Invitrogen™ FAS Monoclonal Antibody (4F8H6)

CD95, also known as Fas or APO-1, is a 46 kDa transmembrane glycoprotein that functions as a cell death receptor in the tumor necrosis factor receptor (TNFR) superfamily. It is expressed by a wide range of hematopoietic and non-hematopoietic cells, including monocytes, neutrophils, lymphocytes, and fibroblasts. CD95 also exists in a soluble form weighing approximately 26 kDa. The interaction of CD95 with its ligand, FasL, induces apoptosis, playing a crucial role in peripheral tolerance and anti-viral immune responses. Upon stimulation, CD95 leads to the aggregation of its intracellular Fas-associated death domains (FADD), formation of the death-inducing signaling complex (DISC), and activation of caspases. This cascade results in apoptosis. CD95 is also involved in activating NF-kappaB, MAPK3/ERK1, and MAPK8/JNK, and transduces proliferative signals in normal diploid fibroblasts and T cells. There are at least eight alternatively spliced transcript variants encoding seven distinct isoforms of CD95. Isoforms lacking the transmembrane domain may negatively regulate apoptosis mediated by the full-length isoform. The Fas/Fas ligand system is implicated in several human diseases, including AIDS, hepatitis, and cancer, highlighting its importance in immune regulation and disease pathology.