Inhibitor-resistant type I receptors reveal specific requirements for TGF-β signaling in vivo
Inhibitor-resistant type I receptors reveal specific requirements for TGF-β signaling in vivo
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DOI：
10.1016/j.ydbio.2006.03.050
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发表时间：
2006-07-15
影响因子：
2.7
通讯作者：
Whitman, Malcolm
中科院分区：
文献类型：
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作者：
Ho, Diana M.;Chan, Joanne;Whitman, Malcolm
激活素/神经胶质细胞样TGF-β超家族配体通过I型受体Alk 4、Alk 5和Alk 7发出信号，并负责介导发育中的许多基本过程。SB-431542是激活素/nodal信号传导的化学抑制剂，通过特异性干扰I型受体发挥作用。在这里，我们使用的是耐药突变受体，以检查SB-431542在非洲爪蟾和斑马鱼胚胎的疗效和特异性。SB-431542治疗消除了体内Smad 2磷酸化，并产生了与节点信号传导途径中遗传突变体中观察到的表型非常相似的表型。抑制剂抗性Alk 4在抑制剂处理后有效地挽救Smad 2信号传导、发育表型和标记基因表达。该系统用于检查I型受体对几种激活素/nodal配体的特异性。我们发现，Alk 4可以有效地拯救信号通过广泛的配体，而Alk 7只能微弱地拯救信号通过相同的配体。在整个胚胎中，原肠胚形成过程中的节点信号可以用Alk 4拯救，但不能用Alk 7，而Alk 5只能通过发育后期表达的配体介导信号。ALK抑制剂SB-431542与耐药ALK的组合提供了一套强大的工具，用于检查胚胎发生期间的nodal/激活素信号传导。(c)2006年爱思唯尔公司All rights reserved.
Activin/nodal-like TGF-beta superfamily ligands signal through the type I receptors Alk4, Alk5, and Alk7, and are responsible for mediating a number of essential processes in development. SB-431542, a chemical inhibitor of activin/nodal signaling, acts by specifically interfering with type I receptors. Here, we use inhibitor-resistant mutant receptors to examine the efficacy and specificity of SB-431542 in Xenopus and zebrafish embryos. Treatment with SB-431542 eliminates Smad2 phosphorylation in vivo and generates a phenotype very similar to those observed in genetic mutants in the nodal signaling pathway. Inhibitor-resistant Alk4 efficiently rescues Smad2 signaling, developmental phenotype, and marker gene expression after inhibitor treatment. This system was used to examine type I receptor specificity for several activin/nodal ligands. We find that Alk4 can efficiently rescue signaling by a wide range of ligands, while Alk7 can only weakly rescue signaling by the same ligands. In whole embryos, nodal signaling during gastrulation can be rescued with Alk4, but not Alk7, while Alk5 can only mediate signaling by ligands expressed later in development. The combination of the ALK inhibitor SB-431542 with inhibitor-resistant ALKs provides a powerful set of tools for examining nodal/activin signaling during embryogenesis. (c) 2006 Elsevier Inc. All rights reserved.