Artificial Nanopores that Mimic the Transport Selectivity of the Nuclear Pore Complex

Nuclear pore complexes (NPCs) act as effective and robust gateways to the nucleus, allowing only the passage of selected macromolecules across the nuclear envelope. NPCs are comprised of an elaborate scaffold that defines a ~30 nm diameter passageway between the nucleus and cytoplasm. This scaffold anchors proteins termed FG-nups, whose natively disordered domains line the passageway and form an effective barrier to the diffusion of most macromolecules1. However, cargo-carrying transport factors overcome this barrier by transient binding to the FG-nups. To test whether nothing more than a passageway and a lining of transport factor-binding FG-nups are sufficient for selective transport, we designed a functionalized membrane that incorporates just these two elements. We demonstrate that this membrane functions as a nanoselective filter, efficiently passing transport factors (NTF2, Kap95, Kap121) and transport factor-cargo complexes (Kap95/IbbGFP, NTF2/RanGDP) that specifically bind FG-nups, whilst significantly inhibiting the passage of proteins that do not bind. We show that the selectivity is based on the strength of binding to the FG-nups and pore geometry, as it is in vivo2. The data also supports our in silico prediction that competition between transport factors and nonspecific macromolecules enhances the selectivity of the NPC3. This effect has not been a major feature of other models for nuclear transport. In summary, we show that our artificial system faithfully reproduces key features of trafficking through the NPC, including transport factor-mediated cargo import. Nano-devices of this kind are useful for assessing the significance of parameters that govern NPC gating, and have many potential applications including the purification of macromolecules from crude mixtures.