Ile-177 and Ser-180 in the S1 segment are critically important in Kv1.1 channel function
Ile-177 and Ser-180 in the S1 segment are critically important in Kv1.1 channel function
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DOI：
10.1074/jbc.274.17.11487
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发表时间：
1999-04-23
影响因子：
4.8
通讯作者：
Koren, G
中科院分区：
文献类型：
--
作者：
Mathur, R;Zhou, J;Koren, G
Ile-177 和 Ser-180 是电压门控 K+ 通道 Shaker、Shab、Show 和 Shal 亚家族的第一个跨膜片段 (S1) 中的保守残基。在这里，我们报告，Kv1.1 中的这些残基突变为亮氨酸、脯氨酸或精氨酸，消除了非洲爪蟾卵母细胞中外向钾电流的表达。将这些突变型 cRNA 和野生型 Kv1.1 cRNA 注射到非洲爪蟾卵母细胞中，会产生强大的显性负效应，导致 Kv1.1 编码电流受到抑制。 COS-7细胞的瞬时转染实验表明，S1突变体指导Kv1.1多肽的合成。定量免疫共沉淀分析表明，大多数 S1 突变体共同组装并形成同源多聚体和异源多聚体复合物。此外，突变的多肽可以到达转染的 Sol8 细胞的质膜。我们得出结论，Ile-177 和 Ser-180 的突变不会干扰多聚通道复合物的组装或这些复合物靶向质膜。这些残基可能参与螺旋-螺旋相互作用，这对于电压门控钾通道的正常功能至关重要。
Ile-177 and Ser-180 are conserved residues in the first transmembrane segment (S1) of the Shaker, Shab, Show, and Shal subfamilies of voltage-gated K+ channels. Here we report that the mutation of these residues in Kv1.1 to leucine, proline, or arginine abolished the expression of outward potassium currents in Xenopus oocytes. Go-injection of these mutant cRNAs and wild type Kv1.1 cRNA into Xenopus oocytes exerted a potent dominant negative effect resulting in the suppression of Kv1.1-encoded currents. Transient transfection experiments of COS-7 cells revealed that the S1 mutants directed the synthesis of Kv1.1 polypeptides. Quantitative co-immunoprecipitation assays revealed that most of the S1 mutants coassembled and formed both homo- and heteromultimeric complexes. Furthermore, the mutated polypeptides could reach the plasma membranes of transfected Sol8 cells. We conclude that mutations of Ile-177 and Ser-180 do not interfere with either the assembly of multimeric channel complexes or the targeting of these complexes to the plasma membrane. It is likely that these residues are involved in helix-helix interactions that are critical to the proper functioning of voltage-gated potassium channels.