Protein-protein interaction among hnRNPs shuttling between nucleus and cytoplasm

Jong Heon Kim, Bumsuk Hahm, Yoon Ki Kim, Mieyoung Choi, Sung Key Jang

Research output: Contribution to journalArticlepeer-review

172 Citations (Scopus)


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 α-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 A1, 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.

Original languageEnglish
Pages (from-to)395-405
Number of pages11
JournalJournal of Molecular Biology
Issue number3
Publication statusPublished - 2000 May 5
Externally publishedYes


  • In vitro co-precipitation
  • Protein-protein interaction
  • RNA-related processes
  • Shuttling hnRNPs
  • Yeast two-hybrid

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Molecular Biology


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