Spatial aspects of Ca2+ signalling

Spatial aspects of Ca²⁺ signalling

a, Elementary events (red) result from the entry of external Ca²⁺ across the plasma membrane or release from internal stores in the endoplasmic or sarcoplasmic reticulum (ER/SR). They generate localized concentrations of Ca²⁺ that can activate many processes, including export of cellular material (1), opening of K⁺ channels (2) and metabolism in the mitochondria (3). The Ca²⁺ signals can also enter the nucleus (4). All of these processes respond to the very high concentrations of Ca²⁺ that build up within the sub-domain of the elementary events. b, Global Ca²⁺ signals are produced by coordinating the activity of elementary events to produce a Ca²⁺ wave that spreads throughout the cell. c, The activity of neighbouring cells within a tissue can be coordinated by an intercellular wave that spreads from one cell to the next.