title: Mechanistic insights into cellular alteration of prion by poly-D-lysine: the role of H2H3 domain.
abstract: Misfolding of the prion protein (PrP) is the central feature of prion diseases. The conversion of the normal α-helical PrP(C) into a pathological β-enriched PrP(Sc) constitutes an early event in the infectious process. Several hypotheses, involving different regions of the protein, endeavor to delineate the structural mechanism underlying this change of conformation. All current working hypotheses, however, are based on biophysical and modeling studies, the biological relevance of which still needs to be assessed. We have studied the effect of positively charged polymers on the conversion, using polylysine as a model system, and have investigated a possible mechanism of structural stabilization. We have shown that poly-D-lysine removes proteinase K-resistant PrP from prion-infected SN56 neuroblastoma cells without affecting PrP(C). The effect is enantiospecific since the levorotary isomer, poly-L-lysine, has a markedly weaker effect, likely because of its higher susceptibility to degradation. In vitro cross-linking and NMR studies confirm a direct interaction between polylysine and PrP, which mainly maps to the PrP region containing helices 2 and 3 (H2H3). Interaction prevents conformational conversion and protein aggregation. Our results establish a central role of H2H3 in PrP(Sc) amyloidogenesis and replication and provide biological relevance for the pathological misfolding of this domain.
authors.affiliation: Commissariat à l'Énergie Atomique, Institute of Emerging Diseases and Innovative Therapies, Service d'Étude des Prions et des Infections Atypiques, Fontenay-aux-Roses, France.
authors.forename: Zhou
authors.initials: Z
authors.lastname: Xu
authors.forename: Miquel
authors.initials: M
authors.lastname: Adrover
authors.forename: Annalisa
authors.initials: A
authors.lastname: Pastore
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Prigent
authors.forename: Franck
authors.initials: F
authors.lastname: Mouthon
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Comoy
authors.forename: Human
authors.initials: H
authors.lastname: Rezaei
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Deslys
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D051379:Mice; D008958:Models, Molecular; D011107:Polylysine / Q000737:chemistry*; D018620:PrPSc Proteins / Q000737:chemistry*; D011485:Protein Binding; D017510:Protein Folding; D017434:Protein Structure, Tertiary
chemical_list: D018620:PrPSc Proteins; D011107:Polylysine