Pattern recognition receptor

Pattern recognition receptors (PRRs) play a crucial role in the proper function of the <a href="/facts/Innate_immune_system/lz4BpSQI">innate immune system</a>. PRRs are germline-encoded host sensors, which detect molecules typical for the pathogens. They are <a href="/facts/Protein/Jxmagu3E">proteins</a> expressed mainly by cells of the innate immune system, such as dendritic cells, macrophages, monocytes, neutrophils, as well as by epithelial cells, to identify two classes of molecules: <a href="/facts/Pathogen-associated_molecular_pattern/jLrjQv7T">pathogen-associated molecular patterns</a> (PAMPs), which are associated with microbial <a href="/facts/Pathogens/axMXtV1M">pathogens</a>, and <a href="/facts/Damage-associated_molecular_pattern/6nTcgFu1">damage-associated molecular patterns</a> (DAMPs), which are associated with components of host's cells that are released during cell damage or death. They are also called primitive pattern recognition receptors because they evolved before other parts of the immune system, particularly before <a href="/facts/Adaptive_immunity/bc7zT1Jo">adaptive immunity</a>. PRRs also mediate the initiation of antigen-specific adaptive immune response and release of inflammatory cytokines. PRRs are regulated through a variety of pathways ensure optimal immune and inflammatory response to invaders.
The microbe-specific molecules that are recognized by a given PRR are called pathogen-associated molecular patterns (PAMPs) and include bacterial carbohydrates (such as <a href="/facts/Lipopolysaccharide/Ch967TXw">lipopolysaccharide</a> or LPS, <a href="/facts/Mannose/U05bJ7p8">mannose</a>), nucleic acids (such as bacterial or viral DNA or RNA), bacterial peptides (flagellin, microtubule elongation factors), <a href="/facts/Peptidoglycan/lflRRUNw">peptidoglycans</a> and <a href="/facts/Lipoteichoic_acid/IVL1qjnm">lipoteichoic acids</a> (from Gram-positive bacteria), <a href="/facts/N-Formylmethionine/qpzbCWnR">N-formylmethionine</a>, <a href="/facts/Lipoprotein/FUFotgeL">lipoproteins</a> and fungal <a href="/facts/Glucan/SGarVY1s">glucans</a> and <a href="/facts/Chitin/Fo1f8b86">chitin</a>. PRRs exhibit significant diversity in coevolution with PAMPs. Endogenous stress signals are called damage-associated molecular patterns (DAMPs) and include <a href="/facts/Uric_acid/gPMSfLcT">uric acid</a> and extracellular <a href="/facts/Adenosine_triphosphate/nB9bwgcU">ATP</a>, among many other compounds. There are several subgroups of PRRs. They are classified according to their <a href="/facts/Ligand/6etB3qeW">ligand</a> specificity, function, localization and/or evolutionary relationships.

Pattern recognition receptor open-in-new

Pattern recognition receptor