- Peptide (C)NFSPWTNDPKERIN, corresponding to amino acid residues 179-192 of human FPR1 (Accession P21462). 2nd extracellular loop.
- Cell surface detection of FPR1 in live intact human THP-1 acute monocytic leukemia cells:___ Unstained cells.
___ Cells + Anti-Human FPR1 (extracellular)-ATTO-488 Antibody (#AFR-001-AG), (1:20).
Chemotactic factors from both Gram-positive and Gram-negative bacteria are short peptides with N-formyl methionine at the N-terminus (extensively reviewed in reference 1). These peptides are released from bacteria during infection and activate formyl peptide receptors (FPR), members of the G-protein coupled receptor (GPCR) superfamily. In humans, the FPR family consists mainly of three receptors, FPR1, FPR2/ALX (formerly FPRL1), and FPR3 (formerly FPRL2) which all couple to the Gi subtype of G-proteins and ultimately lead to the activation of phospholipase C and intracellular Ca2+ increase1,2.
FPRL1, or FPR2/ALX as it is commonly called, is a seven transmembrane protein like all GPCRs. This receptor was originally cloned by screening a HL60 neutrophil cDNA library with a FPR1 cDNA probe3. FPR2/ALX shares 69% identity with FPR1 and despite its high homology, it displays relatively low affinity for fmlf, the most potent N-formyl peptide released by bacteria3.
FPR1 was originally found in neutrophils and later found to be distributed in myeloid and non-myeloid cells as is the case for FPR2/ALX and FPR3 (FPR3 though is not expressed in neutrophils). FPR1 is also expressed in multiple organs and tissues including epithelial cells in organs with secretory functions, endocrine cells, liver hepathocytes, smooth muscle cells and endothelial cells, brain spinal cord and both motor and sensory neurons4. FPR2/ALX has a similar tissue distribution to that of FPR1.
While N-formyl peptides were the first peptides found to activate these receptors, the ligand diversity for FPR has proven to be quite broad and demonstrates to be both pro- and anti-inflammatory. They include peptidic ligands originating from bacterial and viral sources (including HIV), endogenous ligands such as chemokines and annexins, short peptides associated with inflammation and infection. Indeed, peptides from Herpes, Ebola and coronavirus 229E are ligands of FPR11.
Species reactivity key:
Anti-Human FPR1 (extracellular) Antibody (#AFR-001) is a highly specific antibody directed against an epitope of the human N-formyl peptide receptor 1. The antibody can be used in western blot and indirect flow cytometry applications. It has been designed to recognize FPR1 from human samples only.
Anti-Human FPR1 (extracellular)-ATTO Fluor-488 Antibody (#AFR-001-AG) is directly labeled with an ATTO-488 fluorescent dye. ATTO dyes are characterized by strong absorption (high extinction coefficient), high fluorescence quantum yield, and high photo-stability. The ATTO-488 label is analogous to the well known dye fluorescein isothiocyanate (FITC) and can be used with filters typically used to detect FITC. Anti-Human FPR1 (extracellular)-ATTO Fluor-488 Antibody is specially suited to experiments requiring simultaneous labeling of different markers.
- Anti-Human FPR1 (extracellular) Antibody (#AFR-001), (for western blot analysis).