NR AWEL
AU Elfrink,K.; Salwierz,A.; Nagel-Steger,L.; Riesner,D.
TI The cellular prion protein: binding to vesicles and membranes of raft-like lipid composition
QU International Conference - Prion 2006: Strategies, advances and trends towards protection of society - 3.10.-6.10.2006, Torino, Italy, Lingotto Conference Centre - Poster sessions S-09
PT Konferenz-Poster
AB The conversion of the cellular isoform of the prion protein (PrPc) into the disease associated isoform (PrPsc) plays a key role in development of prion diseases. Within its cellular pathway PrPc undergoes several posttranslational modifications, i.e. the attachment of two N-linked glycans and a glycosyl phosphatidyl inositole (GPI-) anchor, by which it is linked to the plasma membrane on the exterior cell surface. In order to study the influence of the membrane environment on the conversion process we purified posttranslationally modified PrPc from transgenic CHO-cells (1, 2). We first analyzed the interaction of PrPc with model membranes in vitro before we will go on to conversion studies. Binding of PrPc to model membranes was studied both with lipid vesicles in solution and with lipid bilayers bound on a chip surface. The equilibrium and mechanism of PrPc-membrane-interaction was analyzed quantitatively by surface plasmon resonance. We could observe high affinity of PrPc to lipid bilayers, but only in the presence of the GPI-anchor, i.e. binding of recombinant PrP without GPIanchor was negligible. Additionally binding of PrPc to raft-like lipid membranes was higher as compared to lipid composition of the inner plasma membrane and PrPc in the aggregated, ß-sheet rich structure exhibited only little interaction with the membranes. Depending on the degree of saturation of binding sites the concentration of PrPc released from the membrane into the aqueous solution was estimated to be between 10-9 to 10-7 M. This corresponds to a free energy of the insertion reaction of about -48 kJ/mol. In future we will study the interaction of infectious PrPsc-particles with PrPc presented on the membrane surface in vitro. (1) Blochberger, T.C., Cooper, C., Peretz, D., Tatzelt, J., Griffith, O.H., Baldwin, M.A., Prusiner, S.B. (1997). Prion protein expression in Chinese hamster ovary cells using a glutamine synthetase selection and amplification system. Prot. Eng. 10, 1465-1473. (2) Elfrink, K. Riesner, D. (2004). Purification of PrPc. Techniques in Prion Research. ed. by S. Lehmann and J. Grassi (Birkhaeuser Verlag Basel), 4-15.
AD Institut fuer Physikalische Biologie and Biologisch Medizinisches Forschungszentrum, Heinrich Heine Universität Duesseldorf, Germany. E-mail: elfrink@biophys.uni-duesseldorf.de
SP englisch
PO Italien