Human fucosyltransferase IX:: Specificity towards N-linked glycoproteins and relevance of the cytoplasmic domain in intra-Golgi localization
Human fucosyltransferase IX:: Specificity towards N-linked glycoproteins and relevance of the cytoplasmic domain in intra-Golgi localization
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DOI：
10.1016/j.biochi.2008.03.002
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发表时间：
2008-09-01
期刊：
影响因子：
3.9
通讯作者：
Costa, J.
中科院分区：
文献类型：
--
作者：
Brito, C.;Kandzia, S.;Costa, J.
α 3-岩藻糖基转移酶IX（FUT 9）催化α 3键中的岩藻糖转移到末端II型（Gal β 4GlcNAc）受体上，这是神经元中刘易斯（x）（Le（x））表位生物合成的最后一步。在这项工作中，发现从NT 2N神经元克隆并在HeLa细胞中过表达的FUT 9（FUT 9 wt）有效地岩藻糖基化脱唾液酸红细胞生成素（脱唾液酸EPO）和牛脱唾液酸胎球蛋白，但不唾液酸化EPO。通过HPAEC-PAD和MALDI/TOF-MS进行的分析显示，具有近端岩藻糖的II型二-、三-和四-前体N-聚糖的FUT 9 wt主要单岩藻糖基化，具有和不具有来自脱唾液酸EPO的N-乙酰乳糖胺重复。结果表明，FUT 9可使神经元中的Le（x）载体糖蛋白发生岩藻糖基化。此外，发现FUT 9 wt被Mn 2+活化，并且它能够合成Le（a），尽管程度低于Le（x）和Le（y）。在体内，用FUT 9 wt转染的HeLa细胞重新表达Le（x），如通过免疫荧光显微镜检测的。FUT 9被发现是一个trans-Golgi和trans-Golgi网络（TGN）糖基转移酶，来自共聚焦免疫荧光共定位与分泌途径M-半乳糖基转移酶（trans-Golgi和TGN）和TGN-46（TGN）的标志物。删除的胞质结构域引起的移位的顺式高尔基体，从而表明，信息内高尔基体定位包含在胞质结构域。(C)2008年，Elsevier Masson SAS。All rights reserved.
The alpha 3-fucosyltransferase IX (FUT9) catalyses the transfer of fucose in an alpha 3 linkage onto terminal type II (Gal beta 4GlcNAc) acceptors, the final step in the biosynthesis of the Lewis(x) (Le(x)) epitope, in neurons. In this work, FUT9 cloned from NT2N neurons and overexpressed in HeLa cells (FUT9wt), was found to efficiently fucosylate asialoerythropoietin (asialoEPO), and bovine asialofetuin, but not sialylated EPO. Analysis by HPAEC-PAD and MALDI/TOF-MS revealed predominantly mono-fucosylation by FUT9wt of type II di-, tri- and tetraantermary N-glycans with proximal fucose, with and without N-acetylactosamine repeats from asialoEPO. Minor amounts of difucosylated structures were also found. The results suggested that FUT9 could fucosylate Le(x) carrier-glycoproteins in neurons. Furthermore, FUT9wt was found to be activated by Mn2+ and it was capable of synthesizing Le(a), although to a lesser extent than Le(x) and Le(y). In vivo, HeLa cells transfected with FUT9wt expressed de novo Le(x), as detected by immunofluorescence microscopy. FUT9 was found to be a trans-Golgi and trans-Golgi network (TGN) glycosyltransferase from confocal immunofluorescence co-localization with the markers of the secretory pathway M-galactosyltransferase (trans-Golgi and TGN) and TGN-46 (TGN). Deletion of the cytoplasmic domain caused a shift to the cis-Golgi, thus suggesting that information for intra-Golgi localization is contained within the cytoplasmic domain. (C) 2008 Elsevier Masson SAS. All rights reserved.