Regulation of Cell-Cell Interactions by Matrix Metalloproteases

描述(申请人提供)：信号分子、细胞外基质成分和分泌的蛋白水解酶之间复杂的相互作用调节组织结构、功能和体内平衡。这一建议是建立在最近建立的通过基质金属蛋白酶(MMP)介导的机制来调节细胞外信号的范式之上的。果蝇MMP2裂解硫酸肝素蛋白多糖(HSPG)，将其从支持成纤维细胞生长因子-R信号的细胞表面结合的辅受体转化为可溶的成纤维细胞生长因子抑制因子。这一机制控制着果蝇幼虫的分枝形态发生，但也可能调节其他依赖于成纤维细胞生长因子的过程，包括上皮-间充质相互作用、发育组织者的图案化和组织重塑。除成纤维细胞生长因子外，许多细胞外信号分子还受HSPGs(肝素结合生长因子、血管内皮生长因子、HIV-TAT、WNT、HH、转化生长因子-2)相互作用的调节。可以想象，这些蛋白质的功能也可能受到这里提出的机制的影响。该实验计划将使用申请人建立的细胞培养试验来探索MMP2和DALY之间相互作用的机制基础。这些实验将深入了解细胞表面结合的基质金属蛋白酶的结构-功能关系，并可能获得控制MMPs调控特异性的机制的一般信息。体内实验将探索MMPs、HSPGs和成纤维细胞生长因子之间的调节相互作用，并将检验DALY的蛋白水解性片段可以作为细胞外信号、图案和器官形成的特定调节因子的假设。在最终目的中，在细胞培养和果蝇中的发现将被带到两个哺乳动物系统中，以询问是否可以利用这里描述的基于蛋白分解的调节机制来逆转致癌的成纤维细胞生长因子信号的影响。该提案的实验计划得益于果蝇强大的遗传和成像工具。果蝇系统的另一个优势是MMPs的遗传冗余度大大降低(果蝇有2个MMPs基因，哺乳动物有26个)。果蝇的实验优势被依赖于成纤维细胞生长因子的肿瘤形成的哺乳动物模型所提供的癌症相关性所补充。

DESCRIPTION (provided by applicant): Complex interactions between signaling molecules, extracellular matrix components and secreted proteases regulate tissue structure, function and homeostasis. This proposal is founded on a recently established paradigm for the regulation of extra cellular signaling by matrix metalloprotease (MMP) - mediated mechanisms. Drosophila Mmp2 cleaves the heparin sulfate proteoglycan (HSPG) Dally, to convert it from a cell surface bound co receptor that supports FGF-R signaling to a soluble inhibitor of FGF. This mechanism controls branching morphogenesis in Drosophila larvae, but may also modulate other FGF- dependent processes, including epithelial-mesenchymal interactions, patterning by developmental organizers, and tissue remodeling. Many extracellular signaling molecules in addition to FGF are regulated by interactions with HSPGs, (Heparin binding growth factors, VEGF, HIV-TAT, Wnt, Hh, TGF-2). It is conceivable that the function of these proteins might also be influenced by the mechanism proposed here. The experimental plan will explore the mechanistic basis of the interaction between Mmp2 and Dally using cell culture assays established by the applicant. These experiments will provide insight into the structure-function relationships in cell surface bound matrix metalloproteases and may yield general information on the mechanisms governing the regulatory specificity of MMPs. In vivo experiments will explore the regulatory interplay between MMPs, HSPGs, and FGF and will test the hypothesis that proteolytic fragments of Dally can act as specific regulators of extracellular signaling, patterning and organ formation. In a final aim the findings made in cell culture and in fruit flies will be taken into two mammalian systems to ask whether the proteolysis- based regulatory mechanism characterized here might be exploited to reverse the effects of oncogenic FGF signaling. The experimental plan of the proposal benefits from the powerful genetic and imaging tools available in Drosophila. A further advantage of the fruit fly system is the much-reduced genetic redundancy of MMPs (2 mmp genes in Drosophila vs. 26 in mammals). The experimental advantages of Drosophila are complemented by the cancer relevance provided by the mammalian models of FGF-dependent tumor formation.