FUNCTION AND RECEPTOR SPECIFICITY OF A MINIMAL 20-KILODALTON CELL ADHESIVE FRAGMENT OF FIBRONECTIN
FUNCTION AND RECEPTOR SPECIFICITY OF A MINIMAL 20-KILODALTON CELL ADHESIVE FRAGMENT OF FIBRONECTIN
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DOI：
10.3109/15419069509081275
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发表时间：
1995-01-01
期刊：
影响因子：
--
通讯作者：
YAMADA, KM
中科院分区：
文献类型：
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作者：
AKIYAMA, SK;AOTA, S;YAMADA, KM
先前的研究已经得出了相互矛盾的结论，最小的尺寸和序列的纤连蛋白细胞粘附结构域所需的保留高细胞粘附活性。我们已经表达了一个重组的20 kDa的细胞结合片段的人纤连蛋白组成的第九和第十III型模块，其中包括的精氨酸-甘氨酸-天冬氨酸（RGD）细胞识别位点和第二细胞粘附结构域，协同作用的RGD位点。当以可溶形式用于抑制测定时，该多肽保留了与较大的110 kDa纤连蛋白片段相似的活性，但如果在直接吸附到塑料基质上后测定，则其显示出低细胞粘附活性。然而，粘附功能恢复，如果该片段结合到一个非抑制性的抗纤连蛋白抗体预吸附到塑料基板。抗体结合片段也促进细胞迁移。细胞扩散和迁移都是由α（5）β（1）整合素特异性介导的。含有固定化的20 kDa细胞结合片段的亲和柱有效地结合含有α（5）-、α（3）-和α（v）的纤连蛋白结合整联蛋白。与此相反，固定的11.5 kDa片段，含有的RGD序列，但缺乏协同序列的结合只有很差的作为含有纤连蛋白受体整合素，即使α（3）-和α（V）-含有整合素结合容易。我们的研究结果表明，粘附蛋白被提交给细胞的方式是重要的，大多数细胞粘附活性保留在纤连蛋白的最小20 kDa的片段。
Previous studies have reached conflicting conclusions about the minimal size and sequences of the fibronectin cell-adhesive domain necessary for retention of high cell adhesive activity. We have expressed a recombinant 20 kDa cell-binding fragment of human fibronectin consisting of the ninth and tenth type III modules, which includes the Arg Gly-Asp (RGD) cell recognition site and a second cell adhesive domain that acts synergistically with the RGD site. This polypeptide retained a similar activity as a larger 110 kDa fibronectin fragment when used in soluble form in inhibition assays, but it displayed low cell adhesive activity if assayed after direct adsorption to a plastic substrate. However, adhesive function was restored if the fragment was bound to a non-inhibitory anti-fibronectin antibody pre-adsorbed to the plastic substrate. The antibody-bound fragment also promoted cell migration. Both cell spreading and migration were specifically mediated by the alpha(5) beta(1) integrin. Affinity columns containing immobilized 20 kDa cell-binding fragment effectively bound alpha(5)-, alpha(3)-, and alpha(v)-containing fibronectin-binding integrins. In contrast, an immobilized 11.5 kDa fragment that contained the RGD sequence but lacked the synergistic sequence was bound only poorly by as-containing fibronectin receptor integrins, even though the alpha(3)- and alpha(v)- containing integrins bound readily. Our results indicate that the manner in which adhesion proteins are presented to cells is important and that most cell adhesive activity is retained in a minimal 20 kDa segment of fibronectin.