Inhibition of binding of fibronectin to matrix assembly sites by anti-integrin (alpha 5 beta 1) antibodies.
Inhibition of binding of fibronectin to matrix assembly sites by anti-integrin (alpha 5 beta 1) antibodies.
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DOI：
10.1083/jcb.111.2.699
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发表时间：
1990-08
影响因子：
7.8
通讯作者：
Mosher, D F
中科院分区：
文献类型：
--
作者：
Fogerty, F J;Akiyama, S K;Yamada, K M;Mosher, D F
成纤维细胞具有介导血浆和细胞纤连蛋白组装到细胞外基质中的细胞表面位点。细胞与纤连蛋白的粘附可以通过整合素（α5β1）与纤连蛋白的含有精氨酸-甘氨酸-天冬氨酸（RGDS）的细胞粘附区域的相互作用来介导。我们试图阐明 α5β1 纤连蛋白受体在基质中纤连蛋白组装中的作用。大鼠单克隆抗体 mAb 13 可识别整联蛋白 β 1 亚基，完全阻断 125I-纤连蛋白的结合和基质组装以及纤连蛋白 125I-70-kD 氨基末端片段 (70 kD) 与成纤维细胞层的结合。抗 β1 抗体的 Fab 片段也具有抑制作用。抗体 mAb 16 可识别整合素 α 5 亚基，部分阻断 125I-纤连蛋白和 125I-70-kD 的结合。当细胞层与荧光素化纤连蛋白和抗β1或抗α5共孵育时，抗β1是标记纤连蛋白与细胞层结合的比抗α5更有效的抑制剂。抗-β1 IgG 对 125I-纤连蛋白结合的抑制在 20 分钟内发生。随着纤连蛋白浓度的增加，抗β1 Fab片段或IgG对125I-纤连蛋白结合的抑制不能被克服，这表明抗β1和外源纤连蛋白可能不会竞争相同的结合位点。没有含有 β1 的整联蛋白与固定的 70 kD 结合。这些数据表明β1亚基在外源纤连蛋白的结合和组装中发挥重要作用，可能是通过参与组装位点的组织、再生或循环，而不是通过与纤连蛋白直接相互作用。
Fibroblasts have cell surface sites that mediate assembly of plasma and cellular fibronectin into the extracellular matrix. Cell adhesion to fibronectin can be mediated by the interaction of an integrin (alpha 5 beta 1) with the Arg-Gly-Asp-Ser (RGDS)-containing cell adhesion region of fibronectin. We have attempted to elucidate the role of the alpha 5 beta 1 fibronectin receptor in assembly of fibronectin in matrices. Rat monoclonal antibody mAb 13, which recognizes the integrin beta 1 subunit, completely blocked binding and matrix assembly of 125I- fibronectin as well as binding of the 125I-70-kD amino-terminal fragment of fibronectin (70 kD) to fibroblast cell layers. Fab fragments of the anti-beta 1 antibody were also inhibitory. Antibody mAb 16, which recognizes the integrin alpha 5 subunit, partially blocked binding of 125I-fibronectin and 125I-70-kD. When cell layers were coincubated with fluoresceinated fibronectin and either anti-beta 1 or anti-alpha 5, anti-beta 1 was a more effective inhibitor than anti- alpha 5 of binding of labeled fibronectin to the cell layer. Inhibition of 125I-fibronectin binding by anti-beta 1 IgG occurred within 20 min. Inhibition of 125I-fibronectin binding by anti-beta 1 Fab fragments or IgG could not be overcome with increasing concentrations of fibronectin, suggesting that anti-beta 1 and exogenous fibronectin may not compete for the same binding site. No beta 1-containing integrin bound to immobilized 70 kD. These data indicate that the beta 1 subunit plays an important role in binding and assembly of exogenous fibronectin, perhaps by participation in the organization, regeneration, or cycling of the assembly site rather than by a direct interaction with fibronectin.