CXCR4 and breast cancer: In breast cancer, binding of the chemokine CXCL12 and its G-protein-coupled receptor CXCR4 triggers Gαi2 and promotes its association with the ELMO1/Dock180 complex, which promotes the membrane translocation and activation of Rac1 and Rac2, and thereby contributes to actin cytoskeleton changes during breast cancer metastasis [18].