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

Abstract

Nuclear pore complexes (NPCs) are the gateways between a cell's nucleus and its cytoplasm and allow only selected macromolecules to cross the nuclear envelope. Based on an elucidation of the architecture and mechanism of this complex, Jovanovic-Talisman et al. have designed and produced an artificial nanopore membrane that mimics its selectivity. The membrane features the two vital elements of the natural complex - a simple passageway and a lining of proteins, phenylalanine-glycine nucleoporins, familiarly known as 'FG-nups'. As in the natural complex, the artificial nanopores allow only transport factors and transport-factor-carrying cargoes that specifically bind to FG-nups, to pass. This work opens the way to an array of nature-inspired nanodevices that can detect and sort molecules of medical and industrial significance. Nuclear pore complexes (NPCs) serve as gateways between the nucleus and cytoplasm and allow only the transport of selected macromolecules across the nuclear envelope. NPCs are comprised of a scaffold that anchors proteins called FG-nucleoporins, which contain disordered regions that line the inner surface of the pore and extend into the lumen. This study reports the design of an artificial membrane that functions as a selective filter in allowing efficient passage of transport factors and transport factor carrying cargo that specifically bind to FG-nucleoporins. 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 comprise an elaborate scaffold that defines a ∼30 nm 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-nucleoporins2,3,4,5,6,7,8,9,10. 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.