Neurexophilin-4 belongs to the neurexophilin family where its members are thought to be signaling molecules that resemble neuropeptides and that act by binding to alpha-neurexins and possibly other receptors. Neurexophilins share a common predicted structure composed of 5 domains: an N-terminal signal peptide, a variable N-terminal domain, a highly conserved central domain that is N-glycosylated, a short linker region, and a conserved C-terminal domain that is cysteine-rich. Neurexophilin-4 is a secreted protein that is expressed in brain, spleen and testis.