Sugar-binding properties of VIP36, an intracellular animal lectin operating as a cargo receptor
Sugar-binding properties of VIP36, an intracellular animal lectin operating as a cargo receptor
复制标题
DOI：
10.1074/jbc.m505757200
复制
发表时间：
2005-11-04
影响因子：
4.8
通讯作者：
Kato, K
中科院分区：
文献类型：
--
作者：
Kamiya, Y;Yamaguchi, Y;Kato, K
36 kDa的囊泡整合蛋白(VIP36)是一种细胞内的凝集素，作为一种可能的货物受体，在高尔基体和内质网之间循环。虽然已知VIP36与携带高甘露糖型低聚糖的糖蛋白相互作用，但尚未对识别异构体低聚糖结构的糖结合专一性进行详细分析。在本研究中，我们利用正面亲和层析(FAC)方法分析了VIP36重组糖类识别结构域(VIP36-CRD)的糖结合特性。为此，我们制备了一个由21种低聚糖组成的吡啶层状糖库，并对其进行了FAC分析。FAC数据表明，D_1甘露糖基的糖基化和修剪干扰了VIP36-CRD的结合。VIP36-CRD对糖的结合呈钟形pH依赖关系，最适pH值接近6.5。通过考察VIP36与糖结合的特异性和最适pH值以及它的亚细胞定位以及细胞器的pH，我们认为VIP36结合了保留顺式高尔基体网络中完整的D1甘露糖基分支的糖蛋白，并循环到内质网，在那里，由于较高的pH，它释放了货物，从而有助于糖蛋白的质量控制。
The vesicular integral protein of 36 kDa (VIP36) is an intracellular animal lectin that acts as a putative cargo receptor, which recycles between the Golgi and the endoplasmic reticulum. Although it is known that VIP36 interacts with glycoproteins carrying high mannose-type oligosaccharides, detailed analyses of the sugar-binding specificity that discriminates isomeric oligosaccharide structures have not yet been performed. In the present study, we have analyzed, using the frontal affinity chromatography (FAC) method, the sugar-binding properties of a recombinant carbohydrate recognition domain of VIP36 (VIP36-CRD). For this purpose, a pyridylaminated sugar library, consisting of 21 kinds of oligosaccharides, including isomeric structures, was prepared and subjected to FAC analyses. The FAC data have shown that glucosylation and trimming of the D1 mannosyl branch interfere with the binding of VIP36-CRD. VIP36-CRD exhibits a bell-shaped pH dependence of sugar binding with an optimal pH value of similar to 6.5. By inspection of the specificity and optimal pH value of the sugar binding of VIP36 and its subcellular localization, together with the organellar pH, we suggest that VIP36 binds glycoproteins that retain the intact D1 mannosyl branch in the cis-Golgi network and recycles to the endoplasmic reticulum where, due to higher pH, it releases its cargos, thereby contributing to the quality control of glycoproteins.