CFTR/Regulation of CL Secretion in Normal and CF Airways

描述（由申请人提供）：在过去的15年里，资助的长期目标是了解CFTR的Cl-通道和监管功能。在之前的预算期内，我们特别关注了PDZ结合域的作用，并询问CFTR是否是大分子复合物的成员。我们发现了一种新的蛋白CAL，它将CFTR拴在高尔基体内，并以CFTR为目标在溶酶体中降解。我们还研究了NHE-RF和CAP70这些含PDZ结构域的蛋白如何与CAL相关，从而解决了为什么多个含PDZ结构域的蛋白与CFTR结合的问题。目前的研究假设CFTR与CAL的PDZ结构域的相互作用是通过将CFTR束缚在高尔基体上，以CFTR为目标进行降解或允许其加工到质膜来调节CFTR在等离子体中的量。该提案进一步假设，CAL介导的CFTR是否注定要移动到质膜是由与CAL结合的两个相关蛋白TC10和syntaxin 6决定的。该资助进一步表明，CAL-CFTR与这两种相关蛋白的相互作用在CFTR如何对导致腹泻疾病和呼吸道感染的细菌毒素作出反应中发挥重要作用。总体目标是解决以下三个问题：成熟CFTR向质膜的转运是否受TC10调控？成熟CFTR向质膜的转运是否受Syntaxin6调控？细菌毒素如何在CFTR向质膜的运输中起作用？

DESCRIPTION (provided by applicant): The long-term goal of the grant over the past 15 years has been to understand both the Cl- channel and regulatory functions of CFTR. In the previous budget period, we focused specifically on the role of the PDZ binding domain and asked whether CFTR is a member of a macromolecular complex. We discovered a new protein, CAL that tethers CFTR within the Golgi and targets CFTR for degradation in the lysosome. We also studied NHE-RF and CAP70 how these PDZ domain-containing proteins function in relation to CAL, thus addressing the issue of why multiple PDZ domain-containing proteins bind to CFTR. The present proposal posits that the role of the interaction of CFTR with the PDZ domain of CAL is to regulate the amount of CFTR at the plasma either by tethering it at the Golgi, and targeting CFTR for degradation or allowing it to process to the plasma membrane. The proposal hypothesizes further, that the CAL-mediated decision whether CFTR is destined to move to the plasma membrane or not is determined by two associated proteins that bind to CAL, TC10 and syntaxin 6. The grant suggests further that the CAL-CFTR interaction with these two associated proteins has an important role in how CFTR responds to bacterial toxins that lead to diarrheal diseases and infection in the airways. The overall goal is to address the following three questions: Is the trafficking of mature CFTR to the plasma membrane regulated by TC10? Is the trafficking of mature CFTR to the plasma membrane regulated by Syntaxin6? How do bacterial toxins function in the trafficking of CFTR to the plasma membrane? Relevance: The proposal represents a new area of investigation with implications both for our understanding of diarrheal diseases involving toxins that affect Rho-GTPases and for Pseudomonas infection in lung where the toxin ExoS, may alter CFTR trafficking to the membrane. Once the critical pathways are identified and their roles established, it may be possible to develop drugs to therapeutically alter the switching mechanisms that determine CFTR's fate.