scholarly journals A Conserved Machinery Underlies the Synthesis of a Chitosan Layer in the Candida Chlamydospore Cell Wall

mSphere ◽  
2021 ◽  
Vol 6 (2) ◽  
Author(s):  
Leo D. Bemena ◽  
Kyunghun Min ◽  
James B. Konopka ◽  
Aaron M. Neiman
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Drug Targets ◽  
Therapeutic Strategies ◽  
Effective Strategy ◽  
Fungal Cell ◽  
Detailed Understanding ◽  
Cell Wall Assembly ◽  
Wall Assembly ◽  
Potential Drug Targets

The cell wall is the interface between the fungal cell and its environment and disruption of cell wall assembly is an effective strategy for antifungal therapies. Therefore, a detailed understanding of how cell walls form is critical to identify potential drug targets and develop therapeutic strategies.

scholarly journals The RIM101 Pathway Contributes to Yeast Cell Wall Assembly and Its Function Becomes Essential in the Absence of Mitogen-Activated Protein Kinase Slt2p

2006 ◽  
Vol 5 (3) ◽  
pp. 507-517 ◽  
Author(s):  
F. Castrejon ◽  
A. Gomez ◽  
M. Sanz ◽  
A. Duran ◽  
C. Roncero
Keyword(s):  
Cell Wall ◽  
Protein Kinase ◽  
Yeast Cell ◽  
Cell Walls ◽  
Active Form ◽  
Sodium Dodecyl ◽  
Phenotypic Traits ◽  
Compensatory Response ◽  
Cell Wall Assembly ◽  
Wall Assembly

ABSTRACT The Saccharomyces cerevisiae ynl294cΔ (rim21Δ) mutant was identified in our lab owing to its moderate resistance to calcofluor, although it also displayed all of the phenotypic traits associated with its function as the putative sensor (Rim21p) of the RIM101 pathway. rim21Δ also showed moderate hypersensitivity to sodium dodecyl sulfate, caffeine, and zymolyase, and the cell wall compensatory response in this mutant was very poor, as indicated by the almost complete absence of Slt2 phosphorylation and the modest increase in chitin synthesis after calcofluor treatment. However, the cell integrity pathway appeared functional after caffeine treatment or thermal stress. rim21Δ and rim101Δ mutant strains shared all of the cell-wall-associated phenotypes, which were reverted by the expression of Rim101-531p, the constitutively active form of this transcription factor. Therefore, the absence of a functional RIM101 pathway leads to cell wall defects. rim21Δ, as well as rim101Δ, was synthetic lethal with slt2Δ, a synthetic defect alleviated by osmotic stabilization of the media. The double mutants grown in osmotically stabilized media were extremely hypersensitive to zymolyase and showed thicker cell walls, with poorly defined mannoprotein layers. In contrast, rim21Δ rlm1Δ and rim101Δ rlm1Δ double mutants were fully viable. Taken together, these results show that the RIM101 pathway participates directly in cell wall assembly and that it acts in parallel with the protein kinase C pathway (PKC) in this process independently of the transcriptional effect of the compensatory response mediated by this route. In addition, these results provide new experimental evidence of the direct involvement of the PKC signal transduction pathway through the Sltp2 kinase in the construction of yeast cell walls.

scholarly journals Phosphorylation-dependent activation of the cell wall synthase PBP2a in Streptococcus pneumoniae by MacP

2018 ◽  
Vol 115 (11) ◽  
pp. 2812-2817 ◽  
Author(s):  
Andrew K. Fenton ◽  
Sylvie Manuse ◽  
Josué Flores-Kim ◽  
Pierre Simon Garcia ◽  
Chryslène Mercy ◽  
...  
Keyword(s):  
Cell Wall ◽  
Streptococcus Pneumoniae ◽  
Drug Targets ◽  
Synthetic Activity ◽  
Bacterial Cells ◽  
Cell Wall Assembly ◽  
Division Site ◽  
A Cell ◽  
Wall Assembly

