N-acylethanolamines:: Formation and molecular composition of a new class of plant lipids
N-acylethanolamines:: Formation and molecular composition of a new class of plant lipids
复制标题
DOI：
10.1104/pp.116.3.1163
复制
发表时间：
1998-03-01
期刊：
影响因子：
7.4
通讯作者：
Desouza, AD
中科院分区：
文献类型：
--
作者：
Chapman, KD;Tripathy, S;Desouza, AD
最近，一种不寻常的膜磷脂，N-酰基磷脂酰乙醇胺（NAPE）的生物合成，被发现在激发子处理的烟草（Nicotiana tabacum L.）细胞（K.D.查普曼，A. Conyers-Hackson，R.A. Moreau，S. Tripathy [1995] Physiol Plant 95：120-126）。在这里，我们报告，在诱导NAPE生物合成，N-酰基乙醇胺（NAE）释放NAPE在培养的烟草细胞10分钟后，真菌诱导木聚糖酶处理。在放射性标记实验中，[C-14]NAE（标记在乙醇胺碳上）在培养基中增加约6倍，而与细胞相关的[C-14]NAPE减少约5倍。两个主要的NAE分子种类，N-月桂酰乙醇胺和N-肉豆蔻酰乙醇胺，具体确定了从培养基中提取的脂质，通过气相色谱-质谱法，都增加了诱导剂处理后的浓度。发现NAE仅在细胞外蓄积。微粒体磷脂酶D的活性被发现，形成NAE从NAPE，其活性在体外刺激约20倍的mastoparan，这表明NAPE水解是高度调节，可能是由C-蛋白。此外，NAE酰胺水解酶的活性，催化水解NAE在体外检测烟草告诉匀浆。总的来说，这些结果在结构上表征了一类新的植物脂质，并确定了在激发子处理的烟草细胞中参与其形成和失活的酶机制。最近的证据表明NAPE代谢在哺乳动物细胞中的信号作用（H.H.O. Schmid，P.C. Schmid，V. Natarajan [1996] Chem Phys Lipids 80：133-142）提出了类似机制可以在植物细胞中起作用的可能性。
Recently, the biosynthesis of an unusual membrane phospholipid, N-acylphosphatidylethanolamine (NAPE), was found to increase in elicitor-treated tobacco (Nicotiana tabacum L.) cells (K.D. Chapman, A. Conyers-Hackson, R.A. Moreau, S. Tripathy [1995] Physiol Plant 95: 120-126). Here we report that before induction of NAPE biosynthesis, N-acylethanolamine (NAE) is released from NAPE in cultured tobacco cells 10 min after treatment with the fungal elicitor xylanase. In radiolabeling experiments [C-14]NAE (labeled on the ethanolamine carbons) increased approximately 6-fold in the culture medium, whereas [C-14]NAPE associated with cells decreased approximately 5-fold. Two predominant NAE molecular species, N-lauroylethanolamine and N-myristoylethanolamine, were specifically identified by gas chromatography-mass spectrometry in lipids extracted from culture medium, and both increased in concentration after elicitor treatment. NAEs were found to accumulate extracellularly only. A microsomal phospholipase D activity was discovered that formed NAE from NAPE; its activity in vitro was stimulated about 20-fold by mastoparan, suggesting that NAPE hydrolysis is highly regulated, perhaps by C-proteins. Furthermore, an NAE amidohydrolase activity that catalyzed the hydrolysis of NAE in vitro was detected in homogenates of tobacco tells. Collectively, these results characterize structurally a new class of plant lipids and identify the enzymatic machinery involved in its formation and inactivation in elicitor-treated tobacco cells. Recent evidence indicating a signaling role for NAPE metabolism in mammalian cells (H.H.O. Schmid, P.C. Schmid, V. Natarajan [1996] Chem Phys Lipids 80: 133-142) raises the possibility that a similar mechanism may operate in plant cells.