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: Cristina Fernández, Rafael Núñez-Ramírez, Mercedes Jiménez, Germán Rivas, Rafael Giraldo
• Journal: Scientific reports (Sci Rep) Vol. 6 Pg. 23144 (Mar 17 2016) ISSN: 2045-2322 [Electronic] England
• PMID: 26984374 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Amyloid
• DNA, Bacterial
• Luminescent Proteins
• Unilamellar Liposomes

Topics

• Amyloid (chemistry, metabolism)
• Bacteria (metabolism)
• Circular Dichroism
• DNA, Bacterial (chemistry, metabolism)
• Dynamic Light Scattering
• Luminescent Proteins (genetics, metabolism)
• Microscopy, Confocal
• Microscopy, Electron
• Unilamellar Liposomes (chemistry, metabolism)
• Red Fluorescent Protein