Display Settings:

Format

Send to:

Choose Destination
We are sorry, but NCBI web applications do not support your browser and may not function properly. More information
J Biol Chem. 2003 Jul 25;278(30):28193-200. Epub 2003 May 9.

Importin alpha nuclear localization signal binding sites for STAT1, STAT2, and influenza A virus nucleoprotein.

Author information

  • 1Laboratory of Infectious Disease Immunology, Department of Microbiology, National Public Health Institute, FIN-00300 Helsinki, Finland. krister.melen@ktl.fi

Abstract

Proteins actively transported into the nucleus via the classical nuclear import pathway contain nuclear localization signals (NLSs), which are recognized by the family of importin alpha molecules. Importin alpha contains 10 armadillo (arm) repeats, of which the N-terminal arm repeats 2-4 have been considered as the "major" NLS binding site. Interferon-activated, dimerized signal transducers and activators of transcription (STAT1 and STAT2) directly bind to importin alpha5 via a dimeric nonclassical NLS. Here we show by site-directed mutagenesis that the very C-terminal arm repeats 8 and 9 of importin alpha5 form a unique binding site for STAT1 homodimers and STAT1-STAT2 heterodimers. Influenza A virus nucleoprotein also contains a nonclassical NLS that is recognized by the C-terminal NLS binding site of importin alpha5, comprising arm repeats 7-9. Binding of influenza A virus nucleoprotein to importin alpha3 also occurs via the C-terminal arm repeats. Simian virus 40 large T antigen instead binds to the major N-terminal arm repeats of importin alpha3, indicating that one importin alpha molecule is able to use either its N- or C-terminal arm repeats for binding various NLS containing proteins.

PMID:
12740372
[PubMed - indexed for MEDLINE]
Free full text
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire
    Loading ...
    Write to the Help Desk