High affinity receptor for N-formyl-methionyl peptides (fMLP), which are powerful neutrophil chemotactic factors. Binding of fMLP to the receptor stimulates intracellular calcium mobilization and superoxide anion release. This response is mediated via a G-protein that activates a phosphatidylinositol-calcium second messenger system. Receptor for TAFA4, mediates its effects on chemoattracting macrophages, promoting phagocytosis and increasing ROS release (By similarity). Receptor for cathepsin CTSG, leading to increased phagocyte chemotaxis (By similarity). Internalizes in presence of its ligand, TAFA4. Neutrophils. Phosphorylated; which is necessary for desensitization. Belongs to the G-protein coupled receptor 1 family.