The nuclear pore complex (NPC) is a giant molecular gate that regulates the transport of molecules and macromolecules across the nuclear envelop in a selective and directional manner. Using a coarse-grained one-bead-per-amino-acid model and percolation analysis we have characterized the gel formation of solutions of FG-Nups that line the central channel of the NPC. We show that FG-Nup solutions can indeed form a percolated network (gel) when the concentration of the Nups exceeds a certain limit. Furthermore, we show that this critical concentration depends on the amino acid composition of the FG-Nups and correlates with the ratio between charged and hydrophobic amino acids. Comparison with the protein concentrations inside the yeast NPC reveals that it is very likely that the FG-Nups form a gel phase. (c) 2018 Elsevier Ltd. All rights reserved.