Deficiency in phosphatidylserine decarboxylase activity in the psd1 psd2 psd3 triple mutant of Arabidopsis affects phosphatidylethanolamine accumulation in mitochondria
Deficiency in phosphatidylserine decarboxylase activity in the psd1 psd2 psd3 triple mutant of Arabidopsis affects phosphatidylethanolamine accumulation in mitochondria
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DOI：
10.1104/pp.107.095414
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发表时间：
2007-06-01
期刊：
影响因子：
7.4
通讯作者：
Doermann, Peter
中科院分区：
文献类型：
--
作者：
Nerlich, Annika;von Orlow, Melanie;Doermann, Peter
磷脂酰丝氨酸（PS）脱羧酶参与合成丰富的磷脂酰乙醇胺（PE），特别是在线粒体中，在许多生物体中，包括酵母（Saccharomyces cerevisiae）和动物。拟南芥（Arabidopsis thaliana）含有3个与PS脱羧酶序列相似的基因，在酵母和大肠杆菌中异种表达后，对各自基因产物进行了功能表征。PSD1蛋白定位于线粒体，而PSD2和PSD3则存在于细胞膜系统。为了研究PSD基因在植物磷脂代谢中的作用，我们在拟南芥中获得了psd1、psd2和psd3的插入突变体。单突变体的PS脱羧酶活性均有不同程度的降低，但突变体植株生长和形态表型均不明显。一个三重突变体psd1、psd2、psd3完全缺乏PS脱羧酶活性。在全叶磷脂组成不变的情况下，psd1、psd2、psd3离体线粒体PE含量降低。因此，拟南芥中绝大部分的PE是通过其他途径合成的，但线粒体中大量的PE是由PS脱羧酶反应产生的。这些结果表明，与酵母和动物细胞类似，植物中存在一种特定的磷脂从内质网转移到线粒体的过程。
Phosphatidylserine (PS) decarboxylase is involved in the synthesis of the abundant phospholipid phosphatidylethanolamine (PE), particularly in mitochondria, in many organisms, including yeast (Saccharomyces cerevisiae) and animals. Arabidopsis (Arabidopsis thaliana) contains three genes with sequence similarity to PS decarboxylases, and the respective gene products were functionally characterized after heterologous expression in yeast and Escherichia coli. While the PSD1 protein localizes to mitochondria, PSD2 and PSD3 are found in the endomembrane system. To study the role of PSD genes in plant phospholipid metabolism, Arabidopsis insertional mutants for psd1, psd2, and psd3 were obtained. The single mutants were decreased in PS decarboxylase activity to various extents, but mutant plants showed no obvious growth or morphological phenotype. A triple mutant, psd1 psd2 psd3, was generated that was totally devoid of PS decarboxylase activity. While the phospholipid composition in whole leaves was unchanged, the PE content in isolated mitochondria of psd1 psd2 psd3 was decreased. Therefore, the predominant proportion of PE in Arabidopsis is synthesized by alternative pathways, but a significant amount of mitochondrial PE is derived from the PS decarboxylase reaction. These results imply that, similar to yeast and animal cells, a specific phospholipid transfer from the endoplasmic reticulum to mitochondria exists in plants.