Detection of folding defects in mutant CFTR by ERQC

描述（由申请人提供）： 囊性纤维化是由突变型Cl-通道CFTRAF 508的错误折叠和过早蛋白酶体降解引起的致命性肺部疾病。CFTRAF 508在内质网（ER）中合成，但其折叠在未知的中间步骤停止，并在通过质膜（PM）之前被选择降解。CFTR功能的丧失导致衬在腺体和气道上的粘膜层的水合作用的缺陷以及由于肺衰竭而发生死亡的慢性感染。治疗CF的希望来自于观察到CFTRAF 508中的折叠缺陷被改变细胞折叠环境的化合物拯救。2 RO 1 GM 56981的这一竞争性更新申请旨在通过阐明CFTRAF 508折叠途径中的缺陷步骤和鉴定选择CFTRAF 508降解的ER质量控制（ERQC）因子来帮助开发治疗囊性纤维化的疗法。该建议的三个主要目标如下：1.我们试图确定CFTR突变导致其错误折叠并被泛素蛋白酶体系统降解的机制。2. CFTR是暴露ER腔、ER膜和胞质溶胶中的表面的多位蛋白。因此，我们将确定ERQC机制的组件，这些组件可以感知CFTR中不同子域的折叠状态。然后，我们将确定ER定位和胞质QC因子的作用是如何协调的。3.我们建议应用在我们的基础研究中获得的知识来开发方法，以阻止CFTRAF 508过早降解的选择，并促进其正确折叠。总的来说，我们的研究将提供有关蛋白质QC的基本信息，这将有助于开发治疗CF的疗法。

DESCRIPTION (provided by applicant): Cystic Fibrosis is a fatal lung disease caused by misfolding and premature proteasomal degradation of the mutant Cl- channel CFTRAF508. CFTRAF508 is synthesized in the endoplasmic reticulum (ER), but its folding arrests at an unknown intermediate step and it is selected for degradation prior to passage to the plasma membrane (PM). Loss of CFTR function leads to defects in the hydration of mucosal layers that line glands and airways and chronic infections that death occurs due to lung failure. Hope for the treatment of CF comes from observations that folding defects in CFTRAF508 are rescued by compounds that either alter the cellular folding environment. This competitive renewal application for 2RO1 GM56981 seeks to aid in the development of therapeutics to treat Cystic Fibrosis by elucidating defective steps in the CFTRAF508 folding pathway and identifying ER quality control (ERQC) factors that select CFTRAF508 for degradation. The three major objectives of the proposal are as follows 1. We seek to define the mechanism by which mutations in CFTR cause it to misfold and be degraded the ubiquitin proteasome system. 2. CFTR is a polytopic protein that exposes surfaces in the ER lumen, ER membrane, and cytosol. 'Thus, we will identify the components of the ERQC machinery that sense the folded state of different sub-domains in CFTR. Then, we will determine how the action of the ER localized and cytosolic QC factors is coordinated. 3. We propose to apply the knowledge obtained in our basic studies to develop approaches to block the selection of CFTRAF508 for premature degradation and promote its proper folding. Overall, our studies will provide basic information on protein QC that will aid in the development of therapeutics to treat CF.