Formylpeptide Receptor Phosphorylation Assays

The formylpeptide receptors respond to exogenous ligands such as the bacterial product fMet-Leu-Phe (fMLP). Bacterial protein synthesis is initiated with an N-Formylmethionine (fMet) at the amino terminus. This feature of prokaryotic protein synthesis is used by mammalian immune cells to recognize the invading bacteria. These bacterial peptides are able to induce chemotaxis, degranulation and superoxide production, which are important bactericidal functions. The human genome contains 3 genes coding for a subfamily of three formylpeptide receptors (FPRs). FPRs interact with a diverse collection of exogenous and endogenous ligands including lipoxin A4, annexin I, cathepsin G, amyloid β42 and spinorphin and are among the most promiscuous GPCRs known to date. The primary function of FPR1 is recognition of bacterial mitochondrial formylpeptides. FPR2 is able to interact with a variety of ligands with different structures including lipid mediators such as lipoxin A4. Compared to FPR1 and FPR2, much less is known about the pharmacological properties of FPR3. The FPR1/2 agonists 'compound 17b' and 'compound 43' have shown cardiac protective functions.