NOD-like receptor

They are types of pattern recognition receptors (PRRs),[2] and play key roles in the regulation of innate immune response.

[3][6] Names as CATERPILLER, NOD, NALP, PAN, NACHT, PYPAF were used to describe the NLRs family.

The recognition of their ligands recruits oligomerization of NACHT domain and CARD-CARD interaction with CARD-containing serine-threonin kinase RIP2 which leads to activation of RIP2.

NOD1 recognizes a molecule called meso-diaminopimelic acid (meso-DAP) mostly found in Gram-negative bacteria (for example Helicobacter pylori, Pseudomonas aeruginosa).

NOD2 proteins can sense intracellular muramyl dipeptide (MDP), typical for bacteria such as Streptococcus pneumoniae or Mycobacterium tuberculosis.

[9] The pyrin domain of NLRs binds to an adaptor protein ASC (PYCARD) via PYD-PYD interaction.

The formation of NLRP3 inflammasome can be activated by PAMPs such as microbial toxins (for example alpha-toxin of Staphylococcus aureus) or whole pathogens, for instance Candida albicans, Saccharomyces cerevisiae, Sendai virus, Influenza.

The danger molecule can be extracellular ATP, extracellular glucose, monosodium urate (MSU) crystals, calcium pyrophosphate dihydrate (CPPD), alum, cholesterol or environmental irritants – silica, asbestos, UV irradiation and skin irritants.