Calcium-dependent modulation and plasma membrane targeting of the AKT2 potassium channel by the CBL4/CIPK6 calcium sensor/protein kinase complex
Calcium-dependent modulation and plasma membrane targeting of the AKT2 potassium channel by the CBL4/CIPK6 calcium sensor/protein kinase complex
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DOI：
10.1038/cr.2011.50
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发表时间：
2011-07-01
期刊：
影响因子：
44.1
通讯作者：
Kudla, Joerg
中科院分区：
文献类型：
--
作者：
Held, Katrin;Pascaud, Francois;Kudla, Joerg
钾（K（+））通道功能是许多生理过程的基础。然而，植物钾离子通道活性的调控成分和机制仍然知之甚少。在这里，我们表明，钙（Ca（2+））传感器CBL 4与相互作用的蛋白激酶CIPK 6一起调节活性和质膜（PM）靶向的K（+）通道AKT 2从拟南芥介导的AKT 2易位到PM在植物细胞和增强AKT 2活性卵母细胞。因此，akt 2、cbl 4和cipk 6突变体具有相似的发育和延迟开花表型。此外，CIPK 6的分离的调节C-末端结构域足以通过一种新的靶向途径介导CBL 4-和Ca（2+）-依赖性通道从内质网膜转运到PM，该靶向途径依赖于CBL 4通过肉豆蔻酰化和棕榈酰化的双重脂质修饰。因此，我们描述了离子通道调节的关键机制，其中Ca（2+）传感器通过促进激酶相互作用依赖但磷酸化独立的通道向PM的易位来调节K（+）通道活性。
Potassium (K(+)) channel function is fundamental to many physiological processes. However, components and mechanisms regulating the activity of plant K(+) channels remain poorly understood. Here, we show that the calcium (Ca(2+)) sensor CBL4 together with the interacting protein kinase CIPK6 modulates the activity and plasma membrane (PM) targeting of the K(+) channel AKT2 from Arabidopsis thaliana by mediating translocation of AKT2 to the PM in plant cells and enhancing AKT2 activity in oocytes. Accordingly, akt2, cbl4 and cipk6 mutants share similar developmental and delayed flowering phenotypes. Moreover, the isolated regulatory C-terminal domain of CIPK6 is sufficient for mediating CBL4- and Ca(2+)-dependent channel translocation from the endoplasmic reticulum membrane to the PM by a novel targeting pathway that is dependent on dual lipid modifications of CBL4 by myristoylation and palmitoylation. Thus, we describe a critical mechanism of ion-channel regulation where a Ca(2+) sensor modulates K(+) channel activity by promoting a kinase interaction-dependent but phosphorylation-independent translocation of the channel to the PM.