title: A role for amyloid in cell aggregation and biofilm formation.
abstract: Cell adhesion molecules in Saccharomyces cerevisiae and Candida albicans contain amyloid-forming sequences that are highly conserved. We have now used site-specific mutagenesis and specific peptide perturbants to explore amyloid-dependent activity in the Candida albicans adhesin Als5p. A V326N substitution in the amyloid-forming region conserved secondary structure and ligand binding, but abrogated formation of amyloid fibrils in soluble Als5p and reduced cell surface thioflavin T fluorescence. When displayed on the cell surface, Als5p with this substitution prevented formation of adhesion nanodomains and formation of large cellular aggregates and model biofilms. In addition, amyloid nanodomains were regulated by exogenous peptides. An amyloid-forming homologous peptide rescued aggregation and biofilm activity of Als5p(V326N) cells, and V326N substitution peptide inhibited aggregation and biofilm activity in Als5p(WT) cells. Therefore, specific site mutation, inhibition by anti-amyloid peturbants, and sequence-specificity of pro-amyloid and anti-amyloid peptides showed that amyloid formation is essential for nanodomain formation and activation.
authors.affiliation: Biology Department, Brooklyn College of the City University of New York, Brooklyn, New York, United States of America.
authors.forename: Melissa C
authors.initials: MC
authors.lastname: Garcia
authors.forename: Janis T
authors.initials: JT
authors.lastname: Lee
authors.forename: Caleen B
authors.initials: CB
authors.lastname: Ramsook
authors.forename: David
authors.initials: D
authors.lastname: Alsteens
authors.forename: Yves F
authors.initials: YF
authors.lastname: Dufrêne
authors.forename: Peter N
authors.initials: PN
authors.lastname: Lipke
mesh_terms: D000268:Adhesiveness / Q000187:drug effects; D000595:Amino Acid Sequence; D000682:Amyloid / Q000494:pharmacology*; D052160:Benzothiazoles; D018441:Biofilms / Q000187:drug effects*; D002176:Candida albicans / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D015815:Cell Adhesion Molecules / Q000378:metabolism; D003224:Congo Red / Q000378:metabolism; D005453:Fluorescence; D005656:Fungal Proteins / Q000378:metabolism; D050296:Microbial Viability / Q000187:drug effects; D018625:Microscopy, Atomic Force; D050505:Mutant Proteins / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D049329:Nanostructures / Q000737:chemistry; D010455:Peptides / Q000494:pharmacology; D011137:Polystyrenes / Q000494:pharmacology; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D012995:Solubility / Q000187:drug effects; D013379:Substrate Specificity / Q000187:drug effects; D013844:Thiazoles / Q000378:metabolism
chemical_list: C109455:ALA1 protein, Candida albicans; D000682:Amyloid; D052160:Benzothiazoles; D015815:Cell Adhesion Molecules; D005656:Fungal Proteins; D050505:Mutant Proteins; D010455:Peptides; D011137:Polystyrenes; D013844:Thiazoles; C009462:thioflavin T; D003224:Congo Red