The function to find (FIIND) was initially discovered in two proteins, NLRP1 (aka NALP1, CARD7, NAC, DEFCAP) and CARD8 (aka TUCAN, Cardinal) [1]. NLRP1 is a member of the Nod-like receptor (NLR) protein superfamily and is involved in apoptosis and i ...
The function to find (FIIND) was initially discovered in two proteins, NLRP1 (aka NALP1, CARD7, NAC, DEFCAP) and CARD8 (aka TUCAN, Cardinal) [1]. NLRP1 is a member of the Nod-like receptor (NLR) protein superfamily and is involved in apoptosis and inflammation. To date, it is the only NLR protein known to have a FIIND domain. The FIIND domain is also present in the CARD8 protein where, like in NLRP1, it is followed by a C-terminal CARD domain. Both proteins are described to form an "inflammasome", a macro-molecular complex able to process caspase 1 and activate pro-IL1beta [2]. The FIIND domain is present in only a very small subset of the kingdom of life, comprising primates, rodents (mouse, rat), carnivores (dog) and a few more, such as horse. Publications describing the newly discovered NLRP1 protein failed to identify it as a separate domain; for example, it was taken as part of the adjacent leucine rich repeat domain (LRR) [3]. Upon discovery of CARD8 it was noted that the N-terminal region shared significant sequence identity with an undescribed region in NLRP1 [1]. Before getting its final name, FIIND [2], this domain was termed NALP1-associated domain (NAD) [4]. This is a peptidase domain of the ZU5 superfamily that is predicted to be involved in autoproteolytic cleavage [5].
