Acyl-CoA-binding protein 2 binds lysophospholipase 2 and lysoPC to promote tolerance to cadmium-induced oxidative stress in transgenic Arabidopsis
Acyl-CoA-binding protein 2 binds lysophospholipase 2 and lysoPC to promote tolerance to cadmium-induced oxidative stress in transgenic Arabidopsis
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DOI：
10.1111/j.1365-313x.2010.04209.x
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发表时间：
2010-06-01
期刊：
影响因子：
7.2
通讯作者：
Chye, Mee-Len
中科院分区：
文献类型：
--
作者：
Gao, Wei;Li, Hong-Ye;Chye, Mee-Len
溶血磷脂是应激引起的磷脂代谢的中间产物，溶血磷脂酶解毒溶血磷脂酰胆碱（lysoPC）。许多溶血磷脂酶已在哺乳动物和细菌中发现，但很少有报道从植物中发现。拟南芥溶血磷脂酶2 (lysoPL2) （At1g52760）在酵母双杂交分析和共免疫沉淀分析中被鉴定为酰基辅酶a结合蛋白2 （ACBP2）的蛋白互作物。BLASTP分析表明，lysoPL2与lysoPL1家族的氨基酸同源性为35%。共聚焦显微镜在农侵烟草中发现了自身荧光标记的lysoPL2和ACBP2的共定位，表明质膜是它们亚细胞相互作用的一个位点。锌（Zn）和过氧化氢（H2O2）诱导了LysoPL2 mRNA，与野生型相比，LysoPL2敲除突变体对Zn和H2O2的敏感性增强。与野生型相比，过表达lysoPL2的拟南芥对H2O2和镉（Cd）的耐受性更强，这表明lysoPL2参与了金属诱导应激引起的脂质过氧化后的磷脂修复。cd处理后ACBP2-过表达者和lysoPL2-过表达者的脂质过氧化氢（loh）含量低于野生型，表明ACBP2和lysoPL2在氧化应激中具有保护作用。在体外观察到重组lysoPL2对lysoPC的降解，证实了lysoPL2在lysoPC解毒中的作用。过滤结合实验和脂质竞争实验表明（His）(6)-ACBP2在体外与lysoPC结合。在缺乏酰基辅酶a结合结构域的（His）(6)-ACBP2衍生物中，结合被破坏，证实该结构域赋予lysoPC结合。这些结果表明ACBP2可以结合lysoPC和lysoPL2促进cd诱导的氧化应激中lysoPC的降解。
P>Lysophospholipids are intermediates of phospholipid metabolism resulting from stress and lysophospholipases detoxify lysophosphatidylcholine (lysoPC). Many lysophospholipases have been characterized in mammals and bacteria, but few have been reported from plants. Arabidopsis thaliana lysophospholipase 2 (lysoPL2) (At1g52760) was identified as a protein interactor of acyl-CoA-binding protein 2 (ACBP2) in yeast two-hybrid analysis and co-immunoprecipitation assays. BLASTP analysis indicated that lysoPL2 showed similar to 35% amino acid identity to the lysoPL1 family. Co-localization of autofluorescence-tagged lysoPL2 and ACBP2 by confocal microscopy in agroinfiltrated tobacco suggests the plasma membrane as a site for their subcellular interaction. LysoPL2 mRNA was induced by zinc (Zn) and hydrogen peroxide (H2O2), and lysoPL2 knockout mutants showed enhanced sensitivity to Zn and H2O2 in comparison to wild type. LysoPL2-overexpressing Arabidopsis was more tolerant to H2O2 and cadmium (Cd) than wild type, suggesting involvement of lysoPL2 in phospholipid repair following lipid peroxidation arising from metal-induced stress. Lipid hydroperoxide (LOOH) contents in ACBP2-overexpressors and lysoPL2-overexpressors after Cd-treatment were lower than wild type, indicating that ACBP2 and lysoPL2 confer protection during oxidative stress. A role for lysoPL2 in lysoPC detoxification was demonstrated when recombinant lysoPL2 was observed to degrade lysoPC in vitro. Filter-binding assays and Lipidex competition assays showed that (His)(6)-ACBP2 binds lysoPC in vitro. Binding was disrupted in a (His)(6)-ACBP2 derivative lacking the acyl-CoA-binding domain, confirming that this domain confers lysoPC binding. These results suggest that ACBP2 can bind both lysoPC and lysoPL2 to promote the degradation of lysoPC in response to Cd-induced oxidative stress.