Nectin-3 is a type I transmembrane glycoprotein that belongs to the nectin family. Its precursor is 549 amino acids in length and contains an extended signal sequence of 57 amino acids, an extracellular domain (ECD) of 347 amino acids, a transmembrane segment of 21 amino acids, and a cytoplasmic region of 124 amino acids. It is predominantly expressed in testis and placenta as well as in various cell lines, including epithelial cell lines. Nectin-3 plays a role in cell-cell adhesion through heterophilic trans-interactions with nectin-like proteins or nectins, such as trans-interaction with PVRL2/Nectin-2 at Sertoli-spermatid junctions. Nectin-3 is also involved in the formation of cell-cell junctions, including adherens junctions and synapses.