Herpes virus entry mediator (HVEM), a type I transmembrane protein, is a member of the TNF receptor superfamily. HVEM mediates the entry of herpes simplex virus (HSV) 1 and 2 into T lymphocytes by serving as an attachment site for the HSV envelope glycoprotein D (gD). HVEM also binds two cellular ligands, secreted lymphotoxin a and light. LIGHT is a member of the TNF superfamily produced by activated T cells. This type II transmembrane protein competes with HSV glycoprotein D for binding to HVEM. LIGHT is closely related in sequence to lymphotoxin β (LTβ) and can also bind to the LTβ receptor. LIGHT is also known to induce apoptosis and suppress tumor formation.The gene encoding LIGHT maps to human chromosome 19p13.3.
