Investigation on determinants of substrate specificities of nucleotide-sugar transporters

核苷酸-糖转运蛋白底物特异性决定因素的研究

基本信息

批准号：
15570105
负责人：
ISHIDA Nobuhiro
金额：
$ 2.3万
依托单位：
Chiba Institute of Science, Faculty of Risk and Crisis Management (2005)Tokyo Metropolitan Organization for Medical Research (2003-2004)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

Nucleotide sugar transporters are very hydrophobic proteins ranging from 340 a.a. to 400 a.a. long. They reside in Golgi apparatus and/or ER membrane exposing their C- and N-terminal regions to cytosol, and are highly likely to have ten transmembrane helices. They antiport nucleotide sugars pooled in cytosol into lumen of Golgi apparatus and/or ER lumen with the corresponding nucleoside monophosphates. The transported nucleotide sugars are utilized as sugar donors by glycosyltransferases for synthesis of sugar chains of glycoproteins. glycolipids and polysaccharides.Nucleotide-sugar transporter genes constitute a gene family that was assigned as SLC (solute carrier)35 family by the HUGO gene nomenclature committee. We carried out data mining of the gene databank, and found 23 human genes which shows significant similarity each others. We classified them into 6 subfamilies, from A to F, based on their similarity, and provided the gene symbol to each of the genes.We had found hUGTrel8 (S … More LC35D2) gene that exhibits around 50% similarity with human SLC35D1 (UDP-glucuronic acid/UDP-N-acetylgalactosamine transporter), fruitfly fringe connection (frc) transporter, and nematode SQV-7 transporter, the latter two being involved in developmental and ontological processes. We demonstrated that SLC35D2 was localized in the Golgi apparatus and transported UDP-N-acetylglucosamine. These observations indicate that SLC35D2 is a good candidate for the ortholog of frc transporter.We also biochemically demonstrated that a Drosophila homolog of the human GDP-fucose transporter, the Golgi GDP-fucose transporter (Gfr), specifically transport GDP-fucose in vitro, and generated null mutants of Gfr in Drosophila. The phenotypes of the Drosophila Gfr mutants were rescued by the human GDP-fucose transporters. Hence, these null mutants are good Drosophila models of CDGIIc patients who have defective GDP-fucose transporter to investigate the possible cause of the developmental defects in the patients. Less

核苷酸糖转运蛋白是长度从 340 个氨基酸到 400 个氨基酸的高度疏水性蛋白质，它们存在于高尔基体和/或内质网膜中，将其 C 端和 N 端区域暴露于细胞质中，并且很可能具有 10 个跨膜螺旋。核苷酸糖与相应的核苷单磷酸一起汇集在细胞质中，进入高尔基体腔和/或内质网腔。转运核苷酸糖被糖基转移酶用作糖供体，用于合成糖脂和多糖的糖链。核苷酸-糖转运蛋白基因构成了一个被HUGO基因命名委员会指定为SLC（溶质载体）35家族的基因家族。对基因数据库进行数据挖掘，发现了23个具有显着相似性的人类基因，我们将它们分为6个亚家族，根据它们的相似性，从 A 到 F，并为每个基因提供了基因符号。我们发现 hUGTrel8 (S … 更多 LC35D2) 基因与人类 SLC35D1 (UDP-葡萄糖醛酸/UDP-N) 表现出约 50% 的相似性-乙酰半乳糖胺转运蛋白）、果蝇边缘连接（frc）转运蛋白和线虫 SQV-7 转运蛋白，后两者参与发育和发育我们证明 SLC35D2 定位于高尔基体并转运 UDP-N-乙酰氨基葡萄糖。这些观察结果表明，SLC35D2 是 frc 转运蛋白的直向同源物的良好候选者。我们还从生化角度证明了人类 GDP- 的果蝇同源物。岩藻糖转运蛋白，即高尔基体 GDP-岩藻糖转运蛋白 (Gfr)，在体外特异性转运 GDP-岩藻糖，并产生无效突变体果蝇 Gfr 突变体的表型由人类 GDP-岩藻糖转运蛋白拯救，因此，这些无效突变体是具有缺陷 GDP-岩藻糖转运蛋白的 CDGIIc 患者的良好果蝇模型，用于研究发育缺陷的可能原因。在患者中较少。