Expression of ankyrin G (AnkG), contactin-associated protein (Caspr) and voltage-gated sodium channel (Nav)1.6 in 4.1B-/- mice. Triple immunostaining of AnkG (A), Caspr (B) and Nav1.6 (C) (Caspr and Nav1.6 are merged in D) along the axon of motor neurons (MNs) (labeled with the anti-Peripherin antibody; data not shown) in 4.1B-/- mice. Brackets indicate the Caspr+ domain (A-C). Scale bar = 5 μm.