Polycystins and Cilia in C. elegans

描述（由申请人提供）：纤毛是对人体发育、器官功能和感觉很重要的细胞器。纤毛形成或功能缺陷导致毁灭性的人类疾病或纤毛病，包括常染色体显性多囊肾病（ADPKD）。ADPKD影响1/400-1000人，常导致终末期肾脏疾病。在人类中，多囊蛋白-1或多囊蛋白-2受体通道复合物的突变导致ADPKD。尽管纤毛在人类健康中具有深远的医学意义，但人们对纤毛在形式和功能上的特殊性仍然知之甚少。这项拟议的研究重点是揭示纤毛生物学的基本原理，这些原理在人类研究中是不可能的，在脊椎动物模型系统中也很容易研究。秀丽隐杆线虫是一种透明的多细胞动物，具有特殊的感觉纤毛，其特征使其在体内成像的简单性和可重复性前所未有。我们开发了工具和试剂来研究多囊蛋白在秀丽隐杆线虫中的定位和功能。我们将采用遗传，分子，成像，生化和电生理的方法来解决三个具体目标。首先，我们将剖析多囊蛋白信号通路。接下来，我们将确定调控多囊蛋白定位机制的分子细节，重点关注磷酸肌苷和微管蛋白翻译后修饰的作用。最后，我们将利用对神经元RNAi过敏的转基因动物来鉴定调节PKD-2定位的新基因。这种多学科的方法将提供影响多囊蛋白通道组装和运输的分子的全面图景，并将为一般纤毛受体运输提供关键的见解。因此，这些研究将对人类疾病如ADPKD具有重要意义，其中纤毛起着重要的核心作用。

DESCRIPTION (provided by applicant): Cilia are cellular organelles that are important for human development, organ function, and sensation. Defects in cilia formation or function results in devastating human diseases or ciliopathies, including autosomal dominant polycystic kidney disease (ADPKD). ADPKD affects 1/400-1000 individuals, often resulting in end- stage renal disease. In humans, mutations in the polycystin-1 or polycystin-2 receptor-channel complex cause ADPKD. Despite the profound medical importance of cilia in human health, how cilia are specialized in form and function remains poorly understood. This proposed research is focused on uncovering fundamental principals of cilia biology not possible in human studies or easily studied in vertebrate model systems. C. elegans is a transparent, multicellular animal with specialized sensory cilia, features that enable in vivo imaging that is unprecedented in its simplicity and reproducibility. We have developed the tools and reagents to study polycystin localization and function in C. elegans. We will employ genetic, molecular, imaging, biochemical, and electrophysiological approaches to address three specific aims. First, we will dissect polycystin signaling pathways. Next, we will determine the molecular details of mechanisms regulating polycystin localization, focusing on the roles of phosphoinositides and tubulin post-translational modifications. Finally, we will identify new genes regulating PKD-2 localization using transgenic animals that are hypersensitive to neuronal RNAi. This multidisciplinary approach will provide a comprehensive picture of the molecules that influence polycystin channel assembly and trafficking, and will provide critical insight to ciliary receptor trafficking in general. Thus these studies will have important implications in human diseases such as ADPKD in which cilia play an important and central role. PUBLIC HEALTH RELEVANCE: Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common monogenic diseases, affecting 1/400-1000 individuals, and having no treatment or cure. Several human genetic disorders, including ADPKD, share two common features: ciliary localized gene products and kidney cysts. Given that it is prohibitively difficult in humans to study the connection between ciliary protein function, localization, and disease, alternative experimental systems are necessary. In C. elegans it is feasible to study the roles of human disease gene homologs in cilia formation, morphogenesis, and signaling. This proposal is aimed at understanding the molecular mechanisms controlling the subcellular trafficking of the C. elegans ADPKD gene products.