Protein Domain : Fas receptor IPR008063

Type	Family
Description	Like all apoptotic cell death, T cell receptor (TCR)-mediated death can be divided into two phases: an inductive phase and an effector phase. The effector phase includes a sequence of steps that are common to apoptosis in many cell types, which, if not interrupted, will lead to cell death. Theinduction phase, which often requires the expression of new genes, consists of a set of signals that activate the effector phase. Outside the thymus,most, if not all, of the TCR-mediated apoptosis of mature T cells (sometimes referred to as activation-induced cell death (AICD)) is induced through thesurface antigen Fas pathway: activation through the TCR induces expression of the Fas (CD95) ligand (FasL); the expression of FasL on either aneighbouring cell, or on the Fas-bearing cell, induces trimerisation of Fas, which then initiates a signal-transduction cascade, leading to apoptosis of the Fas-bearing cell. This commitment stage requires the activation of key death-inducing enzymes, termed caspases, which act by cleaving proteins that are essential for cell survival and proliferation [, ].Fas is also known to be essential in the death of hyperactivated peripheral CD4+ cells: in the absence of Fas, mature peripheral T cells do not die, butthe activated cells continue to proliferate, producing cytokines that lead to grossly enlarged lymph nodes and spleen. Fas belongs to the tumournecrosis factor receptor (TNFR) family of cysteine-rich type I membrane receptors; its ligand (FasL) is expressed on activated lymphocytes, NK cells,platelets, certain immune-privileged cells and some tumour cells [ , ].Defects in the Fas-FasL system are associated with various disease syndromes. Mice with non-functional Fas or FasL display characteristics of lympho-proliferative disorder, such as lymphadenopathy, splenomegaly, and elevated secretion of IgM and IgG. These mice also secrete anti-DNA autoantibodies and rheumatoid factor [].
Short Name	Fas_rcpt