GLYCAN PROFILES IN HUMAN MYELOID CELLS ASREGULATED BY SIALIDASE ACTIVITY

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 聚糖决定簇CD 15（也称为刘易斯x或Lex）是人髓样细胞的区别性标志物，并介导中性粒细胞与树突状细胞的粘附。尽管对这种结构有广泛的兴趣，但CD 15表达的潜在机制 仍然相对不被描述。因此，Sackstein实验室研究了与人髓样细胞分化相关的CD 15表达增加的分子基础。分化细胞的流式细胞术分析以及使用聚糖合成和唾液酸酶抑制剂的生物化学研究表明，增加的CD 15表达不是由于CD 15的从头生物合成，而是主要由α（2-3）-唾液酸酶活性的诱导引起的，其从细胞表面唾液酸-CD 15（也称为唾液酸-Lewis x、sLex或CD 15 s）产生CD 15。这种表面CD 15向CD 15的分化相关转化主要发生在糖蛋白上。到目前为止，翻译后聚糖修饰的调节仅归因于糖基转移酶表达的动态变化。这些结果揭示了一个新的范例，证明了高尔基体后膜糖苷酶活性在关键聚糖决定簇的“生物合成”中的关键作用。在报告这些结果的手稿评价期间，该资源提供了聚糖谱，以回应审查人员的要求。该资源还提供2D-凝胶和LC/MS/MS设备的使用权，并为来自Sackstein实验室的博士后研究员Christina Silvescu提供培训，他以前在质谱方面有经验。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The glycan determinant CD15 (also known as Lewis x, or Lex) is a distinguishing marker for human myeloid cells and mediates neutrophil adhesion to dendritic cells. Despite broad interest in this structure, the mechanisms underlying CD15 expression remain relatively uncharacterized. Accordingly, the Sackstein laboratory has investigated the molecular basis of increasing CD15 expression associated with human myeloid cell differentiation. Flow cytometric analysis of differentiating cells together with biochemical studies using inhibitors of glycan synthesis and of sialidases showed that increased CD15 expression is not due to de novo biosynthesis of CD15, but results predominantly from induction of a(2-3)-sialidase activity, which yields CD15 from cell-surface sialyl-CD15 (also known as sialyl-Lewis x, sLex or CD15s). This differentiation-associated conversion of surface CD15s to CD15 occurs mainly on glycoproteins. Until now, modulation of post-translational glycan modifications has been attributed solely to dynamic variations in glycosyltransferase expression. The results unveiled a new paradigm by demonstrating a critical role for post-Golgi membrane glycosidase activity in the 'biosynthesis' of a key glycan determinant. The Resource provided glycan profiles to respond to a reviewers' request during evaluation of the manuscript which reported these results. The Resource is also providing access to 2D-gel and LC/MS/MS equipment and training for postdoctoral fellow Christina Silvescu from the Sackstein laboratory who has previous experience in mass spectrometry.