Cell adhesion molecule 3 is a protein that in humans is encoded by the CADM3 gene. IGSF4B is a brain-specific protein related to the calcium-independent cell-cell adhesion molecules known as nectins. Involved in the cell-cell adhesion. Has both calcium-independent homophilic cell-cell adhesion activity and calcium-independent heterophilic cell-cell adhesion activity with IGSF4, PVRL1 and PVRL3. Interaction with EPB41L1 may regulate structure or function of cell-cell junctions.