A Stabilizing Influence: CAL PDZ Inhibition Extends the Half-Life of ΔF508-CFTR
A Stabilizing Influence: CAL PDZ Inhibition Extends the Half-Life of ΔF508-CFTR
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DOI：
10.1002/anie.201005585
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发表时间：
2010-01-01
影响因子：
16.6
通讯作者：
Madden, Dean R.
中科院分区：
文献类型：
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作者：
Cushing, Patrick R.;Vouilleme, Lars;Madden, Dean R.
从合成到降解，膜蛋白在相互交织的网络中导航，这些网络控制着它们在细胞内的定位和活动。在这些网络的分支点上，蛋白质-蛋白质相互作用通常决定单个蛋白质通过特定途径的通量，从而为治疗调节提供靶点。PDZ （PSD-95、Dlg和ZO-1）蛋白构成了一个主要的运输调节蛋白家族。PDZ蛋白以存在同名蛋白-蛋白相互作用域（PPIDs）为特征，通常结合其伴侣的C端并帮助指导其在整个细胞中的运动。PDZ调控的靶点包括囊性纤维化跨膜传导调节剂（CFTR）、囊性纤维化患者氯离子通道突变（CF）CF是欧洲血统人群中最常见的危及生命的常染色体隐性遗传病。在气道上皮中，CFTR的缺失会损害纤毛黏液的清除并促进慢性细菌感染。[2,3]在约90%的患者中发现的ΔF508等位基因导致蛋白质不能正确折叠。[4,5]然而，如果克服了折叠缺陷，得到的ΔF508-CFTR将保留有限的氯离子通道活性（图1a）。由于仅需要10-35%的野生型（WT）活性就能获得治疗效果，因此已经进行了许多努力，以确定分别解决ΔF508-CFTR主要折叠缺陷和门化缺陷的“校正”和“增强”化合物（图1b）。[8,9]现在越来越多的研究表明，ΔF508-CFTR的成熟和特异性活性可以通过药理学来提高。然而，获救的蛋白质仍然不稳定。[10-12]因此，最佳治疗可能需要修复所有三个缺陷：折叠性、打开概率和稳定性（图1a）。为了确定“稳定剂”——一类可以延长ΔF508-CFTR-we半衰期的新试剂——针对其内吞后运输的关键调节因子。cftr相关配体（CAL）通过其PDZ结构域负调控ΔF508-CFTR细胞表面丰度然而，CFTR不仅与CAL相互作用，还与Na+/H+交换调节因子NHERF1和NHERF2相互作用，抵消CAL的作用，增强了ΔF508-CFTR在根尖膜的活性和丰度。[14-16]在随后的报告中，我们描述了一种新的策略，允许细化十肽抑制剂iCAL3610 （iCAL36； ANSRWPTSII）。iCAL36靶向CAL结构域，但不靶向NHERF、PDZ结构域
From synthesis to degradation, membrane proteins navigate interwoven networks that control their localization and activity within the cell. At branch points within these networks, protein–protein interactions often determine the flux of individual proteins through specific pathways and thus offer targets for therapeutic modulation. The PDZ (PSD-95, Dlg, and ZO-1) proteins constitute a major family of trafficking regulators. Characterized by the presence of eponymous protein–protein interaction domains (PPIDs), PDZ proteins generally bind the C termini of their partners and help direct their movements throughout the cell. The targets of PDZ regulation include the cystic fibrosis transmembrane conductance regulator (CFTR), the chloride channel mutated in patients with cystic fibrosis (CF).[1] CF is the most common life-threatening autosomal recessive disease among people of European ancestry. In airway epithelia, loss of CFTR impairs mucociliary clearance and facilitates chronic bacterial infections.[2, 3] The ΔF508 allele, found in ca. 90% of patients, results in a protein that fails to fold correctly.[4, 5] However, if the folding defect is overcome, the resulting ΔF508-CFTR retains limited chloride channel activity (Figure 1a).[6]Because only 10–35% of wild-type (WT) activity may be required for therapeutic benefit,[7] many efforts have been made to identify “corrector” and “potentiator” compounds that address the primary folding and gating defects of ΔF508-CFTR, respectively (Figure 1b).[8, 9] There is now a growing prospect that the maturation and specific activity of ΔF508-CFTR can be pharmacologically enhanced. However, the rescued protein remains unstable.[10–12] Optimal therapy is thus likely to require repair of all three defects: folding, open probability, and stability (Figure 1a). To identify “stabilizers”–a new class of reagents that extend the half-life of ΔF508-CFTR–we targeted a key regulator of its post-endocytic trafficking. The CFTR-associated ligand (CAL) negatively regulates ΔF508-CFTR cellsurface abundance through its PDZ domain.[13] However, CFTR interacts not only with CAL, but also with the Na+/H+ exchanger regulatory factors NHERF1 and NHERF2, which counteract CAL s effect, enhancing the activity and the abundance of ΔF508-CFTR at the apical membrane.[14–16] In an accompanying report,[17] we describe a novel strategy that permitted elaboration of the decameric peptide inhibitor iCAL3610 (iCAL36; ANSRWPTSII). iCAL36 targets the CAL, but not the NHERF, PDZ domains, despite their