FPR2
Description
The FPR2 (formyl peptide receptor 2) is a protein-coding gene located on chromosome 19.
FPR2 is a G-protein coupled receptor (GPCR) located on the surface of many cell types of various animal species. The human receptor protein is encoded by the FPR2 gene and is activated to regulate cell function by binding any one of a wide variety of ligands including not only certain N-Formylmethionine-containing oligopeptides such as N-Formylmethionine-leucyl-phenylalanine (FMLP) but also the polyunsaturated fatty acid metabolite of arachidonic acid, lipoxin A4 (LXA4). Because of its interaction with lipoxin A4, FPR2 is also commonly named the ALX/FPR2 or just ALX receptor.
== Expression == The FPR2 receptor is expressed on human neutrophils, eosinophils, monocytes, macrophages, T cells, synovial fibroblasts, and intestinal and airway epithelium.
== Function == Many oligopeptides that possess an N-Formylmethionine N-terminal residue such as the prototypical tripeptide N-Formylmethionine-leucyl-phenylalanine (i.e. FMLP), are products of the protein synthesis conducted by bacteria. They stimulate granulocytes to migrate directionally (see chemotaxis) and become active in engulfing (see phagocytosis) and killing bacteria and thereby contribute to host defense by directing the innate immune response of acute inflammation to sites of bacterial invasion. Early studies suggested that these formyl oligopeptides operated by a Receptor (biochemistry) mechanism. Accordingly, the human leukocyte cell line, HL-60 promyelocytes (which do not respond to FMLP), was purposely differentiated to granulocytes (which do respond to FMLP) and used to partially purify and clone a gene that when transfected into FMLP-unresponsive cells bestowed responsiveness to this and other N-formyl oligopeptides. This receptor was initially named the formyl peptide receptor (i.e.
FPR2 is a low-affinity receptor for N-formyl-methionyl peptides, which are powerful neutrophil chemotactic factors. Binding of FMLP to the receptor activates neutrophils through a G-protein-mediated phosphatidylinositol-calcium second messenger system. FPR2 can also bind to LXA4, leading to anti-inflammatory outcomes by counteracting pro-inflammatory signals like LTB4. FPR2 acts as a receptor for the chemokine-like protein FAM19A5, stimulating macrophage chemotaxis and inhibiting TNFSF11/RANKL-induced osteoclast differentiation. FPR2 is also a receptor for humanin.
FPR2 is also known as ALX, ALXR, FMLP-R-II, FMLPX, FPR2A, FPRH1, FPRH2, FPRL1, HM63, LXA4R.
