NRN1 is expressed in postmitotic-differentiating neurons of the developmental nervous system and neuronal structures associated with plasticity in the adult. The expression of this gene can be induced by neural activity and neurotrophins. The encoded protein contains a consensus cleavage signal found in glycosylphoshatidylinositol (GPI)-anchored proteins. In vitro assays demonstrated that this protein promotes neurite outgrowth and arborization, suggesting its role in promoting neuritogenesis.

The deduced 142-amino acid protein contains a 27-amino acid secretory signal peptide at its N terminus and a 27-amino acid GPI signal peptide at its C terminus. The mature rat and human proteins are 100% identical.