Caspase recruitment domains, or caspase activation and recruitment domains (CARDs), are interaction motifs found in a wide array of proteins, typically those involved in processes relating to inflammation and apoptosis. These domains mediate the formation of larger protein complexes via direct interactions between individual CARDs. CARD domains are found on a strikingly wide range of proteins, including helicases, kinases, mitochondrial proteins, caspases, and other cytoplasmic factors.
Caspase-1/Interleukin-1 converting enzyme (ICE) is an evolutionarily conserved enzyme that proteolytically cleaves other proteins, such as the precursors of the inflammatory cytokines interleukin 1β and interleukin 18 as well as the pyroptosis inducer Gasdermin D, into active mature peptides. It plays a central role in cell immunity as an inflammatory response initiator. Once activated through formation of an inflammasome complex, it initiates a proinflammatory response through the cleavage and thus activation of the two inflammatory cytokines, interleukin 1β (IL-1β) and interleukin 18 (IL-18) as well as pyroptosis, a programmed lytic cell death pathway, through cleavage of Gasdermin D. The two inflammatory cytokines activated by Caspase-1 are excreted from the cell to further induce the inflammatory response in neighboring cells.
NLR family pyrin domain containing 3 (NLRP3), is a protein that in humans is encoded by the NLRP3 gene located on the long arm of chromosome 1.
NLRP1 encodes NACHT, LRR, FIIND, CARD domain and PYD domains-containing protein 1 in humans. NLRP1 was the first protein shown to form an inflammasome. NLRP1 is expressed by a variety of cell types, which are predominantly epithelial or hematopoietic. The expression is also seen within glandular epithelial structures including the lining of the small intestine, stomach, airway epithelia and in hairless or glabrous skin. NLRP1 polymorphisms are associated with skin extra-intestinal manifestations in CD. Its highest expression was detected in human skin, in psoriasis and in vitiligo. Polymorphisms of NLRP1 were found in lupus erythematosus and diabetes type 1. Variants of mouse NLRP1 were found to be activated upon N-terminal cleavage by the protease in anthrax lethal factor.
NLR family CARD domain-containing protein 4 is a protein that in humans is encoded by the NLRC4 gene.
NACHT, LRR and PYD domains-containing protein 2 is a protein that in humans is encoded by the NLRP2 gene.
NACHT, LRR and PYD domains-containing protein 7 is a protein that in humans is encoded by the NLRP7 gene.
NACHT, LRR and PYD domains-containing protein 12 is a protein that in humans is encoded by the NLRP12 gene.
NACHT, LRR and PYD domains-containing protein 4 is a protein that in humans is encoded by the NLRP4 gene.
The nucleotide-binding oligomerization domain-like receptors, or NOD-like receptors (NLRs), are intracellular sensors of pathogen-associated molecular patterns (PAMPs) that enter the cell via phagocytosis or pores, and damage-associated molecular patterns (DAMPs) that are associated with cell stress. They are types of pattern recognition receptors (PRRs), and play key roles in the regulation of innate immune response. NLRs can cooperate with toll-like receptors (TLRs) and regulate inflammatory and apoptotic response. They are found in lymphocytes, macrophages, dendritic cells and also in non-immune cells, for example in epithelium. NLRs are highly conserved through evolution. Their homologs have been discovered in many different animal species (APAF1) and also in the plant kingdom.
Inflammasomes are cytosolic multiprotein oligomers of the innate immune system responsible for the activation of inflammatory responses. Activation and assembly of the inflammasome promotes proteolytic cleavage, maturation and secretion of pro-inflammatory cytokines interleukin 1β (IL-1β) and interleukin 18 (IL-18), as well as cleavage of Gasdermin-D. The N-terminal fragment resulting from this cleavage induces a pro-inflammatory form of programmed cell death distinct from apoptosis, referred to as pyroptosis, and is responsible for secretion of the mature cytokines, presumably through the formation of pores in the plasma membrane.
