Fig. 5: Transport mechanism in the yeast NPC.

a All eight complete Kap95 translocation trajectories from the recycling simulation (Fig. 4 and Suppl. Figs. S17–S23), projected in r-z space and overlaid on the average density distribution of the GLFG-Nups (green). The trajectories are color-coded as in Fig. 4, with black indicating dynamic movement and red indicating dwell phases. b Spatial distribution of the slow phase and fast phase of Kap displacements, highlighting regions of low and high mobility, respectively. c Schematic representation of the proposed translocation mechanism. GLFG-Nups form a dense, ring-like structure at the center of the pore (green). Kaps translocate through the NPC via a reduction-of-dimensionality mechanism, moving predominantly along the GLFG-ring surface. Kaps that are temporarily bound to this surface form a coating that shields other Kaps from strong FG interactions, enabling faster movement along the interface between the GLFG-ring and the dynamic Nsp1 network. In contrast, passive translocation of small inert molecules (red) occurs primarily through the central Nsp1 percolation pathway (Fig. 2f and Suppl. Fig. S13). Note that the CT is highly dynamic; average density distributions do not show the complete picture.