Nectins are immunoglobulin superfamily adhesion molecules that participate in the organization of epithelial and endothelial junctions. Sharing high homology with the poliovirus receptor (PVR/CD155), nectins were also named poliovirus receptor-related proteins (PRRs). Four nectins and five nectin-like molecules have been identified. Here we describe the cloning and characterization of human and mouse nectin-like molecular 1 (NECL1). Human and mouse NECL1 share 87.3% identity at the amino acid level. NECL1 contains an ectodomain made of three immunoglobulin-like domains, and a cytoplasmic region homologous to those of glycophorin C and contactin-associated protein. RNA blot and in situ hybridization analysis showed that NECL1 predominantly expressed in the central nervous system, mainly in neuronal cell bodies in a variety of brain regions including the cerebellum, cerebral cortex and hippocampus. In vitro binding assay proved the association of NECL1 with protein 4.1N. NECL1 localizes to the cell-cell junctions and recruits protein 4.1N to the plasma membranes through its C-terminus, thus may regulate the function of the cell-cell junction. We propose that the NECL1 and protein 4.1N complex is involved in the morphological development, stability, and dynamic plasticity of the nervous system.