SUBUNIT STOICHIOMETRY OF A MAMMALIAN K+ CHANNEL DETERMINED BY CONSTRUCTION OF MULTIMERIC CDNAS
SUBUNIT STOICHIOMETRY OF A MAMMALIAN K+ CHANNEL DETERMINED BY CONSTRUCTION OF MULTIMERIC CDNAS
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DOI：
10.1016/0896-6273(92)90239-a
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发表时间：
1992-11-01
期刊：
影响因子：
16.2
通讯作者：
HESS, P
中科院分区：
文献类型：
--
作者：
LIMAN, ER;TYTGAT, J;HESS, P
通过将单个开放阅读框中 2-5 个 K+ 通道亚基的编码序列连接在一起，并用突变（Y379K 或 Y379R）标记各个亚基的表达来检查哺乳动物 K+ 通道 KV1.1 (RCK1) 的亚基化学计量，该突变改变了通道对外部四乙铵离子阻断的敏感性。两条证据表明这些构建体仅通过形成功能性四聚体来导致 K+ 通道表达。首先，包含单个突变亚基的四聚体构建体表达的电流对四乙铵具有敏感性，这与单位点结合等温线很好地拟合。其次，仅作为异源多聚体一部分表达的突变亚基（Y379K）在与三聚体构建体共表达但与四聚体构建体共表达时有助于功能通道的表达。
The subunit stoichiometry of the mammalian K+ channel KV1.1 (RCK1) was examined by linking together the coding sequences of 2-5 K+ channel subunits in a single open reading frame and tagging the expression of individual subunits with a mutation (Y379K or Y379R) that altered the sensitivity of the channel to block by external tetraethylammonium ion. Two lines of evidence argue that these constructs lead to K+ channel expression only through the formation of functional tetramers. First, currents expressed by tetrameric constructs containing a single mutant subunit have a sensitivity to tetraethylammonium that is well fitted by a single site binding isotherm. Second, a mutant subunit (Y379K) that expresses only as part of a heteromultimer contributes to the expression of functional channels when coexpressed with a trimeric construct but not a tetrameric construct.