title: Interaction of toxic and non-toxic HypF-N oligomers with lipid bilayers investigated at high resolution with atomic force microscopy.
abstract: Protein misfolded oligomers are considered the most toxic species amongst those formed in the process of amyloid formation and the molecular basis of their toxicity, although not completely understood, is thought to originate from the interaction with the cellular membrane. Here, we sought to highlight the molecular determinants of oligomer-membrane interaction by atomic force microscopy. We monitored the interaction between multiphase supported lipid bilayers and two types of HypF-N oligomers displaying different structural features and cytotoxicities. By our approach we imaged with unprecedented resolution the ordered and disordered lipid phases of the bilayer and different oligomer structures interacting with either phase. We identified the oligomers and lipids responsible for toxicity and, more generally, we established the importance of the membrane lipid component in mediating oligomer toxicity. Our findings support the importance of GM1 ganglioside in mediating the oligomer-bilayer interaction and support a mechanism of oligomer cytotoxicity involving bilayer destabilization by globular oligomers within GM1-rich ordered raft regions rather than by annular oligomers in the surrounding disordered membrane domains.
authors.affiliation: Department of Nanophysics, Istituto Italiano di Tecnologia, Genova, Italy.|DIBRIS Department, University of Genova, Genova, Italy.
authors.forename: Reinier
authors.initials: R
authors.lastname: Oropesa-Nuñez
authors.affiliation: Department of Nanophysics, Istituto Italiano di Tecnologia, Genova, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Seghezza
authors.affiliation: Department of Nanophysics, Istituto Italiano di Tecnologia, Genova, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Dante
authors.affiliation: Department of Nanophysics, Istituto Italiano di Tecnologia, Genova, Italy.|Department of Physics, University of Genova, Genova, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Diaspro
authors.affiliation: Section of Biochemistry, Department of Biomedical Experimental and Clinical Sciences, University of Florence, Firenze, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Cascella
authors.affiliation: Section of Biochemistry, Department of Biomedical Experimental and Clinical Sciences, University of Florence, Firenze, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Cecchi
authors.affiliation: Section of Biochemistry, Department of Biomedical Experimental and Clinical Sciences, University of Florence, Firenze, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Stefani
authors.affiliation: Section of Biochemistry, Department of Biomedical Experimental and Clinical Sciences, University of Florence, Firenze, Italy.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Chiti
authors.affiliation: Department of Nanophysics, Istituto Italiano di Tecnologia, Genova, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Canale
mesh_terms: D000818:Animals; D019878:Carboxyl and Carbamoyl Transferases / Q000737:chemistry*; D029968:Escherichia coli Proteins / Q000737:chemistry*; D005677:G(M1) Ganglioside / Q000737:chemistry*; D006801:Humans; D008051:Lipid Bilayers / Q000737:chemistry*; D008563:Membrane Lipids / Q000737:chemistry*; D018625:Microscopy, Atomic Force
chemical_list: D029968:Escherichia coli Proteins; D008051:Lipid Bilayers; D008563:Membrane Lipids; D005677:G(M1) Ganglioside; D019878:Carboxyl and Carbamoyl Transferases; C504838:hypF protein, E coli
keywords: AFM; amyloid oligomers; ganglioside GM1; protein aggregation; protein misfolding