ALTERED CHLORIDE-ION CHANNEL KINETICS ASSOCIATED WITH THE DELTA-F508 CYSTIC-FIBROSIS MUTATION
ALTERED CHLORIDE-ION CHANNEL KINETICS ASSOCIATED WITH THE DELTA-F508 CYSTIC-FIBROSIS MUTATION
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DOI：
10.1038/354526a0
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发表时间：
1991-12-19
期刊：
影响因子：
64.8
通讯作者：
LAZDUNSKI, M
中科院分区：
文献类型：
--
作者：
DALEMANS, W;BARBRY, P;LAZDUNSKI, M
囊性纤维化与上皮细胞氯离子转运缺陷有关(参考文献1，2)，这是由一种称为囊性纤维化跨膜电导调节因子3的膜蛋白突变引起的。异源表达CFTR可产生对cAMP敏感的氯离子通道活性4-7。囊性纤维化8中最常见的突变是CFTR508位的苯丙氨酸缺失(Delta-F508 CFTR)。有人认为该突变阻碍了糖蛋白的成熟及其转运到其正常细胞位置9。我们用重组痘苗病毒在Vero细胞中表达了CFIR和Delta-F508 CFTR。尽管到达质膜的Delta-F508CFTR比正常CFTR少得多，但在质膜上有足够的Delta-F508CFTR表达，以便进行功能分析。Delta-F508CFIR的表达降低了cAMP激活的氯离子通道的活性，其电导、阴离子选择性和开放时间动力学与CFIR相似，但关闭时间要长得多，导致开放概率大大降低。因此，Delta-F508突变似乎有两个主要后果，一是限制膜插入的CFTR蛋白的异常易位，二是介导氯离子转运的异常功能。
CYSTIC fibrosis is associated with a defect in epithelial chloride ion transport (reviewed in refs 1, 2) which is caused by mutations in a membrane protein called CFTR (cystic fibrosis transmembrane conductance regulator) 3. Heterologous expression of CFTR produces cyclicAMP-sensitive Cl--channel activity 4-7. Deletion of phenylalanine at amino-acid position 508 in CFTR (DELTA-F508 CFTR) is the most common mutation in cystic fibrosis 8. It has been proposed that this mutation prevents glycoprotein maturation and its transport to its normal cellular location 9. We have expressed both CFIR and DELTA-F508 CFTR in Vero cells using recombinant vaccinia virus. Although far less DELTA-F508 CFTR reached the plasma membrane than normal CFTR, sufficient DELTA-F508 CFTR was expressed at the plasma membrane to permit functional analysis. DELTA-F508 CFIR expression induced a reduced activity of the cAMP-activated Cl- channel, with conductance, anion selectivity and open-time kinetics similar to those of CFIR, but with much greater closed times, resulting in a large decrease of open probability. The DELTA-F508 mutation thus seems to have two major consequences, an abnormal translocation of the CFTR protein which limits membrane insertion, and an abnormal function in mediating Cl- transport.