NR AWEM
AU Elvira,G.; Juanes,M.E.; Calero,M.; Korth,C.; Gasset,M.
TI Alternative translation initiation at the signal sequence coding region constitutively generates a nucleocytoplasmic PrP isoform
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-11
PT Konferenz-Poster
AB Despite all advances, PrPc function both in health and disease remains yet inconclusive in part due to its mysterious molecular diversity that has turned it into a multi-compartmentalized and multifunctional protein family. While PrPc was initially characterized as a glycoprotein attached to the cell surface by a GPI anchor, PrPc is indeed the sum of four basic forms generated at the ER translocation event (PrPSec, NtmPrP, CtmPrP and cytPrP). Out of these forms, cytPrP represents a minor intracellular subset of PrPc which is constitutively populated by the nontranslocated nascent chains in a signal sequence-dependent process. Using SHaPrP signal sequence mutants containing single base insertions causing shift readings at different positions and cell-free translation assays we have found an alternate and minor translation start site at the AUG triplet coding for M15. The resulting synthetic product, HaPrP(15-254), is a novel isoform that accounts for an about 10% of the total PrPc and partitions between the soluble and the membrane phases, in both phases being fully accessible to externally added proteases. In CHO and COS-7 stably transfectants, HaPrPc(15-254) is found intracellularly distributing in a cell-dependent fashion between the nuclear and cytoplasm compartments as judged both by subcellular fractioning and confocal fluorescence microscopy experiments. Analysis of the nuclear population evidences several covalent modifications. The existence of this novel PrPc isoform opens new pathways of function, as the cell cycle regulation.
AD G. Elvira, M.E. Juanes, M. Gasset: Insto Química-Física "Rocasolano", CSIC, Madrid, Spain; M. Calero: Centro Nacional Microbiología ISCIII, Madrid, Spain; C. Korth: Inst.Neuropathology, Heinrich Heine Univ. Düsseldorf, Germany. E-mail: mgasset@iqfr.csic.es
SP englisch
PO Italien