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首页> 外文期刊>The FEBS journal >Voltage- and Ca2+-activated potassium channels in Ca2+ store control Ca2+ release
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Voltage- and Ca2+-activated potassium channels in Ca2+ store control Ca2+ release

机译：Ca2 +中的电压和Ca2 +激活的钾离子通道可控制Ca2 +的释放

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Ca2+ release from Ca2+ stores is a 'quantal' process; it terminates after a rapid release of stored Ca2+. To explain the quantal nature, it has been supposed that a decrease in luminal Ca2+ acts as a 'brake' on store release. However, the mechanism for the attenuation of Ca2+ efflux remains unknown. We show that Ca2+ release is controlled by voltage- and Ca2+-activated potassium channels in the Ca2+ store. The potassium channel was identified as the big or maxi-K (BK)-type, and was activated by positive shifts in luminal potential and luminal Ca2+ increases, as revealed by patch-clamp recordings from an exposed nuclear envelope. The blockage or closure of the store BK channel due to Ca2+ efflux developed lumen-negative potentials, as revealed with an organelle-specific voltage-sensitive dye [DiOC5(3); 3,3'-dipentyloxacarbocyanine iodide], and suppressed Ca2+ release. The store BK channels are reactivated by Ca2+ uptake by Ca2+ pumps regeneratively with K+ entry to allow repetitive Ca2+ release. Indeed, the luminal potential oscillated bistably by approximately 45 mV in amplitude. Our study suggests that Ca2+ efflux-induced store BK channel closures attenuate Ca2+ release with decreases in counter-influx of K+.
机译：从Ca2 +存储中释放Ca2 +是一个“定量”过程。在迅速释放储存的Ca2 +后终止。为了解释数量上的本质，人们认为管腔Ca2 +的减少会在商店释放时起到“刹车”的作用。但是，Ca 2+外排的衰减机理仍然未知。我们表明，Ca2 +释放受Ca2 +存储中的电压激活和Ca2 +激活的钾离子通道控制。钾通道被认为是大钾离子或最大钾离子（BK）型，并通过管腔电位的正向移动而激活，并且管腔Ca2 +升高，这是由裸露的核膜的膜片钳记录所揭示的。 Ca2 +外流引起的商店BK通道的阻塞或关闭形成了管腔负电位，如细胞器特有的电压敏感染料[DiOC5（3）; 3，3'-二戊基氧杂碳菁碘化物]，并抑制Ca2 +释放。储存的BK通道通过Ca2 +泵通过吸收Ca2 +而再生，并随着K +的进入而再生，以允许重复的Ca2 +释放。实际上，管腔电势振幅双稳态振荡约45 mV。我们的研究表明，Ca2 +外流诱导的商店BK通道关闭可减少Ca2 +的释放，同时减少K +的反流入。

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