Proton block and voltage gating are potassium-dependent in the cardiac leak channel Kcnk3
Proton block and voltage gating are potassium-dependent in the cardiac leak channel Kcnk3
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DOI：
10.1074/jbc.m001948200
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发表时间：
2000-06-02
影响因子：
4.8
通讯作者：
Goldstein, SAN
中科院分区：
文献类型：
--
作者：
Lopes, CMB;Gallagher, PG;Goldstein, SAN
钾漏电导最近被发现作为独立的分子实体存在。在这里，基因组结构，心脏定位，和生物物理特性的小鼠的例子被认为是。Kcnk3亚基具有两个成孔P结构域和独特的功能属性。在稳态下，Kcnk3通道表现为开放的、钾选择性的、跨膜孔，其被生理水平的质子抑制。随着电压阶跃，Kcnk3通道在两个阶段中打开和关闭，一个似乎是即时的，一个是时间依赖性的（tau =类似于5 ms）。质子阻断和门控都是钾敏感的;这会产生异常增加的外向通量，因为外部钾水平上升，因为质子阻断减少。单个Kcnk3通道在生理电压范围内打开;因此它们是"泄漏"电导;然而，它们仅短暂地打开，即使在暴露于激活其他钾通道的试剂后也很少打开。
Potassium leak conductances were recently revealed to exist as independent molecular entities. Here, the genomic structure, cardiac localization, and biophysical properties of a murine example are considered. Kcnk3 subunits have two pore-forming P domains and unique functional attributes. At steady state, Kcnk3 channels behave like open, potassium-selective, transmembrane holes that are inhibited by physiological levels of proton. With voltage steps, Kcnk3 channels open and close in two phases, one appears to be immediate and one is time-dependent (tau = similar to 5 ms). Both proton block and gating are potassium-sensitive; this produces an anomalous increase in outward flux as external potassium levels rise because of decreased proton block. Single Kcnk3 channels open across the physiological voltage range; hence they are "leak" conductances; however, they open only briefly and rarely even after exposure to agents that activate other potassium channels.