scholarly journals Cellular Localization of Carbonic Anhydrase Nce103p in Candida albicans and Candida parapsilosis

2020 ◽  
Vol 21 (3) ◽  
pp. 850
Author(s):  
Jiří Dostál ◽  
Jan Blaha ◽  
Romana Hadravová ◽  
Martin Hubálek ◽  
Olga Heidingsfeld ◽  
...  
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Carbonic Anhydrase ◽  
Cellular Localization ◽  
Candida Parapsilosis ◽  
Growth Conditions ◽  
Carbonic Anhydrases ◽  
Atmospheric Conditions ◽  
Low Co2 ◽  
Mitochondrial Fractions

Pathogenic yeasts Candida albicans and Candida parapsilosis possess a ß-type carbonic anhydrase Nce103p, which is involved in CO2 hydration and signaling. C. albicans lacking Nce103p cannot survive in low CO2 concentrations, e.g., in atmospheric growth conditions. Candida carbonic anhydrases are orthologous to the Saccharomyces cerevisiae enzyme, which had originally been detected as a substrate of a non-classical export pathway. However, experimental evidence on localization of C. albicans and C. parapsilosis carbonic anhydrases has not been reported to date. Immunogold labeling and electron microscopy used in the present study showed that carbonic anhydrases are localized in the cell wall and plasmatic membrane of both Candida species. This localization was confirmed by Western blot and mass spectrometry analyses of isolated cell wall and plasma membrane fractions. Further analysis of C. albicans and C. parapsilosis subcellular fractions revealed presence of carbonic anhydrases also in the cytosolic and mitochondrial fractions of Candida cells cultivated in shaken liquid cultures, under the atmospheric conditions.

scholarly journals Conserved Serine/Threonine Kinase Encoded by CBK1 Regulates Expression of Several Hypha-Associated Transcripts and Genes Encoding Cell Wall Proteins in Candida albicans

2002 ◽  
Vol 184 (7) ◽  
pp. 2058-2061 ◽  
Author(s):  
Mark D. McNemar ◽  
William A. Fonzi
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Morphological Differentiation ◽  
Growth Conditions ◽  
Cell Wall Proteins ◽  
Serine Threonine Kinase ◽  
General Role ◽  
Threonine Kinase ◽  
Genes Encoding ◽  
Opportunistic Fungal Pathogen

ABSTRACT The opportunistic fungal pathogen, Candida albicans, is reported to have several potential virulence factors. A potentially significant factor is the ability to undergo morphological transition from yeast to hypha. This alteration of form is accompanied by many changes within the cell, including alterations in gene expression and cell wall composition. We have isolated a gene that encodes a highly conserved serine/threonine kinase that appears to be involved in the regulation of proteins associated with the cell wall. We have assigned the designation CBK1 (cell wall biosynthesis kinase 1) to this gene. Mutants lacking CBK1 form large aggregates of round cells under all growth conditions and lack the ability to undergo morphological differentiation. Additionally, these mutants show an altered pattern of expression of several transcripts encoding proteins associated with the cell wall. The results suggest that the kinase encoded by CBK1 plays a general role in the maintenance and alteration of the cell wall of C. albicans in all morphologies.

scholarly journals Environmentally contingent control of Candida albicans cell wall integrity by transcriptional regulator Cup9

Genetics ◽  
2021 ◽  
Author(s):  
Yuichi Ichikawa ◽  
Vincent M Bruno ◽  
Carol A Woolford ◽  
Hannah Kim ◽  
Eunsoo Do ◽  
...  
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Surface Protein ◽  
Hyphal Growth ◽  
Growth Conditions ◽  
Cell Wall Integrity ◽  
Yeast Growth ◽  
Transcription Factor Genes ◽  
A Cell ◽  
Rna Levels

Abstract The fungal pathogen Candida albicans is surrounded by a cell wall that is the target of caspofungin and other echinocandin antifungals. C. albicans can grow in several morphological forms, notably budding yeast and hyphae. Yeast and hyphal forms differ in cell wall composition, leading us to hypothesize that there may be distinct genes required for yeast and hyphal responses to caspofungin. Mutants in 27 genes reported previously to be caspofungin hypersensitive under yeast growth conditions were all caspofungin hypersensitive under hyphal growth conditions as well. However, a screen of mutants defective in transcription factor genes revealed that Cup9 is required for normal caspofungin tolerance under hyphal and not yeast growth conditions. In a hyphal-defective efg1Δ/Δ background, Cup9 is still required for normal caspofungin tolerance. This result argues that Cup9 function is related to growth conditions rather than cell morphology. RNA-seq conducted under hyphal growth conditions indicated that 361 genes were up-regulated and 145 genes were down-regulated in response to caspofungin treatment. Both classes of caspofungin-responsive genes were enriched for cell wall-related proteins, as expected for a response to disruption of cell wall integrity and biosynthesis. The cup9Δ/Δ mutant, treated with caspofungin, had reduced RNA levels of 40 caspofungin up-regulated genes, and had increased RNA levels of 8 caspofungin down-regulated genes, an indication that Cup9 has a narrow rather than global role in the cell wall integrity response. Five Cup9-activated surface-protein genes have roles in cell wall integrity, based on mutant analysis published previously (PGA31, IFF11) or shown here (ORF19.3499, ORF19.851 or PGA28), and therefore may explain the hypersensitivity of the cup9Δ/Δ mutant to caspofungin. Our findings define Cup9 as a new determinant of caspofungin susceptibility.

