Figure 10

Schematic demonstrating cooperation of positive LCRs, FG motifs and polar residues to form the FG network.

Red spheres (top left box) represent positive charges embedded in positive LCRs, purple spheres (middle left box) represent FG motifs and green spheres (bottom left box) represent polar residues within the central transporter. The highlighted FG Nups domain in the three left boxes represent N-terminal domain of NSP1, i.e. spheres represent location of charged (red) and polar (green) residues and FG motifs (purple). Due to the presence of positive LCRs, the central transporter is positively charged, facilitating transport of negatively charged NTRs. The dynamics of the central network of FG motifs is also regulated via charge repulsion in LCRs. In addition, low charge content of positive LCRs assists these domains of FG Nups to form a collapsed coil conformation. Furthermore, high densities of polar residues among FG repeats promote the hydrophobic interactions and meshwork formation. On the other hand, highly charged stalk domains of FG Nups, which are depleted of polar residues, place the central transporter in the center of the NPC by forming a relaxed coil conformation.