Stimulation of PrP(C) retrograde transport toward the endoplasmic reticulum increases accumulation of PrP(Sc) in prion-infected cells.
Prion diseases are fatal and transmissible neurodegenerative disorders characterized by the accumulation of an abnormally folded isoform of the cellular prion protein (PrP(C)) denoted PrP(Sc). To identify intracellular organelles involved in PrP(Sc) formation, we studied the role of the Ras-related GTP-binding proteins Rab4 and Rab6a in intracellular trafficking of the prion protein and production of PrP(Sc). When a dominant-negative Rab4 mutant or a constitutively active GTP-bound Rab6a protein was overexpressed in prion-infected neuroblastoma N2a cells, there was a marked increase of PrP(Sc) formation. By immunofluorescence and cell fractionation studies, we have shown that expression of Rab6a-GTP delocalizes PrP within intracellular compartments, leading to an accumulation in the endoplasmic reticulum. These results suggest that prion protein can be subjected to retrograde transport toward the endoplasmic reticulum and that this compartment may play a significant role in PrP(Sc) conversion.
Béranger
Florence
F
Institut de Génétique Humaine, UPR CNRS1142, 141 Rue de la Cardonille, 34396, Montpellier Cedex 5, France. Florence.Beranger@igh.cnrs.fr
Mangé
Alain
A
Goud
Bruno
B
Lehmann
Sylvain
S
D000818:Animals; D001692:Biological Transport / Q000502:physiology*; D002458:Cell Fractionation; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism; D051379:Mice; D009154:Mutation; D009447:Neuroblastoma; D018621:PrPC Proteins / Q000235:genetics / Q000378:metabolism*; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics / Q000378:metabolism; D014407:Tumor Cells, Cultured; D020691:rab GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D020695:rab4 GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*
D018621:PrPC Proteins; D016271:Proto-Oncogene Proteins c-myc; C094135:Rab6 protein; D006160:Guanosine Triphosphate; D020691:rab GTP-Binding Proteins; D020695:rab4 GTP-Binding Proteins