GLUCOSE TRIMMING AND REGLUCOSYLATION DETERMINE GLYCOPROTEIN ASSOCIATION WITH CALNEXIN IN THE ENDOPLASMIC-RETICULUM
GLUCOSE TRIMMING AND REGLUCOSYLATION DETERMINE GLYCOPROTEIN ASSOCIATION WITH CALNEXIN IN THE ENDOPLASMIC-RETICULUM
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DOI：
10.1016/0092-8674(95)90395-x
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发表时间：
1995-05-05
期刊：
影响因子：
64.5
通讯作者：
HELENIUS, A
中科院分区：
文献类型：
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作者：
HEBERT, DN;FOELLMER, B;HELENIUS, A
为了确定N -连接寡糖在糖蛋白折叠中的作用，我们分析了在狗胰腺微粒体中体外翻译的流感血凝素（HA）的加工过程。我们发现，与钙连蛋白（一种膜结合的分子伴侣）的结合对具有单葡萄糖基化核心聚糖的分子具有特异性。在微粒体中，这些单葡萄糖基化核心聚糖要么是通过葡糖苷酶I和II从原始的三葡萄糖基化核心寡糖上去除葡萄糖产生的，要么是通过对已经去葡萄糖基化的高甘露糖聚糖重新葡萄糖基化产生的。血凝素从钙连蛋白上完全释放需要葡糖苷酶II去除剩余的葡萄糖。这些结果为内质网中的修剪和重新葡萄糖基化活性提供了解释，并建立了糖基化和折叠之间的直接关联。
To determine the role of N-linked oligosaccharides in the folding of glycoproteins, we analyzed the processing of in vitro translated influenza hemagglutinin (HA) in dog pancreas microsomes. We found that binding to calnexin, a membrane-bound molecular chaperone, was specific to molecules that possessed monoglucosylated core glycans. In the microsomes, these were generated either by glucose removal from the original triglucosylated core oligosaccharide by glucosidases I and II or by reglucosylation of already unglucosylated high mannose glycans. Release of fully folded HA from calnexin required the removal of the remaining glucose by glucosidase II. The results provided an explanation for trimming and reglucosylation activities in the endoplasmic reticulum and established a direct correlation between glycosylation and folding.