scholarly journals O-Mannosylation in Candida albicans Enables Development of Interkingdom Biofilm Communities

mBio ◽  
2014 ◽  
Vol 5 (2) ◽  
Author(s):  
Lindsay C. Dutton ◽  
Angela H. Nobbs ◽  
Katy Jepson ◽  
Mark A. Jepson ◽  
M. Margaret Vickerman ◽  
...  
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Biofilm Formation ◽  
Early Stage ◽  
Growth Conditions ◽  
Wild Type ◽  
Content Type ◽  
Subsequent Performance ◽  
Biofilm Development ◽  
Mutant Cells

ABSTRACTCandida albicansis a fungus that colonizes oral cavity surfaces, the gut, and the genital tract.Streptococcus gordoniiis a ubiquitous oral bacterium that has been shown to form biofilm communities withC. albicans. Formation of dual-speciesS. gordonii-C. albicansbiofilm communities involves interaction of theS. gordoniiSspB protein with the Als3 protein on the hyphal filament surface ofC. albicans. Mannoproteins comprise a major component of theC. albicanscell wall, and in this study we sought to determine if mannosylation in cell wall biogenesis ofC. albicanswas necessary for hyphal adhesin functions associated with interkingdom biofilm development. AC. albicans mnt1Δmnt2Δ mutant, with deleted α-1,2-mannosyltransferase genes and thus defective inO-mannosylation, was abrogated in biofilm formation under various growth conditions and produced hyphal filaments that were not recognized byS. gordonii. Cell wall proteomes of hypha-formingmnt1Δmnt2Δ mutant cells showed growth medium-dependent alterations, compared to findings for the wild type, in a range of protein components, including Als1, Als3, Rbt1, Scw1, and Sap9. Hyphal filaments formed bymnt1Δmnt2Δ mutant cells, unlike wild-type hyphae, did not interact withC. albicansAls3 or Hwp1 partner cell wall proteins or withS. gordoniiSspB partner adhesin, suggesting defective functionality of adhesins on themnt1Δmnt2Δ mutant. These observations imply that early stageO-mannosylation is critical for activation of hyphal adhesin functions required for biofilm formation, recognition by bacteria such asS. gordonii, and microbial community development.IMPORTANCEIn the human mouth, microorganisms form communities known as biofilms that adhere to the surfaces present.Candida albicansis a fungus that is often found within these biofilms. We have focused on the mechanisms by whichC. albicansbecomes incorporated into communities containing bacteria, such asStreptococcus. We find that impairment of early stage addition of mannose sugars toC. albicanshyphal filament proteins deleteriously affects their subsequent performance in mediating formation of polymicrobial biofilms. Our analyses provide new understanding of the way that microbial communities develop, and of potential means to controlC. albicansinfections.

scholarly journals Candida albicans Cell Wall Proteins

2008 ◽  
Vol 72 (3) ◽  
pp. 495-544 ◽  
Author(s):  
W. LaJean Chaffin
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Secretory Pathway ◽  
Structural Integrity ◽  
Growth Conditions ◽  
Physical Contact ◽  
Covalent Attachment ◽  
Cell Wall Proteins ◽  
Contact Interface ◽  
Phenotypic Analysis

SUMMARY The Candida albicans cell wall maintains the structural integrity of the organism in addtion to providing a physical contact interface with the environment. The major components of the cell wall are fibrillar polysaccharides and proteins. The proteins of the cell wall are the focus of this review. Three classes of proteins are present in the candidal cell wall. One group of proteins attach to the cell wall via a glycophosphatidylinositol remnant or by an alkali-labile linkage. A second group of proteins with N-terminal signal sequences but no covalent attachment sequences are secreted by the classical secretory pathway. These proteins may end up in the cell wall or in the extracellular space. The third group of proteins lack a secretory signal, and the pathway(s) by which they become associated with the surface is unknown. Potential constituents of the first two classes have been predicted from analysis of genome sequences. Experimental analyses have identified members of all three classes. Some members of each class selected for consideration of confirmed or proposed function, phenotypic analysis of a mutant, and regulation by growth conditions and transcription factors are discussed in more detail.

