G protein-coupled receptor (GPCR) that plays a key role in the immune system by regulating the migration and activation of white blood cells in response to chemokines (PubMed:28994588). Selectively interacts with eosinophil-attracting chemokines such as eotaxin/CCL11, eotaxin-2/CCL24 and eotaxin-3/CCL26 (PubMed:7622448, PubMed:8642344, PubMed:8676064). Ligand binding triggers intracellular signaling that leads to chemotaxis of immune cells. Mechanistically, signals through GNA14 or GNA16 to induce stimulation of phospholipase Cbeta/PLCB2 and subsequently chemotaxis (PubMed:18406577). Alternatively, transduces signal via GNAI1 resulting in elevated intracellular calcium levels and activation of the PI3K/AKT pathway (PubMed:8676064, PubMed:35570218). May also act as a possible functional receptor for NARS1 (PubMed:30171954). {ECO:0000269|PubMed:18406577, ECO:0000269|PubMed:28994588, ECO:0000269|PubMed:30171954, ECO:0000269|PubMed:7622448, ECO:0000269|PubMed:8642344, ECO:0000269|PubMed:8676064}. (Microbial infection) Alternative coreceptor with CD4 for HIV-1 infection. . This is the function of CCR3 (C-C motif chemokine receptor 3, Ensembl gene identifier ENSG00000183625).