eEF1A mediates the nuclear export of SNAG-containing proteins via the Exportin5-aminoacyl-tRNA complex.

Exportin5 mediates the nuclear export of double-stranded RNAs, including pre-microRNAs, adenoviral RNAs, and tRNAs. When tRNAs are aminoacylated, the Exportin5-aminoacyl (aa)-tRNA complex recruits and coexports the translation elongation factor eEF1A. Here, we show that eEF1A binds to Snail transcription factors when bound to their main target, the E-cadherin promoter, facilitating their export to the cytoplasm in association with the aa-tRNA-Exportin5 complex.

c-Jun localizes to the nucleus independent of its phosphorylation by and interaction with JNK and vice versa promotes nuclear accumulation of JNK.

In order to activate gene expression, transcription factors such as c-Jun have to reside in the nucleus. The abundance of c-Jun in the nucleus correlates with the activity of its target genes. As a consequence of excessive c-Jun activation, cells undergo apoptosis or changes in differentiation whereas decreased c-Jun function can reduce proliferation.

Transport of hypoxia-inducible factor HIF-1alpha into the nucleus involves importins 4 and 7.

Hypoxia-inducible transcription factor 1 (HIF-1) mediates the cellular response to hypoxia. HIF-1 activity is controlled via the synthesis, degradation or intracellular localization of its alpha subunit. HIF-1alpha contains a C-terminal bipartite basic NLS that interacts with importins alpha.

Characterization of Snail nuclear import pathways as representatives of C2H2 zinc finger transcription factors.

Snail proteins are C(2)H(2) class zinc finger transcription factors involved in different processes during embryonic development, as well as in several adult pathologies including cancer and organ fibrosis. The expression of Snail transcription factors is tightly regulated at the transcriptional level and their activity is modulated by their subcellular localization. Given the importance of this gene family in physiology and pathology, it is essential to understand the mechanisms by which Snail proteins are imported into or exported out of the nucleus.

Exportin 7 defines a novel general nuclear export pathway.

Most transport pathways between cell nucleus and cytoplasm are mediated by nuclear transport receptors of the importin beta family. These receptors are in continuous circulation between the two compartments and transfer cargo molecules from one side of the nuclear envelope to the other. RanBP16 is a family member from higher eukaryotes of so far unknown function.

Nuclear import of HIV-1 intracellular reverse transcription complexes is mediated by importin 7.

Human immunodeficiency virus type 1 (HIV-1), like other lentiviruses, can infect non-dividing cells. This property depends on the active nuclear import of its intracellular reverse transcription complex (RTC). We have studied nuclear import of purified HIV-1 RTCs in primary macrophages and found that importin 7, an import receptor for ribosomal proteins and histone H1, is involved in the process.

Importins fulfil a dual function as nuclear import receptors and cytoplasmic chaperones for exposed basic domains.

Many nuclear transport pathways are mediated by importin beta-related transport receptors. Here, we identify human importin (Imp) 4b as well as mouse Imp4a, Imp9a and Imp9b as novel family members. Imp4a mediates import of the ribosomal protein (rp) S3a, while Imp9a and Imp9b import rpS7, rpL18a and apparently numerous other substrates.