CFTR and Ion Channels: Mechanism of Interaction

描述(申请人提供)：囊性纤维化(CF)，高加索人群中最常见的遗传性疾病之一。CFTR编码基因的突变是CF的遗传基础。Cftr是一种多功能蛋白质，可作为cAMP激活的CI通道和离子电导调节器。Cftr是跨膜蛋白ATP结合盒转运蛋白超家族的成员。这个家族的特征是一个高度保守的ATP结合盒，称为核苷酸结合折叠(NBF)。许多致病突变位于cftr的NBF结构域内。第一核苷酸结合区(NBF1)是CFTR与其他离子通道相互作用的重要区域。我们的一般假设是，在CF中，CFTR既不能作为离子电导调节器，也不能作为cAMP刺激的CI通道发挥作用。我们推测，正是这些功能的结合导致了离子转运异常和呼吸道表面液体的改变，最终导致肺部疾病。因此，了解CFTR作为电导调节器的能力的机制对于我们理解CF的基本病理生理可能是极其重要的。这项拟议的研究将检验CFTR与集中在NBF1上的离子通道的相互作用，NBF1是CFTR作为电导调节器和氯离子通道的能力所涉及的区域。具体地说，将检测最常见的突变DF508-CFTR。将使用电生理学、生化和分子技术来确定DF508突变对CFTR作为电导调节器功能的影响。该项目的最终目标是应用从CFTR功能的基础科学研究中获得的见解来改进囊性纤维化患者的临床管理。

DESCRIPTION (provided by applicant): Cystic fibrosis (CF), one of the most common genetic disorders in the Caucasian population. Mutations in the gene that encodes for the CFTR are the genetic basis for CF. CFTR is a multifunctional protein that acts as a cAMP-activated CI- channel and an ion conductance regulator. CFTR is a member of the ATP-Binding Cassette Transporter superfamily of transmembrane proteins. This family is characterized by a highly conserved ATP binding cassette known as a nucleotide binding fold (NBF). Many of the disease-producing mutations reside within the NBF domains of CFTR. The first nucleotide binding domain(NBF1) has been identified as an essential region for CFTR's interactions with other ion channels. Our general hypothesis is that in CF, there is an inability of CFTR to function as an ion conductance regulator, as well as a cAMP-stimulated CI- channel. We postulate that it is the combination of these functions that leads to ion transport abnormalities and alterations in airway surface fluid that eventually result in lung disease. Therefore, understanding the mechanisms that underlie CFTR's ability to act as a conductance regulator may be extremely important in our basic understanding of the pathophysiology of CF. The proposed studies will examine CFTR's interactions with ion channels concentrating on NBF1, a region implicated in both CFTR's ability to function as a conductance regulator and chloride channel. Specifically, DF508-CFTR, the most common mutation, will be examined. Electrophysiological, biochemical and molecular techniques will be used to determine the effects of the DF508 mutation on CFTR's ability to function as a conductance regulator. The ultimate goal of this project is to apply the insights gained from these basic science studies of CFTR function to improve the clinical management of cystic fibrosis patients.