natural soil predator Acanthamoeba castellanii. Furthermore, capsular binding of the protective antibody (18B7), but not the nonprotective antibody (13F1), altered the CSH of C. neoformans strains. Variability in CSH could be an important characteristic in comparing the biological properties of cryptococcal strains. IMPORTANCE The interaction of a microbial cell with its environment is influenced by the biophysical properties of a cell. The affinity of the cell surface for water, defined by the cell surface hydrophobicity (CSH), is a biophysical parameter that varies among different strains of Cryptococcus neoformans. The CSH influences the phagocytosis of the yeast by its natural predator in the soil, the amoeba. Studying variation in biophysical properties like CSH gives us insight into the dynamic host-predator interaction and host-pathogen interaction in a damage-response framework.

scholarly journals Hypothetical Protein Avin_16040 as the S-Layer Protein of Azotobacter vinelandii and Its Involvement in Plant Root Surface Attachment

2015 ◽  
Vol 81 (21) ◽  
pp. 7484-7495 ◽  
Author(s):  
Pauline Woan Ying Liew ◽  
Bor Chyan Jong ◽  
Nazalan Najimudin
Keyword(s):  
Cell Surface ◽  
Deletion Mutant ◽  
Azotobacter Vinelandii ◽  
Plant Root ◽  
Hypothetical Protein ◽  
Surface Hydrophobicity ◽  
Root Surface ◽  
Bacterial Cells ◽  
Wild Type ◽  
Content Type

ABSTRACTA proteomic analysis of a soil-dwelling, plant growth-promotingAzotobacter vinelandiistrain showed the presence of a protein encoded by the hypotheticalAvin_16040gene when the bacterial cells were attached to theOryza sativaroot surface. AnAvin_16040deletion mutant demonstrated reduced cellular adherence to the root surface, surface hydrophobicity, and biofilm formation compared to those of the wild type. By atomic force microscopy (AFM) analysis of the cell surface topography, the deletion mutant displayed a cell surface architectural pattern that was different from that of the wild type.Escherichia colitransformed with the wild-typeAvin_16040gene displayed on its cell surface organized motifs which looked like the S-layer monomers ofA. vinelandii. The recombinantE. colialso demonstrated enhanced adhesion to the root surface.

scholarly journals Cell Signals, Cell Contacts, and the Organization of Yeast Communities

2011 ◽  
Vol 10 (4) ◽  
pp. 466-473 ◽  
Author(s):  
Saul M. Honigberg
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Yeast Species ◽  
Community Organization ◽  
Strain Variation ◽  
Cell Fates ◽  
Content Type ◽  
Growth And Survival ◽  
Fundamental Properties ◽  
Adhesin Proteins ◽  
Fungal Kingdom

ABSTRACT Even relatively simple species have evolved mechanisms to organize individual organisms into communities, such that the fitness of the group is greater than the fitness of isolated individuals. Within the fungal kingdom, the ability of many yeast species to organize into communities is crucial for their growth and survival, and this property has important impacts both on the economy and on human health. Over the last few years, studies of Saccharomyces cerevisiae have revealed several fundamental properties of yeast communities. First, strain-to-strain variation in the structures of these groups is attributable in part to variability in the expression and functions of adhesin proteins. Second, the extracellular matrix surrounding these communities can protect them from environmental stress and may also be important in cell signaling. Finally, diffusible signals between cells contribute to community organization so that different regions of a community express different genes and adopt different cell fates. These findings provide an arena in which to view fundamental mechanisms by which contacts and signals between individual organisms allow them to assemble into functional communities.

scholarly journals Characterization of Human and Murine T-Cell Immunoglobulin Mucin Domain 4 (TIM-4) IgV Domain Residues Critical for Ebola Virus Entry

2016 ◽  
Vol 90 (13) ◽  
pp. 6097-6111 ◽  
Author(s):  
Bethany A. Rhein ◽  
Rachel B. Brouillette ◽  
Grace A. Schaack ◽  
John A. Chiorini ◽  
Wendy Maury
Keyword(s):  
T Cell ◽  
Cell Surface ◽  
Ebola Virus ◽  
Virus Entry ◽  
Binding Pocket ◽  
Cell Surface Receptor ◽  
Target Cells ◽  
Virus Binding ◽  
Content Type ◽  
Amino Terminal

