Embigin, a member of the immunoglobulin superfamily expressed in embryonic cells, enhances cell-substratum adhesion.

Embigin is a glycoprotein belonging to the immunoglobulin superfamily, and is preferentially expressed before 10 days of gestation during mouse embryogenesis. To study its function, an embigin cDNA under the control of beta-actin promoter and Rous sarcoma virus enhancer was introduced into L cells. Transfectants expressing embigin were found to have enhanced cell-substratum adhesion activity, which was evident by microscopic observation and could be determined quantitatively by culturing cells on plastic dishes in serum-free medium containing 0.05% bovine serum albumin. After 6 hr of culture about 50% of the transfected cells adhered to the dish, whereas parental cells scarcely adhered. The enhanced cell-substratum adhesion was Ca2+ dependent and inhibited by an arginine-glycine-aspartic acid peptide, which competitively inhibits integrins, and also by anti-integrin antiserum. Thus, one role of embigin appears to be promotion of integrin-mediated cell-substratum adhesion.