Nuclear localization signal and protein context both mediate importin α specificity of nuclear import substrates

Beate Friedrich, Christina Quensel, Thomas Sommer, Enno Hartmann, Matthias Köhler*

*Corresponding author for this work
50 Citations (Scopus)

Abstract

The "classical" nuclear protein import pathway depends on importin α and importin β. Importin α binds nuclear localization signal (NLS)-bearing proteins and functions as an adapter to access the importin β-dependent import pathway. In humans, only one importin β is known to interact with importie α, while six α importins have been described. Various experimental approaches provided evidence that several substrates are transported specifically by particular α importins. Whether the NLS is sufficient to mediate importin α specificity is unclear. To address this question, we exchanged the NLSs of two well-characterized import substrates, the seven-bladed propeller protein RCC1, preferentially transported into the nucleus by importin α3, and the less specifically imported substrate nucleoplasmin. In vitro binding studies and nuclear import assays revealed that both NLS and protein context contribute to the specificity of importin α binding and transport.

Original languageEnglish
JournalMolecular and Cellular Biology
Volume26
Issue number23
Pages (from-to)8697-8709
Number of pages13
ISSN0270-7306
DOIs
Publication statusPublished - 01.12.2006

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