[Read the Article]
Just as water molecules spontaneously arrange to form geometric snowflakes, the “social” amoeba Dictyostelium discoideum transitions from a collection of unicellular organisms to a fruiting body during its life cycle. This aggregation is guided by cyclic AMP (cAMP): when stimulated with cAMP, cells respond by producing and secreting more of the molecule, which, once levels reach a threshold, results in nondissipating waves of cAMP and collective amoeba movement. Previously it was unclear whether the initiation of this signaling behavior was the responsibility of a few specialized cells or was a simultaneous, collective effort. Gregor et al. used live-cell imaging to show that cAMP pulses originate from a specific location in space, and that non-specialized, individual cells pass through these signaling centers and initiate cAMP-pulsing.