ABSTRACTPhosphatidylserine (PtdSer) receptors that are responsible for the clearance of dying cells have recently been found to mediate enveloped virus entry. Ebola virus (EBOV), a member of theFiloviridaefamily of viruses, utilizes PtdSer receptors for entry into target cells. The PtdSer receptors human and murine T-cell immunoglobulin mucin (TIM) domain proteins TIM-1 and TIM-4 mediate filovirus entry by binding to PtdSer on the virion surface via a conserved PtdSer binding pocket within the amino-terminal IgV domain. While the residues within the TIM-1 IgV domain that are important for EBOV entry are characterized, the molecular details of virion–TIM-4 interactions have yet to be investigated. As sequences and structural alignments of the TIM proteins suggest distinct differences in the TIM-1 and TIM-4 IgV domain structures, we sought to characterize TIM-4 IgV domain residues required for EBOV entry. Using vesicular stomatitis virus pseudovirions bearing EBOV glycoprotein (EBOV GP/VSVΔG), we evaluated virus binding and entry into cells expressing TIM-4 molecules mutated within the IgV domain, allowing us to identify residues important for entry. Similar to TIM-1, residues in the PtdSer binding pocket of murine and human TIM-4 (mTIM-4 and hTIM-4) were found to be important for EBOV entry. However, additional TIM-4-specific residues were also found to impact EBOV entry, with a total of 8 mTIM-4 and 14 hTIM-4 IgV domain residues being critical for virion binding and internalization. Together, these findings provide a greater understanding of the interaction of TIM-4 with EBOV virions.IMPORTANCEWith more than 28,000 cases and over 11,000 deaths during the largest and most recent Ebola virus (EBOV) outbreak, there has been increased emphasis on the development of therapeutics against filoviruses. Many therapies under investigation target EBOV cell entry. T-cell immunoglobulin mucin (TIM) domain proteins are cell surface factors important for the entry of many enveloped viruses, including EBOV. TIM family member TIM-4 is expressed on macrophages and dendritic cells, which are early cellular targets during EBOV infection. Here, we performed a mutagenesis screening of the IgV domain of murine and human TIM-4 to identify residues that are critical for EBOV entry. Surprisingly, we identified more human than murine TIM-4 IgV domain residues that are required for EBOV entry. Defining the TIM IgV residues needed for EBOV entry clarifies the virus-receptor interactions and paves the way for the development of novel therapeutics targeting virus binding to this cell surface receptor.

scholarly journals n-Alkane Chain Length Alters Dietzia sp. Strain DQ12-45-1b Biosurfactant Production and Cell Surface Activity

2012 ◽  
Vol 79 (1) ◽  
pp. 400-402 ◽  
Author(s):  
Xing-Biao Wang ◽  
Yong Nie ◽  
Yue-Qin Tang ◽  
Gang Wu ◽  
Xiao-Lei Wu
Keyword(s):  
Cell Surface ◽  
Carbon Sources ◽  
Cell Surface Hydrophobicity ◽  
Surface Hydrophobicity ◽  
Biosurfactant Production ◽  
Content Type ◽  
Emulsification Activity ◽  
Negative Effect ◽  
Alkane Chain ◽  
Chain Lengths

ABSTRACTUpon growth onn-hexadecane (C16),n-tetracosane (C24), andn-hexatriacontane (C36),Dietziasp. strain DQ12-45-1b could produce different glycolipids, phospholipids, and lipopeptides. Interestingly, cultivation with C36increased cell surface hydrophobic activity, which attenuated the negative effect of the decline of the emulsification activity. These results suggest that the mechanisms of biosurfactant production and cell surface hydrophobicity are dependent upon the chain lengths of then-alkanes used as carbon sources.

scholarly journals Membrane Vesicle Formation as a Multiple-Stress Response Mechanism Enhances Pseudomonas putida DOT-T1E Cell Surface Hydrophobicity and Biofilm Formation

2012 ◽  
Vol 78 (17) ◽  
pp. 6217-6224 ◽  
Author(s):  
Thomas Baumgarten ◽  
Stefanie Sperling ◽  
Jana Seifert ◽  
Martin von Bergen ◽  
Frank Steiniger ◽  
...  
Keyword(s):  
Stress Response ◽  
Cell Surface ◽  
Pseudomonas Putida ◽  
Biofilm Formation ◽  
Membrane Vesicle ◽  
Cell Surface Hydrophobicity ◽  
Surface Hydrophobicity ◽  
Outer Membrane Vesicles ◽  
Stress Factors ◽  
Content Type

ABSTRACTAmong the adaptive responses of bacteria to rapid changes in environmental conditions, those of the cell envelope are known to be the most crucial. Therefore, several mechanisms with which bacteria change their cell surface and membranes in the presence of different environmental stresses have been elucidated. Among these mechanisms, the release of outer membrane vesicles (MV) in Gram-negative bacteria has attracted particular research interest because of its involvement in pathogenic processes, such as that ofPseudomonas aeruginosabiofilm formation in cystic fibrosis lungs. In this study, we investigated the role of MV formation as an adaptive response ofPseudomonas putidaDOT-T1E to several environmental stress factors and correlated it to the formation of biofilms. In the presence of toxic concentrations of long-chain alcohols, under osmotic stress caused by NaCl, in the presence of EDTA, and after heat shock, cells of this strain released MV within 10 min in the presence of a stressor. The MV formed showed similar size and charge properties, as well as comparable compositions of proteins and fatty acids. MV release caused a significant increase in cell surface hydrophobicity, and an enhanced tendency to form biofilms was demonstrated in this study. Therefore, the release of MV as a stress response could be put in a physiological context.

scholarly journals Self-Assembled Amyloid-Like Oligomeric-Cohesin Scaffoldin for Augmented Protein Display on the Saccharomyces cerevisiae Cell Surface

