Molecular mechanism of electrogenic carrier- and pump-mediated vacuolar transport

电载体和泵介导的液泡运输的分子机制

• 批准号: 76388148
• 负责人: Professor Dr. Rainer Hedrich
• 金额: --
• 依托单位: Lehrstuhl für Botanik I: Molekulare Pflanzenphysiologie und Biophysik
• 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 2015-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/76388148?language=en
• 关键词: Molecular; mechanism; electrogenic; carrier; pump

The vacuolar membrane is engaged with solute transport into and out of the major plant organelle. Besides inorganic ions and metabolites, large quantities of protons and sugars are shuttled across this membrane. Two proton pumps, the V-ATPase and the VPPase, generate a proton- and electrical gradient across the vacuolar membrane that drives accumulation and release of sugars. Members of different gene families such as SUC, TMT, and VGT have been associated with a function in sugar transport and modulation of the vacuolar sugar pool. In the first funding period within the consortium we have studied the mode of action and properties of the V-type proton ATPase side by side with those of the sugar carriers SUC4 and TMT1/2. Using single vacuole-techniques combined with molecular approaches, transient overexpression, and electrophysiological analysis with Arabidopsis thaliana and mutants thereof we found that I. V-ATPase feeds back on pH gradient and membrane potential across the vacuolar membraneII. SUC4 operates as a H+/sucrose symporter for sugar release from the vacuoleIII. TMT1/2 represents the first proton-coupled sugar antiporter capable of high capacity glucose and sucrose loading into the vacuole.The central question regarding the 2nd term is how cold and salt alter the transport cycle of distinct vacuolar transporters. Given that the protein kinase VIK interacts with TMT1, in the following research period we will draw our attention on whether and how the TMT1- interacting kinase tunes the activity and selectivity of the sugar transporter. Following up with our proceeding studies on the V-ATPase, we will perform comparative studies regarding the second vacuolar proton pump, the pyrophosphatase (PPase). Furthermore we will draw our attention to ERD6, ERDL6, ERD3 and TLT1 as members of two subclades within the MST(- like) superfamily with a probable function in sugar transport.

液泡膜参与溶质进出植物主要细胞器的运输。除了无机离子和代谢物，大量的质子和糖穿梭在这个膜。两个质子泵，V-ATP酶和VPPase，在液泡膜上产生质子和电梯度，驱动糖的积累和释放。不同基因家族的成员，如SUC，TMT和VGT已与糖运输和液泡糖库的调节功能。在该联盟的第一个资助期内，我们研究了V型质子ATP酶与糖载体SUC 4和TMT 1/2的作用模式和性质。利用单液泡技术结合分子生物学方法、瞬时过表达和电生理分析，我们对拟南芥及其突变体进行了研究。 V-ATPase反馈pH梯度和跨液泡膜的膜电位II。 SUC 4作为H+/蔗糖同向转运体，用于从液泡III中释放糖。 TMT 1/2是第一个能够将高容量葡萄糖和蔗糖装载到液泡中的质子偶联糖反向转运蛋白，关于第二项的中心问题是冷和盐如何改变不同液泡转运蛋白的转运循环。鉴于蛋白激酶VIK与TMT 1相互作用，在接下来的研究中，我们将关注TMT 1相互作用激酶是否以及如何调节糖转运蛋白的活性和选择性。在我们对V-ATPase进行研究的基础上，我们将对第二个液泡质子泵焦磷酸酶（PPase）进行比较研究。此外，我们将提请我们注意ERD 6，ERDL 6，ERD 3和TLT 1作为MST（类）超家族内的两个亚支的成员，可能在糖转运中发挥作用。

项目成果

Arabidopsis V-ATPase activity at the tonoplast is required for efficient nutrient storage but not for sodium accumulation

• DOI: 10.1073/pnas.0913035107
• 发表时间: 2010-02-16
• 期刊: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• 影响因子: 11.1
• 作者: Krebs, Melanie;Beyhl, Diana;Schumacher, Karin
• 通讯作者: Schumacher, Karin