BMP-1-like protease effects on growth factors & hormones

描述（由申请人提供）：4种哺乳动物BMP-1样蛋白酶（BLP）在通过前体的生物合成加工形成ECM中起中心作用，并通过切割细胞外拮抗剂Chordin增强BMP信号传导。在这里，我们展示了BLP切割TGF-β样因子gdf-8（肌生长抑制素）的前结构域序列。分泌的gdf-8通常与其前结构域非共价结合形成潜在复合物。显示BLP切割前结构域序列可激活gdf-8。Golf-8抑制肌肉生长，并且显示前结构域BLP切割位点的突变使前结构域在施用于成年小鼠时成为肌肉生长的有力刺激物。因此，在该位点的切割在生物学上是重要的。我们建议显示哪种BLP可能负责在体内激活gdf-8。Gdf-11（BMP-11）和gdf-8基于其成熟区域中的序列同源性形成TGF-β样分子的亚家族。我们有初步证据表明，gdf-11前肽被BLP切割。我们建议显示，成熟的分泌型gdf-11非共价结合其前结构域，BLP切割前结构域释放和激活成熟的gdf-11，这发生在体内。Gdf-11是神经组织形成的抑制剂。因此，研究gdfs 8和11在体内的激活机制对于如何阻断这种激活，以及如何在肌肉和神经退行性疾病中增强肌肉和神经再生具有重要意义。我们还建议确定哪些BI-Ps可以切割细胞外BMP拮抗剂Chordin-like 1和2，其显示与Chordin的整体同源性，并显示通过蛋白水解调节的迹象。此外，我们提出的证据表明，BLP可能参与催乳素，生长激素/胎盘催乳素家族激素的加工成员，以产生特定的16 kDa的产品。我们建议确定这些激素被哪些BLP裂解，在哪些网站，以及这种裂解是否发生在体内。先前的报道表明，这些激素的16 kDa产物具有生物学重要性。因此，确定这些片段是如何形成的，在调节人类内分泌功能方面具有潜在的重要性。将创建BLP基因的条件性敲除小鼠，用于上述项目的体内部分，以及BLP在发育和体内平衡中的组织特异性作用的未来研究。 最后，我们提出的证据，并提出实验，以进一步确定在体内的前体形式和前结构域的BLP在发展和稳态的作用。

DESCRIPTION (provided by applicant): The 4 mammalian BMP-l-like proteases (BLPs) play central roles in forming the ECM through biosynthetic processing of precursors, and enhance BMP signaling by cleaving the extracellular antagonist Chordin. Here we show BLPs to cleave prodomain sequences of the TGF-b-like factor gdf-8 (myostatin). Secreted gdf-8 is normally noncovalently bound to its prodomain in a latent complex. Cleavage of prodomain sequences by BLPs is shown to activate gdf-8. Golf-8 inhibits muscle growth, and mutation of the prodomain BLP cleavage site is shown to make the prodomain a powerful stimulator of muscle growth when administered to adult mice. Thus, cleavage at this site is biologically important. We propose showing which BLP may be responsible for activating gdf-8 in vivo. Gdf-11 (BMP-11) and gdf-8 form a subfamily of TGF-b-like molecules based on sequence homologies in their mature regions. We have preliminary evidence that the gdf-11 propeptide is cleaved by BLPs. We propose showing that mature secreted gdf-11 noncovalently binds its prodomain, that BLPs cleave the prodomain to release and activate mature gdf-11, and that this occurs in vivo. Gdf-11 is an inhibitor of neural tissue formation. Therefore, characterizing the mechanisms for in vivo activation of gdfs 8 and 11 has important implications for how such activation might be blocked, and thus how muscle and nerve regeneration may be enhanced in musculo- and neuro-degenerative diseases. We also propose determining which BI-Ps may cleave extracellular BMP antagonists Chordin-like 1 and 2, which show much overall homology with Chordin and which show indications of being regulated via proteolysis. In addition, we present evidence that BLPs may be involved in processing members of the prolactin, growth hormone/placental lactogen family of hormones to produce specific 16 kDa product. We propose determining which of these hormones are cleaved by which BLPs, at which sites, and whether such cleavages occur in vivo. Previous reports indicate that 16 kDa products of these hormones to biologically important. Thus, determining how these fragments are formed is of potential importance in regulating human endocrine functions. Conditional knockout mice for BLP genes will be created, for in vivo portions of the projects described above, and for future studies of the tissue-specific roles of BLPs in development and homeostasis. Finally, we present evidence for and propose experiments to further determine in vivo roles for the precursor forms and prodomains of BLPs in development and homeostasis.