Figure 13.

Diagram model of the synaptic function of NPR. Diagram illustrates the trans-synaptic signaling role proposed for NPR at both excitatory (left) and inhibitory synapses (right). Presynaptic NPR, either as a homomeric pentamer or as a heteropentameric complex with NP1 and/or NARP, binds to postsynaptic ligands in both excitatory and inhibitory synapses and thereby activates trans-synaptic signaling. In excitatory synapses, NPR binds via its pentraxin domain to the NTD of AMPARs and activates AMPARs by stabilizing them on the surface, whereas in inhibitory synapses NPR binds to an as yet unknown postsynaptic ligand, but its trans-synaptic signaling function also requires postsynaptic receptor activity.