Chemokines constitute a family of small chemotactic cytokines. They typically have a size of 8-16 kDa and are classified into 4 classes, depending on the spacing of their conserved N-terminal cysteine residues. The CC- and CXC-chemokine classes are the ones with the most members, while the XC and CX3C-classes have only 1 or 2 members. On a structural level, the chemokines are hallmarked by a typical feature, termed the “chemokine fold”, which is characterized by a disordered N-terminus and a 3-strand antiparallel β-sheet that is supported by an α-helix at the C-terminus. Among the various roles they exert, the regulation of leukocyte trafficking is most established and in focus as drivers of inflammatory diseases e.g. atherosclerosis. The large diversity of chemokines also allows the generation of specific messages to attract defined subsets of leukocytes to sites of inflammation or infection. Chemokines bind to and activate G protein-coupled 7-transmembrane receptors. Some of those were found to be human immunodeficiency virus co-receptors, which made them interesting drug targets to combat HIV and strongly pushed chemokine research in the 1990s. Currently, chemokine receptors are mainly investigated as drug targets to treat autoimmune diseases, although major successes are still outstanding. Besides their roles in inflammation, chemokines also have homeostatic functions, e.g. in directing lymphocytes to lymphoid organs or to retain blood cells to the bone marrow.
Platelets are a rich source of chemokines (e.g. CCL5 and CXCL4), and this property is investigated in the department of Biochemistry.
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