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Efg1 Controls Caspofungin-Induced Cell Aggregation of Candida albicans through the Adhesin Als1

Author:
Gregori, Christa, Glaser, Walter, Frohner, Ingrid E., Reinoso-Martín, Cristina, Rupp, Steffen, Schüller, Christoph, Kuchler, Karl
Source:
Eukaryotic cell 2011 v.10 no.12 pp. 1694-1704
ISSN:
1535-9778
Subject:
Candida albicans, agar, beta-glucans, biogenesis, cell aggregates, cell walls, drugs, flocculation, fungi, glucose, humans, hypersensitivity, mannose, phenotype, signal transduction, transcription (genetics), virulence
Abstract:
Echinocandin drugs such as caspofungin (CASP), micafungin, and anidulafungin inhibit fungal cell wall biogenesis by blocking Fks1-mediated β-glucan deposition into the cell surface. Candins have become suitable drugs to treat life-threatening diseases caused by several fungal species, including Candida albicans, that are pathogenic for humans. Here, we present the discovery of a novel CASP-induced flocculation phenotype of C. albicans, which formed large cell aggregates in the presence of CASP. High concentrations of sugars such as mannose or glucose inhibit CASP-induced flocculation and improve survival of C. albicans cells exposed to CASP. Notably, exposure of C. albicans cells to CASP triggers Efg1-dependent expression of the adhesin ALS1 and induces invasive growth on agar plates. Indeed, cells lacking either Efg1 or Als1 show strongly diminished CASP-induced flocculation, and the absence of Efg1 leads to marked CASP hypersensitivity. On the other hand, CASP-induced invasive growth is enhanced in cells lacking Efg1. Hence, CASP stress drives an Efg1-dependent response, indicating that this multifunctional transcriptional regulator, which is otherwise involved in filamentation, white-to-opaque switching, and virulence, also modulates cell wall remodeling upon CASP challenge. Taken together, our data suggest that CASP-induced cell wall damage activates Efg1 in parallel with the known cell integrity stress signaling pathway to coordinate cell wall remodeling.
Agid:
143539