Integration of cell attachment, cytoskeletal localization, and signaling by integrin-linked kinase (ILK), CH-ILKBP, and the tumor suppressor PTEN
Integration of cell attachment, cytoskeletal localization, and signaling by integrin-linked kinase (ILK), CH-ILKBP, and the tumor suppressor PTEN
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DOI：
10.1091/mbc.e03-05-0308
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发表时间：
2003-12-01
影响因子：
3.3
通讯作者：
Dedhar, S
中科院分区：
文献类型：
--
作者：
Attwell, S;Mills, J;Dedhar, S
细胞附着以及整联蛋白下游细胞骨架和信号复合物的组装是紧密相连和协调的。尽管许多细胞内蛋白与这些过程有关，但生化和遗传学研究中正在出现一种新的范式，该范式涉及整合素连接激酶 (ILK) 及其相互作用蛋白，例如 CH-ILKBP (α-parvin)、桩蛋白和 PINCH，将整合素与肌动蛋白细胞骨架和信号复合物偶联。对果蝇、秀丽隐杆线虫和小鼠的遗传学研究表明，ILK 作为衔接蛋白在介导整合素依赖性细胞附着和细胞骨架组织中发挥着重要作用。在这里，我们使用几种不同的方法证明，抑制 ILK 激酶活性或表达会导致细胞附着、细胞迁移、F-肌动蛋白组织以及人体细胞中 CH-ILKBP 和桩蛋白的特定细胞骨架定位的抑制。我们还证明，ILK 的激酶活性在细胞骨架部分中升高，并且细胞骨架内 CH-ILKBP 与 ILK 的相互作用刺激 ILK 活性以及下游向 PKB/Akt 和 GSK-3 的信号传导。有趣的是，CH-ILKBP 与 ILK 的相互作用受到 Pi3 激酶途径的调节，因为药物抑制剂或肿瘤抑制因子 PTEN 对 Pi3 激酶活性的抑制会抑制这种相互作用以及细胞附着和信号传导。这些数据表明，ILK 的激酶和接头特性以 Pi3 激酶依赖性方式共同发挥作用，调节整合素介导的细胞附着和信号转导。
Cell attachment and the assembly of cytoskeletal and signaling complexes downstream of integrins are intimately linked and coordinated. Although many intracellular proteins have been implicated in these processes, a new paradigm is emerging from biochemical and genetic studies that implicates integrin-linked kinase (ILK) and its interacting proteins, such as CH-ILKBP (alpha-parvin), paxillin, and PINCH in coupling integrins to the actin cytoskeleton and signaling complexes. Genetic studies in Drosophila, Caenorhabditis elegans, and mice point to an essential role of ILK as an adaptor protein in mediating integrin-dependent cell attachment and cytoskeletal organization. Here we demonstrate, using several different approaches, that inhibiting ILK kinase activity, or expression, results in the inhibition of cell attachment, cell migration, F-actin organization, and the specific cytoskeletal localization of CH-ILKBP and paxillin in human cells. We also demonstrate that the kinase activity of ILK is elevated in the cytoskeletal fraction and that the interaction of CH-ILKBP with ILK within the cytoskeleton stimulates ILK activity and downstream signaling to PKB/Akt and GSK-3. Interestingly, the interaction of CH-ILKBP with ILK is regulated by the Pi3 kinase pathway, because inhibition of Pi3 kinase activity by pharmacological inhibitors, or by the tumor suppressor PTEN, inhibits this interaction as well as cell attachment and signaling. These data demonstrate that the kinase and adaptor properties of ILK function together, in a Pi3 kinase-dependent manner, to regulate integrin-mediated cell attachment and signal transduction.