Guanosine diphosphatase is required for protein and sphingolipid glycosylation in the Golgi lumen of Saccharomyces cerevisiae.
Guanosine diphosphatase is required for protein and sphingolipid glycosylation in the Golgi lumen of Saccharomyces cerevisiae.
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DOI：
10.1083/jcb.122.2.307
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发表时间：
1993-07
期刊：
影响因子：
--
通讯作者：
Robbins PW
中科院分区：
文献类型：
--
作者：
Abeijon C;Yanagisawa K;Mandon EC;Häusler A;Moremen K;Hirschberg CB;Robbins PW
目前的模型核苷酸糖使用的高尔基体预测内腔核苷二磷酸酶的关键作用。在糖转移到内源性大分子受体后，酶将核苷二磷酸转化为核苷一磷酸，后者又在偶联的反向转运蛋白反应中离开高尔基体腔，允许额外的核苷酸糖从胞质溶胶进入。为了验证这个模型，我们克隆了S.酿酒酵母鸟苷二磷酸酶，并构建无效突变。该突变应降低GDP-甘露糖和GMP的浓度，并增加高尔基体腔中GDP的浓度。这些改变反过来又会降低该隔室中蛋白质和脂质的甘露糖基化。事实上，我们发现了蛋白质如几丁质酶和羧肽酶Y的O-和N-糖基化以及转化酶的糖基化不足的部分阻断。此外，甘露糖肌醇磷酸神经酰胺水平大幅降低。
Current models for nucleotide sugar use in the Golgi apparatus predict a critical role for the lumenal nucleoside diphosphatase. After transfer of sugars to endogenous macromolecular acceptors, the enzyme converts nucleoside diphosphates to nucleoside monophosphates which in turn exit the Golgi lumen in a coupled antiporter reaction, allowing entry of additional nucleotide sugar from the cytosol. To test this model, we cloned the gene for the S. cerevisiae guanosine diphosphatase and constructed a null mutation. This mutation should reduce the concentrations of GDP-mannose and GMP and increase the concentration of GDP in the Golgi lumen. The alterations should in turn decrease mannosylation of proteins and lipids in this compartment. In fact, we found a partial block in O- and N-glycosylation of proteins such as chitinase and carboxypeptidase Y and underglycosylation of invertase. In addition, mannosylinositolphosphorylceramide levels were drastically reduced.