A functional bipartite nuclear localisation signal in the cytokine interleukin-5

David A. Jans, Lyndall J. Briggs, Sonja E. Gustin, Patricia Jans, Sally Ford, Ian G. Young

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Interleukin (IL)-5 is central in regulating eosinophilia in allergic disease and parasitic infections. We have identified a bipartite nuclear localisation signal (NLS) within amino acids 95-111 of human IL-5 (hIL-5), also present in mouse IL-5 (mIL-5). hIL-5 and mIL-5 were labelled fluorescently, and nuclear uptake subsequent to membrane binding and internalisation by intact receptor expressing cells visualised and quantified using confocal laser scanning microscopy. hIL-5 and mIL-5 were shown to be transported to the nucleus in in vivo and in vitro nuclear protein import assays. The hIL-5 NLS was able to target a heterologous protein to the nucleus both in vivo and in vitro. Mutations within the proximal arm of the NLS abrogated nuclear targeting activity, confirming its bipartite nature. The results imply a nuclear signalling role for IL-5 additional to pathways linked to the membrane receptor system.

Original languageEnglish
Pages (from-to)315-320
Number of pages6
JournalFEBS Letters
Issue number3
Publication statusPublished - 14 Apr 1997
Externally publishedYes


  • Confocal laser scanning microscopy
  • Cytokine receptor
  • Interleukin-5
  • Microinjection
  • Nuclear protein import

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