Lipid raft-associated protein sorting in exosomes
Lipid raft-associated protein sorting in exosomes
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DOI：
10.1182/blood-2003-03-0871
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发表时间：
2003-12-15
期刊：
影响因子：
20.3
通讯作者：
Vidal, M
中科院分区：
文献类型：
--
作者：
de Gassart, A;Géminard, C;Vidal, M
外泌体是由多囊内体与细胞表面融合后细胞分泌的小膜囊泡。外泌体膜中蛋白质特异性分选的机制远未阐明。我们在这里证明，使用不同的细胞，一些分子通过与外泌体膜的脂筏结构域的关联在细胞外介质中释放。免疫印迹法可检测到各种典型的筏相关分子。外泌体和从不同来源的外泌体分离的Triton X-100不溶性级分。主要组织相容性复合体（MHC）11类分子与从Daudi分泌的外泌体分离的洗涤剂抗性组分的部分定位通过免疫印迹证明，并通过MHC 11类分子和神经节苷脂G（M1）的电子显微镜共定位证实。此外，我们发现外泌体相关的林恩（1）与在细胞分离的洗涤剂抗性结构域中检测到的林恩相比具有较低的分子量，（2）从外泌体分离的Triton X-100不溶性部分中不存在，以及（3）在Triton X-114中失去了其分配能力。外泌体林恩可能被分泌囊泡中含有的半胱天冬酶-3样活性切割。总之，这些数据突出了外泌体膜中脂质微结构域的存在，并表明它们参与囊泡形成和结构，以及外泌体在调控机制中的直接影响。(C)2003年，美国血液学会。
Exosomes are small membrane vesicles secreted by cells upon fusion of multivesicular endosomes with the cell surface. The mechanisms underlying the specific sorting of proteins in exosomal membranes are far from being unraveled. We demonstrate here, using different cells, that some molecules are released in the extracellular medium via their association with lipid raft domains of the exosomal membrane. Various typical raft-associated molecules could be detected by immunoblot in. exosomes and Triton X-100-insoluble fractions isolated from exosomes of different origins. Partial localization of major histocompatibility complex (MHC) class 11 molecules with detergent-resistant fractions isolated from Daudi-secreted exosomes was demonstrated by immunoblot and confirmed by electron microscopy colocalization of MHC class 11 molecules and ganglioside G(M1). Moreover, we found that exosome-assoclated Lyn (1) had a lower molecular weight compared with Lyn detected in cell-isolated detergent-resistant domains, (2) was absent from the Triton X-100-insoluble fraction isolated from exosomes, and (3) had lost its partitioning capacity in Triton X-114. Exosomal Lyn is probably cleaved by a caspase-3-like activity contained in secreted vesicles. All together, the data highlight the presence of lipid microdomains in exosomal membranes and suggest their participation in vesicle formation and structure, as well as the direct implication of exosomes in regulatory mechanisms. (C) 2003 by The American Society of Hematology.