Abstract：
BACKGROUND: The Wnt signaling pathway is highly conserved in metazoans and regulates a large array of cellular processes including motility, polarity and fate determination, and stem cell homeostasis. Modulation of the actin cytoskeleton via the non-canonical Wnt pathway regulate cell polarity and cell migration that are required for proper vertebrate gastrulation and subsequent neurulation. However, the mechanism(s) of how the non-canonical pathway mediates actin cytoskeleton modulation is not fully understood.
RESULTS: Herein, we characterize the role of the Formin-homology protein; dishevelled associated activator of morphogenesis 2 (Daam2) protein in the Wnt signaling pathway. Co-immunoprecipitation assays confirm the binding of Daam2 to dishevelled2 (Dvl2) as well as the domains within these proteins required for interaction; additionally, the interaction between Daam2 and Dvl2 was Wnt-regulated. Sub-cellular localization studies reveal Daam2 is cytoplasmic and regulates the cellular actin cytoskeleton by modulating actin filament formation. During Xenopus development, a knockdown or loss of Daam2 specifically produces neural tube closure defects indicative of a role in non-canonical signaling. Additionally, our studies did not identify any role for Daam2 in canonical Wnt signaling in mammalian culture cells or the Xenopus embryo.
CONCLUSIONS: Our studies together identify Daam2 as a component of the non-canonical Wnt pathway and Daam2 is a regulator of neural tube morphogenesis during vertebrate development.
RESULTS: Herein, we characterize the role of the Formin-homology protein; dishevelled associated activator of morphogenesis 2 (Daam2) protein in the Wnt signaling pathway. Co-immunoprecipitation assays confirm the binding of Daam2 to dishevelled2 (Dvl2) as well as the domains within these proteins required for interaction; additionally, the interaction between Daam2 and Dvl2 was Wnt-regulated. Sub-cellular localization studies reveal Daam2 is cytoplasmic and regulates the cellular actin cytoskeleton by modulating actin filament formation. During Xenopus development, a knockdown or loss of Daam2 specifically produces neural tube closure defects indicative of a role in non-canonical signaling. Additionally, our studies did not identify any role for Daam2 in canonical Wnt signaling in mammalian culture cells or the Xenopus embryo.
CONCLUSIONS: Our studies together identify Daam2 as a component of the non-canonical Wnt pathway and Daam2 is a regulator of neural tube morphogenesis during vertebrate development.
摘要：
背景：Wnt信号通路在后生动物中高度保守，并调节包括运动在内的大量细胞过程，极性和命运决定，和干细胞稳态。通过非规范Wnt途径调节肌动蛋白细胞骨架可调节适当的脊椎动物原肠胚形成和随后的神经形成所需的细胞极性和细胞迁移。然而,非规范途径如何介导肌动蛋白细胞骨架调节的机制尚未完全了解。
结果：这里，我们描述了Formin同源蛋白的作用；Wnt信号通路中形态发生2（Daam2）蛋白的相关激活剂。免疫共沉淀试验证实了Daam2与dishevelled2（Dvl2）的结合以及相互作用所需的这些蛋白质中的结构域;此外，Daam2和Dvl2之间的相互作用受Wnt调控。亚细胞定位研究表明，Daam2是细胞质的，并通过调节肌动蛋白丝的形成来调节细胞肌动蛋白细胞骨架。在非洲爪狼发育过程中,Daam2的敲低或缺失特异性地产生神经管闭合缺陷,其指示在非规范信号传导中的作用。此外,我们的研究没有发现Daam2在哺乳动物培养细胞或非洲爪狼胚胎中的经典Wnt信号传导中的任何作用。
结论：我们的研究共同确定Daam2是非规范Wnt通路的组成部分，而Daam2是脊椎动物发育过程中神经管形态发生的调节剂。
结果：这里，我们描述了Formin同源蛋白的作用；Wnt信号通路中形态发生2（Daam2）蛋白的相关激活剂。免疫共沉淀试验证实了Daam2与dishevelled2（Dvl2）的结合以及相互作用所需的这些蛋白质中的结构域;此外，Daam2和Dvl2之间的相互作用受Wnt调控。亚细胞定位研究表明，Daam2是细胞质的，并通过调节肌动蛋白丝的形成来调节细胞肌动蛋白细胞骨架。在非洲爪狼发育过程中,Daam2的敲低或缺失特异性地产生神经管闭合缺陷,其指示在非规范信号传导中的作用。此外,我们的研究没有发现Daam2在哺乳动物培养细胞或非洲爪狼胚胎中的经典Wnt信号传导中的任何作用。
结论：我们的研究共同确定Daam2是非规范Wnt通路的组成部分，而Daam2是脊椎动物发育过程中神经管形态发生的调节剂。
