Caspase activation and recruitment domain found in Caspase-1 and related proteins
Caspase activation and recruitment domain (CARD) similar to those found in Caspase-1 (CASP1, ICE) and related proteins, including CARD-only proteins such as ICEBERG or CARD18, INCA (CARD17), CARD16 (COP1, PSEUDO-ICE), CARD8 (DACAR, NDPP1, TUCAN), and CARD12 (NLRC4), as well as ICE-like caspases such as CASP12, CASP5 (ICH-3) and CASP4 (TX, ICH-2). Caspases are aspartate-specific cysteine proteases with functions in apoptosis and immune signaling. CASP1 plays a central role in the cellular response to a wide variety of microbial and non-microbial stimuli, being activated by the inflammasome or the pyroptosome. CARD8 binds itself and the initiator caspase-9, interfering with the binding of APAF-1 and suppressing caspase-9 activation. CARD12 is a Nod-like receptor (NLR) that plays an important role in the innate immune response to Gram-negative bacteria. Caspase-4 (CASP4), -5 (CASP5), and -12 (CASP12) are inflammatory caspases implicated in inflammation and endoplasmic reticulum stress-induced apoptosis. In general, CARDs are death domains (DDs) found associated with caspases. They are known to be important in the signaling pathways for apoptosis, inflammation and host-defense mechanisms. 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 PYRIN and DED (Death Effector Domain). 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.",