A saturated FG-repeat hydrogel can reproduce the permeability properties of nuclear pore complexes

Cell. 2007 Aug 10;130(3):512-23. doi: 10.1016/j.cell.2007.06.024.


The permeability barrier of nuclear pore complexes (NPCs) controls the exchange between nucleus and cytoplasm. It suppresses the flux of inert macromolecules > or = 30 kDa but allows rapid passage of even very large cargoes, provided these are bound to appropriate nuclear transport receptors. We show here that a saturated hydrogel formed by a single nucleoporin FG-repeat domain is sufficient to reproduce the permeability properties of NPCs. Importin beta and related nuclear transport receptors entered such hydrogel >1000x faster than a similarly sized inert macromolecule. The FG-hydrogel even reproduced import signal-dependent and importin-mediated cargo influx, allowing importin beta to accelerate the gel entry of a large cognate cargo more than 20,000-fold. Intragel diffusion of the importin beta-cargo complex occurred rapidly enough to traverse an NPC within approximately 12 ms. We extend the "selective phase model" to explain these effects.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Calcium-Binding Proteins / metabolism
  • Glycine / chemistry
  • Humans
  • Hydrogels / chemistry*
  • Models, Biological*
  • Nuclear Pore Complex Proteins / chemistry*
  • Nuclear Pore Complex Proteins / genetics
  • Nuclear Pore Complex Proteins / metabolism*
  • Nuclear Proteins / metabolism
  • Nucleocytoplasmic Transport Proteins / metabolism
  • Permeability
  • Phenylalanine / chemistry
  • Pregnancy Proteins / metabolism
  • Protein Structure, Tertiary
  • Repetitive Sequences, Amino Acid*
  • Reproducibility of Results
  • Saccharomyces cerevisiae Proteins / metabolism


  • Calcium-Binding Proteins
  • Hydrogels
  • NSP1 protein, S cerevisiae
  • NTF2 protein, S cerevisiae
  • NUTF2 protein, human
  • Nuclear Pore Complex Proteins
  • Nuclear Proteins
  • Nucleocytoplasmic Transport Proteins
  • Pregnancy Proteins
  • Saccharomyces cerevisiae Proteins
  • Phenylalanine
  • Glycine