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.
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.
Pyroptosis is a highly inflammatory form of programmed cell death that occurs most frequently upon infection with intracellular pathogens and is likely to form part of the antimicrobial response. This process promotes the rapid clearance of various bacterial, viral, fungal and protozoan infections by removing intracellular replication niches and enhancing the host's defensive responses. Pyroptosis can take place in immune cells and is also reported to occur in keratinocytes and some epithelial cells.
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 hematopoietic. The expression is also seen within glandular epithelial structures including the lining of the small intestine, stomach. 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.
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. In the case of dysregulation of inflammasome activation, an assortment of major diseases, such as cancer, autoimmune, metabolic and neurodegenerative diseases may arise.
A pyrin domain is a protein domain and a subclass of protein motif known as the death fold; it allows a pyrin domain containing protein to interact with other proteins that contain a pyrin domain. It is also known as a PYD or PAAD/DAPIN domain, and is distantly evolutionarily related to the Death domain family of protein domains. Proteins containing a pyrin domain are frequently involved in biological processes called inflammation and apoptosis. Proteins that possess a pyrin domain include intracellular microbial sensors called NOD-like receptors, and proteins associated with their function, such as PYCARD and certain fish caspases.
NLRX1 or NLR family member X1, short for nucleotide-binding oligomerization domain, leucine rich repeat containing X1 is a protein that in humans is encoded by the NLRX1 gene. It is also known as NOD-like receptor X1, NLR family, X1, NOD5, NOD9, and CLR11.3, and is a member of the NOD-like receptor family of pattern recognition receptors.
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.
NLRP11, short for NOD-like receptor family pyrin domain containing 11, is an intracellular protein of mammals. It is also known as NALP11, PYPAF6, NOD17, PAN10, and CLR19.6, and is one of 14 pyrin domain containing members of the NOD-like receptor family of cytoplasmic receptors. The function of NLRP11 is currently unknown.
NLRP14, short for NOD-like receptor family pyrin domain containing 14, is an intracellular protein of mammals associated with a role in spermatogenesis. It is also known as NALP14, NOD5, GC-LRR, Nalp-iota, PAN8, and CLR11.2, and is one of 14 pyrin domain containing members of the NOD-like receptor family of cytoplasmic receptors. NLRP14 is found exclusively in the testes where it is expressed within spermatogonia, spermatocytes and spermatids.
NLRP (Nucleotide-binding oligomerization domain, Leucine rich Repeat and Pyrin domain containing), also abbreviated as NALP, is a type of NOD-like receptor. NLRP proteins are part of the innate immunity and detect conserved pathogen characteristics such as peptidoglycan. It is thought that NLRP proteins sense inherent danger, and link this with microbial products, creating a response under the concept of the inflammasome including K+ efflux and caspase 1 activation. NLRP is also known to be associated with a number of hereditary diseases. Research suggests NLRP proteins may be involved in combating retroviruses in gametes. Currently there are at least 13 known human NALP genes named as NALP1 through NALP13.
