Involved in filopodium assembly; positive regulation of excitatory synapse assembly; and protein homooligomerization. Acts upstream of or within ventral spinal cord development. Located in axon; dendrite; and plasma membrane. Is integral component of membrane. Is expressed in central nervous system; dorsal root ganglion; gut; and urinary system. Orthologous to human VSTM5 (V-set and transmembrane domain containing 5). [provided by Alliance of Genome Resources, Apr 2022]