Kruse C, Willkomm D, Gebken J, Schuh A, Stossberg H, Vollbrandt T, Müller P K
Department of Medical Molecular Biology of the Medical University of Lübeck, Ratzeburger Allee 160, 23535 Lübeck, Germany.
Cell Mol Life Sci. 2003 Oct;60(10):2219-27. doi: 10.1007/s00018-003-3235-0.
The-multi-KH domain protein vigilin has been identified by ex vivo experiments as both a tRNA- and/or mRNA-binding protein. We show here that in vitro under conditions previously shown to allow tRNA binding, recombinant vigilin also binds to selected mRNA species and ribosomal RNA. An in vivo link of vigilin to mRNA and rRNA was elucidated by several approaches. (i) Coexpression/costimulation of vigilin was found with many other proteins independently of whether their mRNA was translated on free or membrane-bound ribosomes. (ii) A close codistribution of vigilin with free ribosomes was seen in the cytoplasm while nucleoli were a major organelle of vigilin accumulation in the nucleus. (iii) Furthermore, free and membrane-bound ribosomes can be enriched for vigilin which suggests that this binding does not depend on the class of mRNA translated. Therefore, we suggest that vigilin does not distinguish between free or membrane-bound ribosomes but is generally necessary for the localization of mRNAs to actively translating ribosomes.
多KH结构域蛋白vigilin已通过体外实验被鉴定为一种tRNA和/或mRNA结合蛋白。我们在此表明,在先前已证明允许tRNA结合的条件下进行体外实验时,重组vigilin也能与选定的mRNA种类和核糖体RNA结合。通过几种方法阐明了vigilin在体内与mRNA和rRNA的联系。(i)发现vigilin与许多其他蛋白质共表达/共刺激,无论它们的mRNA是在游离核糖体还是膜结合核糖体上翻译。(ii)在细胞质中观察到vigilin与游离核糖体紧密共分布,而核仁是vigilin在细胞核中积累的主要细胞器。(iii)此外,游离核糖体和膜结合核糖体都可以富集vigilin,这表明这种结合不依赖于所翻译的mRNA类别。因此,我们认为vigilin不会区分游离核糖体或膜结合核糖体,而是mRNA定位到活跃翻译核糖体的普遍必需条件。