Biophysical bases and the physiological implications of the posttranslational regulation of the Arabidopsis thaliana K+ channel AKT2

AKT2是模式植物拟南芥中唯一的钾通道。这种电压门控的K+通道具有特殊的门控特性，受磷酸化等翻译后修饰的强烈调节。当非磷酸化的AKT2作为一个向内纠偏钾通道仅介导K+摄取时。然而，在其磷酸化形式下，AKT2是被锁开的，因此可以在质膜上向两个方向运输K+。尽管最近的出版物首次提供了对AKT2独特门控的见解，但其调控以及这种调控的生理含义仍然存在争议。这一建议是根据自己最近的三份出版物提出的，其目的是澄清AKT2活性调控的某些方面。计划的工作结合了生物物理学、分子生物学、植物生理学、生物化学和计算模拟方法。它涉及突变AKT2通道的产生及其在异源表达系统中的分析，表达突变AKT2通道的转基因植物的分析以及AKT2蛋白翻译后修饰的生化鉴定。这些实验的结果将与计算模拟相补充，以模拟表达AKT2的植物细胞的电行为。不同方法的综合结果将使我们对独特的K+通道AKT2的生理作用有一个详细的了解。

AKT2 is unique among potassium channels in the model plant Arabidopsis thaliana. This voltage-gated K+ channel has exceptional gating properties that are strongly regulated by posttranslational modifications as e.g. phosphorylation. When nonphosphorylated AKT2 behaves as an inward-rectifying potassium channel mediating K+ uptake only. In its phosphorylated form, however, AKT2 is locked open and can therefore transport K+ in both directions over the plasmamembrane. Although recent publications provided first insights into the unique gating of AKT2, its regulation as well as the physiological implications of this regulation are still matter of debate.This proposal, which is based on three recent own publications, was designed to clarify certain aspects of the regulation of the activity of AKT2. The planned work combines biophysical, molecular biological, plant physiological, biochemical and computational simulation approaches. It involves the generation of mutated AKT2 channels and their analyses in heterologous expression systems, the analysis of transgenic plants expressing mutated AKT2 channels and the biochemical identification of posttranslational modifications at the AKT2 protein. The results of these experiments will be complemented with computational simulations to model the electrical behavior of plant cells expressing AKT2. The combined results of the different approaches will allow to develop a detailed picture on the physiological role of the unique K+ channel AKT2.