Identification of the hydrophobic glycoproteins of Caenorhabditis elegans
Identification of the hydrophobic glycoproteins of Caenorhabditis elegans
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DOI：
10.1093/glycob/cwi075
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发表时间：
2005-10-01
期刊：
影响因子：
4.3
通讯作者：
Mahuran, DJ
中科院分区：
文献类型：
--
作者：
Fan, XL;She, YM;Mahuran, DJ
疏水性蛋白质，如整合膜蛋白，很难分离，因此难以在蛋白质组学水平上进行研究。然而，膜糖蛋白中含有的Asn连接的（N-连接的）碳水化合物（N-聚糖）在分化、胚胎发生、炎症、癌症和转移以及其他重要的细胞过程中是重要的。因此，这些蛋白质和它们的糖基化位点在一个良好的表征模式生物的鉴定是第一步，了解N-聚糖和它们的相关蛋白质在体内功能的机制。本研究采用蛋白质组学方法对秀丽隐杆线虫提取物中的117个疏水性N-糖基化蛋白进行了鉴定，分析了195个糖肽，其中199个糖肽为天冬酰胺连接的寡糖。大多数被鉴定的蛋白质参与细胞粘附、代谢或小分子的运输。此外，有18种蛋白质的功能是未知的或通过序列同源性预测的，还有两种蛋白质先前仅根据C. elegans数据库。由于N-糖基化是在内质网（ER）的内腔中启动的，我们的数据可以用来重新评估以前预测的这些蛋白质的亚细胞定位。同样，N-糖基化位点的鉴定有助于建立相关糖蛋白的膜拓扑结构。秀丽隐杆线虫菌株目前在我们已经鉴定的17个基因中具有突变。强大的遗传工具可用于C。elegans可用于制备在编码N-糖基化蛋白质的基因中具有突变的其它菌株，从而确定N-聚糖功能。
Hydrophobic proteins such as integral membrane proteins are difficult to separate, and therefore to study, at a proteomics level. However, the Asn-linked (N-linked) carbohydrates (N-glycans) contained in membrane glycoproteins are important in differentiation, embryogenesis, inflammation, cancer and metastasis, and other vital cellular processes. Thus, the identification of these proteins and their sites of glycosylation in a well-characterized model organism is the first step toward understanding the mechanisms by which N-glycans and their associated proteins function in vivo. In this report, a proteomics method recently developed by our group was applied to identify 117 hydrophobic N-glycosylated proteins of Caenorhabditis elegans extracts by analysis of 195 glycopeptides containing 199 Asn-linked oligosaccharides. Most of the proteins identified are involved in cell adhesion, metabolism, or the transport of small molecules. In addition, there are 18 proteins for which no function is known or predictable by sequence homologies and two proteins which were previously predicted to exist only on the basis of genomic sequences in the C. elegans database. Because N-glycosylation is initiated in the lumen of the endoplasmic reticulum (ER), our data can be used to reassess the previously predicted subcellular localizations of these proteins. As well, the identification of N-glycosylation sites helps establish the membrane topology of the associated glycoproteins. Caenorhabditis elegans strains are presently available with mutations in 17 of the genes we have identified. The powerful genetic tools available for C. elegans can be used to make other strains with mutations in genes encoding N-glycosylated proteins and thereby determine N-glycan function.