Pyrin Death Domain found in ASC (Apoptosis-associated speck-like protein containing a CARD) and similar proteins. ASC is an adaptor molecule that functions in the assembly of the 'inflammasome', a multiprotein platform, which is responsible for caspase-1 activation and regulation of IL-1beta maturation. ASC contains two domains from the Death Domain (DD) superfamily, an N-terminal pyrin-like domain and a C-terminal Caspase activation and recruitment domain (CARD). Through these 2 domains, ASC serves as an adaptor for inflammasome integrity and oligomerizes to form supramolecular assemblies. Included in this family is human PYNOD (also known as NLRP10 or NOD8) which via its Pyrin domain suppresses oligomerization of ASC, and ASC-mediated NF-kappaB activation. Other members of this subfamily are associated with ATPase domains and their function remains unknown. In general, Pyrin is a subfamily of the DD superfamily and functions in several signaling pathways. 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 and Death Effector Domain (DED). They serve as adaptors in signaling pathways and can recruit other proteins into signaling complexes.
Jiyao W et al.(2023). "The conserved domain database in 2023.",