AMINO-ACID-RESIDUES REQUIRED FOR FAST NA+-CHANNEL INACTIVATION - CHARGE NEUTRALIZATIONS AND DELETIONS IN THE III-IV-LINKER
AMINO-ACID-RESIDUES REQUIRED FOR FAST NA+-CHANNEL INACTIVATION - CHARGE NEUTRALIZATIONS AND DELETIONS IN THE III-IV-LINKER
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DOI：
10.1073/pnas.89.22.10905
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发表时间：
1992-11-15
影响因子：
11.1
通讯作者：
GOLDIN, AL
中科院分区：
文献类型：
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作者：
PATTON, DE;WEST, JW;GOLDIN, AL
连接电压门控Na+通道IH和IV结构域的细胞质连接物被认为参与了快速失活。该连接体在克隆的各种Na+通道中高度保守。在大鼠脑IIA Na+通道中，它由53个氨基酸组成，其中15个是带电的。为了研究该连接体在失活中的作用，我们以不同的组合突变了所有15个带电残基。除了一个外，所有这些突变体都表达了功能性通道，所有这些通道的失活动力学与野生型通道相似。然后，我们构建了一系列跨越III-IV连接子的缺失突变，以确定连接子的任何区域是否对快速失活至关重要。删除前10个氨基酸完全消除了通道中的快速失活，而删除后10个氨基酸对失活没有实质性影响。这些结果表明，III-IV连接体氨基端的一些残基对Na+通道的快速失活至关重要，但高度保守的正电荷和成对的负电荷残基并不是必需的。
The cytoplasmic linker connecting domains IH and IV of the voltage-gated Na+ channel is thought to be involved in fast inactivation. This linker is highly conserved among the various Na+ channels that have been cloned. In the rat brain IIA Na+ channel, it consists of 53 amino acids of which 15 are charged. To investigate the role of this linker in inactivation, we mutated all 15 of the charged residues in various combinations. All but one of these mutants expressed functional channels, and all of these inactivated with kinetics similar to the wild-type channel. We then constructed a series of deletion mutations that span the III-IV linker to determine if any region of the linker is essential for fast inactivation. Deletion of the first 10 amino acids completely eliminated fast inactivation in the channel, whereas deletion of the last 10 amino acids had no substantial effect on inactivation. These results demonstrate that some residues in the amino end of the III-IV linker are critical for fast Na+-channel inactivation, but that the highly conserved positively charged and paired negatively charged residues are not essential.