A pyrin domain is a protein domain and a subclass of protein motif known as the death fold, the 4th and most recently discovered member of the death domain superfamily (DDF). It was originally discovered in the pyrin protein, or marenostrin, encoded by MEFV. The mutation of the MEFV gene is the cause of the disease known as Familial Mediterranean Fever. The domain is encoded in 23 human proteins and at least 31 mouse genes.
NLRP5, short for NOD-like receptor family pyrin domain containing 5, is an intracellular protein that plays a role in early embryogenesis. NLRP5 is also known as NACHT, LRR and PYD domains-containing protein 5 (NALP5), Mater protein homolog (MATER), PYPAF8, PAN11, and CLR19.8, and is one of 14 pyrin domain containing members of the NOD-like receptor family of cytoplasmic receptors known to mammals.
NLRP6, short for NOD-like receptor family pyrin domain containing 6, is an intracellular protein that plays a role in the immune system. It is also known as NALP6, PYPAF5, PAN3, and CLR11.4, and is one of 14 pyrin domain containing members of the NOD-like receptor family of pattern recognition receptors. As with several other NOD-like receptors, NLRP6's role in immunity is related to its ability to regulate caspase-1 and NF-κB activity.
NLRP8, short for NOD-like receptor family pyrin domain containing 8, is an intracellular protein that is expressed in the ovaries, testes, and preimplantation embryos of mammals. It is also known as NALP8, NOD16, PAN4, and CLR19.2, and is one of 14 pyrin domain containing members of the NOD-like receptor family of cytoplasmic receptors.
NLRP9, short for NOD-like receptor family pyrin domain containing 9, is an intracellular protein that is expressed in the ovaries, testes, oocytes, and preimplantation embryos of mammals that is likely involved in reproductive processes. It is also known as NALP9, NOD6, PAN12, and CLR19.1, and is one of 14 pyrin domain containing members of the NOD-like receptor family of cytoplasmic receptors.
NLRP10, short for NOD-like receptor family pyrin domain containing 10, is an intracellular protein of mammals that functions in apoptosis and the immune system. It is also known as NALP10, NOD8, PAN5, Pynod, and CLR11.1, and is one of 14 pyrin domain containing members of the NOD-like receptor family of cytoplasmic receptors, although it differs from other NOD-like receptors by lacking the characteristic leucine-rich repeat domain. It is also believed that it helps regulate the inflammatory response. NLRP8 reduces inflammatory and innate immune responses by inhibiting the activity of two proteins associated with the inflammasome; caspase-1 and PYCARD.
NOD-like receptor family pyrin domain containing 11 is a protein that in humans is encoded by the NLRP11 gene located on the long arm of human chromosome 19q13.42. NLRP11 belongs to the NALP subfamily, part of a large subfamily of caterpiller. It is also known as NALP11, PYPAF6, NOD17, PAN10, and CLR19.6
NLRP13, short for NOD-like receptor family pyrin domain containing 13, is an intracellular protein of mammals. It is also known as NALP13, NOD14, PAN13, and CLR19.7, and is one of 14 pyrin domain containing members of the NOD-like receptor family of cytoplasmic receptors. The function of NLRP13 is currently unknown.
NLRP (Nucleotide-binding oligomerization domain, Leucine rich Repeat and Pyrin domain containing), also abbreviated as NALP, is a type of NOD-like receptor. NOD-like receptors are a type of pattern recognition receptor that are found in the cytosol of the cell, recognizing signals of antigens in the cell. NLRP proteins are part of the innate immune system and detect conserved pathogen characteristics, or pathogen-associated molecular patterns, such as such as peptidoglycan, which is found on some bacterial cells. It is thought that NLRP proteins sense danger signals linked to microbial products, initiating the processes associated with the activation of the inflammasome, including K+ efflux and caspase 1 activation. NLRPs are also known to be associated with a number of diseases. Research suggests NLRP proteins may be involved in combating retroviruses in gametes. As of now, there are at least 14 different known NLRP genes in humans, which are named NLRP1 through NLRP14. The genes translate into proteins with differing lengths of leucine-rich repeat domains.
