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Studies on carbohydrate structures of plasma membrane blycoproteins in relation to the loss of cell adhesion.

质膜糖蛋白碳水化合物结构与细胞粘附丧失相关的研究。

基本信息

批准号：
62580108
负责人：
FURUKAWA Kiyoshi
金额：
$ 0.96万
依托单位：
University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1988
项目状态：
已结题

项目摘要

The carbohydrate structures of plasma membrane glycoproteins prepared from tissue forming cells and from non-tissue forming cells have been determined. The results showed that various tissues of rat contain mainly biantennary complex-type and high-mannose type sugar chains with different amounts of tri- and tetraantennary complex-type ones, of sialic acid, of fucose, of -galactose, of bisecting N-acetylglucosamine and of lactosaminoglycan in a tissue specific manner. When two rat ascites hepatoma cells were analyzed in comparison to normal livers, they were primarily tri- and tetraantennary complex-type sugar chains and those with a repeating structure which are different from that of livers. However, one ascites hepatoma cells, AH414, which lose cell adhesion and are present as single cells, expressed fucosyl hybrid-type sugar chains in much larger amount than livers and the other ascites hepatoma cells, AH7974, which maintain partial intercellular adhesion.When mucin-type glycoprotei … More ns associated with plasma membranes of liver and two ascites hepatoma of rat were analyzed by using a low density WGA-Sepharose column to which sialyl mucin-type glycoproteins preferentially bind, AH414 cells showed the presence of highly sialylated glycoprotein(s) with clusted mucin-type sugar chains, which were detected but in much lesser amount in liver and AH7974 cells. The carbohydrate structures of them were turned out to be GalNAc, Gal 1-GalNAc and Gal 1-(GlcNAc 1-)GalNAc.The above results indicated that the appearance of hybrid-type sugar chains as well as highly sialylated mucin-type sugar chains in plasma membrane glycoproteins may be related to the loss of cell adhesion of originally tissue forming cells. The activities of galactosyltransferases that are involved in the synthesis of Asn-linked and mucin-type sugar chains in the transformed cells were high, which probably may reflect the increased synthesis of branched Asn-linked sugar chains and of highly sialylated clustered mucin-type glycoproteins. Less

测定了从组织形成细胞和非组织形成细胞制备的质膜糖蛋白的碳水化合物结构。结果表明，大鼠不同组织中主要含有二天线复合型和高甘露糖型糖链，并含有不同量的三天线和四天线复合型糖链、唾液酸糖链、岩藻糖糖链、半乳糖糖链、N-乙酰氨基葡萄糖裂解糖链和乳糖胺糖链。将两个大鼠腹水肝癌细胞与正常肝脏进行比较分析，发现它们主要是三角和四角复合型糖链，并具有与肝脏不同的重复结构。然而，其中一种腹水肝癌细胞AH414失去了细胞黏附并以单细胞形式存在，其表达岩藻糖基杂交型糖链的量远高于肝脏和另一种腹水肝癌细胞AH7974，AH7974细胞保持部分细胞间黏附。当粘素型糖蛋白…用唾液酸型糖蛋白优先结合的低密度WGA-Sepharose柱分析了更多与大鼠肝脏质膜和两个腹水型肝癌相关的糖蛋白。AH414细胞显示出高度唾液酸化的糖蛋白(S)和聚集的粘蛋白型糖链，在肝脏和AH7974细胞中检测到较少的唾液酸糖蛋白。其糖链结构为GalNAc、Gal1-GalNAc和Gal1-(GlcNAc 1-)GalNac。以上结果表明，质膜糖蛋白中杂交型糖链和高唾液酸化粘蛋白糖链的出现可能与原组织形成细胞的细胞黏附丧失有关。转化细胞中参与合成ASN连接糖链和粘蛋白类型糖链的半乳糖基转移酶活性较高，这可能反映了支链ASN连接糖链和高度唾液酸化的成簇粘蛋白糖蛋白合成增加。较少