Proteomic and biochemical analyses of human B cell-derived exosomes -: Potential implications for their function and multivesicular body formation
Proteomic and biochemical analyses of human B cell-derived exosomes -: Potential implications for their function and multivesicular body formation
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DOI：
10.1074/jbc.m207550200
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发表时间：
2003-03-28
影响因子：
4.8
通讯作者：
Stoorvogel, W
中科院分区：
文献类型：
--
作者：
Wubbolts, R;Leckie, RS;Stoorvogel, W
外泌体是 60-100 nm 的膜囊泡，由于多囊泡体与质膜融合而被分泌到细胞外环境中。在这里，我们确定了高度纯化的人 B 细胞来源的外泌体的蛋白质和脂质组成。质谱分析表明大量存在主要组织相容性复合物 (MHC) I 类和 II 类、热休克同源 70、热休克蛋白 90、整合素 α4、CD45、moesin、微管蛋白（α 和 β）、肌动蛋白、G(i)alpha(2) 和多种其他蛋白质。 α4-整合素可以将 B 细胞衍生的外泌体引导至滤泡树突细胞，之前将其描述为潜在的靶细胞。网格蛋白、热休克同源物 70 和热休克蛋白 90 可能参与多泡体的蛋白质分选。外泌体还富含胆固醇、鞘磷脂和神经节苷脂 GM3，这些脂质通常富含于耐洗涤剂的膜中。大多数外泌体相关蛋白，包括 MHC II 类和四跨膜蛋白，不溶于含有 3-[(3-胆酰胺丙基)二甲基铵]-1-丙磺酸 (CHAPS) 的缓冲液。多囊泡体相关 MHC II 类也对 CHAPS 具有抵抗力，而质膜相关 MHC II 类很容易溶解。总之，这些数据表明，膜蛋白从限制膜募集到多囊泡体的内部囊泡中可能涉及它们并入含有四跨膜蛋白的耐去污剂膜域。
Exosomes are 60-100-nm membrane vesicles that are secreted into the extracellular milieu as a consequence of multivesicular body fusion with the plasma membrane. Here we determined the protein and lipid compositions of highly purified human B cell-derived exosomes. Mass spectrometric analysis indicated the abundant presence of major histocompatibility complex (MHC) class I and class II, heat shock cognate 70, heat shock protein 90, integrin alpha4, CD45, moesin, tubulin (alpha and beta), actin, G(i)alpha(2), and a multitude of other proteins. An alpha4-integrin may direct B cell-derived exosomes to follicular dendritic cells, which were described previously as potential target cells. Clathrin, heat shock cognate 70, and heat shock protein 90 may be involved in protein sorting at multivesicular bodies. Exosomes were also enriched in cholesterol, sphingomyelin, and ganglioside GM3, lipids that are typically enriched in detergent-resistant membranes. Most exosome-associated proteins, including MHC class II and tetraspanins, were insoluble in 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonic acid (CHAPS)-containing buffers. Multivesicular body-linked MHC class II was also resistant to CHAPS whereas plasma membrane-associated MHC class II was solubilized readily. Together, these data suggest that recruitment of membrane proteins from the limiting membranes into the internal vesicles of multivesicular bodies may involve their incorporation into tetraspanin-containing detergent-resistant membrane domains.