Cloning of two novel human importin alpha subunits and analysis of the expression pattern of the importin-alpha protein family


  • M. Koehler
  • S. Ansieau
  • S. Prehn
  • A. Leutz
  • H. Haller
  • E. Hartmann


  • FEBS Letters


  • FEBS Lett 417 (1): 104-108


  • The import of many proteins into the nucleus is mediated by the importin-alpha/beta heterodimer. While only one importin-beta gene has been found, several forms of importin-alpha have been described. In addition to the three human importin-alphas already identified, we report here the primary structure of two new human importin-alpha proteins. The five known human importin-alpha subunits can be classified into three subfamilies that appear conserved in higher eukaryotic organisms. We show by immunoblotting that the different importin-alpha subfamilies are expressed in a variety of human tissues and mammalian cell lines.