Table 1.
Complexity of the ligand-receptor system in the chemokine family. There are 4 subfamilies of chemokines, classified according to the position of the N-terminal cystein residues: CC, CXC, CX3C and XC. The chemokine-chemokine receptor system is quite complex, since some chemokines can activate several receptors, and a single receptor can have several ligands (bold text). To date, 5 atypical receptors have been characterized, which do not induce activation after ligand binding (last column).
| CC | CXC | CX3C | XC | ATYPICAL CHEMOKINE RECEPTOR |
|---|---|---|---|---|
| CCR1 (CCL3,5,7,8,14,15,16, 23) | CXCR1 (CXCL1,6,7,8) | CX3CR1 (CX3CL1) | XCR1(XCL1,2) | ACKR1 |
| CCR2 (CCL2,7,8,12,13) | CXCR2(CXCL1,2,3,5,6,7,8) | ACKR2 | ||
| CCR3 (CCL5,7,8,11,13,15,24,26) | CXCR3 (CXCL4, CXCL4L1, CXCL9,10,11) | ACKR3 | ||
| CCR4 (CCL17,22) | CXCR4 (CXCL12) | ACKR4 | ||
| CCR5 (CCL3,4,5) | CXCR5 (CXCL13) | ACKR5 | ||
| CCR6 (CCL20) | CXCR6 (CXCL16) | |||
| CCR7 (CCL19,21) | CXCR7 (CXCL12) | |||
| CCR8 (CCL1,4,17) | ||||
| CCR9 (CCL25) | ||||
| CCR10 (CCL27, 28) | ||||
| CCR11 (CCL8,13) |