Plant plasma membrane water channels conduct the signalling molecule H2O2
Plant plasma membrane water channels conduct the signalling molecule H2O2
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DOI：
10.1042/bj20080287
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发表时间：
2008-08-15
影响因子：
4.1
通讯作者：
Ludewig, Uwe
中科院分区：
文献类型：
--
作者：
Dynowski, Marek;Schaaf, Gabriel;Ludewig, Uwe
H2 O2是一种寿命相对较长的活性氧物质，在细胞和生物体之间发出信号。H_2O_2信号在植物对胁迫的反应、对病原菌的防御和细胞程序性死亡的调节中是必不可少的。虽然H2 O2跨膜扩散通常被认为是脂质双层的被动性质，但天然膜代表H2 O2的显著屏障。在本研究中，我们解决了这个问题，是否通道可能促进过氧化氢跨质膜传导。几种植物质膜水通道蛋白在酵母中的表达，包括来自拟南芥的PIP 2;1（其中PIP是质膜内在蛋白），增强了H2 O2的毒性，并且当暴露于IL时增加了负载染料的酵母的荧光。表达水通道蛋白的酵母对H2 O2的敏感性通过改变水通道蛋白的门控和选择性的突变而改变。采用分子动力学模拟方法，以菠菜中SoPIP 2; 1的晶体结构为基础，比较了水、H2 O2和尿素的传导行为。计算确定的基板之间的传导差异，并揭示关键参与过氧化氢传导通道残留物。四聚体和单体的计算结果与生化数据一致。两者合计，结果强烈表明，质膜水通道蛋白孔决定的效率' HO，细胞之间的信号I。水通道蛋白存在于大多数物种中，它们促进H2 O2扩散的能力在许多生物中可能具有生理意义，特别是在不同物种之间的交流中。
H2O2 is a relatively long-lived reactive oxygen species that signals between cells and organisms. H2O2 signalling in plants is essential for response to stress, defence against pathogeris and the regulation of programmed cell death. Although H2O2 diffusion across membranes is often considered as a passive property of lipid bilayers, native membranes represent significant barriers for H2O2. In the present Study we addressed the question of whether channels might facilitate H2O2 conduction across plasma membranes. The expression of several plant plasma membrane aquaporins in yeast, including PIP2;1 from Arabidopsis (where PIP is plasma membrane intrinsic protein), enhanced the toxicity of H2O2 and increased the fluorescence of dye-loaded yeast when exposed to Ill The sensitivity of aquaporin-expressing yeast to H2O2 wits altered by Mutations that alter gating and the selectivity of the aquaporins. The conduction of water, H2O2 and urea was compared, using molecular dynamics simulations based on the crystal structure of SoPIP2; 1 from spinach. The calculations identify differences in the conduction between the substrates and reveal channel residues critically involved in H2O2 conduction. The results of the calculations oil tetramers and monomers are in agreement with the biochemical data. Taken together, the results strongly suggest that plasma membrane aquaporin pores determine the efficiency of' HO, signalling I between cells. Aquaporins are present in most species and their capacity to facilitate the diffusion of H2O2 may be of physiological significance in many organisms and particularly in communication between different species.