Ludwig Englmeier

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Active transport between the nucleus and cytoplasm involves primarily three classes of macromolecules: substrates, adaptors, and receptors. Some transport substrates bind directly to an import or an export receptor while others require one or more adaptors to mediate formation of a receptor-substrate complex. Once assembled, these transport complexes are(More)
We investigated the role of RanBP3, a nuclear member of the Ran-binding protein 1 family, in CRM1-mediated protein export in higher eukaryotes. RanBP3 interacts directly with CRM1 and also forms a trimeric complex with CRM1 and RanGTP. However, RanBP3 does not bind to CRM1 like an export substrate. Instead, it can stabilize CRM1-export substrate(More)
Nuclear export of intron-containing human immunodeficiency virus type 1 (HIV-1) RNA is mediated by the viral Rev protein that contains both an RNA binding domain specific for the viral Rev response element (RRE) and a nuclear export signal (NES). The cellular CRM1 (Exportin1) protein functions as a nuclear export receptor for proteins carrying a Rev-like(More)
BACKGROUND The transport of macromolecules between the nucleus and cytoplasm is an energy-dependent process. Substrates are translocated across the nuclear envelope through nuclear pore complexes (NPCs). Translocation requires nucleocytoplasmic transport receptors of the importin beta family, which interact both with the NPC and, either directly or via an(More)
Axin is a negative regulator of the Wnt pathway essential for down-regulation of beta-catenin. Axin has been considered so far as a cytoplasmic protein. Here we show that, although cytoplasmic at steady state, Axin shuttles in fact in and out of the nucleus; Axin accumulates in the nucleus of cells treated with leptomycin B, a specific inhibitor of the(More)
Vertebrate tRNA export receptor exportin-t (Xpo-t) binds to RanGTP and mature tRNAs cooperatively to form a nuclear export complex. Xpo-t shuttles bidirectionally through nuclear pore complexes (NPCs) but is mainly nuclear at steady state. The steady-state distribution of Xpo-t is shown to depend on its interaction with RanGTP. Two distinct Xpo-t NPC(More)
In red blood cells, protein 4.1 (4.1R) is an 80-kDa protein that stabilizes the spectrin-actin network and anchors it to the plasma membrane. The picture is more complex in nucleated cells, in which many 4.1R isoforms, varying in size and intracellular location, have been identified. To contribute to the characterization of signals involved in differential(More)
We describe a novel assay for the study of RNA export from the nucleus in vitro. Nuclei are assembled in Xenopus egg extract on paramagnetic beads coated with DNA containing a specific template for transcription. T7 RNA polymerase, to which a nuclear localisation signal is attached, is added to the nuclei, and after its import into the assembled nuclei,(More)
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