Coexpression of Drosophila TRP and TRP-like proteins in Xenopus oocytes reconstitutes capacitative Ca2+ entry
Coexpression of Drosophila TRP and TRP-like proteins in Xenopus oocytes reconstitutes capacitative Ca2+ entry
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DOI：
10.1073/pnas.93.24.14146
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发表时间：
1996-11-26
影响因子：
11.1
通讯作者：
Minke, B
中科院分区：
文献类型：
--
作者：
Gillo, B;Chorna, I;Minke, B
容性Ca2+进入是肌醇-脂质信号的一个组成部分，其中肌醇1,4,5-三磷酸（InsP(3)）敏感Ca2+储存的消耗通过一种尚不清楚的机制激活Ca2+内流。这条通路在细胞信号传导中起着核心作用，这是由许多激素、神经递质和生长因子介导的。对果蝇光感受器的研究提供了第一个被认为具有容性的Ca2+进入突变体瞬时受体电位（trp）和果蝇基因编码trp样蛋白（trpl），目前尚不清楚Ca2+储存耗尽信号是如何传递到质膜的，以及trp和trpl是否都参与了这一过程。我们在这里报道，在非洲爪蟾卵母细胞中共表达果蝇TRP和TRPL协同增强内源性Ca2+激活的Cl-电流并产生二价内向电流，这两种电流都被Ca2+储存耗尽激活。在没有Ca2+的情况下，Mg2+是二价电流的主要载流子，该电流具有镧敏感性和Mg2+的电压依赖性阻断效应，这种效应在超极化（向内整流）和去极化（向外整流）电位下都得到缓解。储存操作的二价电流既没有在天然卵母细胞中观察到，也没有在单独表达TRP或TRPL的卵母细胞中观察到，这种电流的产生意味着TRP和TRPL在耗尽激活电流中协同作用。
Capacitative Ca2+ entry is a component of the inositol-lipid signaling in which depletion of inositol 1,4,5-trisphosphate (InsP(3))-sensitive Ca2+ stores activates Ca2+ influx by a mechanism that is still unknown. This pathway plays a central role in cellular signaling, which is mediated by many hormones, neurotransmitters, and growth factors, Studies of Drosophila photoreceptors provided the first putative capacitative Ca2+ entry mutant designated transient receptor potential (trp) and a Drosophila gene encoding TRP-like protein (trpl), It is not clear how the Ca2+ store depletion signal is relayed to the plasma membrane and whether both TRP and TRPL participate in this process. We report here that coexpressing Drosophila TRP and TRPL in Xenopus oocytes synergistically enhances the endogenous Ca2+-activated Cl- current and produces a divalent inward current, Both of these currents are activated by Ca2+ store depletion. In the absence of Ca2+, Mg2+ is the main charge carrier of the divalent current, This current is characterized by lanthanum sensitivity and a voltage-dependent blocking effect of Mg2+, which Is relieved at both hyperpolarizing (inward rectification) and depolarizing (outward rectification) potentials. The store-operated divalent current is neither observed in native oocytes nor in oocytes expressing either TRP or TRPL alone, The production of this current implicates a cooperative action of TRP and TRPL in the depletion-activated current.