NEW PARADIGMS OF CFTR REGULATION

描述(改编自申请人的摘要)：CFTR氯离子通道 与两种主要的人类疾病有关：囊性纤维化(低CFTR活性) 和分泌性腹泻(CFTR活性过高)。理性的发展 任何一种疾病的治疗策略都需要更好地了解 激活或停用CFTR通道。尽管很明显，CFTR是 受PKA刺激，介导大调节域(R)的磷酸化 域)在该通道内，控制CFTR门控的机制仍然 默默无闻。我们将探讨CFTR监管的两个新范式：1) 通过分子内相互作用稳定CFTR通道活性 氨基末端尾巴(N-Tail)和R结构域；2)CFTR的偶联 通过分子间相互作用对膜运输机械的门控 在CFTRN-Tail和Synaxin 1A之间。这些范例将由 追求三个具体目标。首先，N-尾巴的机制 将定义稳定的CFTR通道活动。Subaim包括测试 假设N-Tail通过调制 R结构域内关键残基的磷酸化。第二，结构性的 将定义N-尾和R结构域之间相互作用的基础。这个 将描述这些域之间的物理相互作用的性质 并假设CFTR通道门控可以被以下多肽破坏 阻止此域间交互将进行测试。第三，假设 CFTR通道门控由该离子通道之间的相互作用调节 被测试且膜式运输机械的部件协调 上皮细胞离子转运和蛋白质转运的调节。这个 拟议研究的结果应提供有关以下方面的新信息 控制cftr氯通道活性的机制；信息 这可能会导致更有效的策略来操纵CFTR函数 涉及这种离子通道的疾病。

DESCRIPTION (Adapted from the Applicant's Abstract): The CFTR chloride channel is implicated in two major human diseases: cystic fibrosis (low CFTR activity) and secretory diarrhea (excessive CFTR activity). The development of rational treatment strategies for either disease requires a better understanding of what activates or inactivates the CFTR channel. Although it is clear that CFTR is stimulated by PKA-mediate phosphorylation of the large regulatory domain (R domain) within this channel, the mechanisms that control CFTR gating are still obscure. Two new paradigms of CFTR regulation will be explored: 1) the stabilization of CFTR channel activity by an intramolecular interaction between the amino-terminal tail (N-tail) and the R domain and 2) the coupling of CFTR gating to the membrane traffic machinery by an intermolecular interaction between the CFTR N-tail and syntaxin 1A. These paradigms will be explored by pursuing three Specific Aims. First, the mechanism by which the N-tail stabilizes CFTR channel activity will be defined. Subaims include testing the hypothesis that the N-tail controls channel gating by modulating the phosphorylation of key residues within the R domain. Second, the structural basis of the interaction between the N-tail and R domain will be defined. The nature of the physical interaction between these domains will be characterized and the hypothesis that CFTR channel gating can be disrupted by peptides that block this interdomain interaction will be tested. Third, the hypothesis that CFTR channel gating is regulated by interactions between this ion channel will be tested and that components of the membrane traffic machinery coordinate the regulation of ion transport and protein traffic in epithelial cells. The results of the proposed study should provide new information regarding the mechanisms that control the activity of the CFTR chloride channel; information that may lead to more effective strategies for manipulating CFTR function in diseases that involve this ion channel.