Cell surface annexin II is a high affinity receptor for the alternatively spliced segment of tenascin-C.
Cell surface annexin II is a high affinity receptor for the alternatively spliced segment of tenascin-C.
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细胞表面膜联蛋白II是Tenascin-C的剪接片段的高亲和力受体。
DOI：
10.1083/jcb.126.2.539
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发表时间：
1994-07
影响因子：
7.8
通讯作者：
Erickson, H P
中科院分区：
文献类型：
--
作者：
Chung, C Y;Erickson, H P
我们用放射配基结合分析法研究了可溶性TN-C与几种细胞系的结合。与U-251 MG人脑胶质瘤细胞和一株牛主动脉内皮细胞有特异性结合，而对仓鼠成纤维细胞无特异性结合。利用与TN-C的特定结构域相对应的重组蛋白定位TN-C的结合位点(S)。选择性剪接片段(TNfnA-D)对天然TN-C的结合抑制作用最强，并与胶质瘤和血管内皮细胞结合。TnfnA-D结合的Scatchard分析表明，每个细胞有2-5×10(5)个结合位点，表观解离常数为2 nM。根据天然TN-C和TnfnA-D柱膜提取物的印迹结合分析和亲和层析，确定TnfnA-D的细胞表面受体是一个35kD的蛋白。蛋白质序列分析表明，这个35kD的受体是膜联蛋白II。膜联蛋白II是一种细胞质蛋白，因此它可能是TN-C的胞外受体，这是令人惊讶的。为了证实它是35-kD受体，我们获得了纯化的膜联蛋白II，并证明了它在NM浓度下与TNfnA-D和Tn-C结合。抗Annexin II的抗体显著地染色活内皮细胞的外表面，并阻断了TNfnA-D与细胞的结合。因此，膜联蛋白II似乎是TN-C选择性剪接片段的受体，并可能介导细胞对细胞外基质中可溶性TN-C的反应。
We have investigated the binding of soluble tenascin-C (TN-C) to several cell lines using a radioligand binding assay. Specific binding was demonstrated to U-251MG human glioma cells and to a line of bovine aortic endothelial cells, but hamster fibroblasts showed no specific binding. Recombinant proteins corresponding to specific domains of TN-C were used to map the binding site(s) in TN-C. The alternatively spliced segment (TNfnA-D) inhibited the binding of native TN-C most strongly, and itself bound to glioma and endothelial cells. Scatchard analysis of TNfnA-D binding indicated 2-5 x 10(5) binding sites per cell, with an apparent 2 nM dissociation constant. The cell surface receptor for TNfnA-D was identified as a 35-kD protein on the basis of blot binding assays and affinity chromatography of membrane extracts on native TN-C and TNfnA-D columns. Protein sequencing indicated that this 35-kD receptor was annexin II. Annexin II is well characterized as a cytoplasmic protein, so it was surprising to find it as a presumably extracellular receptor for TN-C. To confirm that it was the 35-kD receptor, we obtained purified annexin II and demonstrated its binding to TNfnA-D and TN-C at nM concentrations. Antibodies to annexin II prominently stained the external surface of live endothelial cells and blocked the binding of TNfnA-D to the cells. Thus annexin II appears to be a receptor for the alternatively spliced segment of TN-C, and may mediate cellular responses to soluble TN-C in the extracellular matrix.