This gene encodes a membrane protein that mediates apical cell adhesion between trophoblastic cells and luminal epithelial cells of the endometrium and is implicated in the initial attachment during the process of embryo implantation. This gene is related to the MAGED gene family by sequence similarity and chromosome location. Multiple alternatively spliced transcript variants have been found for this gene; however, the full-length nature of some variants has not been defined. Trophinin is directly responsible for homophilic cell adhesion, and could be involved with bystin and tastin in a cell adhesion molecule complex that mediates an initial attachment of the blastocyst to uterine epithelial cells at the time of the embryo implantation.