Enables cell adhesion molecule binding activity; transmembrane transporter binding activity; and type 1 fibroblast growth factor receptor binding activity. Involved in several processes, including homophilic cell adhesion via plasma membrane adhesion molecules; positive regulation of signal transduction; and regulation of synaptic plasticity. Located in several cellular components, including inhibitory synapse; postsynaptic density; and presynaptic membrane. Is active in several cellular components, including GABA-ergic synapse; Schaffer collateral - CA1 synapse; and glutamatergic synapse. Is integral component of postsynaptic density membrane and integral component of presynaptic active zone membrane. Orthologous to human NPTN (neuroplastin). [provided by Alliance of Genome Resources, Apr 2022]