Outward Trafficking of CFTR

这笔赠款的长期目标是了解如何监管CFTR的加工和向质膜的贩运。CFTR是一种蛋白质，存在于几种上皮细胞中，如位于顶端细胞膜的呼吸道。我们以前已经证明CFTR从高尔基体到质膜的运输受到三种蛋白质的调节，含有PDZ结构域的蛋白CAL，小分子量GTP酶TC10和SNARE蛋白STX6，我们现在称之为CAL复合体。本研究认为，CAL除了调节CFTR的表面表达外，还通过与细胞质量控制机制中的蛋白质相互作用来调节未成熟CFTR蛋白的数量，该机制包括对新合成的蛋白质进行内质网加工，然后对错误折叠的蛋白质进行侵袭性降解。这一过程被称为ERAD。为了进一步研究这一问题，我们建议解决以下问题：1.CAL-复合体在处理未成熟的wt-和A508-CFTR过程中起什么生理作用？TC10-GTP/GDP循环和STXe是如何调节ER对未成熟CFTR的处理的？2.CAL-复合体在调节细胞表面被拯救的A508-CFTR中起什么生理作用？TCI 0-GTP/GDP循环是如何调控解救的A508-CFTR转运到质膜的？3.CAL复合体是否与ER质量控制机制中的关键蛋白相互作用？所有这些研究都将采用一种方法的组合，以加强整个计划项目赠款。同样，该提案将获得PPG成员的专业知识和合作，这将提高成功的可能性，而不是作为一个单独的应用程序所能实现的。最终目标是提供有关CFTR如何在极化上皮组织中的大分子复合体中发挥作用的生理过程的新见解。

The long-term goal ofthe grant is to understand how the processing and trafficking of CFTR to the plasma membrane Is regulated. CFTR Is a protein that in several epithelia such as the airway functions at the apical cell membrane. We have shown previously that the trafficking of CFTR from the Golgi to the plasma membrane is regulated by three proteins, the PDZ domain containing protein, CAL, the small molecular weight GTPase, TC10, and the SNARE protein, STX6, which we now refer to as the CALcomplex. The present proposal posits that In addition to its role in regulating the surface expression of CFTR, CAL also plays a role In regulating the amount of immature CFTR protein by interacting with proteins in the cell's quality control mechanism which includes ER processing of newly synthesized proteins followed by proteasomal and aggresomal degradation of incorrectly folded proteins. A process termed ERAD. To study this further we propose to address the following: 1. What is the physiological role ofthe CAL-complex in the processing the Immature wt- and A508-CFTR? Precisely how is the processing of immature CFTR by the ER regulated by the TC10-GTP/GDP cycle and bySTXe? 2. What is the physiological role ofthe CAL-complex in the regulation of rescued A508-CFTR at the cell surface? And precisely how is the trafficking of rescued A508-CFTR to the plasma membrane regulated by TCI 0-GTP/GDP cycle? 3. Does the CAL complex interact with key proteins in the ER quality control mechanism? All of these studies will employ a combination of approaches that will strength the overall Program Project Grant. Likewise, the proposal will gain expertise and collaboration from members of the PPG that will enhance the likelihood of success beyond what could be achieved as an individual stand alone application. The ultimate goal is to provide novel insights into physiological process regarding how CFTR functions in a macromolecular complex In polarized epithelial tissues.