Most bacterial cells are surrounded by an essential cell wall composed of the net-like heteropolymer peptidoglycan (PG). Growth and division of bacteria are intimately linked to the expansion of the PG meshwork and the construction of a cell wall septum that separates the nascent daughter cells. Class A penicillin-binding proteins (aPBPs) are a major family of PG synthases that build the wall matrix. Given their central role in cell wall assembly and importance as drug targets, surprisingly little is known about how the activity of aPBPs is controlled to properly coordinate cell growth and division. Here, we report the identification of MacP (SPD_0876) as a membrane-anchored cofactor of PBP2a, an aPBP synthase of the Gram-positive pathogen Streptococcus pneumoniae. We show that MacP localizes to the division site of S. pneumoniae, forms a complex with PBP2a, and is required for the in vivo activity of the synthase. Importantly, MacP was also found to be a substrate for the kinase StkP, a global cell cycle regulator. Although StkP has been implicated in controlling the balance between the elongation and septation modes of cell wall synthesis, none of its substrates are known to modulate PG synthetic activity. Here we show that a phosphoablative substitution in MacP that blocks StkP-mediated phosphorylation prevents PBP2a activity without affecting the MacP–PBP2a interaction. Our results thus reveal a direct connection between PG synthase function and the control of cell morphogenesis by the StkP regulatory network.

scholarly journals PHR1, a pH-regulated gene of Candida albicans encoding a glucan-remodelling enzyme, is required for adhesion and invasion

Microbiology ◽  
2010 ◽  
Vol 156 (8) ◽  
pp. 2484-2494 ◽  
Author(s):  
Julia Calderon ◽  
Martin Zavrel ◽  
Enrico Ragni ◽  
William A. Fonzi ◽  
Steffen Rupp ◽  
...  
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Crucial Role ◽  
Extracellular Enzymes ◽  
Hyphal Growth ◽  
Fungal Cell ◽  
Cell Monolayers ◽  
Cell Wall Assembly ◽  
Abiotic Surfaces ◽  
Wall Assembly

The fungal cell wall plays a crucial role in host–pathogen interactions. Its formation is the result of the coordinated activity of several extracellular enzymes, which assemble the constituents, and remodel and hydrolyse them in the extracellular space. Candida albicans Phr1 and Phr2 proteins belong to family GH72 of the β-(1,3)-glucanosyltransferases and play a crucial role in cell wall assembly. PHR1 and PHR2, homologues of Saccharomyces cerevisiae GAS1, are differently regulated by extracellular pH. PHR1 is expressed when ambient pH is 5.5 or higher, whereas PHR2 has the reverse expression pattern. Their deletion causes a pH-conditional defect in morphogenesis and virulence. In this work we explored whether PHR1 deletion affects the ability of C. albicans to adhere to and invade human epithelia. PHR1 null mutants exhibited a marked reduction in adhesion to both abiotic surfaces and epithelial cell monolayers. In addition, the mutant was unable to penetrate and invade reconstituted human epithelia. Transcription profiling of selected hyphal-specific and adhesin-encoding genes indicated that in the PHR1 null mutant, HWP1 and ECE1 transcript levels were similarly reduced in both adhesion and suspension conditions. These results, combined with microscopy analysis of the septum position, suggest that PHR1 is not required for the induction of hyphal development but plays a key role in the maintenance of hyphal growth. Thus, the β-(1,3)-glucan processing catalysed by Phr1p is of fundamental importance in the maintenance of the morphological state on which the adhesive and invasive properties of C. albicans greatly depend.

scholarly journals ChsVb, a Class VII Chitin Synthase Involved in Septation, Is Critical for Pathogenicity in Fusarium oxysporum

2007 ◽  
Vol 7 (1) ◽  
pp. 112-121 ◽  
Author(s):  
Magdalena Martín-Urdíroz ◽  
M. Isabel G. Roncero ◽  
José Antonio González-Reyes ◽  
Carmen Ruiz-Roldán
Keyword(s):  
Cell Wall ◽  
Fusarium Oxysporum ◽  
Tomato Fruit ◽  
Infection Process ◽  
Chitin Synthase ◽  
Fungal Cell ◽  
Myosin Motor ◽  
Cell Wall Assembly ◽  
Chitin Synthases ◽  
Wall Assembly

