CD23 is a glycan-binding receptor in some mammalian species
CD23 is a glycan-binding receptor in some mammalian species
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DOI：
10.1074/jbc.ra119.010572
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发表时间：
2019-10-11
影响因子：
4.8
通讯作者：
Taylor, Maureen E.
中科院分区：
文献类型：
--
作者：
Jegouzo, Sabine A. F.;Feinberg, Hadar;Taylor, Maureen E.
CD 23是在B淋巴细胞和其他细胞上发现的低亲和力IgE受体，含有C末端凝集素样结构域，其类似于在许多聚糖结合受体中发现的C型碳水化合物识别结构域（CRD）。在大多数哺乳动物物种中，存在形成糖结合位点所需的CD 23残基，尽管CD 23与IgE的结合不涉及糖。固相结合竞争试验，糖蛋白印迹实验，和聚糖阵列分析采用牛和小鼠CD 23的凝集素样结构域表明，它们结合甘露糖，GlcNAc，葡萄糖，岩藻糖和糖蛋白，这些糖在非还原性末端位置。牛CRD的晶体结构在存在？-甲基甘露糖苷和GlcNAc？一个？2 Man揭示了一系列寡糖配体可以容纳在一个开放的结合位点，其中大多数相互作用是与一个单一的末端糖残基。尽管小鼠CD 23显示出与牛CD 23相似的单糖和糖蛋白结合模式，但结合较弱。相比之下，在使用人CD 23的类似实验中没有观察到糖结合。糖结合活性的缺乏与导致人类的灵长类谱系中CD 23基因突变的积累相关，导致关键糖结合残基的丢失。这些结果与CD 23在许多物种中作为潜在病原微生物以及IgE的受体的作用一致。然而，CD 23结合几种不同配体的能力因物种而异，这表明它在不同的生物体中具有不同的功能。
CD23, the low-affinity IgE receptor found on B lymphocytes and other cells, contains a C-terminal lectin-like domain that resembles C-type carbohydrate-recognition domains (CRDs) found in many glycan-binding receptors. In most mammalian species, the CD23 residues required to form a sugar-binding site are present, although binding of CD23 to IgE does not involve sugars. Solid-phase binding competition assays, glycoprotein blotting experiments, and glycan array analysis employing the lectin-like domains of cow and mouse CD23 demonstrate that they bind to mannose, GlcNAc, glucose, and fucose and to glycoproteins that bear these sugars in nonreducing terminal positions. Crystal structures of the cow CRD in the presence of ?-methyl mannoside and GlcNAc?1?2Man reveal that a range of oligosaccharide ligands can be accommodated in an open binding site in which most interactions are with a single terminal sugar residue. Although mouse CD23 shows a pattern of monosaccharide and glycoprotein binding similar to cow CD23, the binding is weaker. In contrast, no sugar binding was observed in similar experiments with human CD23. The absence of sugar-binding activity correlates with accumulation of mutations in the gene for CD23 in the primate lineage leading to humans, resulting in loss of key sugar-binding residues. These results are consistent with a role for CD23 in many species as a receptor for potentially pathogenic microorganisms as well as IgE. However, the ability of CD23 to bind several different ligands varies between species, suggesting that it has distinct functions in different organisms.