Identification of importin α 7 specific transport cargoes using a proteomic screening approach

Stefanie Hugel, Reinhard Depping, Gunnar Dittmar, Franziska Rother, Ryan Cabot, Matthias D. Sury, Enno Hartmann, Michael Bader*

*Corresponding author for this work

Research output: Contribution to journalArticleResearchpeer-review

18 Citations (Scopus)


The importin α: complex is responsible for the nuclear import of proteins bearing classical nuclear localization signals. In mammals, several importin α subtypes are known to exist that are suggested to have individual functions. Importin α 7 was shown to play a crucial role in early embryonic development in mice. Embryos from importin α 7-depleted females stop at the two-cell stage and show disturbed zygotic genome activation. As there is evidence that individual importin α subtypes possess cargo specificities, we hypothesized that importin α 7 binds a unique set of intracellular proteins. With the use of a collection of in vitro and in vivo binding assays, importin α 7 interaction partners were identified that differed from proteins found to bind to importin α 2 and 3. One of the proteins preferentially binding importin α 7 was the maternal effect protein Brg1. However, Brg1 was localized in oocyte nuclei in importin α 7-deficient embryos, albeit in reduced amounts, suggesting additional modes of nuclear translocation of this factor. An additional SILAC-based screening approach identified Ash2l, Chd3, Mcm3, and Smarcc1, whose nuclear import seems to be disturbed in importin α 7-deficient fibroblasts.

Original languageEnglish
Pages (from-to)1286-1298
Number of pages13
JournalMolecular and Cellular Proteomics
Issue number5
Publication statusPublished - May 2014
Externally publishedYes


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