Assembly of polycystin complexes

描述(申请人提供)：大约0.1%的世界人口受到常染色体显性遗传性多囊肾病(ADPKD)的影响，这是人类最常见的遗传病之一。这种疾病是由两种多囊蛋白PKD1和TRPP2的突变引起的。PKD1是一种质膜受体，可能参与细胞与细胞、细胞与基质的相互作用。TRPP2是一种钙离子通透性的非选择性阳离子通道，存在于内质网和质膜上。在肾脏细胞中，它们形成一个细胞表面复合体，其功能可能是一个机械敏感的钙离子传导通道，可以通过肾小管中的液体流动来调节。TRPP2和PKD1的结合至少部分是由这两种蛋白质细胞质C末端的卷曲结构域介导的。TRPP3与TRPP2相关，但又不同于TRPP2，它还形成一个钙离子渗透性的非选择性阳离子通道，其基因在小鼠体内的缺失与致命的肾脏缺陷有关。它的细胞质C端还含有一个卷曲的卷曲结构域。最近发现，TRPP3与一种名为PKD1L3的类似蛋白结合，形成舌酸的受体。我们的长期目标是了解多囊蛋白功能和调控的结构、分子和细胞机制。近期的目标是研究TRPP2/PKD1和TRPP3/PKD1L3复合体的组装和化学计量比。我们建议解决这两个络合物的盘绕结构域的晶体结构，确定两个络合物在细胞内的亚基化学计量比，研究盘绕结构域相互作用在两个络合物组装中的重要性，以及在PKD1对TRPP2活性的调节和PKD1L3对TRPP3活性的调节中的重要性。我们还建议检验PKD1和PKD1L3分别直接参与TRPP2/PKD1和TRPP3/PKD1L3复合体形成通道孔的假设。这一研究将加深我们对多囊藻毒素功能的分子基础的理解。公共卫生相关性：常染色体显性遗传性多囊肾病(ADPKD)是人类最常见的遗传性疾病之一，由肾脏细胞中多囊蛋白复合体的突变引起。这项研究的目标是了解这些复合体是如何形成的，它们是如何发挥作用的。

DESCRIPTION (provided by applicant): Approximately 0.1% of the world population is affected by autosomal dominant polycystic kidney disease (ADPKD), which is one of the most common genetic diseases in humans. This disease is caused by mutations in two polycystin proteins, PKD1 and TRPP2. PKD1 is a plasma membrane receptor probably involved in cell-cell and cell-matrix interactions. TRPP2 is a Ca2+permeable nonselective cation channel present in the endoplasmic reticulum as well as on the plasma membrane. In kidney cells, they form a cell surface complex that may function as a mechanosensitive Ca2+conducting ion channel that can be regulated by fluid flow in the kidney tubule. The association of TRPP2 and PKD1 is mediated, at least in part, by a coiled coil domain in the cytoplasmic C terminus of both proteins. TRPP3, related to but distinct from TRPP2, also forms a Ca2+permeable nonselective cation channel, and deletion of its gene in mice is linked to fatal kidney defects. Its cytoplasmic C terminus also contains a coiled coil domain. Recently, it has been found that TRPP3 associates with a PKD1-like protein named PKD1L3 to form the receptors for sour taste in the tongue. Our long-term objective is to understand the structural, molecular and cellular mechanisms of the function and regulation of polycystins. The immediate goal is to investigate the assembly and stoichiometry of the TRPP2/PKD1 and TRPP3/PKD1L3 complexes. We propose to solve the crystal structure of the putative coiled coil domain of both complexes, determine the subunit stoichiometry of both complexes in cells, investigate the importance of the coiled coil domain interaction in the assembly of both complexes and in the PKD1 regulation of TRPP2 activity and PKD1L3 regulation of TRPP3 activity. We also propose to test the hypothesis that PKD1 and PKD1L3 directly participate to form the channel pore in the TRPP2/PKD1 complex and the TRPP3/PKD1L3 complex, respectively. This research will enhance our understanding of the molecular basis of polycystin function. PUBLIC HEALTH RELEVANCE: Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common genetic diseases in humans and is caused by mutations of polycystin complexes in kidney cells. The goal of this research is to understand how these complexes are formed and how they function.