ABSTRACT A new myosin motor-like chitin synthase gene, chsVb, has been identified in the vascular wilt fungus Fusarium oxysporum f. sp. lycopersici. Phylogenetic analysis of the deduced amino acid sequence of the chsVb chitin synthase 2 domain (CS2) revealed that ChsVb belongs to class VII chitin synthases. The ChsVb myosin motor-like domain (MMD) is shorter than the MMD of class V chitin synthases and does not contain typical ATP-binding motifs. Targeted disrupted single (ΔchsVb) and double (ΔchsV ΔchsVb) mutants were unable to infect and colonize tomato plants or grow invasively on tomato fruit tissue. These strains were hypersensitive to compounds that interfere with fungal cell wall assembly, produced lemon-like shaped conidia, and showed swollen balloon-like structures in hyphal subapical regions, thickened walls, aberrant septa, and intrahyphal hyphae. Our results suggest that the chsVb gene is likely to function in polarized growth and confirm the critical importance of cell wall integrity in the complex infection process of this fungus.

scholarly journals Pneumocystis carinii BCK1functions in a mitogen-activated protein kinase cascade regulating fungal cell-wall assembly

FEBS Letters ◽  
2003 ◽  
Vol 548 (1-3) ◽  
pp. 59-68 ◽  
Author(s):  
Charles F. Thomas ◽  
Pawan K. Vohra ◽  
John G. Park ◽  
Veenu Puri ◽  
Andrew H. Limper ◽  
...  
Keyword(s):  
Cell Wall ◽  
Protein Kinase ◽  
Pneumocystis Carinii ◽  
Mitogen Activated Protein Kinase ◽  
Fungal Cell ◽  
Cell Wall Assembly ◽  
Mitogen Activated Protein ◽  
Kinase Cascade ◽  
Wall Assembly ◽  
Protein Kinase Cascade

scholarly journals Medicinal genetics approach towards identifying the molecular target of a novel inhibitor of fungal cell wall assembly

2003 ◽  
Vol 48 (4) ◽  
pp. 1029-1042 ◽  
Author(s):  
Kappei Tsukahara ◽  
Katsura Hata ◽  
Kazutaka Nakamoto ◽  
Koji Sagane ◽  
Nao-aki Watanabe ◽  
...  
Keyword(s):  
Cell Wall ◽  
Molecular Target ◽  
Fungal Cell Wall ◽  
Fungal Cell ◽  
Cell Wall Assembly ◽  
Wall Assembly

scholarly journals Bgs3p, a Putative 1,3-β-Glucan Synthase Subunit, Is Required for Cell Wall Assembly in Schizosaccharomyces pombe

2003 ◽  
Vol 2 (1) ◽  
pp. 159-169 ◽  
Author(s):  
Victoria Martín ◽  
Blanca García ◽  
Elena Carnero ◽  
Angel Durán ◽  
Yolanda Sánchez
Keyword(s):  
Cell Wall ◽  
Fission Yeast ◽  
Green Fluorescence Protein ◽  
Cell Wall Biosynthesis ◽  
Calcofluor White ◽  
Fungal Cell ◽  
Glucan Synthase ◽  
Cell Wall Assembly ◽  
Main Components ◽  
Wall Assembly

ABSTRACT β-Glucans are the main components of the fungal cell wall. Fission yeast possesses a family of β-glucan synthase-related genes. We describe here the cloning and characterization of bgs3 +, a new member of this family. bgs3 + was cloned as a suppressor of a mutant hypersensitive to Echinocandin and Calcofluor White, drugs that interfere with cell wall biosynthesis. Disruption of the gene is lethal, and a decrease in Bgs3p levels leads to rounded cells with thicker walls, slightly reduces the amount of the β-glucan, and raises the amount of α-glucan polymer. These cells finally died. bgs3 + is expressed in vegetative cells grown in different conditions and during mating and germination and is not enhanced by stress situations. Consistent with the observed expression pattern, Bgs3-green fluorescence protein (GFP-Bgs3p) was found at the growing tips during interphase and at the septum prior to cytokinesis, always localized to growth areas. We also found GFP-Bgs3p in mating projections, during the early stages of zygote formation, and at the growing pole during ascospore germination. We conclude that Bgs3p localization is restricted to growth areas and that Bgs3p is a glucan synthase homologue required for cell wall biosynthesis and cell elongation in the fission yeast life cycle.

scholarly journals Molecular mechanisms of fungal cell-wall assembly

2010 ◽  
Vol 66 (a1) ◽  
pp. s32-s32
Author(s):  
Alex Schuettelkopf ◽  
Daan van Aalten ◽  
Helge Dorfmueller
Keyword(s):  
Cell Wall ◽  
Molecular Mechanisms ◽  
Fungal Cell Wall ◽  
Fungal Cell ◽  
Cell Wall Assembly ◽  
Wall Assembly
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