Atypical chemokine receptor 4 (ACKR4)

Atypical chemokine receptor that modulates chemokine levels and localization via high-affinity chemokine binding that's uncoupled from classic ligand-driven signal transduction cascades, resulting instead in chemokine sequestration, degradation, or transcytosis. Also called interceptor (internalizing receptor) or chemokine-scavenging receptor or chemokine decoy receptor.

Chemokine-binding does not trigger G-protein-mediated signal transduction but instead induces beta-arrestin recruitment, leading to ligand internalization. Plays an important part in controlling the migration of immune and cancer cells which express chemokine receptors CCR7 and CCR9, by reducing the availability of CCL19, CCL21, and CCL25 via internalization.