Mammalian Notch1 is modified with two unusual forms of O-linked glycosylation found on epidermal growth factor-like modules
Mammalian Notch1 is modified with two unusual forms of O-linked glycosylation found on epidermal growth factor-like modules
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DOI：
10.1074/jbc.275.13.9604
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发表时间：
2000-03-31
影响因子：
4.8
通讯作者：
Haltiwanger, RS
中科院分区：
文献类型：
--
作者：
Moloney, DJ;Shair, LH;Haltiwanger, RS
Notch是一个大的细胞表面受体，已知是一个重要的球员在各种各样的发展级联反应，在这里，我们表明，Notch 1内源性表达在中国仓鼠卵巢细胞修饰与O-连接的岩藻糖和O-连接的葡萄糖，两种不寻常的形式的O-连接的糖基化表皮生长因子样（EGF）模块上发现。有趣的是，这两种修饰都以单糖和寡糖的形式发生。通过外切糖苷酶diglysine，我们确定O-连接的岩藻糖寡糖是一种四糖，其结构与人凝血因子IX上发现的结构相同：Sia-alpha 2，3-Gal-beta 1，4-GlcNAc-beta 1，3-Fuc-alpha 1-O-Ser/Thr。O-连接的葡萄糖的伸长形式似乎是三糖。Notch 1是第一个被鉴定为具有O-连接岩藻糖或O-连接葡萄糖修饰的膜相关蛋白。它也代表了第二个发现的具有延长形式的O-连接的岩藻糖的蛋白质，糖基化位点，其落入Notch的多个EGF模块内，在物种间和Notch同源物内高度保守，由于已知Notch通过EGF模块的子集与其配体相互作用，这些结果表明这些模块的O-连接的碳水化合物修饰可能影响受体-配体相互作用。
Notch is a large cell-surface receptor known to be an essential player in a wide variety of developmental cascades, Here we show that Notch1 endogenously expressed in Chinese hamster ovary cells is modified with O-linked fucose and O-linked glucose saccharides, two unusual forms of O-linked glycosylation found on epidermal growth factor-like (EGF) modules. Interestingly, both modifications occur as monosaccharide and oligosaccharide species, Through exoglycosidase digestions we determined that the O-linked fucose oligosaccharide is a tetrasaccharide with a structure identical to that found on human clotting factor IX: Sia-alpha 2,3-Gal-beta 1,4-GlcNAc-beta 1,3-Fuc-alpha 1-O-Ser/Thr. The elongated form of O-linked glucose appears to be a trisaccharide. Notch1 is the first membrane-associated protein identified with either O-linked fucose or O-linked glucose modifications. It also represents the second protein discovered with an elongated form of O-linked fucose, The sites of glycosylation, which fall within the multiple EGF modules of Notch, are highly conserved across species and within Notch homologs, Since Notch is known to interact with its ligands through subsets of EGF modules, these results suggest that the O-linked carbohydrate modifications of these modules may influence receptor-ligand interactions.