Letter | Published:

Snapshots of nuclear pore complexes in action captured by cryo-electron tomography

Nature volume 449, pages 611615 (04 October 2007) | Download Citation

Abstract

Nuclear pore complexes reside in the nuclear envelope of eukaryotic cells and mediate the nucleocytoplasmic exchange of macromolecules1. Traffic is regulated by mobile transport receptors that target their cargo to the central translocation channel, where phenylalanine-glycine-rich repeats serve as binding sites2. The structural analysis of the nuclear pore is a formidable challenge given its size, its location in a membranous environment and its dynamic nature. Here we have used cryo-electron tomography3 to study the structure of nuclear pore complexes in their functional environment, that is, in intact nuclei of Dictyostelium discoideum. A new image-processing strategy compensating for deviations of the asymmetric units (protomers) from a perfect eight-fold symmetry enabled us to refine the structure and to identify new features. Furthermore, the superposition of a large number of tomograms taken in the presence of cargo, which was rendered visible by gold nanoparticles, has yielded a map outlining the trajectories of import cargo. Finally, we have performed single-molecule Monte Carlo simulations of nuclear import to interpret the experimentally observed cargo distribution in the light of existing models for nuclear import.

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Acknowledgements

We thank F. Melchior for the Ran(Q69L) protein, S. Musser for the NLS–2×GFP plasmid, G. Gerisch and J. Glavy for valuable discussions, and A. Leis for critical reading of the manuscript. This work was supported in part by the European Union 3DEM Network of Excellence.

The structure has been deposited at the Macromolecular Structure database (EBI) under accession code EMD-1394.

Author information

Author notes

    • Ohad Medalia

    Present address: The Department of Life Sciences, The Ben Gurion University and the NIBN, Beer Sheva 84105, Israel.

Affiliations

  1. Max Planck Institute of Biochemistry, D-82152 Martinsried, Germany

    • Martin Beck
    • , Vladan Lučić
    • , Friedrich Förster
    • , Wolfgang Baumeister
    •  & Ohad Medalia

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Competing interests

Reprints and permissions information is available at www.nature.com/reprints.

Corresponding authors

Correspondence to Wolfgang Baumeister or Ohad Medalia.

Supplementary information

PDF files

  1. 1.

    Supplementary Information

    The file contains Supplementary Methods, Supplementary Tables S1-S2 and Supplementary Figures S1-S6 with Legends.

Videos

  1. 1.

    Supplementary Video 1

    The file contains Supplementary Video 1 which shows structural heterogeneity of the Nuclear Pore Complex.

  2. 2.

    Supplementary Video 2

    The file contains Supplementary Video 2 which shows structure of a protomer superimposed with the entire NPC shown as a cutaway view.

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DOI

https://doi.org/10.1038/nature06170

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