Carbonic anhydrase inhibitors. Inhibition of the fungal β-carbonic anhydrases from Candida albicans and Cryptococcus neoformans with boronic acids

2009 ◽  
Vol 19 (10) ◽  
pp. 2642-2645 ◽  
Author(s):  
Alessio Innocenti ◽  
Jean-Yves Winum ◽  
Rebecca A. Hall ◽  
Fritz A. Mühlschlegel ◽  
Andrea Scozzafava ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Carbonic Anhydrase ◽  
Cryptococcus Neoformans ◽  
Boronic Acids ◽  
Carbonic Anhydrases ◽  
Carbonic Anhydrase Inhibitors

scholarly journals β-1,2-Mannosyltransferases 1 and 3 Participate in Yeast and Hyphae O- and N-Linked Mannosylation and Alter Candida albicans Fitness During Infection

2015 ◽  
Vol 2 (3) ◽  
Author(s):  
Flavie Courjol ◽  
Thierry Jouault ◽  
Céline Mille ◽  
Rebecca Hall ◽  
Emmanuel Maes ◽  
...  
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Knockout Mice ◽  
Reference Strain ◽  
Growth Conditions ◽  
Germ Tubes ◽  
Virulence Properties

Abstract β-1,2-mannosylation of Candida albicans glycoconjugates has been investigated through the identification of enzymes involved in the addition of β-1,2-oligomannosides (β-Mans) to phosphopeptidomannan and phospholipomannan. β-1,2-oligomannosides are supposed to have virulence properties that they confer to these glycoconjugates. In a previous study, we showed that cell wall mannoproteins (CWMPs) harbor β-Mans in their O-mannosides; therefore, we analyzed their biosynthesis and impact on virulence. In this study, we demonstrate that O-mannans are heterogeneous and that α-mannosylated O-mannosides, which are biosynthesized by Mnt1 and Mnt2 α-1,2-mannosyltransferases, can be modified with β-Mans but only at the nonreducing end of α-1,2-mannotriose. β-1,2-mannosylation of this O-mannotriose depends on growth conditions, and it involves 2 β-1,2-mannosyltransferases, Bmt1 and Bmt3. These Bmts are essential for β-1,2-mannosylation of CWMPs and expression of β-Mans on germ tubes. A bmt1Δ mutant and a mutant expressing no β-Mans unexpectedly disseminated more in BALB/c mice, whereas they had neither attenuated nor enhanced virulence in C57BL/6 mice. In galectin (Gal)3 knockout mice, the reference strain was more virulent than in C57BL/6 mice, suggesting that the β-Mans innate receptor Gal3 is involved in C. albicans fitness during infection.

scholarly journals The zinc cluster transcription factor Rha1 is a positive filamentation regulator in Candida albicans

2020 ◽  
Author(s):  
Raha Parvizi Omran ◽  
Chris Law ◽  
Vanessa Dumeaux ◽  
Joachim Morschhäuser ◽  
Malcolm Whiteway
Keyword(s):  
Cell Wall ◽  
Transcription Factor ◽  
Candida Albicans ◽  
Transcription Factors ◽  
Transcriptional Profiling ◽  
Hyphal Growth ◽  
Growth Conditions ◽  
Hyphal Development ◽  
Zinc Cluster ◽  
Genes Encoding

AbstractZinc cluster transcription factors are essential fungal specific regulators of gene expression. In the dimorphic pathogen Candida albicans, they control processes ranging from metabolism and stress adaptation to mating, virulence, and antifungal resistance. Here, we have identified the gene CaORF19.1604 as encoding a zinc cluster transcription factor that acts as a regulator of filament development. Hyperactivation of CaORF19.1604, which we have named RHA1 for Regulator of Hyphal Activity, leads to a wrinkled colony morphology under non-hyphal growth conditions, to pseudohyphal growth and filament formation, to invasiveness and enhanced biofilm formation.  Cells with activated Rha1 are sensitive to cell wall modifying agents such as Congo red and the echinocandin drug caspofungin but show normal sensitivity to fluconazole. RNA-sequencing-based transcriptional profiling of the activated Rha1 strain reveals the up-regulation of genes for core filamentation and cell-wall-adhesion-related proteins such as Als1, Als3, Ece1, and Hwp1. Upregulation is also seen for the genes for the hyphal-inducing transcription factors Brg1 and Ume6 and genes encoding several enzymes involved in arginine metabolism, while downregulation is seen for the hyphal repressor Nrg1. The deletion of BRG1 blocks the filamentation caused by activated Rha1, while null mutants of UME6 result in a partial block. Deletion of RHA1 can partially reduce healthy hyphal development triggered by environmental conditions such as Spider medium or serum at 37°C.In contrast to the limited effect of either single mutant, the double rha1 ume6 deletion strain is totally defective in both serum and Spider medium stimulated hyphal development. While the loss of Brg1 function blocks serum-stimulated hyphal development, this block can be significantly bypassed by Rha1 hyperactivity, and the combination of Rha1 hyperactivity and serum addition can generate significant polarization in even brg1 ume6 double mutants. Our results thus suggest that in response to external signals, Rha1 functions to facilitate the switch from an Nrg1 controlled yeast state to a Brg1/Ume6 regulated hyphal state.Author SummaryCandida albicans is the predominant human fungal pathogen, generating a mortality rate of 40% in systemically infected patients. The ability of Candida albicans to change its morphology is a determinant of its tissue penetration and invasion in response to variant host-related stimuli. The regulatory mechanism for filamentation includes a complex network of transcription factors that play roles in regulating hyphae associated genes. We identify here a new regulator of filamentation from the zinc cluster transcription factor family. We present evidence suggesting that this transcription factor assists the Nrg1/Brg1 switch regulating hyphal development.

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