Protein-protein interaction among hnRNPs shuttling between nucleus and cytoplasm
Protein-protein interaction among hnRNPs shuttling between nucleus and cytoplasm
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DOI：
10.1006/jmbi.2000.3687
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发表时间：
2000-05-05
影响因子：
5.6
通讯作者：
Jang, SK
中科院分区：
文献类型：
--
作者：
Kim, JH;Hahm, B;Jang, SK
异质性核糖核蛋白(HnRNPs)参与了多种与RNA相关的生物学过程，如转录、前mRNA加工、成熟的mRNA转运到细胞质和翻译等。从A1到U，大约有20个主要hnRNP已知。其中，hnRNP A、D、E、I和K在细胞核和细胞质之间穿梭。HnRNP E2已被认为可以稳定α-珠蛋白mRNA，并增强脊髓灰质炎病毒mRNA的翻译。HnRNP K调节某些mRNAs的转录和翻译。HnRNP I及其同系物hnRNP L被建议加强一些依赖IRES的mRNAs的翻译。为了更好地了解hnRNPs生物学功能的分子机制，我们利用酵母双杂交系统和体外共沉淀实验研究了6个hnRNPs(hnRNP A1、C1、E2、I、K和L)的蛋白质-蛋白质相互作用。所有测试的hnRNP都表现出同源互作，hnRNP E2、I、K和L之间存在相互作用。对于hnRNP E2和hnRNP K，含有两个KH(K同源)结构域的蛋白质的N末端一半是蛋白质相互作用所必需的，而含有RRM2(RNA识别基序2)的hnRNP I和hnRNP L的第二个四分之一是蛋白质相互作用所必需的。在我们的检测系统中，hnRNP A1和C1没有与其他hnRNPs形成复合体。这表明hnRNP可能分为两类：一类参与hnRNP核心复合体的形成，包括hnRNP A1和C1；另一类包括hnRNP E2、I、K和L，参与各种与RNA相关的生物学过程。第二类蛋白质的不同组合可能与其他因素一起促进不同的生物过程。(C)2000年学术出版社。
Heterogeneous nuclear ribonucleoproteins (hnRNPs) are involved in several RNA-related biological processes such as transcription, pre-mRNA processing, mature mRNA transport to the cytoplasm, and translation. About 20 major hnRNPs from A1 to U are known. Among them, hnRNP A, D, E, I, and K are known to shuttle between the nucleus and the cytoplasm. hnRNP E2 has been seen to stabilize alpha-globin mRNA and to enhance polioviral mRNA translation. hnRNP K modulates transcription and translation of some mRNAs. hnRNP I and its homologue hnRNP L have been suggested to enhance translation of some IRES-dependent mRNAs. In order to better understand the molecular mechanisms of the biological functions of hnRNPs, we investigated protein-protein interactions of six hnRNPs (hnRNP Al, C1, E2, I, K, and L) using the yeast two-hybrid system and in vitro co-precipitation assays. All of the hnRNPs tested exerted homomeric interactions, and hnRNP E2, I, K, and L interacted with each other. In the case of hnRNP E2 and hnRNP K, the N-terminal half of the proteins containing two KH (K homologous) domains were required for protein-protein interaction, and the second quarter of hnRNP I and hnRNP L containing RRM2 (RNA recognition motif 2) was essential for protein-protein interaction. hnRNP A1 and C1 did not form complexes with other hnRNPs in our assay systems. This suggests that the hnRNPs could fall into two groups: one group, including hnRNP A1 and C1, involved in hnRNP core complex formation and another group, including hnRNP E2, I, K, and L, involved in a variety of RNA-related biological processes. Different combinations of the proteins of the second group may facilitate different biological processes in conjunction with other factors. (C) 2000 Academic Press.