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

• Published in: Microbiology (Society for General Microbiology) 2009-06, Vol.155 (6), p.2004-2020
• Main Authors: Moreno-Ruiz, Emilia, Ortu, Giuseppe, de Groot, Piet W. J, Cottier, Fabien, Loussert, Celine, Prevost, Marie-Christine, de Koster, Chris, Klis, Frans M, Goyard, Sophie, d'Enfert, Christophe
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Aminoglycosides - pharmacology; Antifungal Agents - pharmacology; Biofilms; Biological and medical sciences; Candida albicans - drug effects; Candida albicans - physiology; Candida albicans - ultrastructure; Cell Wall - metabolism; Cell Wall - ultrastructure; Fundamental and applied biological sciences. Psychology; Fungal Proteins - physiology; Gene Expression; Glycosylation; Glycosylphosphatidylinositols - metabolism; Green Fluorescent Proteins; Microbiology; Microscopy, Confocal; Microscopy, Electron, Transmission; Miscellaneous; Molecular Sequence Data; Mycology; Recombinant Fusion Proteins - biosynthesis; Staining and Labeling
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/mic.0.028902-0

1 Institut Pasteur, Unité Biologie et Pathogénicité Fongiques, INRA USC2019, Paris, France 2 Sezione di Microbiologia generale ed Applicat, DISAABA, Sassari, Italy 3 Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands 4 Plate-forme de Microscopie Ultrastructurale, Institut Pasteur, Paris, France 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-wall-located, N - and O -glycosylated proteins. The characterization of C. albicans pga59 /pga59 , pga62 /pga62 and pga59 /pga59 pga62 /pga62 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. Correspondence Christophe d'Enfert denfert{at}pasteur.fr Abbreviations: CFW, Calcofluor white; CR, Congo red; GPI, glycosylphosphatidylinositol; MM, molecular mass Present address: Laboratoire de Génétique Moléculaire des Champignons Phytopathogènes, Institut de Génétique Moléculaire, Université Paris-Sud, Orsay, France. Present address: Department of Biosciences, University of Kent, Canterbury, UK. Present address: Laboratoire d'Immunologie des Infections á Trypanosoma, Institut Pasteur, Paris, France.