The function of ACKR3 (atypical chemokine receptor 3, ENSG00000144476) is as follows. Atypical chemokine receptor that controls chemokine levels and localization via high-affinity chemokine binding that is uncoupled from classic ligand-driven signal transduction cascades, resulting instead in chemokine sequestration, degradation, or transcytosis. Also known as interceptor (internalizing receptor) or chemokine-scavenging receptor or chemokine decoy receptor. Acts as a receptor for chemokines CXCL11 and CXCL12/SDF1 (PubMed:16107333, PubMed:19255243, PubMed:19380869, PubMed:20161793, PubMed:22300987). Chemokine binding does not activate G protein-mediated signal transduction but instead induces beta-arrestin recruitment, leading to ligand internalization and activation of MAPK signaling pathway (PubMed:16940167, PubMed:18653785, PubMed:20018651). Required for regulation of CXCR4 protein levels in migrating interneurons, thereby adapting their chemokine responsiveness (PubMed:16940167, PubMed:18653785). In glioma cells, transduces signals via MEK/ERK pathway, mediating resistance to apoptosis. Promotes cell growth and survival (PubMed:16940167, PubMed:20388803). Not involved in cell migration, adhesion or proliferation of normal hematopoietic progenitors but activated by CXCL11 in malignant hemapoietic cells, leading to phosphorylation of ERK1/2 (MAPK3/MAPK1) and enhanced cell adhesion and migration (PubMed:17804806, PubMed:18653785, PubMed:19641136, PubMed:20887389). Plays a regulatory role in CXCR4-mediated activation of cell surface integrins by CXCL12 (PubMed:18653785). Required for heart valve development (PubMed:17804806). Regulates axon guidance in the oculomotor system through the regulation of CXCL12 levels (PubMed:31211835). Acts as a receptor for SHLP2, mediating its effects on activation of proopiomelanocortin neurons in the arcuate nucleus of the hypothalamus which leads to suppression of food intake and increased energy expenditure (PubMed:37468558). {ECO:0000269|PubMed:16107333, ECO:0000269|PubMed:16940167, ECO:0000269|PubMed:17804806, ECO:0000269|PubMed:18653785, ECO:0000269|PubMed:19255243, ECO:0000269|PubMed:19380869, ECO:0000269|PubMed:19641136, ECO:0000269|PubMed:20018651, ECO:0000269|PubMed:20161793, ECO:0000269|PubMed:20388803, ECO:0000269|PubMed:20887389, ECO:0000269|PubMed:22300987, ECO:0000269|PubMed:31211835, ECO:0000269|PubMed:37468558}. (Microbial infection) Acts as a coreceptor with CXCR4 for a restricted number of HIV isolates. .