Arabidopsis plasma membrane protein crucial for Ca2+ influx and touch sensing in roots
Arabidopsis plasma membrane protein crucial for Ca2+ influx and touch sensing in roots
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DOI：
10.1073/pnas.0607703104
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发表时间：
2007-02-27
影响因子：
11.1
通讯作者：
Iida, Hidetoshi
中科院分区：
文献类型：
--
作者：
Nakagawa, Yuko;Katagiri, Takeshi;Iida, Hidetoshi
植物可以像动物一样感知和响应机械刺激。机械感知和响应的早期机制被推测是由尚未确定的感觉复合物含有Ca 2+渗透，拉伸激活（SA）通道。然而，这些复合物的组分或调节剂在植物中的分子水平上知之甚少。在这里，我们报告的分子鉴定质膜蛋白（指定Mcal），相关的Ca 2+流量与机械感应拟南芥。MCA 1 cDNA的克隆功能互补的致死性的酵母midl突变体缺乏一个假定的Ca 2+渗透SA通道组件。Mcal定位于酵母细胞膜上，作为一个完整的膜蛋白，并介导Ca ~（2+）内流。Mcal还增加了拟南芥质膜变形后的[Ca ~（2+）]（cyt）。MCAl过表达植物的生长在高钙培养基中受损，但在低钙培养基中不受损。无mcal植株的初生根不能从较软的琼脂培养基中穿透较硬的琼脂培养基。这些观察结果表明，Mcall起着至关重要的作用，在Ca 2+渗透SA通道系统，导致拟南芥中的mechanosensing。我们期望我们的发现是一个起点，为更深入地了解植物中的机械转导的分子机制。
Plants can sense and respond to mechanical stimuli, like animals. An early mechanism of mechanosensing and response is speculated to be governed by as-yet-unidentified sensory complexes containing a Ca2+-permeable, stretch-activated (SA) channel. However, the components or regulators of such complexes are poorly understood at the molecular level in plants. Here, we report the molecular identification of a plasma membrane protein (designated Mcal) that correlates Ca2+ influx with mechanosensing in Arabidopsis thaliana. MCA1 cDNA was cloned by the functional complementation of lethality of a yeast midl mutant lacking a putative Ca2+-permeable SA channel component. Mcal was localized to the yeast plasma membrane as an integral membrane protein and mediated Ca2+ influx. Mcal also increased [Ca2+](cyt) upon plasma membrane distortion in Arabidopsis. The growth of MCAl-overexpressing plants was impaired in a high-calcium but not a low-calcium medium. The primary roots of mcal-null plants failed to penetrate a harder agar medium from a softer one. These observations demonstrate that Mcall plays a crucial role in a Ca2+-permeable SA channel system that leads to mechanosensing in Arabidopsis. We anticipate our findings to be a starting pointfor a deeper understanding of the molecular mechanisms of mechanotransduction in plants.