Molecular identification of a hyperpolarization-activated channel in sea urchin sperm
Molecular identification of a hyperpolarization-activated channel in sea urchin sperm
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DOI：
10.1038/31248
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发表时间：
1998-06-11
期刊：
影响因子：
64.8
通讯作者：
Kaupp, UB
中科院分区：
文献类型：
--
作者：
Gauss, R;Seifert, R;Kaupp, UB
海胆卵通过趋化肽吸引精子，这引起膜电压以及环AMP、环GMP和Ca 2+离子浓度的复杂变化（综述见参考文献1）。细胞内信号传导途径及其细胞靶点在很大程度上是未知的。我们现在已经从海胆睾丸中克隆了编码通道多肽SPIH的互补DNA。SPIH的功能性表达产生弱K+选择性超极化激活通道，其活性通过cAMP的直接作用而增强。因此，SPIH处于电压和cAMP的双重控制下。SPIH通道，这是局限于精子鞭毛，可能参与鞭毛跳动的控制。SPM电流表现出超极化激活电流（I-h）的所有特征（2，3），其参与中枢神经元的节律性放电，控制心脏的起搏，并通过视网膜光感受器中的强光减少饱和度（2，3）。由于它们的序列（4）和功能特性，I-h通道在电压门控和环核苷酸门控通道的超家族中形成了自己的一类。
Sea urchin eggs attract sperm through chemotactic peptides, which evoke complex changes in membrane voltage and in the concentrations of cyclic AMP, cyclic GMP and Ca2+ ions (see ref. 1 for a review). The intracellular signalling pathways and their cellular targets are largely unknown. We have now cloned, from sea urchin testis, the complementary DNA encoding a channel polypeptide, SPIH, Functional expression of SPIH gives rise to weakly K+-selective hyperpolarization-activated channels, whose activity is enhanced by the direct action of cAMP. Thus, SPIH is under the dual control of voltage and cAMP. The SPIH channel, which is confined to the sperm flagellum, may be involved in the control of flagellar beating. SPM currents exhibit all the hallmarks of hyperpolarization-activated currents (I-h)(2,3), which participate in the rhythmic firing of central neurons, control pacemaking in the heart, and curtail saturation by bright light in retinal photoreceptors(2,3). Because of their sequence(4) and functional properties, I-h channels form a class of their own within the superfamily of voltage-gated and cyclic-nucleotide-gated channels.