ARF1 controls Rac1 signaling to regulate migration of MDA-MB-231 invasive breast cancer cells
ARF1 controls Rac1 signaling to regulate migration of MDA-MB-231 invasive breast cancer cells
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DOI：
10.1016/j.cellsig.2013.05.011
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发表时间：
2013-09-01
影响因子：
4.8
通讯作者：
Claing, Audrey
中科院分区：
文献类型：
--
作者：
Lewis-Saravalli, Sebastian;Campbell, Shirley;Claing, Audrey
adp核糖基化因子（ARFs）是一种单体G蛋白，可调节许多细胞过程，如肌动蛋白细胞骨架的重组。我们之前的研究表明，ARF1在高侵袭性乳腺癌细胞中过表达，并有助于其增强迁移。在这项研究中，我们建议确定ARF1调节这种复杂细胞反应的分子机制。通过研究这种ARF GTPase在细胞迁移过程中与板足形成相关的Rho GTPase Rac1的激活过程中的作用。在这里，我们首先证明了ARF1或Rac1表达的抑制显著影响MDA-MB-231细胞在EGF刺激下的迁移能力。然而，ARF1缺失的影响可以通过过表达Rac1活性突变体Rac1 Q(61)L来逆转。ARF1的耗尽也会损害EGF刺激促进Rac1的gtp负载的能力。为了进一步研究ARF1和Rac1之间可能的串扰，我们接下来研究了它们是否可以形成一个复合体。我们观察到这两个gtpase可以直接相互作用，而不依赖于与它们结合的核苷酸的性质。然而，EGF处理导致Rac1与其效应物IRSp53的关联，这在ARF1缺失的细胞中完全被废除。我们提供的证据表明，这种ARF异构体负责Rac1和IRSp53的质膜靶向，这是板足形成的必要步骤。综上所述，本研究提供了ARF1调控细胞迁移的新机制，并将该GTPase确定为减少乳腺癌患者转移形成的有希望的药理靶点。(c) 2013爱思唯尔公司版权所有。
ADP-ribosylation factors (ARFs) are monomeric G proteins that regulate many cellular processes such as reorganization of the actin cytoskeleton. We have previously shown that ARF1 is overexpressed in highly invasive breast cancer cells and contribute to their enhanced migration. In this study, we propose to define the molecular mechanism by which ARF1 regulates this complex cellular response. by investigating the role of this ARF GTPase on the activation process of Rac1, a Rho GTPase, associated with lamellipodia formation during cell migration. Here, we first show that inhibition of ARF1 or Rac1 expression markedly impacts the ability of MDA-MB-231 cells to migrate upon EGF stimulation. However, the effect of ARF1 depletion can be reversed by overexpression of the Rac1 active mutant, Rac1 Q(61)L. Depletion of ARF1 also impairs the ability of EGF stimulation to promote GTP-loading of Rac1. To further investigate the possible cross-talk between ARF1 and Rac1, we next examined whether they could form a complex. We observed that the two GTPases could directly interact independently of the nature of the nucleotide bound to them. EGF treatment however resulted in the association of Rac1 with its effector IRSp53, which was completely abrogated in ARF1 depleted cells. We present evidences that this ARF isoform is responsible for the plasma membrane targeting of both Rac1 and IRSp53, a step essential for lamellipodia formation. In conclusion, this study provides a new mechanism by which ARF1 regulates cell migration and identifies this GTPase as a promising pharmacological target to reduce metastasis formation in breast cancer patients. (c) 2013 Elsevier Inc. All rights reserved.