Formyl Peptide Receptor 3 (FPR3)

Bao et al. (1992) identified 2 structural homologs of FMLP receptor (FPR1), FPRL1 (FPR2) and FPRL2 (FPR3). Since these 2 structural homologs did not recognize the ligand FMLP, Bao et al. (1992) referred to them as orphan receptors. Nonetheless, they probably function as chemotactic receptors.F2L is an acetylated 21-amino acid peptide derived from the N terminus of intracellular heme-binding protein (HEBP1). F2L bound and activated FPRL2 in the nanomolar range, triggering intracellular calcium release, inhibition of cAMP accumulation, and phosphorylation of MAP kinases. Testing on monocytes and monocyte-derived dendritic cells showed that F2L promoted calcium mobilization and chemotaxis. Migeotte et al. (2005) concluded that F2L is a natural chemoattractant peptide for dendritic cells and monocytes and is specific for FPRL2.