Cell-associated episialin is a complex containing two proteins derived from a common precursor.
Cell-associated episialin is a complex containing two proteins derived from a common precursor.
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细胞相关表唾液酸蛋白是一种复合物，含有源自共同前体的两种蛋白质。
DOI：
10.1016/s0021-9258(18)42677-4
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发表时间：
1992
期刊：
影响因子：
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通讯作者：
John Hilkensll
中科院分区：
文献类型：
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作者：
Marjolijn J. L. LigtenbergS;Lars Kruijshaar;Femke Buijs;Marja van MeijerO;Sergey;V.;Litvinovy;John Hilkensll
上皮唾液粘蛋白episialin的cDNA编码具有大的胞外结构域的跨膜分子，其主要由20个氨基酸的重复组成。在此，我们证实了先前提出的在内质网中发生的上皮唾液酸蛋白的蛋白水解裂解的存在（Hilkens，J.，和Buijs，F.（1988）J.Biol.Chem.263，4215-4222），并显示在体外翻译系统中发生类似的切割。使用截短mRNA的体外翻译，我们将切割位点映射到位于跨膜结构域上游71和53个氨基酸之间的区域。对该区域缺失的突变体的分析表明，体外和体内使用的切割位点相同或非常接近。两种裂解产物保持缔合，尽管它们不通过二硫键连接。因此，来自N末端的亚基（代表实际的粘蛋白样结构域）由于其与C末端亚基的相互作用而保持间接锚定至细胞膜。
cDNA for the epithelial sialomucin episialin encodes a transmembrane molecule with a large extracellular domain, which mainly consists of repeats of 20 amino acids. Here we confirm the existence of a previously proposed proteolytic cleavage of episialin that occurs in the endoplasmic reticulum (Hilkens, J., and Buijs, F. (1988) J. Biol. Chem. 263, 4215-4222) and show that a similar cleavage takes place in in vitro translation systems. Using in vitro translation of truncated mRNAs, we map the cleavage site to a region located between 71 and 53 amino acids upstream of the transmembrane domain. Analysis of a mutant, in which this region has been deleted, indicates that the cleavage sites used in vitro and in vivo are identical or in close proximity. Both cleavage products remain associated although they are not linked through disulfide bonds. Therefore, the subunit derived from the N terminus, which represents the actual mucin-like domain, remains indirectly anchored to the cell membrane as a result of its interaction with the C-terminal subunit.