Growth Control by ABA 2 (GCA2), a central regulator of calcium oscillations

ABA 2 (GCA2) 的生长控制，钙振荡的中央调节剂

• 批准号: 71800568
• 负责人: Professor Dr. Erwin Grill
• 金额: --
• 依托单位: Lehrstuhl für Botanik
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2008
• 资助国家: 德国
• 起止时间: 2007-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/71800568?language=en
• 关键词: Growth; Control; ABA; GCA2; central

The integration of Ca2+ in the signal pathway of the phytohormone abscisic acid (ABA) is largely not understood. The elucidation of this process is a central goal of our studies. Our analysis focuses on the calmodulin-domain containing protein kinase GCA2 that has been characterized as a Ca2+-binding protein. The characterization of the ABA-insensitive mutant gca2-1 points to a role of this gene locus in the integration of ABA, CO2, Ca2+ and hydrogen peroxide. The different signals have in common that they regulate the ABA response pathway leading to both ABA-dependent gene expression and transpirational control. Hence, those signals seem to be integrated early into ABA transduction, at or close to the ABA receptor. Indeed, GCA2 interacts with ABA receptor components and directly associated protein kinases. A deeper understanding of GCA2 action and regulation offers the opportunity to gain access to a fascinating and yet poorly studied research field, namely the molecular mechanisms of integrating exogenous and endogenous (ABA) signals. We see in that research area our long-term scientific challenge. More specifically, we pursue in this project the question whether the GCA2 locus is subjected to natural selection among Arabidopsis ecotypes and the physiological consequences thereof. In this context, we are interested in the molecular mechanisms, i.e. the interplay of GCA2-ABA receptor components via protein interactions and phosphorylation status. The study includes the characterization of known and the identification of novel GCA2 targets and interaction components. The ABA response regulator and transcription factor ABF2 will be a focal point in the study, which emerges as a hub target of Ca2+-dependent protein kinases. In a joint effort, we plan to visualize cellular Ca2+-release and to model the Ca2+-dependent ABF2 regulation. In conclusion, the study together with other project parts will provide novel insights into the molecular mechanisms of integrating the Ca2+signal into ABA response pathways.

植物激素脱落酸(ABA)信号通路中钙离子的整合在很大程度上还不清楚。阐明这一过程是我们研究的中心目标。我们的分析集中在含有钙调蛋白结构域的蛋白激酶GCA2上，该蛋白被描述为一种钙结合蛋白。对ABA不敏感突变体gca2-1的鉴定表明，该基因座在ABA、CO2、Ca~(2+)和过氧化氢的整合中起作用。这些不同的信号有一个共同点，它们都调节ABA反应途径，导致ABA依赖的基因表达和蒸腾控制。因此，这些信号似乎被早期整合到ABA信号转导中，位于ABA受体或靠近ABA受体。事实上，GCA2与ABA受体成分和直接相关的蛋白激酶相互作用。更深入地了解GCA2的作用和调控为人们提供了进入一个引人入胜但研究较少的研究领域的机会，即整合外源和内源(ABA)信号的分子机制。我们在这个研究领域看到了我们长期的科学挑战。更具体地说，我们在这个项目中探讨了GCA2基因座是否在拟南芥生态型中受到自然选择及其生理后果的问题。在这种背景下，我们感兴趣的是分子机制，即GCA2-ABA受体成分通过蛋白质相互作用和磷酸化状态的相互作用。这项研究包括已知的GCA2靶标和相互作用成分的表征和鉴定。ABA反应调节因子和转录因子ABF2将是这项研究的焦点，它是钙依赖蛋白激酶的中心靶标。在一项共同努力中，我们计划可视化细胞内钙释放，并对钙依赖的ABF2调节进行建模。总之，这项研究与其他项目部分一起，将为将钙信号整合到ABA反应途径中的分子机制提供新的见解。