MOLECULAR MECHANISMS OF POLYCYSTIN FUNCTION

常染色体显性遗传性多囊肾病是一种常见的遗传性疾病 疾病，基因频率为200-1000个人中有1个，引起 约占所有终末期肾病的6%-9%。ADPKD IS 其特征是从上皮样组织中生长出巨大的上皮衬里的囊肿 受累肾脏的肾单位和集合管。约85%的 ADPKD的病例是由于PKD1基因的突变所致。的产品 PKd1基因，多囊蛋白-1，被认为是一个大的，膜相关的 可能作为黏附分子受体的蛋白质，可能 调节细胞与细胞或细胞与基质的相互作用。PKD2的产物 多囊蛋白-2基因与钙通道家族相似 蛋白质，因此可能参与钙介导的信号转导。 多囊蛋白-1和多囊蛋白-2也被认为通过 C-末端胞质结构域，增加了它们发挥功能的可能性 以协调的方式接收细胞外信号并传输 它们进入细胞质。然而，这些蛋白质的功能并不是 为人所知。序列分析表明，C-末端胞浆 多囊蛋白-1和-2的结构域具有许多保守的基序， 提示这些蛋白质通过介导信号转导发挥作用。 因此，这一提议的中心假设是， 多囊蛋白-2和多囊蛋白-2由信号转导介导，因此， 这些蛋白质是磷酸化的底物，它们与之相互作用 异三聚体G蛋白，多囊蛋白磷酸化调节 多囊蛋白-2和-2以及多囊蛋白-2和多囊蛋白-2之间的相互作用 -2和异三聚体G蛋白。这一假设将由 具体目标如下：1)C-末端胞浆结构域 将对多囊蛋白-1和多囊蛋白-2进行检测，以确定它们是否 体外和体内磷酸化的底物，2)影响 多囊蛋白-1和多囊蛋白-2相互作用中的磷酸化 将在体外和体内进行测定，以及3) 多囊蛋白-1和多囊蛋白-2的相互作用及异三聚体G- 蛋白质及多囊蛋白磷酸化对这些蛋白质的影响 相互作用，将在体外和体内进行测试。

Autosomal dominant polycystic kidney disease (ADPKD) is a common inherited disease, with a gene frequency of 1 in 200-1,000 individuals, giving rise to approximately 6-9% of all end-stage renal disease. ADPKD is characterized by the growth of large epithelial-lined cysts from the nephrons and collecting ducts of affected kidneys. Approximately 85% of the cases of ADPKD are due to mutations in the PKD1 gene. The product of the PKD1 gene, polycystin-1, is thought to be a large, membrane-associated protein that may function as a receptor of adhesion molecule, possibly mediating cell-cell or cell-matrix interactions. The product of the PKD2 gene, polycystin-2 shows similarity to a family of calcium channel proteins and thus may be involved in calcium-mediated signal transduction. Polycystin-1 and -2 are also thought to interact with each other via the C-terminal cytosolic domains, raising the possibility that they function in a coordinated fashion to receive extracellular signals and transmit them to the cytoplasm. The functions of these proteins, however, are not known. Sequence analysis has revealed that the C-terminal cytosolic domains of polycystin-1 and -2 have a number of conserved motifs that suggest that these proteins function by mediating signal transduction. Thus, the central hypothesis of this proposal is that the functions of polycystin-2 and -2 are mediated by signal transduction and, as such, that these proteins are substrates for phosphorylation, that they interact with heterotrimeric G-proteins, and that polycystin phosphorylation regulates the interactions between polycystin-2 and -2 and between polycystin-2 and -2 and heterotrimeric G-proteins. This hypothesis will be addressed by the following specific aims: 1) The C-terminal cytosolic domains of polycystin-1 and polycystin-2 will be tested to determine if they are substrates for phosphorylation in vitro and in vivo, 2) The effects of phosphorylation of polycystin-1 and polycystin-2 on their interactions with each other will be determined in vitro and in vivo, and 3) Interactions between polycystin-1 and polycystin-2 and heterotrimeric G- proteins and the effects of polycystin phosphorylation on these interactions, will be tested in vitro and in vivo.