A cell surface receptor mediates extracellular Ca2+ sensing in guard cells
A cell surface receptor mediates extracellular Ca2+ sensing in guard cells
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DOI：
10.1038/nature01932
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发表时间：
2003-09-11
期刊：
影响因子：
64.8
通讯作者：
Pei, ZM
中科院分区：
文献类型：
--
作者：
Han, SC;Tang, RH;Pei, ZM
细胞外Ca 2+（Ca-o（2+））是动物和植物各种生理和发育过程所必需的（1-3）。为了应对不同的Ca-o（2+）水平，植物保持相对恒定的内部Ca 2+含量，这表明Ca 2+稳态的精确调节机制（4）。然而，关于植物如何监测Ca-o（2+）状态以及是否存在Ca-o（2+）敏感受体的研究却知之甚少。Ca-o（2+）通过诱导胞质Ca 2+浓度（[Ca 2 +]（i））（5-8）的增加促进气孔关闭对保卫细胞的影响为Ca-o（2+）传感提供了线索。在这里，我们已经使用了一个功能筛选试验在哺乳动物细胞9分离拟南芥互补DNA克隆编码的钙离子敏感受体，CAS。CAS定位于质膜，表现出低亲和力/高容量的Ca 2+结合，并介导Ca-o（2+）诱导的[Ca 2 +]（i）增加。CAS主要在茎中表达，包括保卫细胞。CAS的抑制破坏了保卫细胞中的Ca-o（2+）信号传导，并且损害了响应于Ca 2+缺乏的抽薹（在向种子生产过渡时的快速向上生长），因此我们得出结论，CAS可能是植物中Ca-o（2+）的主要转导器。
Extracellular Ca2+ (Ca-o(2+)) is required for various physiological and developmental processes in animals and plants(1-3). In response to varied Ca-o(2+) levels, plants maintain relatively constant internal Ca2+ content, suggesting a precise regulatory mechanism for Ca2+ homeostasis(4). However, little is known about how plants monitor Ca-o(2+) status and whether Ca-o(2+)-sensing receptors exist. The effects of Ca-o(2+) on guard cells in promoting stomatal closure by inducing increases in the concentration of cytosolic Ca2+ ([Ca2+](i))(5-8) provide a clue to Ca-o(2+) sensing. Here we have used a functional screening assay in mammalian cells 9 to isolate an Arabidopsis complementary DNA clone encoding a Ca2+-sensing receptor, CAS. CAS is localized to the plasma membrane, exhibits low-affinity/high-capacity Ca2+ binding, and mediates Ca-o(2+)-induced [Ca2+](i) increases. CAS is expressed predominantly in the shoot, including guard cells. Repression of CAS disrupts Ca-o(2+) signalling in guard cells, and impairs bolting (swift upward growth at the transition to seed production) in response to Ca2+ deficiency, so we conclude that CAS may be a primary transducer of Ca-o(2+) in plants.