Syndecan-4 signals cooperatively with integrins in a Rho-dependent manner in the assembly of focal adhesions and actin stress fibers
Syndecan-4 signals cooperatively with integrins in a Rho-dependent manner in the assembly of focal adhesions and actin stress fibers
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DOI：
10.1073/pnas.96.6.2805
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发表时间：
1999-03-16
影响因子：
11.1
通讯作者：
Goetinck, PF
中科院分区：
文献类型：
--
作者：
Saoncella, S;Echtermeyer, F;Goetinck, PF
纤维连接蛋白上的细胞组装局部粘连和肌动蛋白应激纤维依赖于涉及整合素和细胞表面硫酸乙酰肝素蛋白多糖的黏附介导的信号。这两种细胞表面受体与纤维连接蛋白的不同结构域相互作用，为了试图确定参与其中的硫酸乙酰肝素蛋白多糖，我们使用纤维连接蛋白缺失(FN-/-)的小鼠成纤维细胞在分析过程中消除内源性纤维连接蛋白的贡献。FN-/-成纤维细胞被接种在纤维连接蛋白的细胞结合域或针对小鼠β1整合素链的抗体上，附着但不能扩散，也不形成局灶性粘连或肌动蛋白应激纤维。当这些细胞用针对小鼠syndecan-4胞外区的抗体处理时，它们完全扩散并组装局灶粘连和肌动蛋白应激纤维，这些结果与在完整纤维连接蛋白上看到的细胞中看到的没有区别，这些结果确定syndecan-4是参与组装过程的一种硫酸乙酰肝素蛋白多糖。抗体刺激的局部粘连和肌动应激纤维在纤维连接蛋白细胞结合域上的组装可以被小GTP结合蛋白Rho的抑制剂C3外移酶阻断，用溶血磷脂酸处理细胞，溶血磷脂酸激活Rho，导致纤维连接蛋白细胞结合域上成纤维细胞中焦点粘连和肌动应激纤维的充分铺展和组装。我们得出结论，Syndecan-4和整合素可以协同作用，产生细胞扩散的信号，并组装焦点粘连和肌动蛋白应激纤维。我们进一步得出结论，这些联合信号是以依赖于Rho的方式调节的。
The assembly of focal adhesions and actin stress fibers by cells plated on fibronectin depends on adhesion-mediated signals involving both integrins and cell-surface heparan sulfate proteoglycans. These two cell-surface receptors interact with different domains of fibronectin, To attempt to identify the heparan sulfate proteoglycans involved, we used fibronectin-null (FN-/-) mouse fibroblasts to eliminate the contribution of endogenous fibronectin during the analysis. FN-/- fibroblasts plated on the cell-binding domain of fibronectin or on antibodies directed against mouse beta 1 integrin chains attach but fail to spread and do not form focal adhesions or actin stress fibers. When such cells are treated with antibodies directed against the ectodomain of mouse syndecan-4, they spread fully and assemble focal adhesions and actin stress fibers indistinguishable from those seen in cells plated on intact fibronectin, These results identify syndecan-4 as a heparan sulfate proteoglycan involved in the assembly process. The antibody-stimulated assembly of focal adhesions and actin stress fibers in cells plated on the cell-binding domain of fibronectin can be blocked with C3 exotransferase, an inhibitor of the small GTP-binding protein Rho, Treatment of cells with lysophosphatidic acid, which activates Rho, results in full spreading and assembly of focal adhesions and actin stress fibers in fibroblasts plated on the cell-binding domain of fibronectin. We conclude that syndecan-4 and integrins can act cooperatively in generating signals for cell spreading and for the assembly of focal adhesions and actin stress fibers. We conclude further that these joint signals are regulated in a Rho-dependent manner.