Fas

Similar to other cell processes, the balance between cell survival and cell death is an important equilibrium that when altered expression of genes can lead to a variety of disease.

Apoptosis, also called programmed cell death, is an essential process in development and disease. The signaling networks that carry out apoptosis is consists of a series of endoproteases called caspases which are synthesized as inactive zymogens. Caspses are grouped into two classes: initiator caspases and effector caspases. Initiator caspases are activated by the assembly of multi-protein complexes such as the death-inducing signaling complex (DISC) (1).

Fas is a member of the tumor necrosis factor (TNF)-receptor superfamily and plays a key role in the physiological regulation of programmed cell death. This receptor contains a death domain which enables the formation of a signaling complex that includes Fas-associated death domain protein (FADD), caspase 8, and caspase 10. The auto-proteolytic processing of these complexed caspases triggers a downstream cascade that leads to membrane-mediated apoptosis.

Cells undergo apoptotic programmed cell death in response to various stimuli. The process is required for morphogenesis, tissue homeostasis, and host defense. Certain cytokines such as tumor necrosis factor (TNF) and Fas ligand signal through death domain-containing receptors such as tumor necrosis factor receptor 1 (TNFR1) and Fas.

Cells undergo apoptotic programmed cell death in response to various stimuli, and this key mechanism is necessary for cellular morphogenesis, tissue homeostasis, and host defense. Particular cytokines such as tumor necrosis factor (TNF) and the Fas ligand signal through their cooperative death domain-containing receptors tumor necrosis factor receptor 1 (TNFR1) and Fas. Like its cousin TRAIL-R1, TRAIL-R2 is widely expressed in both normal tissues as well as in many types of tumor cells.