Human ether-a-go-go-related gene 1 channels are physically linked to β1 integrins and modulate adhesion-dependent signaling
Human ether-a-go-go-related gene 1 channels are physically linked to β1 integrins and modulate adhesion-dependent signaling
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DOI：
10.1091/mbc.e04-10-0940
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发表时间：
2005-06-01
影响因子：
3.3
通讯作者：
Arcangeli, A
中科院分区：
文献类型：
--
作者：
Cherubini, A;Hofmann, G;Arcangeli, A
整合素家族的粘附受体主要参与细胞-细胞外基质的粘附。此外，整合素触发多种参与细胞迁移、增殖、存活和分化的信号通路。我们之前已经证明，在神经母细胞瘤和白血病细胞中，含有β(1)亚基的整合素的激活可导致人类乙醚相关基因（hERG）通道携带的钾电流选择性增加；这种电流激活调节这些细胞的粘附依赖性分化。我们假设整合素和hERG通道之间的串扰可以追溯到由两种蛋白质组成的大分子信号复合物的组装。我们在SH-SY5Y神经母细胞瘤细胞和人胚胎肾293细胞中验证了这一假设，这些细胞稳定地转染了hERG1，因此在质膜上只表达了全长的hERG1蛋白。β(1)整合素和hERG1在这些细胞中共沉淀，并在细胞内和表面膜区室中共定位。这两种蛋白还与小泡蛋白-1共沉淀，表明该复合物位于脂筏/小泡中。在β(1)整合素介导的纤维连接蛋白粘附后，转染herg1的细胞经历hERG电流的激活；伴随这种激活，局灶黏附激酶与hERG1蛋白结合并发生酪氨酸磷酸化。使用herg1特异性抑制剂，我们发现局灶黏附激酶的酪氨酸磷酸化严格依赖于hERG通道活性。同样，小GTPase Rac1的活性也依赖于hERG电流。总的来说，这些数据表明hERG1蛋白与β(1)整合素结合并调节粘附受体信号传导。
Adhesive receptors of the integrin family are primarily involved in cell-extracellular matrix adhesion. Additionally, integrins trigger multiple signaling pathways that are involved in cell migration, proliferation, survival, and differentiation. We previously demonstrated that the activation of integrins containing the beta(1) subunit leads to a selective increase in potassium currents carried by the human ether-a-go-go-related gene (hERG) channels in neuroblastoma and leukemia cells; this current activation modulates adhesion-dependent differentiation in these cells. We hypothesized that the cross-talk between integrins and hERG channels could be traced back to the assembly of a macromolecular signaling complex comprising the two proteins. We tested this hypothesis in both SH-SY5Y neuroblastoma cells and in human embryonic kidney 293 cells stably transfected with hERG1 and, therefore, expressing only the full-length hERG1 protein on the plasma membrane. The beta(1) integrin and hERG1 coprecipitate in these cells and colocalize in both intracellular and surface membrane compartments. The two proteins also coprecipitate with caveolin-1, suggesting the localization of the complex in lipid rafts/caveolae. hERG1-transfected cells undergo an activation of hERG currents after beta(1) integrin-mediated adhesion to fibronectin; concomitant with this activation, the focal adhesion kinase associates with the hERG1 protein and becomes tyrosine phosphorylated. Using hERG1-specific inhibitors, we show that the tyrosine phosphorylation of focal adhesion kinase is strictly dependent on hERG channel activity. Similarly, the activity of the small GTPase Rac1 turned out to be dependent on hERG currents. On the whole, these data indicate that the hERG1 protein associates with beta(1) integrins and modulates adhesion receptor signaling.