title: RepA-WH1, the agent of an amyloid proteinopathy in bacteria, builds oligomeric pores through lipid vesicles.
abstract: RepA-WH1 is a disease-unrelated protein that recapitulates in bacteria key aspects of human amyloid proteinopathies: i) It undergoes ligand-promoted amyloidogenesis in vitro; ii) its aggregates are able to seed/template amyloidosis on soluble protein molecules; iii) its conformation is modulated by Hsp70 chaperones in vivo, generating transmissible amyloid strains; and iv) causes proliferative senescence. Membrane disruption by amyloidogenic oligomers has been found for most proteins causing human neurodegenerative diseases. Here we report that, as for PrP prion and α-synuclein, acidic phospholipids also promote RepA-WH1 amyloidogenesis in vitro. RepA-WH1 molecules bind to liposomes, where the protein assembles oligomeric membrane pores. Fluorescent tracer molecules entrapped in the lumen of the vesicles leak through these pores and RepA-WH1 can then form large aggregates on the surface of the vesicles without inducing their lysis. These findings prove that it is feasible to generate in vitro a synthetic proteinopathy with a minimal set of cytomimetic components and support the view that cell membranes are primary targets in protein amyloidoses.
authors.affiliation: Department of Cellular and Molecular Biology Centro de Investigaciones Biológicas-CSIC, E28040 Madrid, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Fernández
authors.affiliation: Electron Microscopy Facility, Centro de Investigaciones Biológicas-CSIC, E28040 Madrid, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Núñez-Ramírez
authors.affiliation: Department of Cellular and Molecular Biology Centro de Investigaciones Biológicas-CSIC, E28040 Madrid, Spain.
authors.forename: Mercedes
authors.initials: M
authors.lastname: Jiménez
authors.affiliation: Department of Cellular and Molecular Biology Centro de Investigaciones Biológicas-CSIC, E28040 Madrid, Spain.
authors.forename: Germán
authors.initials: G
authors.lastname: Rivas
authors.affiliation: Department of Cellular and Molecular Biology Centro de Investigaciones Biológicas-CSIC, E28040 Madrid, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Giraldo
mesh_terms: D000682:Amyloid / Q000737:chemistry / Q000378:metabolism*; D001419:Bacteria / Q000378:metabolism*; D002942:Circular Dichroism; D004269:DNA, Bacterial / Q000737:chemistry / Q000378:metabolism; D000067493:Dynamic Light Scattering; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal; D008854:Microscopy, Electron; D053835:Unilamellar Liposomes / Q000737:chemistry / Q000378:metabolism*; D000097573:Red Fluorescent Protein
chemical_list: D000682:Amyloid; D004269:DNA, Bacterial; D008164:Luminescent Proteins; D053835:Unilamellar Liposomes; D000097573:Red Fluorescent Protein