Efficiency, selectivity, and robustness of nucleocytoplasmic transport

Area of Science:

• Molecular Biology
• Biophysics
• Cell Biology

Background:

• Nuclear pore complexes (NPCs) facilitate selective and high-throughput transport between the nucleus and cytoplasm.
• FG nups (phenylalanine-glycine repeat-containing nucleoporins) line NPCs and possess flexible, unstructured regions crucial for transport.
• Transport involves soluble factors binding to FG nup regions, mediating cargo passage.

Purpose of the Study:

• To model the dynamics of nucleocytoplasmic transport using an effective potential approach.
• To explain the high selectivity and throughput of NPCs based on FG nup interactions.
• To account for the observed insensitivity of transport to variations in FG nup abundance.

Main Methods:

• Developed a physical model of nucleocytoplasmic transport dynamics.
• Modeled transport as diffusion in an effective potential arising from FG nup-transport factor interactions.
• Incorporated principles of molecular binding and competition for NPC binding sites and space.

Main Results:

• Demonstrated how specific binding of transport factors to FG nups facilitates efficient transport.
• Explained NPC selectivity through the interplay of binding affinity and competition for FG nup sites.
• Provided a theoretical basis for transport remaining functional even with significant FG nup mass reduction.

Conclusions:

• The FG nup-mediated transport model accurately reflects NPC function and selectivity.
• Understanding these interactions can inform the design of artificial nanomolecular sorting devices.
• The model offers insights into the adaptability and robustness of the nuclear transport machinery.