O-glycosylation pattern of CD24 from mouse brain
O-glycosylation pattern of CD24 from mouse brain
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DOI：
10.1515/bc.2009.044
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发表时间：
2009-07-01
影响因子：
3.7
通讯作者：
Geyer, Rudolf
中科院分区：
文献类型：
--
作者：
Bleckmann, Christina;Geyer, Hildegard;Geyer, Rudolf
细胞粘附分子CD 24是一种高度糖基化的糖蛋白，在中枢神经系统、免疫系统和肿瘤生物学中起重要作用。由于CD 24仅包含约30个氨基酸的短蛋白质核心，并且在物种之间保守性低，因此已经提出CD 24的功能由其糖基化模式介导。我们目前的研究提供了证据表明，CD 24与细胞粘附分子L1的相互作用是由携带α 2，3-连接唾液酸的O-连接聚糖介导的。此外，去N-糖基化的CD 24显示分别促进或抑制小脑神经元或背根神经节神经元的神经突生长，达到与未处理的CD 24相同的程度。因此，本研究的重点是通过电喷雾离子阱质谱法对化学释放的全甲基化CD 24 O-聚糖进行结构解析。我们的分析揭示了粘蛋白型和O-甘露糖基聚糖的不同混合物的存在，所述混合物部分携带功能相关的表位，例如3-连接的唾液酸、二唾液酸基序、Le（X）、唾液酸-Le（X）或HNK-1单元。因此，我们的数据提供了基础，进一步研究碳水化合物决定簇的贡献CD 24介导的生物活性。
The cell adhesion molecule CD24 is a highly glycosylated glycoprotein that plays important roles in the central nervous system, the immune system and in tumor biology. Since CD24 comprises only a short protein core of approximately 30 amino acids and low conservation among species, it has been proposed that the functions of CD24 are mediated by its glycosylation pattern. Our present study provides evidence that interaction of CD24 with the cell adhesion molecule L1 is mediated by O-linked glycans carrying alpha 2,3-linked sialic acid. Furthermore, de-N-glycosylated CD24 was shown to promote or inhibit neurite outgrowth of cerebellar neurons or dorsal root ganglion neurons, respectively, to the same extent as untreated CD24. Therefore, this study is focused on the structural elucidation of the chemically released, permethylated CD24 O-glycans by electrospray ionization ion trap mass spectrometry. Our analyses revealed the occurrence of a diverse mixture of mucin-type and O-mannosyl glycans carrying, in part, functionally relevant epitopes, such as 3-linked sialic acid, disialyl motifs, Le(X), sialyl-Le(X) or HNK-1 units. Hence, our data provide the basis for further studies on the contribution of carbohydrate determinants to CD24-mediated biological activities.