Février Benoît, Vilette Didier, Laude Hubert, Raposo Graça
Centre National de la Recherche Scientifique, Unité Mixte de Recherche 144, Institut Curie, 75005 Paris, France.
Traffic. 2005 Jan;6(1):10-7. doi: 10.1111/j.1600-0854.2004.00247.x.
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.
在某些细胞类型中，内体多囊泡体可能以胞吐方式与细胞表面融合。在此过程中，其腔内直径为50 - 90纳米的小囊泡被释放到细胞外环境中。这些释放的囊泡被称为外泌体。细胞可利用外泌体分泌来排出靶向多囊泡体内腔囊泡的分子，但特定细胞类型会将外泌体用作细胞间通讯装置，用于细胞间蛋白质和脂质的传递。外泌体的分子组成由内体中的分选事件决定，这些事件与腔内囊泡的产生同时发生。作为其他与脂筏相关的成分，糖基磷脂酰肌醇连接的朊病毒蛋白会通过多囊泡体。非神经元细胞模型中的最新发现表明朊病毒蛋白与分泌的外泌体相关。因此，外泌体可能构成传染性朊病毒蛋白传播的载体，在朊病毒传播中绕过细胞间接触。
