A consequence of intracellular calcium signalling is that calcium released
into the cytosol is extruded from the cell. New research shows that when th
e interstitial space is constricted, calcium extruded from one cell may inc
rease levels of calcium in the surrounding medium sufficiently to activate
calcium-sensing receptors on the surfaces of adjacent cells. Thus, the calc
ium that serves as an intracellular signal can also serve as an extracellul
ar signal to recruit neighbouring cells.