title: Screening for toxic amyloid in yeast exemplifies the role of alternative pathway responsible for cytotoxicity.
abstract: The relationship between amyloid and toxic species is a central problem since the discovery of amyloid structures in different diseases. Despite intensive efforts in the field, the deleterious species remains unknown at the molecular level. This may reflect the lack of any structure-toxicity study based on a genetic approach. Here we show that a structure-toxicity study without any biochemical prerequisite can be successfully achieved in yeast. A PCR mutagenesis of the amyloid domain of HET-s leads to the identification of a mutant that might impair cellular viability. Cellular and biochemical analyses demonstrate that this toxic mutant forms GFP-amyloid aggregates that differ from the wild-type aggregates in their shape, size and molecular organization. The chaperone Hsp104 that helps to disassemble protein aggregates is strictly required for the cellular toxicity. Our structure-toxicity study suggests that the smallest aggregates are the most toxic, and opens a new way to analyze the relationship between structure and toxicity of amyloid species.
authors.affiliation: IBGC, UMR 5095, CNRS Université Bordeaux 2 "Victor Segalen", Bordeaux, France.
authors.forename: Julien
authors.initials: J
authors.lastname: Couthouis
authors.forename: Karine
authors.initials: K
authors.lastname: Rébora
authors.forename: Françoise
authors.initials: F
authors.lastname: Immel
authors.forename: Karine
authors.initials: K
authors.lastname: Berthelot
authors.forename: Michel
authors.initials: M
authors.lastname: Castroviejo
authors.forename: Christophe
authors.initials: C
authors.lastname: Cullin
mesh_terms: D000682:Amyloid / Q000633:toxicity*; D004353:Drug Evaluation, Preclinical / Q000379:methods*; D049452:Green Fluorescent Proteins; D006360:Heat-Shock Proteins / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins / Q000502:physiology; D013329:Structure-Activity Relationship; D015003:Yeasts / Q000737:chemistry*
chemical_list: D000682:Amyloid; D006360:Heat-Shock Proteins; D029701:Saccharomyces cerevisiae Proteins; C070972:HsP104 protein, S cerevisiae; D049452:Green Fluorescent Proteins