Arabidopsis mutants lacking long chain base phosphate lyase are fumonisin-sensitive and accumulate trihydroxy-18:1 long chain base phosphate
Arabidopsis mutants lacking long chain base phosphate lyase are fumonisin-sensitive and accumulate trihydroxy-18:1 long chain base phosphate
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DOI：
10.1074/jbc.m705074200
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发表时间：
2007-09-21
影响因子：
4.8
通讯作者：
Dunn, Teresa M.
中科院分区：
文献类型：
--
作者：
Tsegaye, Yoseph;Richardson, Christopher G.;Dunn, Teresa M.
鞘氨醇长链碱基（LCB）及其磷酸化衍生物（LCB-P）是真核生物中重要的信号分子。 LCB-P 的细胞水平受到负责其合成的 LCB 激酶活性和负责其分解代谢的 LCB-P 磷酸酶和裂合酶活性的协调作用的严格控制。尽管最近的研究表明 LCB-P 作为植物中的调节分子，但与酵母和哺乳动物相比，人们对其在植物中的代谢和功能知之甚少。为了研究 LCB-P 在植物中的功能，我们对编码 LCB-P 代谢酶的拟南芥基因进行了鉴定和表征。在这项研究中，拟南芥 At1g27980 基因被证明编码拟南芥中唯一可检测到的 LCB-P 裂合酶活性。对 LCB-P 裂合酶活性进行了表征，并生成并分析了缺乏裂合酶的突变植物系。虽然在其他生物体中，LCB-P裂解酶活性的丧失与高水平LCB/LCB-P的积累和发育异常有关，但突变植物的鞘脂谱与野生型植物的鞘脂谱非常相似，并且没有观察到发育异常。因此，这些研究表明裂合酶在正常植物发育和生长期间维持鞘脂代谢中发挥次要作用。然而，在神经酰胺合酶抑制剂伏马菌素 B-1 处理扰动鞘脂合成时，揭示了裂合酶的明确作用。
The sphingoid long chain bases (LCBs) and their phosphorylated derivatives (LCB-Ps) are important signaling molecules in eukaryotic organisms. The cellular levels of LCB-Ps are tightly controlled by the coordinated action of the LCB kinase activity responsible for their synthesis and the LCB-P phosphatase and lyase activities responsible for their catabolism. Although recent studies have implicated LCB-Ps as regulatory molecules in plants, in comparison with yeast and mammals, much less is known about their metabolism and function in plants. To investigate the functions of LCB-Ps in plants, we have undertaken the identification and characterization of Arabidopsis genes that encode the enzymes of LCB-P metabolism. In this study the Arabidopsis At1g27980 gene was shown to encode the only detectable LCB-P lyase activity in Arabidopsis. The LCB-P lyase activity was characterized, and mutant plant lines lacking the lyase were generated and analyzed. Whereas in other organisms loss of LCB-P lyase activity is associated with accumulation of high levels of LCB/LCB-Ps and developmental abnormalities, the sphingolipid profiles of the mutant plants were remarkably similar to those of wild-type plants, and no developmental abnormalities were observed. Thus, these studies indicate that the lyase plays a minor role in maintenance of sphingolipid metabolism during normal plant development and growth. However, a clear role for the lyase was revealed upon perturbation of sphingolipid synthesis by treatment with the inhibitor of ceramide synthase, fumonisin B-1.