Regulation of matrix metalloprotease acitvity in Xenopus embryos and A6 cells

在胚胎发生过程中，不同物种利用各种保守策略促进新的细胞信号事件。当细胞在胚胎中分裂时，它们由许多分泌的蛋白质结合在一起，当细胞需要迁移时，这些蛋白质需要被改变。这些分泌的细胞外基质（ECM）蛋白的引导是发育的基础，因为ECM的变化促进了所需的新的细胞间相互作用。基质金属蛋白酶（Matrix metalloproteinases, MMPs）是一种分泌酶，可切割外膜，从而影响许多细胞迁移和信号事件。MMP功能通过多种方式调节，包括使用分泌抑制剂（MMPs的组织抑制剂[TIMPs]）和大多数MMPs作为酶原的分泌，这些酶原需要通过去除前肽在细胞外被激活。亲MMPs的激活是复杂的，通常由其他已经激活的MMPs引起。膜型（MT） MMPs是以活性形式分泌的MMPs的一个亚家族。矛盾的是，TIMPs与MT-MMPs一起激活pro-MMPs。然而，MMP被激活的微环境因其他细胞表面蛋白的参与而进一步复杂化，如RECK和，其作用也可以调节MMP的活性。我们将使用青蛙胚胎来了解TIMPs如何直接调节MMPS，因为它们抑制了它们的催化活性，以及TIMPs如何间接调节其他细胞过程，然后对MMP功能产生次要影响。由于TIMPs有两个不同的结构域，一个与MMPs结合，另一个与细胞表面分子结合，我们将研究这些结构域如何在体内-在整个胚胎中协同工作。其他体外细胞培养工作表明，MMP依赖和独立的功能在调节适当的MMP活性方面至关重要，因此在许多发育过程中都是必需的。利用青蛙的发展作为模型系统，我们将产生有意义的数据，这将有助于我们理解细胞迁移和信号传导的基本机制，因为它们发挥着许多重要的生物学作用。

During embryogenesis different species utilize a variety of conserved strategies that facilitate novel cell signaling events. As cell divide within an embryo they are held together by many secreted proteins which need to be altered when cells need to migrate. Guidance by these secreted extracellular matrix (ECM) proteins is fundamental to development, as changes in the ECM facilitates needed novel cell-cell interactions. Matrix metalloproteinases (MMPs) are secreted enzymes that cleave the ECM and thus influence numerous cell migration and signalling events. MMP function is regulated in a number of ways, including the use of secreted inhibitors (tissue inhibitors of MMPs [TIMPs]) and the secretion of most MMPs as zymogens that need to be activated extracellularly through the removal of a pro-peptide. The activation of pro-MMPs is complex and often brought about by other already active MMPs. Membrane type (MT) MMPs are a sub-family of MMPs that are secreted in an active form. Paradoxically, TIMPs work with MT-MMPs to activate pro-MMPs. However the microenvironment is which MMPs are activated is further complicated by the involvement of other cell surface proteins, such as RECK, and, whose actions can also regulate MMP activity. We will use frog embryos to understand how MMPS are regulated directly by TIMPs, as they inhibit their catalytic activity, and indirectly, as TIMPs can regulate other cellular processes that then have secondary effects on MMP functions. As TIMPs have two distinct domains, one that binds MMPs, and the other that binds to cell surface molecules, we will investigate how these domains work together in vivo - in a whole embryo. Other in vitro cell culture work has shown that MMP dependent and independent functions are crucial in regulating proper MMP activity and as such are required in many developmental processes. Using the development of frog as a model system we will generate meaningful data that will contribute much to our understanding the fundamental mechanisms involved in cell migration and signalling as these play many important biological roles.