A soluble interleukin 6 receptor isolated from conditioned medium of human breast cancer cells is encoded by a differentially spliced mRNA.
A soluble interleukin 6 receptor isolated from conditioned medium of human breast cancer cells is encoded by a differentially spliced mRNA.
复制标题
从人乳腺癌细胞的条件培养基中分离出的可溶性白细胞介素 6 受体由差异剪接的 mRNA 编码。
作者：
J. Oh;M. Revel;J. Chebath
人白细胞介素6受体（IL-6 R）在细胞上表达为80 kDa的跨膜蛋白（gp 80，配体结合单位）或较小的可溶性对应物（sIL-6 R，约55 kDa）。重组或天然sIL-6 R通过与细胞表面的信号转导亚基gp 130结合而结合IL-6并刺激生物活性。sIL-6 R的起源尚不清楚。除了gp 80 mRNA外，造血细胞还表达IL-6 R mRNA，其中跨膜结构域被剪接掉，预测在C末端具有经修饰的基本序列的较短蛋白质。我们表明，剪接的mRNA表达在人T47 D乳腺癌细胞和可溶性IL-6 R蛋白确实是由这些细胞分泌。针对剪接蛋白C-末端的抗体检测通过经典和免疫亲和层析从T47 D上清液纯化的sIL-6 R中的55-65 kDa糖基化物质。糖基化的或去除O-和N-连接的多糖后的剪接的T47 D IL-6 R具有与来自CHO细胞的重组剪接的IL-6 R相同的大小。重组剪接的IL-6 R作为IL-6激动剂作用于细胞以刺激从IL-6诱导型增强子的转录。
The human interleukin 6 receptor (IL-6R) is expressed on cells as a transmembrane protein of 80 kDa (gp80, ligand binding unit), or as a smaller soluble counterpart (sIL-6R, approximately 55 kDa). Recombinant or natural sIL-6Rs bind IL-6 and stimulate biological activity by association with the signal transducing subunit gp130 at the cell surface. The origin of sIL-6Rs is not clear. Haematopoietic cells express, in addition to the gp80 mRNA, an IL-6R mRNA where the transmembrane domain is spliced out, predicting a shorter protein with a modified basic sequence at the C-terminus. We show that the spliced mRNA is expressed in human T47D breast carcinoma cells and soluble IL-6R protein is indeed secreted by these cells. An antibody against the C-terminus of the spliced protein detects a 55-65 kDa glycosylated species in sIL-6R purified from T47D supernatant by classical and immunoaffinity chromatography. The spliced T47D IL-6R, glycosylated or after removal of O- and N-linked polysaccharides, has the same size as a recombinant spliced IL-6R from CHO cells. The recombinant spliced IL-6R acts on cells as an IL-6 agonist to stimulate transcription from IL-6 inducible enhancers.