Intrinsically disordered nuclear pore proteins show ideal-polymer morphologies and dynamics

Area of Science:

• Cell Biology
• Biophysics
• Computational Biology

Background:

• The nuclear pore complex (NPC) regulates transport between the nucleus and cytoplasm.
• Intrinsically disordered FG Nups form the NPC's selective barrier, but their behavior is poorly understood.
• Existing models describe FG Nup behavior as either polymer brushes or hydrogels.

Purpose of the Study:

• To investigate the physical behavior of FG Nups within the NPC.
• To determine whether FG Nups behave more like polymer brushes or hydrogels.
• To elucidate the mechanisms underlying the NPC's selective transport barrier.

Main Methods:

• Mesoscale computational simulations were employed.
• Simulations were compared against a wide range of experimental data.
• Analysis focused on FG Nup interactions and collective behavior.

Main Results:

• FG Nups exist at a crossover point between polymer brush and hydrogel regimes.
• Repulsive and attractive interactions between FG Nups are balanced.
• FG Nup behavior closely resembles that of ideal polymer chains.

Conclusions:

• The balanced interactions allow FG Nups to form a cohesive yet dynamic transport barrier.
• This unique property enables efficient sealing of the barrier while permitting rapid molecular rearrangements for transport.
• FG Nup behavior explains the NPC's ability to facilitate rapid and selective nucleocytoplasmic transport.