Institute for Cellular and Molecular Biology, The University of Texas at Austin , 1 University Station, Austin, Texas 78712-0159, United States.
J Proteome Res. 2011 Oct 7;10(10):4624-33. doi: 10.1021/pr200434y. Epub 2011 Sep 23.
Microvesicles (exosomes) are important mediators of intercellular communication, playing a role in immune regulation, cancer progression, and the spread of infectious agents. The biological functions of these small vesicles are dependent on their composition, which is regulated by mechanisms that are not well understood. Although numerous proteomic studies of these particles exist, little is known about their glycosylation. Carbohydrates are involved in protein trafficking and cellular recognition. Glycomic analysis may thus provide valuable insights into microvesicle biology. In this study, we analyzed glycosylation patterns of microvesicles derived from a variety of biological sources using lectin microarray technology. Comparison of the microvesicle glycomes with their parent cell membranes revealed both enrichment and depletion of specific glycan epitopes in these particles. These include enrichment in high mannose, polylactosamine, α-2,6 sialic acid, and complex N-linked glycans and exclusion of terminal blood group A and B antigens. The polylactosamine signature derives from distinct glycoprotein cohorts in microvesicles of different origins. Taken together, our data point to the emergence of microvesicles from a specific membrane microdomain, implying a role for glycosylation in microvesicle protein sorting.
微泡（外泌体）是细胞间通讯的重要介质，在免疫调节、癌症进展和传染病原体传播中发挥作用。这些小泡的生物学功能取决于其组成，而其组成受机制的调控，这些机制尚不清楚。尽管已经有许多针对这些颗粒的蛋白质组学研究，但对其糖基化知之甚少。碳水化合物参与蛋白质运输和细胞识别。糖组学分析因此可以为微泡生物学提供有价值的见解。在这项研究中，我们使用凝集素微阵列技术分析了来自各种生物来源的微泡的糖基化模式。将微泡糖组与它们的母细胞膜进行比较，揭示了这些颗粒中特定糖基化表位的富集和耗尽。这些包括高甘露糖、多乳糖胺、α-2,6 唾液酸和复杂 N-连接糖基化的富集以及末端血型 A 和 B 抗原的排除。多乳糖胺特征源于不同来源的微泡中不同的糖蛋白群。总之，我们的数据表明微泡是从特定的膜微区中出现的，这意味着糖基化在微泡蛋白分拣中起作用。
