The function of ENSG00000183813 (CCR4, C-C motif chemokine receptor 4) is as follows. High affinity receptor for the C-C type chemokines CCL17/TARC, CCL22/MDC and CKLF isoform 1/CKLF1. The activity of this receptor is mediated by G(i) proteins which activate a phosphatidylinositol-calcium second messenger system. Can function as a chemoattractant homing receptor on circulating memory lymphocytes and as a coreceptor for some primary HIV-2 isolates. In the CNS, could mediate hippocampal-neuron survival. {ECO:0000269|PubMed:10466728, ECO:0000269|PubMed:10754297, ECO:0000269|PubMed:16137713, ECO:0000269|PubMed:9169480, ECO:0000269|PubMed:9430724}.