Description
FasL is a type II membrane protein belonging to the TNF family of cytokines. FasL induces apoptosis when it binds to cells expressing the Fas antigen. FasL was first discovered on the cell surface of T cells and NK cells. Expressed on the cell surface of activated T cells, FasL kills T cells and activated B cells leading to down-regulation of the immune response. The full length of FasL contains 281 amino acid residues, consisting of the transmembrane domain, extracellular domain and the cytoplasmic region. A metalloproteinase cleaves the membrane-bound FasL to produce soluble FasL (sFasL), which exists as a homotrimer. The sFasL shows lower cytotoxic activity than membrane bound FasL. Recombinant Fas Ligand is a soluble 19.9kD protein containing 175 amino acid residues, comprising of only the extracellular domain of FasL