The nucleoporin nup153 plays a critical role in multiple types of nuclear export.
The nucleoporin nup153 plays a critical role in multiple types of nuclear export.
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核孔蛋白 nup153 在多种类型的核输出中发挥着关键作用。
DOI：
10.1091/mbc.10.3.649
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发表时间：
1999
影响因子：
3.3
通讯作者：
Forbes,DJ
中科院分区：
文献类型：
--
作者：
Ullman,KS;Shah,S;Powers,MA;Forbes,DJ
核质运输的基本过程是通过核孔进行的。外周孔结构大概准备与运输受体和它们的货物相互作用，因为这些受体复合物首先遇到孔。在核输出中可能起重要作用的一种这样的外围结构是位于孔的核侧的篮状结构。目前，Nup 153是唯一已知定位于该篮表面的核孔蛋白，这表明Nup 153可能是RNA或蛋白质在输出过程中遇到的第一个孔组分之一。本研究采用Nup 153抗体研究Nup 153在异种卵母细胞核输出中的作用。我们发现Nup 153抗体阻断三种主要的RNA输出，即snRNA、mRNA和5S rRNA。Nup 153抗体还阻断内斯蛋白输出途径，特别是HIV Rev蛋白的输出，以及Rev依赖性RNA输出。并非所有的输出都被阻断; Nup 153抗体并不阻碍tRNA的输出或importin β向细胞质的再循环。此处使用的特异性抗体也不影响核输入，无论是由输入蛋白α/β还是由转运蛋白介导。总的来说，结果表明Nup 153对多种RNA和蛋白质的输出至关重要，参与了其输出途径的重要转折点。这个连接点似乎是tRNA在其输出过程中绕过的连接点。我们询问是否可以观察到RNA和Nup 153之间的物理相互作用，使用同源物作为相互作用的序列独立探针。Nup 153与包括Nup 98在内的其他四种核孔蛋白不同，与poly（G）强烈相关，与poly（U）显著相关。因此，Nup 153在测试的核孔蛋白中与RNA相互作用的能力是独特的，并且必须通过接头蛋白直接或间接地这样做。这些结果表明Nup 153在多种货物的出口中具有独特的机械作用。
The fundamental process of nucleocytoplasmic transport takes place through the nuclear pore. Peripheral pore structures are presumably poised to interact with transport receptors and their cargo as these receptor complexes first encounter the pore. One such peripheral structure likely to play an important role in nuclear export is the basket structure located on the nuclear side of the pore. At present, Nup153 is the only nucleoporin known to localize to the surface of this basket, suggesting that Nup153 is potentially one of the first pore components an RNA or protein encounters during export. In this study, anti-Nup153 antibodies were used to probe the role of Nup153 in nuclear export inXenopusoocytes. We found that Nup153 antibodies block three major classes of RNA export, that of snRNA, mRNA, and 5S rRNA. Nup153 antibodies also block the NES protein export pathway, specifically the export of the HIV Rev protein, as well as Rev-dependent RNA export. Not all export was blocked; Nup153 antibodies did not impede the export of tRNA or the recycling of importin β to the cytoplasm. The specific antibodies used here also did not affect nuclear import, whether mediated by importin α/β or by transportin. Overall, the results indicate that Nup153 is crucial to multiple classes of RNA and protein export, being involved at a vital juncture point in their export pathways. This juncture point appears to be one that is bypassed by tRNA during its export. We asked whether a physical interaction between RNA and Nup153 could be observed, using homoribopolymers as sequence-independent probes for interaction. Nup153, unlike four other nucleoporins including Nup98, associated strongly with poly(G) and significantly with poly(U). Thus, Nup153 is unique among the nucleoporins tested in its ability to interact with RNA and must do so either directly or indirectly through an adaptor protein. These results suggest a unique mechanistic role for Nup153 in the export of multiple cargos.