Membrane raft microdomains in chemokine receptor function

Cell chemotaxis requires the acquisition and maintenance of both spatial an d functional asymmetry between initially equivalent cell parts. In leukocyt es one becomes the leading edge and the other, the rear edge or uropod. The acquisition of this cell polarity is controlled by an array of chemoattrac tants, including those of the chemokine family. We propose that chemokine r eceptor activation in highly organized lipid raft domains is a major determ inant for the correct localization of the signaling pathways leading to the cell asymmetries required for migration. The lateral organization imposed by membrane raft microdomains is discussed in the context of other chemokin e receptor activities, such as its role as a human immunodeficiency virus ( HIV) coreceptor.