NR AWJH
AU Lutz,J.; Brabeck,C.; Lingappa,V.R.; Bürkle,A.
TI Impact of the hydrophobic core region on PrPc topology and metabolism
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 CE-26
PT Konferenz-Poster
AB The cellular prion protein (PrPc) is a GPI-anchored cell surface protein. A small subset of PrPc molecules, however, can be integrated into the ER-membrane via its transmembrane domain (TM), which also harbors one of the most highly conserved regions of PrPc, termed the hydrophobic core. A mutation in TM is implicated in Gerstmann-Sträussler-Scheinker Syndrome (GSS) resulting in an enhanced formation of a transmembrane form (CtmPrP), which has thus been postulated to be a neurotoxic intermediate in prion diseases besides PrPsc. Furthermore, a mutant of murine PrPc, missing eight amino acids within TM, trans-dominantly inhibits accumulation of PrPsc in mouse neuroblastoma cells. In order to elucidate a possible physiological function of the transmembrane domain, we created a set of different mutants, carrying micro-deletions from two to eight amino acids within the hydrophobic core of PrPc between codons 114 and 121. These mutations show a reduced formation of TM topology, which correlates with the reduction of the hydrophobic character of TM in the mutants. In addition, our mutants exhibited alterations in the formation of the C1 fragment, which is generated by alpha-cleavage during the normal PrPc metabolism, in vitro and in vivo. The dependence of cleavage efficiency on the amino acid sequence of the hydrophobic core segment indicates that this region might function as recognition site for the proteases responsible for PrPc alpha-cleavage. Interestingly, a mutant G113V, which corresponds to a prion disease associated mutation in humans, showed increased CtmPrP topology as well as decreased alpha-cleavage in our in vitro assay. The effect of decreased TM topology as well as decreased alpha-cleavage on PrPc function is further investigated in transgenic mice expressing the deletion mutant 114-121.
AD J. Lutz: Molecular Toxicology Group, University of Konstanz, Konstanz, Germany, and CPMC Research Institute, California Pacific Medical Center, San Francisco, USA; C. Brabeck, A. Bürkle: Molecular Toxicology Group, University of Konstanz, Konstanz, Germany; V.R. Lingappa: CPMC Research Institute, California Pacific Medical Center, San Francisco, USA
SP englisch
PO Italien