Differential modulation of cell adhesion by interaction between adhesive and counter-adhesive proteins: Characterization of the binding of vitronectin to osteonectin (BM40, SPARC)
Differential modulation of cell adhesion by interaction between adhesive and counter-adhesive proteins: Characterization of the binding of vitronectin to osteonectin (BM40, SPARC)
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DOI：
10.1042/bj3240311
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发表时间：
1997-05-15
影响因子：
4.1
通讯作者：
Preissner, KT
中科院分区：
文献类型：
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作者：
Rosenblatt, S;Bassuk, JA;Preissner, KT
肝素结合形式的玻璃体粘连蛋白是一种多功能黏附糖蛋白，与体内不同部位的细胞外基质（ECM）有关，并有助于促进细胞黏附和调节血管生成部位的细胞周蛋白水解。在本研究中，我们描述了玻璃体粘连蛋白与抗粘连蛋白骨粘连蛋白（也称为SPARC或BM40）的相互作用。骨连接素和玻璃体连接素都与培养的内皮细胞的ECM有关，并且定位于肾组织的血管壁切片。在体外，玻璃体连接蛋白的肝素结合多聚异构体以饱和的方式与固定骨连接蛋白结合，在30-40 nM处具有半最大结合。血浆玻璃体粘连蛋白与纤溶酶原激活物抑制剂1 （PAI-1）共孵育，引起多聚体形成，诱导玻璃体粘连蛋白与骨粘连蛋白结合。结合在生理离子强度下是最佳的，并且二元配合物通过组织转谷氨酰胺酶介导的交联来稳定。以浓度依赖性的方式，PAI-1、CaCl2、肝素和硫酸肝素，而不是其他糖胺聚糖，干扰玻璃体连接蛋白与骨连接蛋白的结合。利用玻璃钢连接蛋白衍生的合成肽以及重组骨连接蛋白的突变体，我们发现玻璃钢连接蛋白的肝素结合区域与骨连接蛋白的c端区域相互作用，该区域含有具有抗粘附特性的高亲和力Ca2+结合位点。体外培养的内皮细胞粘附被骨连接素部分破坏，玻璃连接素以浓度依赖性的方式相应地逆转。这些结果表明，玻璃体连接素和骨连接素之间的特定相互作用调节细胞粘附，从而可能调节血管生成过程中内皮细胞的功能。
Heparin-binding forms of vitronectin, a multifunctional adhesive glycoprotein, are associated with the extracellular matrix (ECM) at different locations in the body and serve to promote cell adhesion and the regulation of pericellular proteolysis at sites of angiogenesis. In the present study we characterized the interactions of vitronectin with the counter-adhesive protein osteonectin (also termed SPARC or BM40). Osteonectin and vitronectin were both found associated with the ECM of cultured endothelial cells and were localized in vessel wall sections of kidney tissue. In vitro, the heparin-binding multimeric isoform of vitronectin bound to immobilized osteonectin in a saturable manner with half-maximal binding at 30-40 nM. Preincubation of plasma vitronectin with plasminogen activator inhibitor 1 (PAI-1), which provoked multimer formation, induced the binding of vitronectin to osteonectin. Binding was optimal at physiological ionic strength, and binary complexes were stabilized by tissue transglutaminase-mediated cross-linking. In a concentration-dependent fashion, PAI-1, CaCl2, heparin and heparan sulphate, but not other glycosaminoglycans, interfered with the binding of vitronectin to osteonectin. Using vitronectin-derived synthetic peptides as well as mutant forms of recombinant osteonectin, we found that the heparin-binding region of vitronectin interacted with the C-terminal region of osteonectin that contains a high-affinity Ca2+-binding site with counter-adhesive properties. Adhesion of cultured endothelial cells was partly abrogated by osteonectin and was correspondingly reversed by vitronectin in a concentration-dependent manner. These results indicate that specific interactions between vitronectin and osteonectin modulate cell adhesion and might thereby regulate endothelial cell function during angiogenesis.