CD37 is a member of the transmembrane 4 superfamily, also known as the tetraspanin family. Most of these members are cell-surface proteins that are characterized by the presence of four hydrophobic domains. The proteins mediate signal transduction events that play a role in the regulation of cell development, activation, growth and motility. CD37 is a cell surface glycoprotein that is known to comple, Xenopus/Amphibian, with integrins and other transmembrane 4 superfamily proteins. It may play a role in T-cell-B-cell interactions.