Illustration of the APM, which includes the APMS and the phospholipid bilayer.

Ankyrin G binds to the 15th repeat of β-spectrin near its carboxyl terminus and to Nav in the axon. α-spectrin and β-spectrin filaments are connected at actin junctions. It is unknown how the phospholipid bilayer is anchored at the actin rings; we indicate a generic actin-associated protein that connects the actin rings to the phospholipid bilayer. Cluster of lipids in the individual layer are represented by a particle with a diameter of 2.5 nm, which is approximately the thickness of a single phospholipid bilayer. We chose the size of TMPs and IMPs of both the inner and outer leaflets to be 5 nm when they interact with other membrane proteins and lipids. However, the IMPs of the inner leaflet and TMPs have additional components that extend towards the cytosol, whereas the IMPs of the outer leaflet do not have inner extension regions. The effective size of the IMPs of the inner leaflet and the TMPs is considered to be 20 nm and 25 nm, respectively, when they interact with the APMS.