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

骨形态发生蛋白（BMP）是信号分子转化生长因子（TGF）“B“家族的成员，并且对于胚胎发育和组织稳态是必需的。BMP信号是高度保守的从苍蝇到人类，并在多个发育阶段，包括胚胎背腹（DV）轴的图案和骨形成过程中发挥重要作用。这种保守性意味着强大的模式生物，如果蝇，可以用来可视化体内信号。BMP（在果蝇中称为Dpp）信号传导由一组与Dpp形成抑制复合物的蛋白质控制。一种这样的调节剂，Sog通过结合Dpp起作用，从而物理地阻止它们与细胞表面上的受体结合。Sog由一种调节剂，扭曲的原肠胚形成辅助，它可以具有促Dpp和抗Dpp功能。最近，这个信号通路的一个新成员被发现，Shrew，一种新的扭曲原肠胚样蛋白，其功能是通过增加Dpp活性来调节果蝇中的DV模式，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.