Regulation of ATP production by mitochondrial Ca²⁺

Stimulation of mitochondrial oxidative metabolism by Ca²⁺ is now generally recognised as important for the control of cellular ATP homeostasis. Here, we review the mechanisms through which Ca²⁺ regulates mitochondrial ATP synthesis. We focus on cardiac myocytes and pancreatic β-cells, where tight control of this process is likely to play an important role in the response to rapid changes in workload and to nutrient stimulation, respectively. We also describe a novel approach for imaging the Ca²⁺-dependent regulation of ATP levels dynamically in single cells.