Figure 8. αII Spectrin is a universal neuronal structural protein.

In neurons, αII spectrin is ubiquitously expressed and interacts with different β spectrins in different neuronal microdomains. In the AIS, αII/βIV spectrin complexes are required to stabilize ankyrin-G that also interacts with GABARAP to stabilize GABA_ARs in somatodendritic domains. The αII/βIV spectrin complex likely also stabilizes gephyrin in the AIS through F-actin. In the more distal axon, αII/βII spectrin complexes interact with ankyrin-B to modulate organelle transport, and particularly retrograde transport. In dendrites, αII/βIII spectrin complexes function in dendritic development, likely through interactions with ankyrin-R.