New mammalian chloride channel identified by expression cloning-猫眼课题宝

通过表达克隆鉴定出新的哺乳动物氯离子通道

DOI：

10.1038/356238a0

发表时间：

1992

期刊：

Nature

影响因子：

64.8

通讯作者：

中科院分区：

综合性期刊1区

文献类型：

作者：

M. Paulmichl;Yi Li;K. Wickman;M. Ackerman;E. Peralta;D. Clapham

离子通道选择性渗透氯离子调节细胞功能不同的兴奋性和控制细胞体积1 -5。使用表达克隆技术，从上皮细胞系中分离出互补DNA，进行测序，并通过定点诱变检查其推定结构。该cDNA编码一个235个氨基酸的蛋白质，在非洲爪蟾卵母细胞中表达时产生了一个氯离子选择性外向电流。表达的，向外整流氯电流是钙不敏感的，并被施加到细胞表面的核苷酸阻断。一个假定的核苷酸结合位点的突变导致核苷酸阻断的损失，但引起对细胞外钙离子浓度的依赖。这种假定的通道蛋白的不寻常序列表明了一类与其他先前克隆的氯离子通道无关的新的离子通道6 -11。

ION channels selectively permeable to chloride ions regulate cell functions as diverse as excitability and control of cell volume1–5. Using expression cloning techniques, a complementary DNA from an epithelial cell line has been isolated, sequenced and its putative structure examined by site-directed mutagenesis. This cDNA, encoding a 235-amino-acid protein, gave rise to a chloride-selective outward current when expressed in Xenopus oocytes. The expressed, outwardly rectifying chloride current was calcium-insensitive and was blocked by nucleotides applied to the cell surface. Mutation of a putative nucleotide-binding site resulted in loss of nucleotide block but incurred dependence on extracellular calcium concentration. The unusual sequence of this putative channel protein suggests a new class of ion channels not related to other previously cloned chloride channels6–11.