Rescuing cystic fibrosis transmembrane conductance regulator (CFTR) processing mutants by transcomplementation
Rescuing cystic fibrosis transmembrane conductance regulator (CFTR) processing mutants by transcomplementation
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DOI：
10.1073/pnas.0400459101
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发表时间：
2004-05-25
影响因子：
11.1
通讯作者：
Kirk, KL
中科院分区：
文献类型：
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作者：
Cormet-Boyaka, E;Jablonsky, M;Kirk, KL
大多数囊性纤维化（CF）病例是由阻断CIF基因产物（CF跨膜电导调节剂（CFTR）氯通道）的生物合成成熟的突变引起的。cftr加工突变体不能逃离内质网，并被迅速降解。目前诱导CFTR突变体成熟的努力针对的是生物合成途径的成分（例如伴侣），而不是CFTR本身。这些方法本质上是非特异性的。本研究表明，最常见的cf引起突变体（DeltaF508-CFTR）与其他几种CFTR处理突变体或野生型CFTR蛋白的氨基片段共表达时，可以形成成熟的、功能性的氯离子通道，到达细胞表面。这种转互补效应需要致病突变两侧的区域与互补片段之间的特定匹配；例如，氨基酸片段与DeltaF508-CFTR互补而与H1085R（一个羧基加工突变体）不互补，而羧基片段与H1085R互补而与DeltaF508-CFTR不互补。反补片段不影响CFTR与Hsc70的相互作用，Hsc70是CFTR生物合成中的一种伴侣。相反，它们可能通过阻断相同或邻近CFTR多肽区域之间的非生产性相互作用来促进CFTR成熟，从而阻止正常加工。这些发现表明，有可能开发针对CFTR特定致病突变体的CF疗法（例如，用于基因治疗的mini-cDNA构建物）。
Most cases of cystic fibrosis (CF) are caused by mutations that block the biosynthetic maturation of the CIF gene product, the CF transmembrane conductance regulator (CFTR) chloride channel. CFTR-processing mutants fail to escape the endoplasmic reticulum and are rapidly degraded. Current efforts to induce the maturation of CFTR mutants target components of the biosynthetic pathway (e.g., chaperones) rather than CFTR per se. Such methods are inherently nonspecific. Here we show that the most common CF-causing mutant (DeltaF508-CFTR) can form mature, functional chloride channels that reach the cell surface when coexpressed with several other CFTR-processing mutants or with amino fragments of the wild-type CFTR protein. This transcomplementation effect required a specific match between the region flanking the disease-causing mutation and the complementing fragment; e.g., amino fragments complemented DeltaF508-CFTR but not H1085R (a carboxy-processing mutant), whereas a carboxy fragment complemented H1085R but not DeltaF508-CFTR. Transcomplementing fragments did not affect CFTR interactions with Hsc70, a chaperone previously implicated in CFTR biosynthesis. Instead, they may promote CFTR maturation by blocking nonproductive interactions between domains within the same or neighboring CFTR polypeptides that prevent normal processing. These findings indicate that it may be possible to develop CF therapies (e.g., mini-cDNA constructs for gene therapy) that are tailored to specific disease-causing mutants of CFTR.