SR-PSOX/CXCL16

CXCL16, also known as SR-PSOX (scavenger receptor that binds phosphatidylserine and oxidized lipoprotein), is one member of the ELR-negative CXC chemokine subfamily. CXCL16 is a multifunctional protein involved in various inflammatory diseases, atherosclerosis, and cancer. CXCL16 can be observed in many cell types. CXCL16 is expressed in soluble or transmembrane forms and can be observed in many cell types, including inflammatory cells (such as macrophages, neutrophils, dendritic cells and monocytes) and non-inflammatory cells (such as lung epithelial cells and renal cells). CXCL16 plays important roles both in the natural immune barrier and in the occurrence and development of autoimmune diseases^[1][2].
CXCL16 is primarily expressed on the surface of antigen-presenting cells (APCs) and consists of a chemokine domain (∼89 amino acids), a mucin-type stalk (∼110 amino acids), a single-pass transmembrane domain (∼20 amino acids), and a cytoplasmic tail (∼27 amino acids). CXCL16 is the only ligand of the CXCR6 receptor. Soluble CXCL16 induces the migration of CXCR6+ cells (including Th1 cells, NK cells and activated CD8 + T-cells), M2-macrophage infiltration, interactions between APC and CD8 + T-cells, the cellular immune response and inflammatory response, and the development of thymocytes. Membrane-bound CXCL16 can promote the adhesion of CXCR6+ cells. CXCL16 specifically binds oxidized low-density lipoprotein (OxLDL), leading to its internalization and degradation. CXCL16 may play important roles in the formation of atherosclerotic lesions. CXCL16 on macrophages and dendritic cells mediates the adhesion and phagocytosis of bacteria, such as Escherichia coli and Staphylococcus aureus, and bacterial recognition is mediated by the chemokine domain of CXCL16^[1][2].