Artificial nanopores that mimic the transport selectivity of the nuclear pore complex

Abstract

Nuclear pore complexes (NPCs) act as effective and robust gateways between the nucleus and the cytoplasm, selecting for the passage of particular macromolecules across the nuclear envelope. NPCs are comprised of an elaborate scaffold that defines a ∼30nm diameter passageway connecting the nucleus and the cytoplasm. This scaffold anchors proteins termed ‘phenylalanine-glycine’ (FG)-nucleoporins, the natively disordered domains of which line the passageway and extend into its lumen1. Passive diffusion through this lined passageway is hindered in a size-dependent manner. However, transport factors and their cargo-bound complexes overcome this restriction by transient binding to the FG-nucleoporins2–10. To test whether a simple passageway and a lining of transport-factor-binding FG-nucleoporins are sufficient for selective transport, we designed a functionalized membrane that incorporates just these two elements. Here we demonstrate that this membrane functions as a nanoselective filter, efficiently passing transport factors and transport-factor–cargo complexes that specifically bind FG-nucleoporins, while significantly inhibiting the passage of proteins that do not. This inhibition is greatly enhanced when transport factor is present. Determinants of selectivity include the passageway diameter, the length of the nanopore region coated with FG-nucleoporins, the binding strength to FG-nucleoporins, and the antagonistic effect of transport factors on the passage of proteins that do not specifically bind FG-nucleoporins. We show that this artificial system faithfully reproduces key features of trafficking through the NPC, including transport-factor-mediated cargo import.

Distinct, but not completely separate spatial transport routes in the nuclear pore complex

“…[70][71][72][73][74][75] Finally, the complexity of natively unfolded FG Nups in the NPC makes mimicking real nuclear transport in artificial pores challenging. [76][77][78] Therefore, an imaging technique that can map real-time nuclear transport at an exceptionally high spatiotemporal resolution in 3D in the NPCs of living cells is urgently needed.…”

Effects of rotational symmetry breaking in polymer-coated nanopores

“…NPC transport properties have also been mimicked in artificial devices by coating solid-state nanopores with selected proteins from the NPC central channel. 16,23,24 Besides their technological and biological importance, polymer-grafted pores are also of great fundamental interest. In the confinement of a cylindrical nanopore, polymer/polymer interactions have been shown, via numerical simulations, [25][26][27][28][29] to yield a wide and rich pattern of possible morphologies.…”

Nernst-Planck model of photo-triggered, pH–tunable ionic transport through nanopores functionalized with “caged” lysine chains

“…Nanoscale pores have been studied extensively in the last decade due to the new basic phenomena involved and the potential applications in medicine, [1][2][3] nanofluidics, [4][5][6][7] membrane science 8,9 and biotechnology. 10,11 Polymer samples containing single asymmetric nanopores and multipore arrays obtained by track-etching 12 are of particular interest because they mimic some of the transport properties of biological ion channels.…”