Discrete signaling functions are thought to be initiated by recruiting different types of signal transducers to the TNFR superfamily complexes. Thus far, two major classes of signal transducers have been identified. Clustering of the death domain proteins may to lead to the further recruitment of caspase-8, and subsequently, to cell death. A second class of signal transducers which help orchestrate the functions of the TNFR superfamily members are the TRAF proteins. To date, six members of the TRAF family have been found.
None exhibit enzymatic activity, suggesting they operate solely as signal adapters.