Activity of guard cell anion channel SLAC1 is controlled by drought-stress signaling kinase-phosphatase pair
Activity of guard cell anion channel SLAC1 is controlled by drought-stress signaling kinase-phosphatase pair
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DOI：
10.1073/pnas.0912021106
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发表时间：
2009-12-15
影响因子：
11.1
通讯作者：
Hedrich, Rainer
中科院分区：
文献类型：
--
作者：
Geiger, Dietmar;Scherzer, Soenke;Hedrich, Rainer
在干旱胁迫下，植物激素脱落酸（ABA）诱导气孔关闭，并以钙依赖和非依赖的方式激活保卫细胞阴离子通道。ABA信号通路的两个关键组分是蛋白激酶OST1（开放气孔1）和蛋白磷酸酶ABI1（ABA不敏感1）。最近鉴定出的保卫细胞阴离子通道SLAC1似乎是该信号通路中的关键离子通道，但在异源表达时没有电活性。通过split YFP实验，我们确定OST1是SLAC1和ABI1的相互作用伙伴。在非洲爪蟾卵母细胞中SLAC1与OST1共表达时，与SLAC1相关的阴离子电流与在保卫细胞中观察到的相似。然而，将ABI1整合到SLAC1/OST1复合物中会阻止SLAC1的激活。我们的研究表明，SLAC1代表了由磷酸化/去磷酸化控制的保卫细胞中缓慢、失活、弱电压依赖性阴离子通道。
In response to drought stress the phytohormone ABA (abscisic acid) induces stomatal closure and, therein, activates guard cell anion channels in a calcium-dependent as well as-independent manner. Two key components of the ABA signaling pathway are the protein kinase OST1 (open stomata 1) and the protein phosphatase ABI1 (ABA insensitive 1). The recently identified guard cell anion channel SLAC1 appeared to be the key ion channel in this signaling pathway but remained electrically silent when expressed heterologously. Using split YFP assays, we identified OST1 as an interaction partner of SLAC1 and ABI1. Upon coexpression of SLAC1 with OST1 in Xenopus oocytes, SLAC1-related anion currents appeared similar to those observed in guard cells. Integration of ABI1 into the SLAC1/OST1 complex, however, prevented SLAC1 activation. Our studies demonstrate that SLAC1 represents the slow, deactivating, weak voltage-dependent anion channel of guard cells controlled by phosphorylation/dephosphorylation.