Kruse C, Willkomm D K, Grünweller A, Vollbrandt T, Sommer S, Busch S, Pfeiffer T, Brinkmann J, Hartmann R K, Müller P K
Department of Medical Molecular Biology, Medical University of Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany.
Biochem J. 2000 Feb 15;346 Pt 1(Pt 1):107-15.
Vigilin is a ubiquitous multi heterogeneous nuclear ribonucleoprotein (hnRNP) K homologous (KH)-domain protein. Here we demonstrate that purified recombinant human vigilin binds tRNA molecules with high affinity, although with limited specificity. Nuclear microinjection experiments revealed for the first time that the immuno-affinity-purified nuclear vigilin core complex (VCC(N)) as well as recombinant vigilin accelerate tRNA export from the nucleus in human cells. The nuclear tRNA receptor exportin-t is part of the VCC(N). Elongation factor (EF)-1alpha is enriched in VCC(N) and its cytoplasmic counterpart VCC(C), whereas EF-1beta, EF-1gamma and EF-1delta are basically confined to the VCC(C). Our results suggest further that vigilin and exportin-t might interact during tRNA export, provide evidence that the channeled tRNA cycle is already initiated in the nucleus, and illustrate that intracellular tRNA trafficking is associated with discrete changes in the composition of cellular cytoplasmic multi-protein complexes containing tRNA.
vigilin是一种普遍存在的多异质核核糖核蛋白（hnRNP）K同源（KH）结构域蛋白。在此我们证明，纯化的重组人vigilin以高亲和力结合tRNA分子，尽管特异性有限。核显微注射实验首次揭示，免疫亲和纯化的核vigilin核心复合物（VCC(N)）以及重组vigilin可加速人细胞中tRNA从细胞核的输出。核tRNA受体exportin-t是VCC(N)的一部分。延伸因子（EF）-1α在VCC(N)及其细胞质对应物VCC(C)中富集，而EF-1β、EF-1γ和EF-1δ基本局限于VCC(C)。我们的结果进一步表明，vigilin和exportin-t可能在tRNA输出过程中相互作用，提供了通道化tRNA循环已在细胞核中启动的证据，并表明细胞内tRNA运输与含有tRNA的细胞质多蛋白复合物组成的离散变化有关。
