Regulation of nuclear localization signal-importin α interaction by Ca2+/S100A6

FEBS Lett. 2010 Nov 19;584(22):4517-23. doi: 10.1016/j.febslet.2010.09.052. Epub 2010 Oct 21.


Although the precise intracellular roles of S100 proteins are not fully understood, these proteins are thought to be involved in Ca(2+)-dependent diverse signal transduction pathways. In this report, we identified importin α as a novel target of S100A6. Importin α contains armadillo repeats, essential for binding to nuclear localization signals. Based on the results from GST pull-down assay, gel-shift assay, and co-immunoprecipitation, we demonstrated that S100A6 specifically interacts with the armadillo repeats of importin α in a Ca(2+)-dependent manner, resulting in inhibition of the nuclear localization signal (NLS)-importin α complex formation in vitro and in vivo. These results indicate S100A6 may regulate the nuclear transport of NLS-cargos in response to increasing concentrations of intracellular Ca(2+).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Binding Sites
  • COS Cells
  • Calcium / metabolism*
  • Chlorocebus aethiops
  • Humans
  • Molecular Sequence Data
  • Mutation
  • Nuclear Localization Signals / chemistry
  • Nuclear Localization Signals / metabolism*
  • Protein Binding
  • Protein Structure, Tertiary
  • S100 Proteins / metabolism*
  • Simian virus 40
  • alpha Karyopherins / chemistry
  • alpha Karyopherins / genetics
  • alpha Karyopherins / metabolism*
  • beta Karyopherins / metabolism


  • Nuclear Localization Signals
  • S100 Proteins
  • alpha Karyopherins
  • beta Karyopherins
  • Calcium