Related Experiment Video
Updated: Nov 16, 2025

Author Spotlight: Exploring Cellular Processes by Modeling Ligands in Cryo-EM Maps
Published on: July 19, 2024
Structural view of the Ran-Importin beta interaction at 2.3 A resolution
1Max-Planck-Institut für molekulare Physiologie, Dortmund, Germany.
Abstract:
Transport receptors of the Importin beta family shuttle between the nucleus and cytoplasm and mediate transport of macromolecules through nuclear pore complexes. They interact specifically with the GTP-binding protein Ran, which in turn regulates their interaction with cargo. Here, we report the three-dimensional structure of a complex between Ran bound to the nonhydrolyzable GTP analog GppNHp and a 462-residue fragment from Importin beta. The structure of Importin beta shows 10 tandem repeats resembling HEAT and Armadillo motifs. They form an irregular crescent, the concave site of which forms the interface with Ran-triphosphate. The importin-binding site of Ran does not overlap with that of the Ran-binding domain of RanBP2.
Related Concept Videos
Nuclear Localization Signals and Import
Directionality of Nuclear Transport
Nuclear Export
NES are of three types- the canonical 10-residue long leucine-rich signal and other...
Directing Proteins to the Rough Endoplasmic Reticulum
Protein Translocation Machinery on the ER Membrane
Sec61 protein conducting channel
In eukaryotes, the translocon complex comprises a core heterotrimeric translocator channel called the Sec61 complex. This channel includes three transmembrane proteins, Sec61α, Sec61β, and Sec61γ, and is the largest subunit of the...
Nuclear Protein Sorting
Proteins targeted to the nucleus carry nuclear localization signals or NLS recognized by import receptors in the cytosol. Similarly, proteins with nuclear export signals are recognized by export receptors. Import and export receptors are...

