BetaII-spectrin gaps and patches emerge from the patterned assembly of the actin/spectrin membrane skeleton in human motor neuron axons.

βII-spectrin forms a distinctive gaps-and-patches pattern in human motor neuron axons, revealing a patterned assembly of the actin/spectrin membrane skeleton.

• Why it matters: Understanding the organization of the cytoskeleton in motor neurons is crucial because their long axons are vulnerable in neuromuscular diseases like amyotrophic lateral sclerosis, yet the mechanisms of MPS assembly remain unclear.
• What they did: Using confocal and super-resolution imaging, the study examined βII-spectrin distribution and MPS patterning in induced pluripotent stem cell-derived human motor neuron axons, revealing a gap-and-patch pattern influenced by actin dynamics.
• The result: The findings suggest that spectrin incorporation into MPS patches depletes neighboring regions, creating long-range gaps and patches, which advances understanding of cytoskeletal organization and its role in axonal integrity.