Lüscher B, Rousseaux-Schmid M, Naim H Y, MacDonald H R, Bron C
J Immunol. 1985 Sep;135(3):1937-44.
The biosynthesis and maturation of the three subunits alpha (Mr = 37,000), beta (Mr = 32,000), and gamma (Mr = 27,000) of the mouse Lyt-2/3 antigenic complex have been studied by using two monoclonal antibodies directed against a monomorphic determinant of the Lyt-2 antigen. Short time-pulse labeling of thymocytes reveals three different high mannose intermediates that give rise upon endo-beta-N-acetyl-glucosaminidase H digestion to three distinct precursor polypeptides of Mr = 22,000 (alpha P), Mr = 18,000 (beta P), and Mr = 19,500 (gamma P). Pulse-chase analysis indicates rapid posttranslational processing, because mature forms already appear after 10 min of chase. The half-life of the endo-H-sensitive early forms are in the range of 20 to 30 min. Both the alpha and beta subunits are suggested to contain three N-asparagine-linked oligosaccharides, one of which is of the high mannose type. In contrast, the gamma-chain contains only one such glycan unit of the complex type. Moreover, the results presented show that all three chains undergo additional posttranslational modifications. Finally, the data suggest that the cytoplasmic domains of these chains are of different size.
利用两种针对Lyt-2抗原单态决定簇的单克隆抗体，研究了小鼠Lyt-2/3抗原复合物的三个亚基α（Mr = 37,000）、β（Mr = 32,000）和γ（Mr = 27,000）的生物合成与成熟过程。对胸腺细胞进行短时间脉冲标记，发现了三种不同的高甘露糖中间体，经内切β-N-乙酰葡糖胺酶H消化后，产生三种不同的前体多肽，Mr分别为22,000（αP）、18,000（βP）和19,५00（γP）。脉冲追踪分析表明存在快速的翻译后加工过程，因为在追踪10分钟后就已出现成熟形式。内切H敏感的早期形式的半衰期在20到30分钟范围内。α和β亚基均被认为含有三个N-天冬酰胺连接的寡糖，其中一个是高甘露糖型。相比之下，γ链仅含有一个复合型的此类聚糖单元。此外，所呈现的结果表明，所有三条链都经历了额外的翻译后修饰。最后，数据表明这些链的胞质结构域大小不同。
