MIP‐3α, MIP‐3β and fractalkine induce the locomotion and the mobilization of intracellular calcium, and activate the heterotrimeric G proteins in human natural killer cells

We demonstrate here that the CC chemokines macrophage inflammatory protein‐3α (MIP‐3α), macrophage inflammatory protein‐3β (MIP‐3β) and the CX3C chemokine fractalkine induce the chemotaxis of interleukin‐2 (IL‐2)‐activated natural killer (IANK) cells. In addition, these chemokines enhance the binding of [γ‐35S]guanine triphosphate ([γ‐35S]GTP) to IANK cell membranes, suggesting that receptors for these chemokines are G protein‐coupled. Our results show that MIP‐3α receptors are coupled to Go, Gq and Gz, MIP‐3β receptors are coupled to Gi, Gq and Gs, whereas fractalkine receptors are coupled to Gi, and Gz. All three chemokines induced a robust calcium response flux in IANK cells. Cross‐desensitization experiments show that MIP‐3α, MIP‐3β or fractalkine use receptors not shared by each other or by the CC chemokine regulated on activation, normal, T‐cell expressed, and secreted (RANTES), the CXC chemokines stromal‐derived factor‐1α (SDF‐1α) and interferon‐inducible protein‐10 (IP‐10), or the C chemokine lymphotactin.