CCR4 is a G-protein-coupled chemokine receptor with dual roles in immune regulation and RNA metabolism. As an immune receptor, CCR4 functions as a high-affinity receptor for chemokines CCL17/TARC and CCL22/MDC, mediating Th2 cell and regulatory T cell (Treg) migration 1. CCR4 expression on Tregs is particularly elevated in tumor microenvironments, where it promotes their accumulation and immunosuppressive function 2. In pulmonary fibrosis, increased CCR4 expression on BAL CD4+ lymphocytes correlates with disease severity, suggesting pathogenic involvement in fibrotic inflammation 3. Beyond immunity, CCR4 functions as a catalytic subunit of the CCR4-NOT deadenylase complex, a central post-transcriptional regulator that removes poly(A) tails from mRNAs 4. YTHDF2 recruits CCR4-NOT to m6A-modified RNAs, promoting their degradation 5. Mammalian CCR4-NOT recognizes stalled ribosomes and couples translation to mRNA decay through ribosomal ubiquitination 6. During HCMV infection, host CCR4-NOT preferentially deadenylates cellular mRNAs while sparing viral transcripts, allowing viral gene expression dominance 7. These findings establish CCR4 as a therapeutic target in allergy, fibrosis, and cancer immunotherapy, while its deadenylase function represents a key control point in gene expression regulation.