SPECIFIC BINDING OF ANGIOGENIN TO CALF PULMONARY-ARTERY ENDOTHELIAL-CELLS
SPECIFIC BINDING OF ANGIOGENIN TO CALF PULMONARY-ARTERY ENDOTHELIAL-CELLS
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DOI：
10.1073/pnas.86.21.8427
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发表时间：
1989-11-01
影响因子：
11.1
通讯作者：
BARRITAULT, D
中科院分区：
文献类型：
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作者：
BADET, J;SONCIN, F;BARRITAULT, D
血管生成素(Ang)可与小牛肺动脉内皮细胞特异性结合。细胞结合为4度。~(125)I标记的人重组Ang的C是时间和浓度依赖的，可逆的，并且随着未标记分子数量的增加而饱和。这种相互作用被证明是特异的，因为大量过量的未标记Ang使标记Ang结合减少了80%，而类似剂量的结构相关蛋白质RNaseA则没有影响。Scatchard对结合数据的分析揭示了两个明显的成分。高亲和力部位，表观解离常数为5倍。10-9M代表细胞特异性相互作用。第二组分由低亲和力/高容量位点组成，表观解离常数为0.2倍。10-6M，主要与胞周成分有关。高亲和力Ang结合部位因细胞密度不同而不同，在牛主动脉、角膜和肾上腺皮质毛细血管内皮细胞上可见，而在中国仓鼠肺成纤维细胞上未见。二价铜，一种血管生成的调节剂，被发现可以诱导比细胞结合放射性增加几倍。胎盘核糖核酸酶抑制剂是Ang的核糖核溶解和血管生成活性的紧密结合抑制剂，只有在没有铜的情况下才能取消125I标记的人重组Ang结合。
Specific binding of angiogenin (ANG) to calf pulmonary artery endothelial cells was demonstrated. Cellular binding at 4.degree. C of 125I-labeled human recombinant ANG was time and concentration dependent, reversible, and saturable in the presence of increasing amounts of the unlabeled molecules. The interaction was shown to be specific since a large excess of unlabeled ANG reduced labeled ANG binding by >80%, whereas similar doses of RNase A, a structurally related protein, had no effect. Scatchard analyses of binding data revealed two apparent components. High-affinity sites with an apparent dissociation constant of 5 .times. 10-9M were shown to represent cell-specific interactions. The second component, comprising low-affinity/high-capacity sites with an apparent dissociation constant of 0.2 .times. 10-6 M, was essentially associated with pericellular components. High-affinity ANG binding sites varied with cell density and were found on other endothelial cells from bovine aorta, cornea, and adrenal cortex capillary but not on Chinese hamster lung fibroblasts. Divalent copper, a modulator of angiogenesis, was found to induce a severalfold increase in specific cell-bound radioactivity. Placental ribonuclease inhibitor, a tight-binding inhibitor of both ribonucleolytic and angiogenic activities of ANG, abolished 125I-labeled human recombinant ANG binding only in the absence of copper.