2012 ◽  
Vol 78 (9) ◽  
pp. 3249-3255 ◽  
Author(s):  
Zhenlin Han ◽  
Bei Zhang ◽  
Yi E. Wang ◽  
Yi Y. Zuo ◽  
Wei Wen Su
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Surface ◽  
Fusion Protein ◽  
Fold Increase ◽  
Scaffolding Protein ◽  
Yeast Display ◽  
Protein Scaffold ◽  
Content Type ◽  
Self Assembled ◽  
Novel Protein

ABSTRACTIn this study, a molecular self-assembly strategy to develop a novel protein scaffold for amplifying the extent and variety of proteins displayed on the surface ofSaccharomyces cerevisiaeis presented. The cellulosomal scaffolding protein cohesin and its upstream hydrophilic domain (HD) were genetically fused with the yeast Ure2p N-terminal fibrillogenic domain consisting of residues 1 to 80 (Ure2p1-80). The resulting Ure2p1-80-HD-cohesin fusion protein was successfully expressed inEscherichia colito produce self-assembled supramolecular nanofibrils that serve as a novel protein scaffold displaying multiple copies of functional cohesin domains. The amyloid-like property of the nanofibrils was confirmed via thioflavin T staining and atomic force microscopy. These cohesin nanofibrils attached themselves, via a green fluorescent protein (GFP)-dockerin fusion protein, to the cell surface ofS. cerevisiaeengineered to display a GFP-nanobody. The excess cohesin units on the nanofibrils provide ample sites for binding to dockerin fusion proteins, as exemplified using an mCherry-dockerin fusion protein as well as theClostridium cellulolyticumCelA endoglucanase. More than a 24-fold increase in mCherry fluorescence and an 8-fold increase in CelA activity were noted when the cohesin nanofibril scaffold-mediated yeast display was used, compared to using yeast display with GFP-cohesin that contains only a single copy of cohesin. Self-assembled supramolecular cohesin nanofibrils created by fusion with the yeast Ure2p fibrillogenic domain provide a versatile protein scaffold that expands the utility of yeast cell surface display.

scholarly journals Phosphorylation and Proteasome Recognition of the mRNA-Binding Protein Cth2 Facilitates Yeast Adaptation to Iron Deficiency

mBio ◽  
2018 ◽  
Vol 9 (5) ◽  
Author(s):  
Antonia M. Romero ◽  
Mar Martínez-Pastor ◽  
Gang Du ◽  
Carme Solé ◽  
María Carlos ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Iron Deficiency ◽  
Metabolic Pathways ◽  
Binding Protein ◽  
Cellular Metabolism ◽  
Iron Depletion ◽  
Content Type ◽  
Amino Terminal ◽  
Mrna Binding Protein ◽  
Mrna Binding

ABSTRACT Iron is an indispensable micronutrient for all eukaryotic organisms due to its participation as a redox cofactor in many metabolic pathways. Iron imbalance leads to the most frequent human nutritional deficiency in the world. Adaptation to iron limitation requires a global reorganization of the cellular metabolism directed to prioritize iron utilization for essential processes. In response to iron scarcity, the conserved Saccharomyces cerevisiae mRNA-binding protein Cth2, which belongs to the tristetraprolin family of tandem zinc finger proteins, coordinates a global remodeling of the cellular metabolism by promoting the degradation of multiple mRNAs encoding highly iron-consuming proteins. In this work, we identify a critical mechanism for the degradation of Cth2 protein during the adaptation to iron deficiency. Phosphorylation of a patch of Cth2 serine residues within its amino-terminal region facilitates recognition by the SCFGrr1 ubiquitin ligase complex, accelerating Cth2 turnover by the proteasome. When Cth2 degradation is impaired by either mutagenesis of the Cth2 serine residues or deletion of GRR1, the levels of Cth2 rise and abrogate growth in iron-depleted conditions. Finally, we uncover that the casein kinase Hrr25 phosphorylates and promotes Cth2 destabilization. These results reveal a sophisticated posttranslational regulatory pathway necessary for the adaptation to iron depletion. IMPORTANCE Iron is a vital element for many metabolic pathways, including the synthesis of DNA and proteins, and the generation of energy via oxidative phosphorylation. Therefore, living organisms have developed tightly controlled mechanisms to properly distribute iron, since imbalances lead to nutritional deficiencies, multiple diseases, and vulnerability against pathogens. Saccharomyces cerevisiae Cth2 is a conserved mRNA-binding protein that coordinates a global reprogramming of iron metabolism in response to iron deficiency in order to optimize its utilization. Here we report that the phosphorylation of Cth2 at specific serine residues is essential to regulate the stability of the protein and adaptation to iron depletion. We identify the kinase and ubiquitination machinery implicated in this process to establish a posttranscriptional regulatory model. These results and recent findings for both mammals and plants reinforce the privileged position of E3 ubiquitin ligases and phosphorylation events in the regulation of eukaryotic iron homeostasis.

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