title: Identifying critical sites of PrP(c)-PrP(Sc) interaction in prion-infected cells by dominant-negative inhibition.
abstract: A direct physical interaction of the prion protein isoforms is a key element in prion conversion. Which sites interact first and which parts of PrP(c) are converted subsequently is presently not known in detail. We hypothesized that structural changes induced by PrP(Sc) interaction occur in more than one interface and subsequently propagate within the PrP(C) substrate, like epicenters of structural changes. To identify potential interfaces we created a series of systematically-designed mutant PrPs and tested them in prion-infected cells for dominant-negative inhibition (DNI) effects. This showed that mutant PrPs with deletions in the region between first and second α-helix are involved in PrP-PrP interaction and conversion of PrP(C) into PrP(Sc). Although some PrPs did not reach the plasma membrane, they had access to the locales of prion conversion and PrP(Sc) recycling using autophagy pathways. Using other series of mutant PrPs we already have identified additional sites which constitute potential interaction interfaces. Our approach has the potential to characterize PrP-PrP interaction sites in the context of prion-infected cells. Besides providing further insights into the molecular mechanisms of prion conversion, this data may help to further elucidate how prion strain diversity is maintained.
authors.affiliation: Department of Comparative Biology & Experimental Medicine; Faculty of Veterinary Medicine; University of Calgary; Calgary, AB Canada.
authors.forename: Yuzuru
authors.initials: Y
authors.lastname: Taguchi
authors.affiliation: Department of Comparative Biology & Experimental Medicine; Faculty of Veterinary Medicine; University of Calgary; Calgary, AB Canada; Departments of Molecular Biology and of Veterinary Sciences; University of Wyoming; Laramie, Wyoming, USA.
authors.forename: Hermann M
authors.initials: HM
authors.lastname: Schätzl
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D045744:Cell Line, Tumor; D051379:Mice; D008969:Molecular Sequence Data; D018621:PrPC Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018620:PrPSc Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017096:Prion Diseases / Q000235:genetics / Q000378:metabolism*; D011487:Protein Conformation; D054730:Protein Interaction Domains and Motifs; D025941:Protein Interaction Mapping; D017384:Sequence Deletion
chemical_list: D018621:PrPC Proteins; D018620:PrPSc Proteins
keywords: PrPC-PrPSc interaction; dominant-negative inhibition; epicenter of structural changes; interaction interface; prion conversion