Tumor necrosis factor receptor superfamily member 1B (TNFRSF1B, also known as TNFR2, type 2 TNFR, TNFBR, TNFR80, TNF-R75, TNF-R-II, p75, CD120b) binds TNF-alpha, but lacks the death domain (DD) that is associated with the cytoplasmic domain of TNFRSF1A (TNFR1) []. It is inducible and expressed exclusively by oligodendrocytes, astrocytes, T cells, thymocytes, myocytes, endothelial cells, and in human mesenchymal stem cells []. TNFRSF1B protects oligodendrocyte progenitor cells (OLGs) against oxidative stress, and induces the up-regulation of cell survival genes []. While pro-inflammatory and pathogen-clearing activities of TNF are mediated mainly through activation of TNFRSF1A, a strong activator of NF-kappaB, TNFRSF1B is more responsible for suppression of inflammation []. Although the affinities of both receptors for soluble TNF are similar, TNFRSF1B is sometimes more abundantly expressed and thought to associate with TNF, thereby increasing its concentration near TNFRSF1A receptors, and making TNF available to activate TNFRSF1A (a ligand-passing mechanism) [].This entry represents the N-terminal domain of TNFR1B. TNF-receptors are modular proteins. The N-terminal extracellular part contains a cysteine-rich region responsible for ligand-binding. This region is composed of small modules of about 40 residues containing 6 conserved cysteines; the number and type of modules can vary in different members of the family [, , ].
This subfamily of tumor necrosis factor receptor 1A (TNFRSF1, also known as type I TNFR, TNFR1, DR1, TNFRSF1A, CD120a, p55) is found in teleosts. It binds TNF-alpha, through the death domain (DD), and activates NF-kappaB, mediates apoptosis and activates signaling pathways controlling inflammatory, immune, and stress responses. It mediates signal transduction by interacting with antiapoptotic protein BCL2-associated athanogene 4 (BAG4/SODD) and adaptor proteins TRAF2 and TRADD that play regulatory roles [, ].Knockout studies in zebrafish embryos have shown that a signaling balance between TNFRSF1A and TNFRSF1B is required for endothelial cell integrity. TNFRSF1A signals apoptosis through caspase-8, whereas TNFRSF1B signals survival via NF-kappaB in endothelial cells. Thus, this apoptotic pathway seems to be evolutionarily conserved, as TNFalpha promotes apoptosis of human endothelial cells and triggers caspase-2 and P53 activation in these cells via TNFRSF1A [].This entry represents the N-terminal domain of TNFR1A from teleosts. TNF-receptors are modular proteins. The N-terminal extracellular part contains a cysteine-rich region responsible for ligand-binding. This region is composed of small modules of about 40 residues containing 6 conserved cysteines; the number and type of modules can vary in different members of the family [, , ].
