Alpha v integrins mediate the rise in intracellular calcium in endothelial cells on fibronectin even though they play a minor role in adhesion.
Alpha v integrins mediate the rise in intracellular calcium in endothelial cells on fibronectin even though they play a minor role in adhesion.
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DOI：
10.1074/jbc.270.50.30235
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发表时间：
1994-04
影响因子：
4.8
通讯作者：
M. A. Schwartz;K. Denninghoff
中科院分区：
文献类型：
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作者：
M. A. Schwartz;K. Denninghoff
摘要我们研究了哪些整合素介导了内皮细胞在纤维连接蛋白（FN）上铺展所引发的细胞内钙（[Ca 2 +]i）升高。固定在玻璃表面上的特异性抗整联蛋白单克隆抗体被用作触发细胞扩散的激动剂。这些实验表明，α v的抗体可以诱导[Ca 2 +]i的上升，而α 5 β 1的两种抗体是无活性的，尽管它们能够诱导细胞扩散和细胞内pH值升高。然后将溶液中的抗体用作激动剂来阻断特定整合素与FN的结合。这些实验还表明，α v整联蛋白而不是α 5 β 1介导了在FN上铺展的细胞中[Ca 2 +]i的升高。在功能阻断抗整联蛋白抗体和FN柱上的表面标记的细胞提取物的亲和层析的存在下进行粘附测定，以表征与FN结合的整联蛋白。两种方法均显示α v整联蛋白和α 5 β 1参与FN结合;然而，α v整联蛋白的贡献远小于α 5 β 1的贡献。这些结果表明，两个受体FN在相同的细胞可以触发不同的细胞内信号通路，此外，整合素的粘附的贡献是几乎检测不到的细胞反应可以有重大影响。结果还表明，钙信号通路的激活的特异性主要存在于整合素α亚基。
Abstract We have investigated which integrins mediate the elevation of intracellular calcium ([Ca2+]i) triggered by spreading of endothelial cells on fibronectin (FN). Specific anti-integrin monoclonal antibodies immobilized on glass surfaces were used as agonists to trigger cell spreading. These experiments demonstrated that an antibody to alpha v could induce the rise in [Ca2+]i, whereas two antibodies to alpha 5 beta 1 were inactive, despite their ability to induce cell spreading and elevation of intracellular pH. Antibodies in solution were then used as agonists to block association of specific integrins with FN. These experiments also showed that alpha v integrin(s) but not alpha 5 beta 1 mediated the rise in [Ca2+]i in cells spreading on FN. Adhesion assays in the presence of function-blocking anti-integrin antibodies and affinity chromatography on FN columns of surface-labeled cell extracts were carried out to characterize the integrins that bind to FN. Both methods showed that alpha v integrin(s) and alpha 5 beta 1 participate in FN binding; however, the contribution from alpha v integrin(s) was much less than that of alpha 5 beta 1. These results demonstrate that two receptors for FN on the same cells can trigger distinct intracellular signaling pathways and, furthermore, that an integrin whose contribution to adhesion is barely detectable can have a major effect on cellular responses. The results also suggest that the specificity for activation of the calcium signaling pathway resides primarily in the integrin alpha subunit.