NR AOZV
AU Treiber,C.; Multhaup,G.
TI Towards Clarifying the Role of Dimerization/Oligomerization of PrP
QU International Conference - Prion diseases: from basic research to intervention concepts - TSE-Forum, 08.10.-10.10.2003, Gasteig, München - Poster session - BR-37
PT Konferenz-Poster
AB
A physical interaction between PrPc and PrPsc is an essential prerequisite of the prion hypothesis. Accordingly, PrPsc preferentially binds to homologous PrPc resulting in the formation of nascent PrPsc. Posttranslational modifications are a glycosylphosphatidylinositol (GPI) membrane anchor and two N-linked carbohydrate moieties that are surrounded by a single disulfide bond between Cys179 and Cys214. The amino-terminal part of PrPc gains structure upon binding of copper with the repeat sequence PHGGGWGQ.
We expressed the posttranslationally modified form of mouse PrP (residues 23-230) in the methylotrophic yeast Pichia pastoris. An engineered multiple cysteine mutant of the central hydrophobic core resulted in a significantly increased intracellular aggregation into dimers and higher oligomers compared with wild-type PrP revealing one contact site between dimers. Dynamic light scattering analysis of the copper binding domain indicated that the PHGGGWGQ region represents a second site which is directly involved in PrP aggregation. At and above physiological pH and at equimolar stoichiometry of copper, the human prion octarepeat fragment exhibited extensive aggregation.
We propose that the two identified potential contact sites in PrP are not simple dimerization sites, but rather may act as essential determinants of dynamic PrP interactions. Mutations in the two domains are known to be associated with familial CJD or Gerstmann-Straeussler-Scheinker syndrome and underline the importance of both regions for functional analysis of PrP and its role in pathogenesis.
Supported by the TSE-Programm MWK Baden-Wuerttemberg
AD Carina Treiber, Gerd Multhaup, FU-Berlin, Germany; Carina Treiber, ZMBH, Germany
SP englisch
PO Deutschland