Tissue‐specific modulation of the mitochondrial calcium uniporter by magnesium ions

Abstract

This paper analyzes the kinetics of the Ca²⁺ uniporter of mitochondria from rat heart, kidney and liver operating in a range of Ca²⁺ concentrations near the steady-state value (1–4μM). Heart mitochondria exhibit the lowest activity, and physiological Mg²⁺ concentrations inhibit the mitochondrial Ca²⁺ uniporter by approx. 50% in heart and kidney, and by 20% in liver. At physiological Ca²⁺ and Mg²⁺ concentrations the external free Ca²⁺ maintained by respiring mitochondria in vitro is higher in heart and kidney with respect to liver mitochondria. This behaviour could represent an adaptation of different mitochondria to their specific intracellular environment.