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Upon starvation, individual Dictyostelium amoebae chemotax toward aggregation centers in tightly packed streams in which cells are organized in head-to-tail chains. A recent report in Cell shows that this behavior requires localization of adenylyl cyclase and the production and secretion of the chemoattractant cAMP at the posterior of individual cells. These findings suggest a relay and communication system to regulate the long-range coordinated movement of cells.