ISOLATION OF THE THROMBOSPONDIN MEMBRANE-RECEPTOR
ISOLATION OF THE THROMBOSPONDIN MEMBRANE-RECEPTOR
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DOI：
10.1172/jci112918
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发表时间：
1987-04-01
影响因子：
15.9
通讯作者：
NACHMAN, RL
中科院分区：
文献类型：
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作者：
ASCH, AS;BARNWELL, J;NACHMAN, RL
血小板反应蛋白 (TSP) 是一种具有广泛组织分布的 450 kD 多功能糖蛋白，在血小板刺激后分泌，与活化的血小板表面结合，并支持血小板聚集。我们已经鉴定并分离了血小板、内皮细胞、单核细胞和多种人类肿瘤细胞系中存在的 88 kD 膜糖蛋白，它是 TSP 的膜结合位点。在单克隆抗体 OKM5 存在的情况下，内源性血小板 TSP 与凝血酶和离子载体刺激的人血小板的结合受到抑制。 TSP 与 C32 黑色素瘤细胞和 HT1080 纤维肉瘤细胞的结合是特异性的，并且也可以被 OKM5 Mab 抑制。细胞标记和特异性免疫沉淀证明了单个 88-kK 糖蛋白的生物合成。 TSP 与分离的膜蛋白的结合是特异性的且可饱和的。这些研究鉴定出一种 88 kD 的膜糖蛋白，它与单克隆抗体 OKM5 发生反应，并且可能充当细胞 TSP 受体。
Thrombospondin (TSP), a 450-kD multifunctional glycoprotein with a broad tissue distribution, is secreted upon platelet stimulation, binds to the activated platelet surface, and supports platelet aggregation. We have identified and isolated an 88-kD membrane glycoprotein present in platelets, endothelial cells, monocytes, and a variety of human tumor cell lines that is the membrane binding site for TSP. Endogenous platelet TSP binding to thrombin- and ionophore-stimulated human platelets was inhibited in the presence of the monoclonal antibody OKM5. TSP binding to C32 melanoma cells and HT1080 fibrosarcoma cells was specific and also inhibitable with OKM5 Mab. Cell labeling followed by specific immunoprecipitation demonstrated biosynthesis of a single 88-kK glycoprotein. Binding of TSP to the isolated membrane protein was specific and saturable. These studies identify an 88-kD membrane glycoprotein that reacts with the monoclonal antibody, OKM5, and may function as the cellular TSP receptor.