Mammalian PIG-X and yeast Pbn1p are the essential components of glycosylphosphatidylinositol-mannosyltransferase I
Mammalian PIG-X and yeast Pbn1p are the essential components of glycosylphosphatidylinositol-mannosyltransferase I
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DOI：
10.1091/mbc.e04-09-0802
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发表时间：
2005-03-01
影响因子：
3.3
通讯作者：
Kinoshita, T
中科院分区：
文献类型：
--
作者：
Ashida, H;Hong, YJ;Kinoshita, T
在内质网（ER）内，甘露糖和葡萄糖，从dolichol-磷酸-甘露糖和-葡萄糖捐赠，被转移到N-聚糖和GPI-锚前体，和丝氨酸/苏氨酸残基在许多蛋白质。介导这些反应的糖基转移酶是具有共同特征的ER驻留多跨膜蛋白，形成>10种酶的超家族。在这里，我们报告的糖基磷脂酰肌醇甘露糖基转移酶I（GPI-MT-I），它转移的GPI锚前体的四个甘露糖的第一个重要组成部分。我们分离了一个中国仓鼠卵巢（CHO）细胞突变体缺陷GPI-MT-I，但不是其催化成分PIG-M。突变基因，称为磷脂酰肌醇聚糖类X（PIG-X），编码一个252个氨基酸的ER驻留I型跨膜蛋白与一个大的内腔域。PIG-X和PIG-M形成复合物，并且PIG-M的表达是
Within the endoplasmic reticulum (ER), mannoses and glucoses, donated from dolichol-phosphate-mannose and -glucose, are transferred to N-glycan and GPI-anchor precursors, and serine/threonine residues in many proteins. Glycosyltransferases that mediate these reactions are ER-resident multitransmembrane proteins with common characteristics, forming a superfamily of >10 enzymes. Here, we report an essential component of glycosylphosphatidylinositolmannosyltransferase I (GPI-MT-I), which transfers the first of the four mannoses in the GPI-anchor precursors. We isolated a Chinese hamster ovary (CHO) cell mutant defective in GPI-MT-I but not its catalytic component PIG-M. The mutant gene, termed phosphatidylinositolglycan-class X (PIG-X), encoded a 252-amino acid ER-resident type I transmembrane protein with a large lumenal domain. PIG-X and PIG-M formed a complex, and PIG-M expression was