Figure 13. Clarin-1 is required for the compact organization of presynaptic Ca_v1.3 Ca²⁺ channels and postsynaptic GluA2/3 AMPA receptors.

(A) Schematic diagram of an IHC synaptic active zone in control (top panel) and clarin-1–deficient (bottom panel) mice. In the presynaptic active zone of release, clarin-1 interacts with Ca_Vβ₂, harmonin, and the F-actin cytoskeleton to cluster Ca_v1.3 Ca²⁺ channels close to the synaptic vesicles. The lack of clarin-1 results in a dislocation of the synaptic F-actin network associated with a spatial disorganization of both presynaptic Ca_v1.3 channels and postsynaptic GluA2/3 glutamate receptors. (B) Schematic representation of molecular interactions between clarin-1 and other proteins in the IHC synaptic active zone. Clarin-1 may be required for the trans-synaptic alignment of the Ca_v1.3 channel complex (harmonin-Ca_vβ₂-Ca_Vα₁) and postsynaptic glutamate receptors.