Crosstalk between Hippo and TGFβ: Subcellular Localization of YAP/TAZ/Smad Complexes
Crosstalk between Hippo and TGFβ: Subcellular Localization of YAP/TAZ/Smad Complexes
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DOI：
10.1016/j.jmb.2015.04.015
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发表时间：
2015-10-23
影响因子：
5.6
通讯作者：
Soderberg, Ola
中科院分区：
文献类型：
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作者：
Grannas, Karin;Arngarden, Linda;Soderberg, Ola
Hippo通路在生长控制、增殖和肿瘤抑制中起着至关重要的作用。信号通路的活性与细胞密度感应和组织组织结构相关。此外，Hippo通路有助于通过与生长因子介导的信号通路如TGF β的串扰来协调细胞过程。在这里，我们已经检查了本地化的蛋白质之间的相互作用的Hippo途径（雅普/TAZ）和TGF β（Smad 2/3）信号通路，通过使用原位邻近连接测定。我们研究了雅普/TAZ和Smad 2/3之间蛋白复合物的形成，并研究了这些相互作用如何受到HaCaT角质形成细胞和Smad 4缺陷型HT 29结肠癌细胞中TGF β刺激和细胞密度的影响。我们证明TGF β诱导HaCaT细胞中雅普/TAZ-Smad 2/3复合物的形成。在稀疏细胞条件下，检测到的复合物的程度较高，主要位于细胞核中，而在密集培养条件下，复合物较少，主要位于细胞质中。令人惊讶的是，我们在HT 29细胞中没有检测到任何雅普/TAZ Smad 2/3复合物。为了检查Smad 4缺陷是否是相互作用缺乏的原因，我们用靶向Smad 4的siRNA处理HaCaT细胞。然而，我们仍然可以在siRNA处理的细胞中观察到复合物的形成，这表明Smad 4对于雅普Smad 2/3相互作用不是必需的。总之，本研究显示HaCaT细胞中雅普/TAZ Smad 2/3复合物的局部化、密度依赖性形成，并提供了支持Hippo和TGF β信号通路之间串扰的证据。(C)2015爱思唯尔有限公司版权所有。
The Hippo pathway plays a crucial role in growth control, proliferation and tumor suppression. Activity of the signaling pathway is associated with cell density sensing and tissue organization. Furthermore, the Hippo pathway helps to coordinate cellular processes through crosstalk with growth-factor-mediated signaling pathways such as TGF beta. Here we have examined the localization of interactions between proteins of the Hippo pathway (YAP/TAZ) and TGF beta (Smad2/3) signaling pathway by using in situ proximity ligation assays. We investigated the formation of protein complexes between YAP/TAZ and Smad2/3 and examined how these interactions were affected by TGF beta stimulation and cell density in HaCaT keratinocytes and in Smad4-deficient HT29 colon cancer cells. We demonstrate that TGF beta induces formation of YAP/TAZ-Smad2/3 complexes in HaCaT cells. Under sparse cell conditions, the complexes were detected to a higher degree and were predominantly located in the nucleus, while under dense culture conditions, the complexes were fewer and mainly located in the cytoplasm. Surprisingly, we could not detect any YAP/TAZ Smad2/3 complexes in HT29 cells. To examine if Smad4 deficiency was responsible for the absence of interactions, we treated HaCaT cells with siRNA targeting Smad4. However, we could still observe complex formation in the siRNA-treated cells, suggesting that Smad4 is not essential for the YAP Smad2/3 interaction. In conclusion, this study shows localized, density-dependent formation of YAP/TAZ Smad2/3 complexes in HaCaT cells and provides evidence supporting a crosstalk between the Hippo and the TGF beta signaling pathways. (C) 2015 Elsevier Ltd. All rights reserved.