Members of the TNF ligand/TNF receptor superfamily play key roles in a large number of biological events. For instance, members of the TNF ligand/TNF receptor superfamily figure prominently in the complex interplay of positive and negative signals that regulate T cell activation, maintenance of T cell effector function, promotion of maturation of antigen-presenting cells, such as dendritic cells, and the T cell stimulation of APCs. TNF receptors are broadly classified in three groups Receptors in the first group contain a death domain in their cytoplasmic tails. Receptors in the second group contain a TRAF interaction motif in their cytoplasmic tails. The third group of TNF receptors do not contain functional intracellular signaling domains but can act as decoy receptors.
