Cell type-specific post-Golgi apparatus localization of a "resident" endoplasmic reticulum glycoprotein, glucosidase II.
Cell type-specific post-Golgi apparatus localization of a "resident" endoplasmic reticulum glycoprotein, glucosidase II.
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DOI：
10.1083/jcb.110.2.309
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发表时间：
1990-02
期刊：
影响因子：
--
通讯作者：
Roth J
中科院分区：
文献类型：
--
作者：
Brada D;Kerjaschki D;Roth J
葡萄糖苷酶 II 是一种天冬酰胺连接的寡糖加工酶，是内质网的常驻糖蛋白。在肾小管细胞中，与之前在肝细胞中的发现相反，我们通过光学和电子显微镜发现葡萄糖苷酶 II 的免疫反应性主要存在于高尔基体后结构中。大多数免疫标记位于质膜下方的内吞结构中。免疫沉淀证实纯化的刷状缘制剂中存在葡萄糖苷酶 II 亚基。肾葡萄糖苷酶II含有携带内H敏感、高甘露糖以及内H抗性寡糖链的种类。某些种类的葡萄糖苷酶 II 含有唾液酸。唾液酸化物质具有酶活性。这项研究表明，一种被认为是内质网驻留物的酶可能在某些细胞类型中表现出不同的定位。
Glucosidase II, an asparagine-linked oligosaccharide processing enzyme, is a resident glycoprotein of the endoplasmic reticulum. In kidney tubular cells, in contrast to previous findings on hepatocytes, we found by light and electron microscopy immunoreactivity for glucosidase II predominantly in post-Golgi apparatus structures. The majority of immunolabel was in endocytotic structures beneath the plasma membrane. Immunoprecipitation confirmed presence of the glucosidase II subunit in purified brush border preparations. Kidney glucosidase II contained species carrying endo H-sensitive, high mannose as well as endo H- resistant oligosaccharide chains. Some species of glucosidase II contained sialic acid. The sialylated species were enzymatically active. This study demonstrates than an enzyme presumed to be a resident of the endoplasmic reticulum may show alternative localizations in some cell types.