Glycerol reverses the misfolding phenotype of the most common cystic fibrosis mutation
Glycerol reverses the misfolding phenotype of the most common cystic fibrosis mutation
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DOI：
10.1074/jbc.271.2.635
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发表时间：
1996-01-12
影响因子：
4.8
通讯作者：
Kopito, RR
中科院分区：
文献类型：
--
作者：
Sato, S;Ward, CL;Kopito, RR
囊性纤维化跨膜传导调节因子(CFTR)中常见的Delta F508突变干扰了新生CFTR多肽的生物合成折叠，导致它们在凝胶装置附近的细胞内隔室中滞留和快速降解，野生型CFTR折叠的途径或Phe(508)缺失干扰这一过程的机制尚不清楚。我们研究了甘油对CFTR和Delta F508在体内折叠的影响，甘油是一种已知的稳定蛋白质构象的多元醇。瞬时和稳定的Delta F508转基因载体与10%的甘油孵育后，DeltaF508蛋白显著积累，表明它们被转移到内质网(ER)远端的一个隔室。这种积累伴随着平均全细胞cAMP激活的氯电导的增加，这表明甘油拯救的Delta F508多肽形成了功能性的质膜CFTR通道，这些作用是剂量和时间依赖的，并且完全可逆，甘油处理也稳定了正常情况下迅速降解的未成熟(核心糖基化)Delta F508和CFTR分子。甘油的这些影响并不是由于内质网质量控制过程的普遍中断，而是似乎与特定CFTR突变的温度敏感性程度有关，这些数据表明了一种模型，在该模型中，甘油用于稳定CFTR生物合成中原本不稳定的中间体，使其保持在能够折叠并随后从内质网质量控制装置释放的构象中。
The common Delta F508 mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) interferes with the biosynthetic folding of nascent CFTR polypeptides, leading to their retention and rapid degradation in an intracellular compartment proximal to the Gels apparatus, Neither the pathway by which wild-type CFTR folds nor the mechanism by which the Phe(508) deletion interferes with this process is well understood, We have investigated the effect of glycerol, a polyhydric alcohol known to stabilize protein conformation, on the folding of CFTR and Delta F508 in vivo. Incubation of transient and stable Delta F508 tranfectants with 10% glycerol induced a significant accumulation of Delta F508 protein bearing complex N-linked oligosaccharides, indicative of their transit to a compartment distal to the endoplasmic reticulum (ER). This accumulation was accompanied by an increase in mean whole cell cAMP activated chloride conductance, suggesting that the glycerol-rescued Delta F508 polypeptides form functional plasma membrane CFTR channels, These effects were dose- and time-dependent and fully reversible, Glycerol treatment also stabilized immature (core-glycosylated) Delta F508 and CFTR molecules that are normally degraded rapidly. These effects of glycerol were not due to a general disruption of ER quality control processes but appeared to correlate with the degree of temperature sensitivity of specific CFTR mutations, These data suggest a model in which glycerol serves to stabilize an otherwise unstable intermediate in CFTR biosynthesis, maintaining it in a conformation that is competent for folding and subsequent release from the ER quality control apparatus.