Members of the tumor necrosis factor receptor (TNFR) family play a key role in regulating the immune response to infection. They are cell-surface proteins that interact with a corresponding TNF-related ligand family. The receptors share homology in the extracellular domain, which contains 3 to 6 cysteine-rich pseudorepeats, but are generally not related in their cytoplasmic regions. However, the intracellular domains (ICDs) of TNFR family members TNFR1 and FAS/APO1/CD95, which can activate apoptotic cell death, do have a region of homology in an oligomerization interface known as the death domain. (from OMIM 603366) [ ]