Structure and functional analysis of Shrew, a novel modulator of the BMP signalling pathway

骨形态发生蛋白(BMPs)是转化生长因子B家族信号分子中的一员，对胚胎发育和组织动态平衡是必不可少的。BMP信号从果蝇到人类高度保守，并在多个发育阶段发挥重要作用，包括胚胎背腹(DV)轴的形成和骨形成。这种守恒意味着，像果蝇这样强大的模式生物可以用来可视化体内的信号。BMP(在果蝇中称为DPP)信号由一组蛋白质控制，这些蛋白质与DPP形成抑制复合体。SOG就是一种这样的调节剂，它通过与DPP结合来发挥作用，从而在物理上阻止它们与细胞表面的受体结合。SOG由一种名为扭曲原肠作用的调节器辅助，它既有支持DPP的功能，也有反对DPP的功能。最近，在这个信号通路中发现了一个新的成员，Shrew，一种新的扭曲的原肠形成蛋白，它通过增加DPP活性来调节果蝇DV模式的形成，尽管其作用机制尚不清楚。

Bone morphogenetic proteins (BMPs) are members of the transforming growth factor (TGF)"B"family of signalling molecules and are essential for embryonic development and tissue homeostasis. BMP signalling is highly conserved from flies to humans and plays an important role at multiple developmental stages, including patterning of the embryonic dorsal-ventral (DV) axis and during bone formation. This conservation means that powerful model organisms such as Drosophila can be utilised to visualise signalling in vivo. BMP (called Dpp in Drosophila) signalling is controlled by a group of proteins which form inhibitory complexes with Dpp. One such regulator, Sog acts by binding to Dpp thereby physically preventing their association with receptors on the cell surface. Sog is assisted by a modulator, twisted gastrulation, which can have both pro- and anti-Dpp functions. Recently, a new member of this signalling pathway was discovered, Shrew, a novel twisted gastrulation-like protein that functions to regulate DV patterning in Drosophila by increasing Dpp activity, although its mechanism of action is unknown.