cAMP Receptor and G-protein Interactions Control Development in Dictyostelium

Transmembrane signaling is vital to the development of the cellular slime mold Dictyostelium. Starvation initiates a developmental program in which single cells spontaneously form a multicellular structure composed of two cell types. The aggregation ofthese single cells is organized by extracellular cAMP. Aggregation centers form that produce waves of cAMP at precisely timed intervals. The cAMP binds to a surface receptor trig-gering cAMP production and secretion, which prop-agates the wave throughout he population, cAMP binding also triggers a number of biochemical respon-ses associated with chemotaxis, uch as guanylate cy-clase activation and myosin phosphorylation. The cAMP gradient that orients the cells toward the aggre-gation center is established as the leading edge of th