Chemokine receptors

G protein-coupled receptors (GPCRs) with seven transmembrane α-helices (TM7), which belong to the rhodopsin superfamily. Chemokine receptors bind their respective ligands with high affinity. The binding of a chemokine to its specific receptor on the cell surface, mediated by a Ga1-containing G-protein complex, leads to the formation of a short-lived intracellular signal. The subsequent signal transduction then leads to the activation of protein kinase C (PKC) and mitogen-activated protein kinase (MAPK). Some chemokine receptors, such as CXCR4, can lead to the generation of longer-lasting signals through activation of protein kinase B. Activation of the protein kinases ultimately results in chemotaxis of the target cell directed towards the source of the chemokines. Chemokine receptors are classified similarly to the chemokine subfamilies.

A distinction is made between:

• 11 CC chemokine receptors (CCR1-CCR11)
• and
• 6 CXC chemokine receptors (CXCR1-CXCR6).

Carriers of a certain variant (delta 32) of the chemokine receptor CCR5 show a certain resistance to infections caused by the human immunodeficiency virus 1 (HIV-1). The reason for this is that CCR5 functions alongside CD4 as a coreceptor in an HIV-1 infection.

1. Baggiolini M (1998) Chemokines and leukocyte traffic. Nature 392: 565-568
2. Rossi D, Zlotnik A (2000) The biology of chemokines and their receptors. Ann Rev Immunol 18: 217-242
3. Zlotnik A, Yoshie O (2000) Chemokines: a new classification system and their role in immunity. Immunity 12: 121-127