Visualizing nuclear pore complex plasticity with pan-Expansion Microscopy.

Area of Science:

• Cell Biology
• Molecular Biology
• Neuroscience

Background:

• Nuclear pore complex (NPC) plasticity is key to cell function but poorly understood.
• Existing technologies lack the resolution to study individual NPC variations.
• Understanding NPC plasticity requires advanced imaging techniques.

Purpose of the Study:

• To evaluate Pan Expansion Microscopy (Pan-ExM) for visualizing NPC plasticity.
• To investigate the molecular basis and consequences of NPC structural changes.
• To explore NPC alterations in the context of amyotrophic lateral sclerosis (ALS).

Main Methods:

• Utilized Pan-ExM for 16-20 fold isotropic cell expansion, preserving proteome.
• Employed deep learning for NPC segmentation into tripartite structures.
• Analyzed NPC diameter variations and the localization of nucleoporin POM121.

Main Results:

• Pan-ExM successfully visualized diverse NPC diameters, with a bias for dilated NPCs at the basal nuclear surface.
• Disruption of LINC complex connections normalized NPC diameter biases, indicating regulation by nuclear envelope tension.
• Transmembrane nucleoporin POM121 was found at the nuclear ring, but shifted to the inner ring in aged iPSNs from an ALS patient.

Conclusions:

• Pan-ExM is a powerful tool for visualizing NPC plasticity at single NPC resolution.
• NPC structural plasticity is influenced by nuclear envelope tension.
• POM121 relocalization in aged iPSNs suggests a potential early mechanism in C9orf72-linked ALS.