Sano Yorikata, Inamura Kohei, Miyake Akira, Mochizuki Shinobu, Kitada Chika, Yokoi Hiromichi, Nozawa Katsura, Okada Hidetsugu, Matsushime Hitoshi, Furuichi Kiyoshi
Molecular Medicine Laboratories, Institute for Drug Discovery Research, Yamanouchi Pharmaceutical Co., Ltd., 21 Miyukigaoka, Tsukuba, Ibaraki, 305-8585, Japan.
J Biol Chem. 2003 Jul 25;278(30):27406-12. doi: 10.1074/jbc.M206810200. Epub 2003 May 17.
To find a novel human ion channel gene we have executed an extensive search by using a human genome draft sequencing data base. Here we report a novel two-pore domain K+ channel, TRESK (TWIK-related spinal cord K+ channel). TRESK is coded by 385 amino acids and shows low homology (19%) with previously characterized two-pore domain K+ channels. However, the most similar channel is TREK-2 (two-pore domain K+ channel), and TRESK also has two pore-forming domains and four transmembrane domains that are evolutionarily conserved in the two-pore domain K+ channel family. Moreover, we confirmed that TRESK is expressed in the spinal cord. Electrophysiological analysis demonstrated that TRESK induced outward rectification and functioned as a background K+ channel. Pharmacological analysis showed TRESK to be inhibited by previously reported K+ channel inhibitors Ba2+, propafenone, glyburide, lidocaine, quinine, quinidine, and triethanolamine. Functional analysis demonstrated TRESK to be inhibited by unsaturated free fatty acids such as arachidonic acid and docosahexaenoic acid. TRESK is also sensitive to extreme changes in extracellular and intracellular pH. These results indicate that TRESK is a novel two-pore domain K+ channel that may set the resting membrane potential of cells in the spinal cord.
为了找到一个新的人类离子通道基因，我们利用人类基因组草图测序数据库进行了广泛的搜索。在此，我们报告一种新的双孔结构域钾通道，即TRESK（与TWIK相关的脊髓钾通道）。TRESK由385个氨基酸编码，与先前鉴定的双孔结构域钾通道显示出低同源性（19%）。然而，最相似的通道是TREK - 2（双孔结构域钾通道），并且TRESK也具有两个孔形成结构域和四个跨膜结构域，这些结构域在双孔结构域钾通道家族中是进化保守的。此外，我们证实TRESK在脊髓中表达。电生理分析表明，TRESK诱导外向整流并作为背景钾通道发挥作用。药理学分析显示，TRESK被先前报道的钾通道抑制剂Ba2 +、普罗帕酮、格列本脲、利多卡因、奎宁、奎尼丁和三乙醇胺抑制。功能分析表明，TRESK被不饱和游离脂肪酸如花生四烯酸和二十二碳六烯酸抑制。TRESK对细胞外和细胞内pH的极端变化也敏感。这些结果表明，TRESK是一种新的双孔结构域钾通道，可能设定脊髓中细胞的静息膜电位。
