Acts as a ligand for C-C chemokine receptor CCR2 (By similarity). Signals through binding and activation of CCR2 and induces a strong chemotactic response and mobilization of intracellular calcium ions (By similarity). Exhibits a chemotactic activity for monocytes and basophils but not neutrophils or eosinophils (By similarity). Plays an important role in mediating peripheral nerve injury-induced neuropathic pain (PubMed:29993042). Increases NMDA-mediated synaptic transmission in both dopamine D1 and D2 receptor-containing neurons, which may be caused by MAPK/ERK-dependent phosphorylation of GRIN2B/NMDAR2B (PubMed:29993042). Monomer or homodimer; in equilibrium. Is tethered on endothelial cells by glycosaminoglycan (GAG) side chains of proteoglycans. Interacts with TNFAIP6 (via Link domain). By platelet-derived growth factor (PubMed:23233732). Up-regulated upon hypertonic conditions (PubMed:23233732). Up-regulated in the dopamine D1 and D2 receptor-containing neurons of nucleus accumbens shell after spinal nerve ligation (PubMed:29993042). Processing at the N-terminus can regulate receptor and target cell selectivity (By similarity). Deletion of the N-terminal residue converts it from an activator of basophil to an eosinophil chemoattractant (By similarity). N-Glycosylated. The polymorphisms in strain SJL/J may be associated with severity of clinical symptoms of experimental allergic encephalomyelitis, an animal model of multiple sclerosis, and susceptibility to the monophasic remitting/nonrelapsing form of the disease. Belongs to the intercrine beta (chemokine CC) family.