NOD-like receptor

The nucleotide-binding oligomerization domain-like receptors, in short NOD-like receptors (NLRs) are intracellular sensors of PAMPs that enter the cell via phagocytosis or pores and DAMPs that are associated with cell stress. They are part of pattern recognition receptors and play key roles in regulation of innate immune response. NLRs can cooperate with Toll-like receptors and regulate inflammatory and apoptotic response. They are found in lymphocytes, macrophages, dendritic cells and also in nonimmune 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 (disease-resistance R protein).

NLRs contain 3 domains – central NACHT (NOD or NBD – nucleotide-binding domain) domain, which is common to all NLRs, most of NLRs have also C-terminal leucine-rich repeat (LRR) and variable N-terminal interaction domain. NACHT domain mediates ATP-dependent self-oligomerization and LRR senses the presence of ligand. N-terminal domain is responsible for homotypic protein-protein interaction and it can consist of caspase recruitment domain (CARD), pyrin domain (PYD), acidic transactivating domain or baculovirus inhibitor repeats (BIRs).

Names as CATERPILLER, NOD, NALP, PAN, NACHT, PYPAF were used to describe the NLRs family. The nomenclature was unified by the HUGO Gene Nomenclature Committee in 2008. The family was characterized as NLRs to provide description of the families features – NLR means nucleotide-binding domain and leucine-rich repeat containing gene family.

This system divides NLRs into 4 subfamilies based on the type of N-terminal domain:

There is also an additional subfamily NLRX which doesn’t have significant homology to any N-terminal domain. A member of this subfamily is NLRX1.

...
Wikipedia