Death Domain: a protein-protein interaction domain
Death Domains (DDs) are protein-protein interaction domains found in a variety of domain architectures. Their common feature is that they form homodimers by self-association or heterodimers by associating with other members of the DD superfamily including CARD (Caspase activation and recruitment domain), DED (Death Effector Domain), and PYRIN. Structural analysis of DD-DD complexes show that the domains interact with each other in many different ways. DD-containing proteins serve as adaptors in signaling pathways and they can recruit other proteins into signaling complexes. In mammals, they are prominent components of the programmed cell death (apoptosis) pathway and are found in a number of other signaling pathways. In invertebrates, they are involved in transcriptional regulation of zygotic patterning genes in insect embryogenesis, and are components of the ToII/NF-kappaB pathway, a conserved innate immune pathway in animal cells.