Yamaguchi A, Ide T, Hatakeyama M, Doi T, Kono T, Uchiyama T, Kikuchi K, Taniguchi T, Uede T
Department of Pathology, Sapporo Medical College, Japan.
Int Immunol. 1989;1(2):160-8. doi: 10.1093/intimm/1.2.160.
The structural basis of the high affinity interleukin-2 receptor which was previously reconstituted in a cultured murine T cell line, EL4 by expressing either wild-type Tac antigen complementary DNA (cDNA) or a chimeric cDNA was characterized. The chimeric cDNA encodes a membrane portion whose extracellular portion consists of that of Tac antigen whereas transmembrane and cytoplasmic portions consists of those the human insulin beta chain. The Tac antigen/anti-Tac antibody complex was treated by chemical crosslinking reagents, purified by goat anti-mouse immunoglobulin (Ig), and was analysed by SDS-PAGE. We here demonstrated the presence in mouse EL4 transfectants of a novel membrane protein which is closely associated with the products of transfected cDNAs in the absence of interleukin-2. The protein is 75 kDa in size and is detected in cells which express high affinity interleukin-2 receptor but not in cells which only express low affinity interleukin-2 receptor. The transmembrane region and the cytoplasmic region of Tac antigen is not necessary for the formation of the complex consisting of Tac antigen and 75 kDa molecule, indicating that a murine 75 kDa molecule associates with Tac antigen extra-cellularly.
之前通过表达野生型Tac抗原互补DNA（cDNA）或嵌合cDNA在培养的小鼠T细胞系EL4中重建的高亲和力白细胞介素-2受体的结构基础得到了表征。嵌合cDNA编码一个膜部分，其细胞外部分由Tac抗原的细胞外部分组成，而跨膜和细胞质部分由人胰岛素β链的相应部分组成。Tac抗原/抗Tac抗体复合物用化学交联试剂处理，通过山羊抗小鼠免疫球蛋白（Ig）纯化，并通过SDS-PAGE进行分析。我们在此证明，在小鼠EL4转染细胞中存在一种新型膜蛋白，在没有白细胞介素-2的情况下，它与转染cDNA的产物密切相关。该蛋白大小为75 kDa，在表达高亲和力白细胞介素-2受体的细胞中可检测到，而在仅表达低亲和力白细胞介素-2受体的细胞中未检测到。Tac抗原的跨膜区域和细胞质区域对于由Tac抗原和75 kDa分子组成的复合物的形成不是必需的，这表明一种小鼠75 kDa分子在细胞外与Tac抗原结合。
