Caspase activation and recruitment domain of NOD2, repeat 1
Caspase activation and recruitment domain (CARD) similar to that found in human NOD2 (CARD15), repeat 1. NOD2 is a member of the Nod-like receptor (NLR) family, which plays a central role in the innate immune response. NLRs typically contain an N-terminal effector domain, a central nucleotide-binding domain and a C-terminal ligand-binding region of several leucine-rich repeats (LRRs). In NOD2, as well as NOD1, the N-terminal effector domain is a CARD. NOD2 contains two N-terminal CARD repeats. Mutations in NOD2 have been associated with Crohns disease and Blau syndrome. Nod2-CARDs have been shown to interact with the CARD domain of the downstream effector RICK (RIP2, CARDIAK), a serine/threonine kinase. 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.