Tumor necrosis factor receptor superfamily member 6 (TNFRSF6) in teleosts; also known as fas cell surface death receptor (FasR)
This subfamily of TNFRSF6 (also known as fas cell surface death receptor (FasR) or Fas; APT1; CD95; FAS1; APO-1; FASTM; ALPS1A) is found in teleosts. It contains a death domain and plays a central role in the physiological regulation of programmed cell death. In humans, it has been implicated in the pathogenesis of various malignancies and diseases of the immune system. The receptor interactions with the Fas ligand (FasL), allowing the formation of a death-inducing signaling complex that includes Fas-associated death domain protein (FADD), caspase 8, and caspase 10; autoproteolytic processing of the caspases in the complex triggers a downstream caspase cascade, leading to apoptosis. This receptor has also been shown to activate NF-kappaB, MAPK3/ERK1, and MAPK8/JNK, and is involved in transducing the proliferating signals in normal diploid fibroblast and T cells. In channel catfish and the Japanese rice fish, medaka, homologs of Fas receptor (FasR), as well as FADD and caspase 8, have been identified and characterized, and likely constitute the teleost equivalent of the death-inducing signaling complex (DISC). FasL/FasR are involved in the initiation of apoptosis and suggest that mechanisms of cell-mediated cytotoxicity in teleosts are similar to those used by mammals; presumably, the mechanism of apoptosis induction via death receptors was evolutionarily established during the appearance of vertebrates.