Depletion of the Membrane-Associated Acyl-Coenzyme A-Binding Protein ACBP1 Enhances the Ability of Cold Acclimation in Arabidopsis
Depletion of the Membrane-Associated Acyl-Coenzyme A-Binding Protein ACBP1 Enhances the Ability of Cold Acclimation in Arabidopsis
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DOI：
10.1104/pp.109.147066
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发表时间：
2010-03-01
期刊：
影响因子：
7.4
通讯作者：
Chye, Mee-Len
中科院分区：
文献类型：
--
作者：
Du, Zhi-Yan;Xiao, Shi;Chye, Mee-Len
在拟南芥（Arabidopsis thaliana）中，一个由六个基因组成的家族编码酰基辅酶A结合蛋白（ACBP）。该家族的一个成员ACBP1含有一个氨基末端跨膜结构域，该结构域将其靶向质膜和内质网。为了研究ACBP1的功能，使用脂质分析来表征ACBP1过表达的转基因拟南芥植物。ACBP1过表达者在几种二不饱和磷脂酰胆碱（PC）中表现出减少，这促使我们研究它们是否在冷冻应激中发生了改变。ACBP1过表达表现出增加的冷冻敏感性伴随着PC的减少和磷脂酸（PA）的增加，而acbp1突变体植物表现出增强的抗冻性与PC积累和PA减少。我们还显示了重组真核ACBP（ACBP1）与PA的结合，表明ACBP1过表达者中PA相互作用增强的可能性。由于磷脂酶D α 1（PLD α 1）是促进PC水解为PA的主要酶，因此检查PLD α 1表达，并且观察到在ACBP 1过表达体中PLD α 1的表达高于在acbp 1突变体植物中。与此相反，PLD δ的表达，这在抗冻性中起着积极的作用，下降ACBP 1过表达，但增加acbp1突变体植物。鉴于ACBP1定位于内质网和质膜，它可以通过其结合PA的能力维持膜相关PA池来调节PLDa1和PLDd的表达。此外，这两种基因型显示没有改变脯氨酸和可溶性糖含量或冷调节（COR6.6和COR47）基因表达，这表明ACBP1介导的反应是PLD相关的，是独立的渗透压累积。
In Arabidopsis (Arabidopsis thaliana), a family of six genes encodes acyl-coenzyme A-binding proteins (ACBPs). A member of this family, ACBP1, contains an amino-terminal transmembrane domain that targets it to the plasma membrane and the endoplasmic reticulum. To investigate ACBP1 function, ACBP1-overexpressing transgenic Arabidopsis plants were characterized using lipid analysis. ACBP1 overexpressors showed reduction in several species of diunsaturated phosphatidylcholine (PC), prompting us to investigate if they were altered in response to freezing stress. ACBP1 overexpressors demonstrated increased freezing sensitivity accompanied by a decrease in PC and an increase in phosphatidic acid (PA), while acbp1 mutant plants showed enhanced freezing tolerance associated with PC accumulation and PA reduction. We also showed binding of a recombinant eukaryotic ACBP (ACBP1) to PA, indicative of the possibility of enhanced PA interaction in ACBP1 overexpressors. Since phospholipase D alpha 1 (PLD alpha 1) is a major enzyme promoting the hydrolysis of PC to PA, PLD alpha 1 expression was examined and was observed to be higher in ACBP1 overexpressors than in acbp1 mutant plants. In contrast, the expression of PLD delta, which plays a positive role in freezing tolerance, declined in the ACBP1 overexpressors but increased in acbp1 mutant plants. Given that ACBP1 is localized to the endoplasmic reticulum and plasma membrane, it may regulate the expression of PLDa1 and PLDd by maintaining a membrane-associated PA pool through its ability to bind PA. Moreover, both genotypes showed no alterations in proline and soluble sugar content or in cold-regulated (COR6.6 and COR47) gene expression, suggesting that the ACBP1-mediated response is PLD associated and is independent of osmolyte accumulation.