Fas (APO-1, CD95) is an ~42 kDa cell surface protein that mediates apoptosis when cross-linked with agonistic anti-Fas antibodies or Fas ligand (FasL). Fas belongs to the TNF (tumor necrosis factor)/NGF (nerve growth factor) receptor family, and is expressed in various tissue and cells including the thymus, liver, ovary and lung. FasL is a 40 kDa TNF family member membrane protein that induces apoptosis by binding to Fas, its cell-surface receptor. FasL is expressed on activated T and NK cells. Both Fas and FasL are thought to play an important role in the apoptotic processes that take place during T cell development.
Recombinant soluble human Fas was expressed in the Baculovirus Expression Vector System and purified from insect cell lysate using an anti-Fas antibody. This form of Fas lacks the transmembrane domain of the Fas receptor, and has been referred to as FasΔTM. It has a 63-base pair deletion starting at nucleotide sequence (700) GA TCC AGA and ending at nucleotide sequence GTT TGG G (762). The purity and the integrity of the protein were verified by SDS-PAGE, and ELISA. FasΔTM has a reduced molecular weight of ~40 kDa.