Outward Trafficking of CFTR

该基金的长期目标是了解CFTR到质膜的加工和运输是如何被调节的。CFTR是一种在一些上皮细胞（如气道）的顶细胞膜上起作用的蛋白。我们之前已经证明，CFTR从高尔基体到质膜的运输是由三种蛋白质调节的，PDZ结构域蛋白CAL，小分子量GTPase TC10和SNARE蛋白STX6，我们现在称之为CALcomplex。本研究认为，除了调节CFTR的表面表达外，CAL还通过与细胞质量控制机制中的蛋白质相互作用，包括内质网加工新合成的蛋白质，然后是蛋白酶体和聚合体降解错误折叠的蛋白质，从而调节未成熟CFTR蛋白的数量。称为ERAD的进程。为了进一步研究这一点，我们建议解决以下问题：cal复合物在加工未成熟wt-和A508-CFTR中的生理作用是什么？确切地说，在TC10-GTP/GDP周期和stxe的调控下，ER对未成熟CFTR的加工是如何进行的？2. cal复合物在细胞表面调控获救的A508-CFTR中的生理作用是什么？确切地说，获救的A508-CFTR如何被TCI 0-GTP/GDP循环调节到质膜？3. 在内质网质量控制机制中，CAL复合体是否与关键蛋白相互作用？所有这些研究都将采用多种方法来加强整个计划项目拨款。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，而不仅仅是作为单独的应用程序所能取得的成功。最终目标是为CFTR在极化上皮组织大分子复合物中如何发挥作用的生理过程提供新的见解。

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.