Ankyrins are bifunctional linker proteins that tether L1 to the membrane associated, spectrin based actin cytoskeleton. Spectrin is a tetramer of two alpha- and two beta-chains. The spectrin alpha chain has 21 and the beta chain has 16 (conventional beta) or 30 (heavy beta) successive triple helix repeats. At the N-terminus of beta spectrin, there is a pair of CH (calponin homology) domains which together form an actin binding domain, while the triple helical repeats 14-15 bind ankyrin.
Interaction with spectrin bound F-actin blocks the mobility of L1 and this immobilization mediates adjacent neuron adhesions.