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

描述（由申请人提供）：4种哺乳动物BMP-l样蛋白酶（BLPs）通过前体的生物合成加工在形成ECM中发挥核心作用，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BLPs切割tgf -b样因子gdf-8（肌肉生长抑制素）的原域序列。分泌的gdf-8通常在潜伏复合体中与其原结构域非共价结合。BLPs对原结构域序列的切割可激活gdf-8。Golf-8抑制肌肉生长，并且当给药给成年小鼠时，显示前域BLP切割位点的突变使前域成为肌肉生长的强大刺激物。因此，该位点的裂解在生物学上是重要的。我们建议在体内显示哪种BLP可能负责激活gdf-8。基于成熟区序列同源性，Gdf-11 （BMP-11）和gdf-8形成了tgf -b样分子亚家族。我们有初步证据表明gdf-11前肽是被blp切割的。我们建议证明成熟的分泌gdf-11非共价结合其前结构域，BLPs切割前结构域以释放和激活成熟的gdf-11，并且这在体内发生。Gdf-11是神经组织形成的抑制剂。因此，表征gdfs 8和11的体内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可能会切割细胞外BMP拮抗剂Chordin样1和2，它们与Chordin具有很大的整体同源性，并显示出通过蛋白水解调节的迹象。此外，我们提供的证据表明，blp可能参与加工催乳素、生长激素/胎盘乳原家族激素的成员，以产生特定的16 kDa产物。我们建议确定哪些激素被哪些blp切割，在哪些位点切割，以及这种切割是否发生在体内。以往的报道表明，16 kDa的产物对这些激素具有重要的生物学意义。因此，确定这些片段如何形成对调节人类内分泌功能具有潜在的重要性。将创建BLP基因的条件敲除小鼠，用于上述项目的体内部分，以及用于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，我们提供了证据并提出了进一步确定BLPs前体形式和原结构域在体内发育和体内平衡中的作用的实验。

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.