Distinct domains of the Candida albicans adhesin Eap1p mediate cell–cell and cell–substrate interactions

Li, Fang; Palecek, Sean P.

doi:10.1099/mic.0.2007/013789-0

Cited by 84 publications

(60 citation statements)

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“…the S. cerevisiae Ccw12 protein, also a short and presumably abundant GPI-cell wall protein as indicated by a high codon adaptation index; Christie et al, 2004;Ragni et al, 2007). Heterologous expression of derivatives of the C. albicans Eap1 protein in S. cerevisiae suggests that a larger repeated domain encompassing the 42 aa domain is involved in cellular aggregation (Li & Palecek, 2008). Interestingly, the 42 aa domain harbours three conserved cysteine residues along with aromatic residues, serine and threonine residues and hydrophobic residues.…”

Section: Discussionmentioning

confidence: 99%

The GPI-modified proteins Pga59 and Pga62 of Candida albicans are required for cell wall integrity

et al. 2009

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The fungal cell wall is essential in maintaining cellular integrity and plays key roles in the interplay between fungal pathogens and their hosts. The PGA59 and PGA62 genes encode two short and related glycosylphosphatidylinositol-anchored cell wall proteins and their expression has been previously shown to be strongly upregulated when the human pathogen Candida albicans grows as biofilms. Using GFP fusion proteins, we have shown that Pga59 and Pga62 are cell-walllocated, N-and O-glycosylated proteins. The characterization of C. albicans pga59D/pga59D, pga62D/pga62D and pga59D/pga59D pga62D/pga62D mutants suggested a minor role of these two proteins in hyphal morphogenesis and that they are not critical to biofilm formation. Importantly, the sensitivity to different cell-wall-perturbing agents was altered in these mutants. In particular, simultaneous inactivation of PGA59 and PGA62 resulted in high sensitivity to Calcofluor white, Congo red and nikkomicin Z and in resistance to caspofungin. Furthermore, cell wall composition and observation by transmission electron microscopy indicated an altered cell wall structure in the mutant strains. Collectively, these data suggest that the cell wall proteins Pga59 and Pga62 contribute to cell wall stability and structure. INTRODUCTIONThe cell wall is an essential component of fungal cells, preserving cellular integrity and playing a central role in the interaction of fungi with their environment. This is particularly the case for pathogenic fungi such as the opportunistic yeast pathogen Candida albicans, where the cell wall has been shown to play central roles in adhesion, virulence, biofilm formation, infection and immunomodulation (Albrecht et al., 2006;Douglas, 2003;Netea et al., 2006;Richard et al., 2002b;Sundstrom, 2002). Because of the essential role of the cell wall in cellular integrity and fungal specificity of some enzymes involved in its biogenesis, it is a recognized target for the development of novel antifungals (e.g. echinocandins that target the b-1,3-glucan synthase) (Latge, 2007).The organization of the fungal cell wall has been mainly characterized in the yeasts Saccharomyces cerevisiae and C. albicans and in the filamentous fungus Aspergillus fumigatus (Klis et al., 2006;Latge, 2007;Lesage & Bussey, 2006;Ruiz-Herrera et al., 2006). The yeast cell wall has a bilayered structure. The inner part is composed of a network of b-1,3-glucan molecules linked by hydrogen bonds. These chains can be bound covalently to b-1,6-glucan molecules and to chitin chains. The outer part of the cell wall is composed mainly of mannoproteins (Klis et al., 2006Lesage & Bussey, 2006). Most proteins in the cell wall of ascomycetous yeasts are glycosylphosphatidylinositolanchored proteins (GPI-modified proteins) that become covalently linked to b-1,6-glucan through a remnant of their GPI anchor. As the b-1,6-glucan moiety can be linked to b-1,3-glucan or chitin, the cell wall GPI-modified proteins are strongly linked to the cell wall Klis et al., 2001;Richard & Plaine, 2007).GPI-...

