Enables identical protein binding activity. Involved in regulation of synaptic vesicle exocytosis. Acts upstream of or within neuron projection extension. Located in extracellular space. Is anchored component of plasma membrane. Part of AMPA glutamate receptor complex. Is active in glutamatergic synapse. Is expressed in several structures, including central nervous system; genitourinary system; gut; limb mesenchyme; and liver. Orthologous to human NRN1 (neuritin 1). [provided by Alliance of Genome Resources, Apr 2022]