Outward Trafficking of CFTR

该资助的长期目标是了解 CFTR 向质膜的加工和运输是如何受到调节的。 CFTR 是一种在多种上皮细胞（例如气道）中在顶端细胞膜上发挥作用的蛋白质。我们之前已经表明，CFTR 从高尔基体到质膜的运输受到三种蛋白质的调节，即含有 PDZ 结构域的蛋白质 CAL、小分子量 GTP 酶 TC10 和 SNARE 蛋白质 STX6，我们现在将其称为 CAL 复合体。目前的提议认为，除了在调节 CFTR 表面表达方面的作用之外，CAL 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 蛋白的量，其中包括新合成蛋白质的 ER 处理，然后是错误折叠蛋白质的蛋白酶体和聚集体降解。称为 ERAD 的过程。为了进一步研究这一点，我们建议解决以下问题： 1. CAL 复合物在处理未成熟 wt- 和 A508-CFTR 中的生理作用是什么？ ER 对未成熟 CFTR 的处理到底是如何受 TC10-GTP/GDP 循环和 STXe 调节的？ 2. CAL复合物在细胞表面拯救A508-CFTR的调节中的生理作用是什么？被拯救的 A508-CFTR 向质膜的运输到底是如何受 TCI 0-GTP/GDP 循环调节的？ 3. CAL复合物是否与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多种方法的组合，以加强整个计划项目拨款。同样，该提案将获得 PPG 成员的专业知识和协作，这将提高成功的可能性，超越作为单独的独立应用程序所能实现的目标。最终目标是为有关 CFTR 如何在极化上皮组织中的大分子复合物中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.