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Section: Discussionmentioning

confidence: 99%

The GPI-modified proteins Pga59 and Pga62 of Candida albicans are required for cell wall integrity

et al. 2009

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“…Among them, mannans could be one of the potential surface ligands because these polysaccharides are particularly abundant at the outermost layer (Gow et al 2012). However, the composition and molecular architecture of the cell wall of C. albicans are quite complex (Klotz et al 2007;Li and Palecek 2008), and other surface-associated glycoproteins and adhesins (e.g., Als and Eap1) potentially interact with GtfB. Clearly, further studies are needed to identify the binding partners as well as their spatial localization on the fungal surface that mediates GtfB-C. albicans adhesion.…”

Section: Discussionmentioning

confidence: 99%

Binding Force Dynamics of Streptococcus mutans–glucosyltransferase B to Candida albicans

et al. 2015

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Candida albicans cells are often detected with Streptococcus mutans in plaque biofilms from children affected with early childhood caries. The coadhesion between these 2 organisms appears to be largely mediated by the S. mutans-derived exoenzyme glucosyltransferase B (GtfB); GtfB readily binds to C. albicans cells in an active form, producing glucans locally that provide enhanced binding sites for S. mutans. However, knowledge is limited about the mechanisms by which the bacterial exoenzyme binds to and functions on the fungal surface to promote this unique cross-kingdom interaction. In this study, we use atomic force microscopy to understand the strength and binding dynamics modulating GtfB-C. albicans adhesive interactions in situ. Single-molecule force spectroscopy with GtfB-functionalized atomic force microscopy tips demonstrated that the enzyme binds with remarkable strength to the C. albicans cell surface (~2 nN) and showed a low dissociation rate, suggesting a highly stable bond. Strikingly, the binding strength of GtfB to the C. albicans surface was ~2.5-fold higher and the binding stability, ~20 times higher, as compared with the enzyme adhesion to S. mutans. Furthermore, adhesion force maps showed an intriguing pattern of GtfB binding. GtfB adhered heterogeneously on the surface of C. albicans, showing a higher frequency of adhesion failure but large sections of remarkably strong binding forces, suggesting the presence of GtfB binding domains unevenly distributed on the fungal surface. In contrast, GtfB bound uniformly across the S. mutans cell surface with less adhesion failure and a narrower range of binding forces (vs. the C. albicans surface). The data provide the first insights into the mechanisms underlying the adhesive and mechanical properties governing GtfB interactions with C. albicans. The strong and highly stable GtfB binding to C. albicans could explain, at least in part, why this bacterially derived exoenzyme effectively modulates this virulent cross-kingdom interaction.

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“…Protein adhesins are widely distributed among bacteria; thus, adhesin mediated coaggregation may be one of the major strategies for multi-species biofilm formation. For example, protein adhesins are also observed in fungi and can mediate fungi-bacteria interactions [42][43]. The S. oralis SspB adhesin was reported to interact with cell wall Als3 protein of Candida albicans (C. albicans) and promote development of fungal-bacterial multi-species communities [44].…”

Section: Structure Development Of Multiple-species Biofilmsmentioning

confidence: 99%

Current understanding of multi‐species biofilms

et al. 2011

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Direct observation of a wide range of natural microorganisms has revealed the fact that the majority of microbes persist as surface-attached communities surrounded by matrix materials, called biofilms. Biofilms can be formed by a single bacterial strain. However, most natural biofilms are actually formed by multiple bacterial species. Conventional methods for bacterial cleaning, such as applications of antibiotics and/or disinfectants are often ineffective for biofilm populations due to their special physiology and physical matrix barrier. It has been estimated that billions of dollars are spent every year worldwide to deal with damage to equipment, contaminations of products, energy losses, and infections in human beings resulted from microbial biofilms. Microorganisms compete, cooperate, and communicate with each other in multi-species biofilms. Understanding the mechanisms of multi-species biofilm formation will facilitate the development of methods for combating bacterial biofilms in clinical, environmental, industrial, and agricultural areas. The most recent advances in the understanding of multi-species biofilms are summarized and discussed in the review.

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Distinct domains of the Candida albicans adhesin Eap1p mediate cell–cell and cell–substrate interactions

Cited by 84 publications

References 44 publications

The GPI-modified proteins Pga59 and Pga62 of Candida albicans are required for cell wall integrity

The GPI-modified proteins Pga59 and Pga62 of Candida albicans are required for cell wall integrity

Binding Force Dynamics of Streptococcus mutans–glucosyltransferase B to Candida albicans

Current understanding of multi‐species biofilms

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