A voltage-dependent Ca2+ homeostat operates in the plant vacuolar membrane
A voltage-dependent Ca2+ homeostat operates in the plant vacuolar membrane
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DOI：
10.1111/nph.17272
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发表时间：
2021-03-30
期刊：
影响因子：
9.4
通讯作者：
Roelfsema, M. Rob G.
中科院分区：
文献类型：
--
作者：
Dindas, Julian;Dreyer, Ingo;Roelfsema, M. Rob G.
细胞质钙信号由多种生物和非生物刺激引起，并在植物的细胞和长距离信号传导中发挥重要作用。虽然质膜在细胞质 Ca2+ 信号传导中的功能已被深入研究，但液泡膜的作用仍然难以捉摸。采用新开发的液泡电压钳技术与活细胞成像相结合，研究液泡膜在拟南芥膨出根毛细胞的 Ca2+ 和 pH 稳态中的作用。液泡膜的去极化导致 Ca2+ 浓度快速增加，并使细胞碱化。液泡膜电位、细胞液pH和Ca2+浓度之间的关系表明，液泡H+/Ca2+交换机制在细胞液Ca2+稳态中起着核心作用。数学模型进一步表明，当电压依赖性液泡 Ca2+ 稳态与最近发现的用于液泡膜电兴奋性的 K+ 通道依赖性模块耦合时，可能有助于钙信号传导。
Cytosolic calcium signals are evoked by a large variety of biotic and abiotic stimuli and play an important role in cellular and long distance signalling in plants. While the function of the plasma membrane in cytosolic Ca2+ signalling has been intensively studied, the role of the vacuolar membrane remains elusive.A newly developed vacuolar voltage clamp technique was used in combination with live-cell imaging, to study the role of the vacuolar membrane in Ca2+ and pH homeostasis of bulging root hair cells of Arabidopsis.Depolarisation of the vacuolar membrane caused a rapid increase in the Ca2+ concentration and alkalised the cytosol, while hyperpolarisation led to the opposite responses.The relationship between the vacuolar membrane potential, the cytosolic pH and Ca2+ concentration suggests that a vacuolar H+/Ca2+ exchange mechanism plays a central role in cytosolic Ca2+ homeostasis. Mathematical modelling further suggests that the voltage-dependent vacuolar Ca2+ homeostat could contribute to calcium signalling when coupled to a recently discovered K+ channel-dependent module for electrical excitability of the vacuolar membrane.