Phosphatidylethanolamine and phosphatidylcholine biosynthesis by the Kennedy pathway occurs at different sites in Trypanosoma brucei.
Phosphatidylethanolamine and phosphatidylcholine biosynthesis by the Kennedy pathway occurs at different sites in Trypanosoma brucei.
复制标题
DOI：
10.1038/srep16787
复制
发表时间：
2015-11-18
影响因子：
4.6
通讯作者：
Bütikofer P
中科院分区：
文献类型：
--
作者：
Farine L;Niemann M;Schneider A;Bütikofer P
磷脂酰乙醇胺（PE）和磷脂酰胆碱（PC）是生物膜中最丰富的磷脂。在许多真核生物中，肯尼迪途径的CDP-乙醇胺和CDP-胆碱分支代表了生产PE和PC的主要且通常是必需的途径，其中乙醇胺和胆碱/乙醇胺磷酸转移酶（分别为EPT和CEPT）催化各自途径中的最后反应。虽然PE和PC合成的位点通常被认为是内质网（ER），但缺乏关于不同磷酸转移酶定位的详细信息。在单细胞寄生虫布氏锥虫中，肯尼迪途径的两个分支对于培养中的细胞生长至关重要。我们以前报道过T.布氏杆菌EPT（TbEPT）催化醚型PE分子物种的产生，而T.布氏菌CEPT（TbCEPT）合成二酰基型PE和PC分子种类。我们现在表明，这两种酶定位于ER的不同亚室。通过在T.结合亚细胞分级和酶活性测量，发现TbEPT仅存在于核周ER中，这是一个位于核膜附近但与核膜不同的独特区域。相反，在本体ER中检测到TbCEPT。
Phosphatidylethanolamine (PE) and phosphatidylcholine (PC) are among the most abundant phospholipids in biological membranes. In many eukaryotes, the CDP-ethanolamine and CDP-choline branches of the Kennedy pathway represent major and often essential routes for the production of PE and PC, with ethanolamine and choline/ethanolamine phosphotransferases (EPT and CEPT, respectively) catalysing the last reactions in the respective pathways. Although the site of PE and PC synthesis is commonly known to be the endoplasmic reticulum (ER), detailed information on the localization of the different phosphotransferases is lacking. In the unicellular parasite, Trypanosoma brucei, both branches of the Kennedy pathway are essential for cell growth in culture. We have previously reported that T. brucei EPT (TbEPT) catalyses the production of ether-type PE molecular species while T. brucei CEPT (TbCEPT) synthesizes diacyl-type PE and PC molecular species. We now show that the two enzymes localize to different sub-compartments of the ER. By expressing a series of tagged forms of the two enzymes in T. brucei parasites, in combination with sub-cellular fractionation and enzyme activity measurements, TbEPT was found exclusively in the perinuclear ER, a distinct area located close to but distinct from the nuclear membrane. In contrast, TbCEPT was detected in the bulk ER.