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

拟南芥K通道AKT2翻译后调控的生物物理基础和生理意义

• 批准号: 33504487
• 负责人: Professor Dr. Ingo Dreyer
• 金额: --
• 依托单位: Centro de Bioinformatica y Simulacion Molecular
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2007
• 资助国家: 德国
• 起止时间: 2006-12-31 至 2010-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/33504487?language=en
• 关键词: Biophysical; bases; physiological; implications; posttranslational

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.

Akt2是模式植物拟南芥中独一无二的钾通道。这种电压门控的K+通道具有特殊的门控特性，这些特性受到翻译后修饰的强烈调控，例如磷酸化。当非磷酸化时，AKT2作为一个内向整流钾通道，只调节K+的吸收。然而，在其磷酸化形式中，AKT2是锁定开放的，因此可以在质膜上双向运输K+。尽管最近的出版物首次对AKT2的独特门控提供了见解，但它的调控以及这一调控的生理意义仍然存在争议。这一建议基于最近发表的三篇论文，旨在澄清AKT2活性调控的某些方面。计划中的工作结合了生物物理、分子生物学、植物生理、生化和计算模拟方法。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。这些实验的结果将得到计算机模拟的补充，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能够对独特的K+通道AKT2的生理作用产生详细的了解。