The FasL gene (FAS is the acronym for FS7-associated cell surface antigen) is located on chromosome 1q24.3. The encoded protein, a transmembrane protein (see FASLG below), belongs to the tumor necrosis factor superfamily. The main function of the encoded transmembrane protein is the induction of apoptosis, which is triggered by binding to FAS. The FAS/FASLG pathway is essential for the regulation of the immune system, including activation-induced cell death (AICD) of T cells and cell death induced by cytotoxic T lymphocytes.
Diseases associated with FASLG include autoimmune lymphoproliferative syndrome and lung cancer. Defects in this gene may be associated with some cases of systemic lupus erythematosus (SLE). Alternatively spliced transcript variants have been described.