Nup84, a novel nucleoporin that is associated with CAN/Nup214 on the cytoplasmic face of the nuclear pore complex.
Nup84, a novel nucleoporin that is associated with CAN/Nup214 on the cytoplasmic face of the nuclear pore complex.
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DOI：
10.1083/jcb.137.5.989
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发表时间：
1997-06-02
影响因子：
7.8
通讯作者：
Burke, B
中科院分区：
文献类型：
--
作者：
Bastos, R;dePouplana, LR;Burke, B
从核孔复合物的细胞质面延伸的短纤维被认为含有核输入底物的对接位点。这些细丝的一个组成部分是大的O-连接糖蛋白CAN/Nup 214。在非变性条件下进行的免疫沉淀研究，并使用各种抗体，揭示了一种新的nonglycosylated核孔蛋白，Nup 84，这是紧密相关的CAN/Nup 214。与这种关联一致，发现Nup 84暴露在核孔复合物的细胞质表面上。cDNA序列分析表明，Nup 84既不包含GLGG也不包含XFXFG重复，这是许多其他核孔复合物蛋白的特征。然而，二级结构的预测表明，Nup 84包含一个卷曲螺旋COOH末端结构域，这一结论得到了该分子区域与原肌球蛋白家族的各种成员之间的显着序列相似性的观察的支持。突变和表达的研究表明，推定的卷曲螺旋结构域是需要与核孔复合物的细胞质面的协会，而它是Nup 84的NH 2-末端区域，包含与CAN/Nup 214的相互作用的网站。这些结果表明，Nup 84可能在CAN/Nup 214与核孔复合物的中心框架的连接中起作用，以这种方式，Nup 84可能在孔复合物与细胞质之间的界面的组织中起中心作用。
The short filaments extending from the cytoplasmic face of nuclear pore complexes are thought to contain docking sites for nuclear import substrates. One component of these filaments is the large O-linked glycoprotein CAN/Nup214. Immunoprecipitation studies carried out under nondenaturing conditions, and using a variety of antibodies, reveal a novel nonglycosylated nucleoporin, Nup84, that is tightly associated with CAN/Nup214. Consistent with such an association, Nup84 is found to be exposed on the cytoplasmic face of the nuclear pore complex. cDNA sequence analyses indicate that Nup84 contains neither the GLFG nor the XFXFG repeats that are a characteristic of a number of other nuclear pore complex proteins. Secondary structure predictions, however, suggest that Nup84 contains a coiled-coil COOH-terminal domain, a conclusion supported by the observation of significant sequence similarity between this region of the molecule and various members of the tropomyosin family. Mutagenesis and expression studies indicate that the putative coiled-coil domain is required for association with the cytoplasmic face of the nuclear pore complex, whereas it is the NH2-terminal region of Nup84 that contains the site of interaction with CAN/Nup214. These findings suggest a model in which Nup84 may function in the attachment of CAN/Nup214 to the central framework of the nuclear pore complex, In this way, Nup84 could play a central role in the organization of the interface between the pore complex and the cytoplasm.