Assembly of polycystin complexes

摘要 大约0.1%的世界人口受到常染色体显性多囊肾病的影响 ADPKD是人类最常见的遗传性疾病之一。这种疾病是由 两种多囊蛋白PKD 1和TRPP 2的突变。PKD 1可能是一种质膜受体， 参与细胞与细胞和细胞与基质的相互作用。TRPP 2是一种Ca 2+可渗透的非选择性阳离子通道 存在于内质网和质膜上。在肾细胞中，它们形成一个细胞 表面复合物，其可用作机械敏感性Ca 2+传导离子通道， 由肾小管中的液体流动调节。TRPP 2和PKD 1的结合是介导的，至少在 部分，通过在两种蛋白质的胞质C末端的卷曲螺旋结构域。TRPP 3，相关但不同 来自TRPP 2，也形成Ca 2+可渗透的非选择性阳离子通道，并且在小鼠中缺失其基因， 与致命的肾缺陷有关其胞质C末端也含有卷曲螺旋结构域。近日 已经发现TRPP 3与名为PKD 1 L3的PKD 1样蛋白结合形成受体， 舌头上的酸味。我们的长期目标是了解结构，分子和细胞 多囊蛋白的功能和调节机制。当前的目标是调查 TRPP 2/PKD 1和TRPP 3/PKD 1 L3复合物的组装和化学计量。我们建议解决 这两种复合物的假定卷曲螺旋结构域的晶体结构，决定了 这两种复合物在细胞中，调查的重要性，卷曲螺旋结构域的相互作用，在组装 这两种复合物和PKD 1调节TRPP 2活性和PKD 1 L3调节TRPP 3活性。 我们还提出验证PKD 1和PKD 1 L3直接参与形成通道孔的假设 在TRPP 2/PKD 1复合物和TRPP 3/PKD 1 L3复合物中分别。这项研究将提高 我们对多囊蛋白功能的分子基础的理解。

Abstract 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.