Spatiotemporal dynamics of Ca2+ signaling and its physiological roles

Abstract

Changes in the intracellular Ca2+ concentration regulate numerous cell functions and display diverse spatiotemporal dynamics, which underlie the versatility of Ca2+ in cell signaling. In many cell types, an increase in the intracellular Ca2+ concentration starts locally, propagates within the cell (Ca2+ wave) and makes oscillatory changes (Ca2+ oscillation). Studies of the intracellular Ca2+ release mechanism from the endoplasmic reticulum (ER) showed that the Ca2+ release mechanism has inherent regenerative properties, which is essential for the generation of Ca2+ waves and oscillations. Ca2+ may shuttle between the ER and mitochondria, and this appears to be important for pacemaking of Ca2+ oscillations. Importantly, Ca2+ oscillations are an efficient mechanism in regulating cell functions, having effects supra-proportional to the sum of duration of Ca2+ increase. Furthermore, Ca2+ signaling mechanism studies have led to the development of a method for specific inhibition of Ca2+ signaling, which has been used to identify hitherto unrecognized functions of Ca2+ signals. © 2010 The Japan Academy.