Visualizing nuclear pore complex plasticity with pan-Expansion Microscopy

The exploration of cell-type and environmentally-responsive nuclear pore complex (NPC) plasticity requires new, accessible tools. Using pan-Expansion Microscopy (pan-ExM), NPCs were identified by machine learning-facilitated segmentation with resolved cytoplasmic rings (CR), inner rings (IR) and nuclear rings (NR). They exhibited a large range of diameters with a bias for dilated NPCs at the basal nuclear surface in clusters suggestive of local islands of nuclear envelope (NE) tension. Whereas hyperosmotic shock constricted NPCs analogously to those found in annulate lamellae (AL), depletion of LINC complexes specifically eliminated the modest nuclear surface diameter biases. Therefore, LINC complexes may contribute locally to nuclear envelope tension to toggle NPC diameter between dilated, but not constricted, states. Lastly, POM121 shifts from the NR to the IR specifically in induced pluripotent stem cell derived neurons (iPSNs) from a patient with C9orf72 amyotrophic lateral sclerosis (ALS). Thus, pan-ExM is a powerful tool to visualize NPC plasticity in physiological and pathological contexts at single NPC resolution.