The GLFG repetitive region of the nucleoporin Nup116p interacts with Kap95p, an essential yeast nuclear import factor.
The GLFG repetitive region of the nucleoporin Nup116p interacts with Kap95p, an essential yeast nuclear import factor.
复制标题
核孔NUP116P的GLFG重复区域与KAP95P相互作用，KAP95P是必不可少的酵母核进口因子。
DOI：
10.1083/jcb.131.6.1699
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发表时间：
1995-12
影响因子：
7.8
通讯作者：
Wente, S R
中科院分区：
文献类型：
--
作者：
Iovine, M K;Watkins, J L;Wente, S R
Nup116p是酵母核孔复合体(NPC)蛋白家族中的一员，它们共享重复的四肽GLFG基序的氨基末端区域。以前的实验表征了nup116零突变体中发生的独特的形态扰动：对温度敏感的核膜封口覆盖在鼻咽癌细胞质表面(Wente，S.R.和G.Blobel)。1993年。J.细胞生物学。123：275-284)。从三个方面剖析了Nup116P在NPC功能中作用的结构基础。首先，对NUP116进行了缺失突变分析，发现该区域是鼻咽癌功能所必需的。对于其他四个酵母GLFG家族成员(Nup49p、Nup57p、Nup100p和Nup145p)则不是这样。此外，删除Nup116p的GLFG重复序列的一半或用Nup100p的GLFG区域或Nsp1p的FXFG重复区域替换Nup116p的GLFG区域将取消Nup116p的功能。在半允许生长温度下，缺乏Nup116P的GLFG区域的细胞对核进口的能力减弱。其次，Nup116p的GLFG区的过表达严重抑制了细胞的生长，迅速阻止了多腺苷化RNA的输出，并使核仁碎裂。虽然它抑制了核输出，但在薄片电子显微镜下，过表达的GLFG区域主要分布在细胞质中，NPC/核被膜结构没有受到干扰。最后，通过生化和双杂交分析，鉴定了Nup116p的GLFG区与Kap95p之间的相互作用，Kap95p是脊椎动物核输入因子p97/Imp90/Karopherin beta的重要酵母同源物。这些数据表明，Nup116P的GLFG区域在调节核运输方面具有重要作用。
Nup116p is a member of a family of five yeast nuclear pore complex (NPC) proteins that share an amino terminal region of repetitive tetrapeptide "GLFG" motifs. Previous experiments characterized the unique morphological perturbations that occur in a nup116 null mutant: temperature-sensitive formation of nuclear envelope seals over the cytoplasmic face of the NPC (Wente, S. R., and G. Blobel. 1993. J. Cell Biol. 123:275-284). Three approaches have been taken to dissect the structural basis for Nup116p's role in NPC function. First, deletion mutagenesis analysis of NUP116 revealed that the GLFG region was required for NPC function. This was not true for the other four yeast GLFG family members (Nup49p, Nup57p, Nup100p, and Nup145p). Moreover, deletion of either half of Nup116p's GLFG repeats or replacement of Nup116p's GLFG region with either Nup100p's GLFG region or Nsp1p's FXFG repetitive region abolishes the function of Nup116p. At a semipermissive growth temperature, the cells lacking Nup116p's GLFG region displayed a diminished capacity for nuclear import. Second, overexpression of Nup116p's GLFG region severely inhibited cell growth, rapidly blocked polyadenylated-RNA export, and fragmented the nucleolus. Although it inhibited nuclear export, the overexpressed GLFG region appeared predominantly localized in the cytoplasm and NPC/nuclear envelope structure was not perturbed in thin section electron micrographs. Finally, using biochemical and two-hybrid analysis, an interaction was characterized between Nup116p's GLFG region and Kap95p, an essential yeast homologue of the vertebrate nuclear import factor p97/Imp90/karopherin beta. These data show that Nup116p's GLFG region has an essential role in mediating nuclear transport.