title: Altered adherence in strains of Candida albicans harbouring null mutations in secreted aspartic proteinase genes.
abstract: The aspartate proteinase inhibitor pepstatin A has been shown previously to reduce the adherence of Candida albicans yeast cells to human surfaces. This suggests that in addition to their presumed function facilitating tissue penetration, the secreted aspartate proteinases (Saps) of this fungal pathogen may have auxiliary roles as cellular adhesins. We therefore examined the relative adherence of yeast cells of a parental wild-type strain of C. albicans in relation to yeast cells of strains harbouring specific disruptions in various members of the SAP gene family in an otherwise isogenic background. The adhesiveness of delta sap1, delta sap2, delta sap3 null mutants and a triple delta sap 4-6 disruptant was examined on three surfaces--glass coated with poly-L-lysine or a commercial cell-free basement membrane preparation (Matrigel) and on human buccal epithelial cells. Pepstatin A reduced adherence to all surfaces. Adherence of the each of the single SAP null mutants to these three substrates was either reduced or not affected significantly compared to that of the parental strain. The adherence of the delta sap4-6 mutant was reduced on poly-L-lysine and Matrigel, but increased on buccal cells. The results suggest that in addition to a primary enzymatic role, various SAPs may also act singly or synergistically to enhance the adhesiveness to C. albicans cells to certain human tissues.
authors.affiliation: Department of Molecular and Cell Biology, University of Aberdeen, Foresterhill, UK.
authors.forename: H J
authors.initials: HJ
authors.lastname: Watts
authors.forename: F S
authors.initials: FS
authors.lastname: Cheah
authors.forename: B
authors.initials: B
authors.lastname: Hube
authors.forename: D
authors.initials: D
authors.lastname: Sanglard
authors.forename: N A
authors.initials: NA
authors.lastname: Gow
mesh_terms: D016282:Aspartic Acid Endopeptidases / Q000235:genetics* / Q000378:metabolism; D001672:Biocompatible Materials; D002176:Candida albicans / Q000201:enzymology / Q000235:genetics* / Q000472:pathogenicity; D002448:Cell Adhesion / Q000187:drug effects / Q000235:genetics; D003094:Collagen; D004338:Drug Combinations; D004847:Epithelial Cells / Q000382:microbiology; D005800:Genes, Fungal / Q000502:physiology; D006801:Humans; D007797:Laminin; D009154:Mutation; D010436:Pepstatins / Q000494:pharmacology; D011107:Polylysine; D011480:Protease Inhibitors / Q000494:pharmacology; D011509:Proteoglycans; D013379:Substrate Specificity; D014774:Virulence
chemical_list: D001672:Biocompatible Materials; D004338:Drug Combinations; D007797:Laminin; D010436:Pepstatins; D011480:Protease Inhibitors; D011509:Proteoglycans; C014195:Streptomyces pepsin inhibitor; C059485:matrigel; D011107:Polylysine; D003094:Collagen; D016282:Aspartic Acid Endopeptidases; C031375:pepstatin