Cell surface receptor for laminin, epiligrin, fibronectins, entactin, and collagen. integrin alpha3beta1 is the major integrin present in epithelial cells, where it plays a role in the assembly of basement membrane as well as in cell migration, and may regulate the functions of other integrins. Two alternatively spliced isoforms of the alpha subunit (INTEGRIN ALPHA3), are differentially expressed in different cell types.