title: Role of force-sensitive amyloid-like interactions in fungal catch bonding and biofilms.
abstract: The Candida albicans Als adhesin Als5p has an amyloid-forming sequence that is required for aggregation and formation of model biofilms on polystyrene. Because amyloid formation can be triggered by force, we investigated whether laminar flow could activate amyloid formation and increase binding to surfaces. Shearing Saccharomyces cerevisiae cells expressing Als5p or C. albicans at 0.8 dyne/cm(2) increased the quantity and strength of cell-to-surface and cell-to-cell binding compared to that at 0.02 dyne/cm(2). Thioflavin T fluorescence showed that the laminar flow also induced adhesin aggregation into surface amyloid nanodomains in Als5p-expressing cells. Inhibitory concentrations of the amyloid dyes thioflavin S and Congo red or a sequence-specific anti-amyloid peptide decreased binding and biofilm formation under flow. Shear-induced binding also led to formation of robust biofilms. There was less shear-activated increase in adhesion, thioflavin fluorescence, and biofilm formation in cells expressing the amyloid-impaired V326N-substituted Als5p. Similarly, S. cerevisiae cells expressing Flo1p or Flo11p flocculins also showed shear-dependent binding, amyloid formation, biofilm formation, and inhibition by anti-amyloid compounds. Together, these results show that laminar flow activated amyloid formation and led to enhanced adhesion of yeast cells to surfaces and to biofilm formation.
authors.affiliation: Biology Department, City University of New York Brooklyn College and Biochemistry Program, Graduate Center of the City University of New York, New York, New York, USA.
authors.forename: Cho X J
authors.initials: CX
authors.lastname: Chan
authors.affiliation: Biology Department, City University of New York Brooklyn College and Biochemistry Program, Graduate Center of the City University of New York, New York, New York, USA plipke@brooklyn.cuny.edu.
authors.forename: Peter N
authors.initials: PN
authors.lastname: Lipke
mesh_terms: D000595:Amino Acid Sequence; D000682:Amyloid / Q000737:chemistry / Q000235:genetics; D018441:Biofilms / Q000254:growth & development*; D002176:Candida albicans / Q000235:genetics / Q000254:growth & development*; D002448:Cell Adhesion / Q000235:genetics; D015815:Cell Adhesion Molecules / Q000096:biosynthesis* / Q000235:genetics; D005453:Fluorescence; D005656:Fungal Proteins / Q000096:biosynthesis* / Q000235:genetics; D011137:Polystyrenes / Q000737:chemistry; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development*
chemical_list: C109455:ALA1 protein, Candida albicans; D000682:Amyloid; D015815:Cell Adhesion Molecules; D005656:Fungal Proteins; D011137:Polystyrenes