Immunoglobulin Superfamily Member 8 (IGSF8) is a single-pass membrane protein. IGSF8 contains four Ig-like C2 type domains. The Ig-like C2-type domains 3 and 4 are required for interactions with CD81. IGSF8 may regulate proliferation and differentiation of keratinocytes. IGSF8 may participate in the regulation of neurite outgrowth and maintenance of the neural network in the adult brain. It also may play a role on integrin-dependent morphology and motility functions.