FPR1 FPR1 (formyl peptide receptor1), FMLP receptor(FMLPR)
Molecule TypeAntigen ExpressionMolecular Weight
Min / Max
Non-lineage Restricted Molecule
Type 3 glycoprotein, 7 span
Neutrophil
Monocyte
Macrophage
Parenchymal Cell
Liver
50 / 50
75 / 75

Expression
FPR is expressed on neutrophils, monocytes, macrophages and liver parenchymal cells.

Structure
MOLECULAR FAMILY NAME: Belongs to the G-protein coupled receptor family.

FPR1 is a multi-pass type-3, 7 span glycoprotein.  It a member of the rhodopsin superfamily of G protein-coupled receptors.  It is closely related to the other chemoattractant receptors of the family, such as IL-8, C5a and MIP-1a  receptors.  The 3rd cytoplasmic loop is comprised of a potential protein kinase.  A phosphorylation site and the C-terminal region is rich in Ser- and Thr-residues.  The cDNA clone originally reported to encode the rabbit FPR is actually the rabbit orthologue of the IL-8 receptor CD128a.  There are 2 human FPR isoforms that differ by 2 aa, Leu101 and Ala346 in the sequence shown below which are replaced by Val and Glu, respectively and by significant differences in the 5' and 3' untranslated regions.  These probably represent allelic variants.

MOLECULAR MASS
Cell Type Unreduced Reduced
55 - 70 kDa

POST-TRANSCRIPTIONAL MODIFICATION: No information.

POST-TRANSLATIONAL MODIFICATION

FRP1 is phosphorylated which is necessary for desensitization.

Ligands
LIGANDS AND MOLECULES WHICH ASSOCIATED WITH FPR1

FPR binds N-formyl peptides of bacterial and mitochondrial origin, such as the prototype formyl-Met-Leu-Phe (fMLP) with kDa = 1-2 nM. Putative natural ligands for FPR have also been described.  The reconstitution of a functional human FPR in Xenopus oocytes requires a complementary human factor.

Function
N-formyl peptides interact with FPR to induce neutrophil chemotaxis, phagocytosis, production of superoxide radicals and release of proteolytic enzymes from intracellular granules.  FPR1 is a high affinity receptor for N-formyl-methionyl peptides (FMLP) which are powerful neutrophils chemotactic factors.  Binding of FMLP to FPR1 causes activation of neutrophils and activates phospholipase C via a pertussis toxin-sensitive G protein.  This response is mediated via a G-protein that activates a phosphatidylinositol-calcium second messeanger system.  Other activation pathways of the receptor include the stimulations of phospholipases A2 and D.

BIOCHEMICAL ACTIVITY: No information.

DISEASE RELEVANCE AND FUNCTION OF FRP1 IN INTACT ANIMAL: No information.

Comments
MOLECULAR INTERACTION-
PROTEINS AND RNA ELEMENTS WHICH REGULATE TRANSCRIPTION OF FPR1: No information.

SUBSTRATES: No information.

ENZYMES WHICH MODIFY FPR1: No information.

ADDITIONAL SIGHTS OF FPR1

The genes for 2 FPR-line receptors FPRL1 and FPRL2, which show a 69% aa and a 56% aa sequence identity to FPR, have also been mapped to the human chromosome 19.  The FPRL1 molecule is a low affinity receptor for fMLP of kDa = 430 nM, whereas FPRL2 does not bind fMLP and has no known ligand.

Database accession numbers
AnimalPIRSWISSPROTEMGBL/GENBANK
 
HumanEntrezgene 2357P21462
HumanP21462M60626-27
MouseP33766L22181
Antibodies

Revised June 25, 2008


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