CD184, also known as CXCR4, is a CXC chemokine receptor encoded by the CXCR4 gene. It is a G protein-coupled receptor that specifically binds to stromal-derived factor-1 （SDF-1, also known as CXCL12）, which is important for lymphocyte chemotaxis, hematopoietic stem cell homing, and quiescence. CXCR4 is also a co-receptor for HIV infection in CD4+ T cells, particularly for T-cell tropic HIV strains. Additionally, CXCR4 is involved in neuronal guidance during embryogenesis and adult life, and its dysregulation has been implicated in various diseases, including cancer and epilepsy.