CCRL2 is a receptor for the chemokine CCL19 and for chemerin, also called RARRES2. It does not appear to be a signalling receptor. Instead, it may modulate chemokine-triggered immune responses in two ways: by capturing and internalising CCL19, or by presenting the RARRES2 ligand to CMKLR1, which is a functional signalling receptor. CCRL2 also plays a critical role in the development of Th2 responses. This places the protein among the regulators that shape the local chemokine environment, rather than among the receptors that transduce signals directly.

The CCRL2 gene encodes a chemokine receptor-like protein that is predicted to span the membrane seven times and is most closely related to CCR1. The protein belongs to the G protein-coupled receptor 1 family and localises to the cell membrane. According to the NCBI Gene summary, the gene is expressed at high levels in primary neutrophils and primary monocytes. Its expression is further upregulated on neutrophil activation and during monocyte to macrophage differentiation. The gene maps to the region that contains the chemokine receptor gene cluster. Mouse studies use the orthologous Ccrl2 gene.

HGNC classifies CCRL2 in the atypical chemokine receptors group, and the ACKR5 alias reflects this. Earlier names include chemokine (C-C motif) receptor-like 2, and the gene has also been called HCR, CRAM-B, CRAM-A and CKRX. Chemokines and their receptors drive signal transduction that is critical for recruiting effector immune cells to sites of inflammation. The NCBI summary notes that the function of the gene is unknown, while the UniProt annotation describes the ligand-binding and immune-modulating roles above. Researchers investigating CCRL2 antibody reagents, CCRL2 protein or CCRL2 gene expression often do so in the context of chemokine and chemerin biology.