The versatility and universality of calcium signalling

The universality of calcium as an intracellular messenger depends on its en ormous versatility. Cells have a calcium signalling toolkit with many compo nents that can be mixed and matched to create a wide range of spatial and t emporal signals. This versatility is exploited to control processes as dive rse as fertilization, proliferation, development, learning and memory, cont raction and secretion, and must be accomplished within the context of calci um being highly toxic. Exceeding its normal spatial and temporal boundaries can result in cell death through both necrosis and apoptosis.