Department of Horticulture, Foshan University, Foshan, 528000, China.
Department of Plant Cell Biology and Bioengineering, Biological Faculty, Belarusian State University, 4 Independence Avenue, Minsk, 220030, Belarus.
New Phytol. 2018 Oct;220(1):49-69. doi: 10.1111/nph.15266. Epub 2018 Jun 19.
Contents Summary 49 I. Introduction 49 II. Physiological and structural characteristics of plant Ca -permeable ion channels 50 III. Ca extrusion systems 61 IV. Concluding remarks 64 Acknowledgements 64 References 64 SUMMARY: Calcium is an essential structural, metabolic and signalling element. The physiological functions of Ca are enabled by its orchestrated transport across cell membranes, mediated by Ca -permeable ion channels, Ca -ATPases and Ca /H exchangers. Bioinformatics analysis has not determined any Ca -selective filters in plant ion channels, but electrophysiological tests do reveal Ca conductances in plant membranes. The biophysical characteristics of plant Ca conductances have been studied in detail and were recently complemented by molecular genetic approaches. Plant Ca conductances are mediated by several families of ion channels, including cyclic nucleotide-gated channels (CNGCs), ionotropic glutamate receptors, two-pore channel 1 (TPC1), annexins and several types of mechanosensitive channels. Key Ca -mediated reactions (e.g. sensing of temperature, gravity, touch and hormones, and cell elongation and guard cell closure) have now been associated with the activities of specific subunits from these families. Structural studies have demonstrated a unique selectivity filter in TPC1, which is passable for hydrated divalent cations. The hypothesis of a ROS-Ca hub is discussed, linking Ca transport to ROS generation. CNGC inactivation by cytosolic Ca , leading to the termination of Ca signals, is now mechanistically explained. The structure-function relationships of Ca -ATPases and Ca /H exchangers, and their regulation and physiological roles are analysed.
内容摘要 49 I. 引言 49 II. 植物 Ca 通透性离子通道的生理和结构特性 50 III. Ca 外排系统 61 IV. 结论 64 致谢 64 参考文献 64 摘要：钙是一种重要的结构、代谢和信号元素。其生理功能通过细胞膜的协调转运来实现，由 Ca 通透性离子通道、Ca-ATP 酶和 Ca/H 交换器介导。生物信息学分析尚未确定植物离子通道中有任何 Ca 选择性过滤器，但电生理测试确实揭示了植物膜中的 Ca 电导。植物 Ca 电导的生物物理特性已被详细研究，并最近通过分子遗传方法得到了补充。植物 Ca 电导由几个家族的离子通道介导，包括环核苷酸门控通道 (CNGCs)、离子型谷氨酸受体、双孔通道 1 (TPC1)、膜联蛋白和几种类型的机械敏感通道。关键的 Ca 介导反应（例如温度、重力、触摸和激素的感应，以及细胞伸长和保卫细胞关闭）现在与这些家族的特定亚基的活性相关联。结构研究表明 TPC1 中存在独特的选择性过滤器，可通过水合二价阳离子。讨论了 ROS-Ca 枢纽假说，将 Ca 转运与 ROS 生成联系起来。CNGC 被细胞质 Ca 失活，导致 Ca 信号终止，这一机制现在得到了解释。Ca-ATP 酶和 Ca/H 交换器的结构-功能关系及其调节和生理作用进行了分析。
