POST-TRANSLATIONAL MODIFICATION BY GALNAC ON MANNOSYLATED GLYCOPROTEINS

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 糖蛋白α-营养不良聚糖(DG)是脊椎动物O-甘露糖化的最典型的例子，它与DG在连接肌肉细胞和细胞外基质中的作用直接相关，以及糖基化过程中的异常与疾病的联系。中央粘蛋白结构域同时含有O-Man和O-GalNAc糖链，糖基化模式基本保持不变。随着O-Man残基第一次安装在内质网中，我们一直有兴趣确定这如何指导高尔基体中O-GalNAc的后续修饰。翻译后修饰中的一个重要问题是O-甘露糖基化位点与能够安装GalNAc的多肽GalNAc转移酶家族成员的相互作用。为了解决这个问题，我们正在与NIH的Kelly Ten Hagen博士的实验室合作，研究pp-GalNAc转移酶对我们从DG合成的多肽和O-Man糖肽的作用。这些构建物是使用CCRC兰斯·威尔斯实验室的DG上的序列特异性修改数据设计的。该项目结合了Ten Hagen实验室在GalNAc转移酶分析方面的专业知识，以及CCRC的合成和分析能力。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The glycoprotein alpha-dystroglycan (DG) has been the focus of considerable attention for several reasons, being the best characterized example of O-mannosylation in vertebrates, the direct connection between the O-Man glycans and function in DG's role of connecting muscle cells to the extracellular matrix, and the linkage of aberrations in its glycosylation to disease. The central mucin domain bears both O-Man and O-GalNAc glycans in a largely preserved pattern of glycosylation. With the O-Man residues being installed first in the ER, we have been interested in identifying how this directs the subsequent modification with O-GalNAc in the Golgi. An important issue in the post-translational modification is the interplay of sites of O-mannosylation with members of the family of polypeptide GalNAc transferases capable of installing GalNAc. To address this, we are working with the laboratory of Dr. Kelly Ten Hagen at NIH in characterizing the action of pp-GalNAc transferases on peptides and O-Man glycopeptides from DG we have synthesized. The constructs have been designed using sequence specific modification data on DG from Lance Wells' lab at the CCRC. The project combines expertise in GalNAc transferase analysis in the Ten Hagen lab and synthetic and analytical capabilities at the CCRC.