Basement Membrane Homeostasis and Repair

项目摘要 基底膜是普遍存在的保守的细胞外基质薄片， 分开组织类型和隔间。基底膜的厚度和硬度 在不同的组织中有所不同，尽管它们都共享一组共同的核心组件，并且 这些差异的起源和维持尚不清楚。尽管存在广泛的生化反应 了解它们的体外组装后，它们通常被认为是静态的 形成了基底膜，因此人们对基底膜如何在健康或 如何在损坏后进行修复。我实验室的最新数据表明，组装好的 成人组织中的基底膜惊人地动态，需要持续的交联剂。 即使在没有外部损伤的情况下，它们的正常功能也是蛋白质分解的。 这项建议将研究基底膜动态平衡的机制和 修理。首先，我们将测量它们在未受损组织中的组装和拆解率，以及 然后确定交联度和蛋白水解度对这些速率的影响。第二，我们将确定 动态平衡如何与修复过程相似和不同，调查周转 基底膜成分的比率和来源；我们将筛选新的基因 对基底膜的维护和修复非常重要。最后，我们将测试一个激动人心的 一种新的模型，可以解释某些基底膜的不同性质 另一些则是以胶原蛋白伴侣SPARC的活性为中心的模型。所有这些目标都将 利用黑腹果蝇，它拥有紧凑的基因组和优秀的遗传工具。这个 这项研究的发现将对一般细胞生物学和组织修复具有重要意义 具体地说，它们将对基底膜疾病具有临床意义 肿瘤转移，因为基底膜是癌细胞迁移的重要障碍，以及 了解它们的动力学将形成肿瘤转移的模型。

Project Summary Basement membranes are ubiquitous and conserved sheets of extracellular matrix that separate tissue types and compartments. The thickness and stiffness of basement membranes varies in different tissues, even though they all share a common set of core components, and the origin and maintenance of these differences is not understood. Despite extensive biochemical knowledge of their in vitro assembly, they are often considered to be static after they have formed, and so very little is known about how basement membranes are maintained in health or how they are repaired after damage. Recent data from my laboratory indicates that assembled basement membranes in adult tissues are surprisingly dynamic, requiring continuing crosslinking and proteolysis for their proper function even in the absence of external damage. This proposal will investigate mechanisms of basement membrane homeostasis and repair. First, we will measure their assembly and disassembly rates in undamaged tissue, and then determine how crosslinking and proteolysis affect those rates. Second, we will determine how homeostasis is similar to and different from the process of repair, investigating turnover rates and sources of basement membrane components; and we will screen to identify new genes important to basement-membrane maintenance and repair. Finally, we will test an exciting and novel model that may explain how some basement membranes have different properties than others, a model centered on the activity of the collagen chaperone SPARC. All these aims will utilize Drosophila melanogaster, which has a compact genome and excellent genetic tools. The discoveries emerging from this study will be important to cell biology generally, to tissue repair specifically, and they will have clinical relevance to diseases of basement membrane and to tumor metastasis, as basement membranes are important obstacles to cancer cell migration, and understanding their dynamics will shape models of tumor metastasis.