High resolution

Module 5: Figure mitochondrial Ca2+ signalling

Relationship between mitochondrial metabolism and Ca2+ signalling.

Mitochondria are energized by pyruvate, which enters the mitochondrion where it is metabolized by the tricarboxylic acid (TCA) cycle (or citric acid cycle) to produce the reducing equivalents that are transferred to the electron transport chain located in the inner mitochondrial membrane. The subsequent extrusion of protons creates a large (−150 to −180 mV) negative membrane potential across this inner membrane. This large proton gradient is used to energize both ATP synthesis and the uptake of Ca2+. Protons flowing back through the oligomycin-sensitive ATP synthase drive the synthesis of ATP.