Exosomes: a bubble ride for prions?
In certain cell types, endosomal multivesicular bodies may fuse with the cell surface in an exocytic manner. During this process, the small 50-90-nm-diameter vesicles contained in their lumen are released into the extracellular environment. The released vesicles are called exosomes. Exosome secretion can be used by cells to eject molecules targeted to intraluminal vesicles of multivesicular bodies, but particular cell types exploit exosomes as intercellular communication devices for transfer of proteins and lipids between cells. The molecular composition of exosomes is determined by sorting events within endosomes that occur concomitantly with the generation of intraluminal vesicles. As other raft-associated components, the glycosylphosphatidylinositol-linked prion protein transits through multivesicular bodies. Recent findings in non-neuronal cell models indicate prion protein association with secreted exosomes. Thus, exosomes could constitute vehicles for transmission of the infectious prion protein, bypassing cell-cell contact in the dissemination of prions.
Février
Benoît
B
Centre National de la Recherche Scientifique, Unité Mixte de Recherche 144, Institut Curie, 75005 Paris, France.
Vilette
Didier
D
Laude
Hubert
H
Raposo
Graça
G
D000818:Animals; D021941:Caveolae / Q000378:metabolism / Q000648:ultrastructure; D003034:Coated Pits, Cell-Membrane / Q000378:metabolism / Q000648:ultrastructure; D011992:Endosomes / Q000378:metabolism*; D005089:Exocytosis; D006801:Humans; D008562:Membrane Glycoproteins / Q000378:metabolism; D008954:Models, Biological; D018620:PrPSc Proteins / Q000378:metabolism; D017096:Prion Diseases / Q000378:metabolism* / Q000635:transmission; D011328:Prions / Q000378:metabolism*; D022142:Secretory Vesicles / Q000378:metabolism / Q000648:ultrastructure
D008562:Membrane Glycoproteins; D018620:PrPSc Proteins; D011328:Prions