POLYCYSTIN-1 TAIL CLEAVAGE: A NOVEL PKD SIGNALING PATHWAY

Polycystin-1 尾部裂解：一种新颖的 PKD 信号通路

• 批准号: 7070252
• 负责人: Michael J. Caplan
• 金额: $ 17.82万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-30 至 2010-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7070252
• 关键词: autosomal dominant trait; biological signal transduction; calcium channel; cell nucleus; chemical cleavage; enzyme activity; enzyme structure; genetic manipulation; immunocytochemistry; laboratory mouse; membrane proteins; molecular site; pathologic process; phenotype; polycystic kidney; protein localization; protein structure function; protein transport; proteolysis; transcription factor

ADPKD is one of the most common autosomal genetic disorders, affecting approximately 1/1000 individuals. It is characterized by progressive renal cyst development, typically leading to end stage renal disease in late middle age. ADPKD is caused by mutations in the PKD1 or PKD2 genes, which encode the polycystin-1 (PC1) and polycystin-2 (PC2) proteins, respectively. PC1 is a membrane protein that may be involved in signaling from sites of cell-cell contact, while PC2 is a transmembrane protein that shares homology with calcium channels. These two proteins appear to participate in the same signaling pathway; however, their functions are largely unknown. A new signaling paradigm known as regulated intramembrane proteolysis (RIP) has been recently described. In this model, the cytoplasmic portion of a transmembrane receptor is released after ligand interaction and enters the nucleus, where it directly acts as a modulator of gene expression. During the previous funding period of this award we have found that PC1 undergoes a RIP-like proteolytic cleavage that releases its C-terminal tail (CTT), which enters the nucleus and initiates signaling processes. The cleavage occurs in vivo in association with alterations in mechanical stimuli. PC2 modulates the signaling properties of the PC1 CTT, and appears to serve as a cytoplasmic buffer that modulates the quantity of CTT available to enter the nucleus. In order to explore further the role that this cleavage plays in the normal functioning of the polycystin proteins and in the pathogenesis of ADPKD we will 1) identify the enzyme responsible for the release of the PC1 CTT; 2) identify the stimuli and signaling pathways that induce or prevent the cleavage and 3) identify the protein partners with which the CTT fragment interacts and define the collection of genes whose expression is altered through nuclear translocation of the CTT fragment. These studies will begin to unravel the relationship between the cleavage of the PC1 CTT and the pathogenesis of ADPKD, and may perhaps suggest new targets for therapeutic intervention.

ADPKD是最常见的常染色体遗传疾病之一，影响了大约1/1000人。它的特征是进行性肾脏囊肿发育，通常导致中期末期末期肾脏疾病。 ADPKD是由PKD1或PKD2基因中的突变引起的，该突变分别编码Polycystin-1（PC1）和Polycystin-2（PC2）蛋白。 PC1是一种膜蛋白，可能参与细胞 - 细胞接触部位的信号传导，而PC2是一种跨膜蛋白，与钙通道共享同源性。这两种蛋白质似乎参与了相同的信号通路。但是，它们的功能在很大程度上是未知的。最近已经描述了一种称为调节的膜内蛋白水解（RIP）的新信号范式。在此模型中，跨膜受体的细胞质部分是 在配体相互作用后释放并进入细胞核，该核直接充当基因表达的调节剂。在该奖项的前几个资金期间，我们发现PC1经历了释放其C末端尾巴（CTT）的RIP样蛋白水解裂解，该裂解进入了核并启动信号传导过程。裂解与机械刺激的改变有关。 PC2调节PC1 CTT的信号传导特性，并且似乎用作细胞质缓冲液，可调节可用于进入细胞核的CTT的数量。为了进一步探讨这种裂解在多囊蛋白蛋白的正常功能以及ADPKD发病机理中发挥的作用，我们将1）确定负责释放PC1 CTT的酶； 2）确定刺激和信号通路 诱导或预防裂解和3）确定CTT片段相互作用的蛋白质伴侣并定义了基因的收集，其表达通过CTT片段的核转运改变了其表达。这些研究将开始揭示PC1 CTT的切割与ADPKD发病机理之间的关系，并可能提出了治疗干预的新靶标。