Exportin 4:: a mediator of a novel nuclear export pathway in higher eukaryotes
Exportin 4:: a mediator of a novel nuclear export pathway in higher eukaryotes
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DOI：
10.1093/emboj/19.16.4362
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发表时间：
2000-08-15
期刊：
影响因子：
11.4
通讯作者：
Görlich, D
中科院分区：
文献类型：
--
作者：
Lipowsky, G;Bischoff, FR;Görlich, D
转运蛋白β超家族的转运受体负责真核细胞中的许多核输入和输出事件。它们通过核孔复合物介导易位，在细胞核和细胞质之间穿梭，并与RanGT系统合作以隔室特异性方式调节它们与货物分子的相互作用。我们使用亲和层析固定RanGTP分离进一步的候选核转运受体，从而确定exportin 4作为最远的成员importin β家族迄今为止。Exportin 4似乎在高等真核生物中是保守的，但在酵母中缺乏明显的直系同源物。它介导eIF-5A（真核翻译起始因子5A）的核输出，并可能介导其他货物的核输出。eIF-5A中的输出信号似乎是复杂的，并且涉及eIF-5A特有的羟腐胺赖氨酸修饰。我们讨论了eIF-5A的核输出可能的细胞作用。
Transport receptors of the importin beta superfamily account for many of the nuclear import and export events in eukaryotic cells. They mediate translocation through nuclear pore complexes, shuttle between nucleus and cytoplasm and co-operate with the RanGTPase system to regulate their interactions with cargo molecules in a compartment-specific manner. We used affinity chromatography on immobilized RanGTP to isolate further candidate nuclear transport receptors and thereby identified exportin 4 as the most distant member of the importin beta family so far. Exportin 4 appears to be conserved amongst higher eukaryotes, but lacks obvious orthologues in yeast. It mediates nuclear export of eIF-5A (eukaryotic translation initiation factor 5A) and possibly that of other cargoes. The export signal in eIF-5A appears to be complex and to involve the hypusine modification that is unique to eIF-5A. We discuss possible cellular roles for nuclear export of eIF-5A.