title: Deletions of endocytic components VPS28 and VPS32 affect growth at alkaline pH and virulence through both RIM101-dependent and RIM101-independent pathways in Candida albicans.
abstract: Ambient pH signaling involves a cascade of conserved Rim or Pal products in ascomycetous yeasts or filamentous fungi, respectively. Recent evidences in the fungi Aspergillus nidulans, Saccharomyces cerevisiae, Yarrowia lipolytica, and Candida albicans suggested that components of endosomal sorting complexes required for transport (ESCRT) involved in endocytic trafficking were needed for signal transduction along the Rim pathway. In this study, we confirm these findings with C. albicans and show that Vps28p (ESCRT-I) and Vps32p/Snf7p (ESCRT-III) are required for the transcriptional regulation of known targets of the Rim pathway, such as the PHR1 and PHR2 genes encoding cell surface proteins, which are expressed at alkaline and acidic pH, respectively. We additionally show that deletion of these two VPS genes, particularly VPS32, has a more drastic effect than a RIM101 deletion on growth at alkaline pH and that this effect is only partially suppressed by expression of a constitutively active form of Rim101p. Finally, in an in vivo mouse model, both vps null mutants were significantly less virulent than a rim101 mutant, suggesting that VPS28 and VPS32 gene products affect virulence both through Rim-dependent and Rim-independent pathways.
authors.affiliation: Laboratoire de Microbiologie et Génétique Moléculaire, INRA, CBAI, 78850 Thiverval-Grignon, France.
authors.forename: Muriel
authors.initials: M
authors.lastname: Cornet
authors.forename: Frédérique
authors.initials: F
authors.lastname: Bidard
authors.forename: Patrick
authors.initials: P
authors.lastname: Schwarz
authors.forename: Grégory
authors.initials: G
authors.lastname: Da Costa
authors.forename: Sylvie
authors.initials: S
authors.lastname: Blanchin-Roland
authors.forename: Françoise
authors.initials: F
authors.lastname: Dromer
authors.forename: Claude
authors.initials: C
authors.lastname: Gaillardin
mesh_terms: D000468:Alkalies / Q000378:metabolism; D000818:Animals; D002176:Candida albicans / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity*; D002177:Candidiasis / Q000382:microbiology*; D004268:DNA-Binding Proteins / Q000502:physiology*; D004705:Endocytosis / Q000235:genetics / Q000502:physiology; D005656:Fungal Proteins / Q000235:genetics / Q000502:physiology*; D017353:Gene Deletion; D005786:Gene Expression Regulation; D006863:Hydrogen-Ion Concentration; D007668:Kidney / Q000382:microbiology; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics; D051379:Mice; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000502:physiology; D014158:Transcription, Genetic; D033921:Vesicular Transport Proteins / Q000235:genetics / Q000502:physiology*; D014774:Virulence
chemical_list: D000468:Alkalies; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D008562:Membrane Glycoproteins; D009687:Nuclear Proteins; C091515:PHR1 protein, Candida albicans; C489602:RIM101 protein, Candida albicans; D033921:Vesicular Transport Proteins