Chemoattractant receptors and leukocyte recruitment: More than cell migration

Chemoattractants induce cell migration through the activation of a distinct family of structurally related heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptors. Over the past few years, several receptors in this family have been identified that recognize different classes of chemoattractants but do not induce cell migration. These atypical "chemoattractant receptors" are unable to activate transduction events that lead directly to cell migration, but appear nonetheless to play a nonredundant role in leukocyte recruitment by shaping the chemoattractant gradient, either by removing, transporting, or concentrating their cognate ligands.