| Primary Identifier | IPR027347 | Type | Family |
| Short Name | Formyl_pep_3_rcpt |
| description | Formyl peptide receptors (FPR) are members of the rhodopsin-like G-protein coupled receptor family and are involved in chemotaxis [, ]. They were originally identified by their ability to bind N-formyl peptides (typified by fMet-Leu-Phe (fMLP)), produced by the degradation of either bacterial or host cells [, ]but subsequent ligands have been discovered, containing many microbial agonists derived from both bacteria and viruses [, ].FPRs were initially found on leukocytes, but they are expressed in other cells, for example, immature dendritic cells, platelets, microglial cells, astrocytes, fibroblasts and platelets [, ]. FPRs are expressed at high levels on polymorphonuclear and mononuclear phagocytes. Formyl peptide receptors are not only involved in mediating immune cell response to infection, but also act to suppress the immune system under certain conditions []. The main responses elicited upon ligation of formylated peptides, are those of morphological polarization, locomotion, production of reactive-oxygen species and release of proteolytic enzymes []. There are three formyl peptide receptor subtypes, FPR1, FPR2 and FPR3 [, ]. The sequence similarity between FPR1 and FPR2 is high (69%), and although there is a large sequence similarity also between FPR2 and FPR3 (83%), FPR3 can not bind formylated peptides [, ]. Formyl peptide receptor 3 (FPR3) is primarily a receptor of monocytes, macrophages and dendritic cells. It is also expressed on mouse, but not human, neutrophils [, , ]. Although FPR3 is found in human monocytes, studies have shown that approximately one third of individuals lack cell surface expression of this receptor [, ]. The functions of FPR3, other than directing cell migration, remain to be characterised [, ]. |
