Assays of mitochondrial Ca²⁺ transport and Ca²⁺ efflux via the MPTP

Studying Ca²⁺ transport in mitochondria in connection with energy production, as well as cell death, is of great importance. Ca²⁺ activates several key enzymes in the mitochondrial matrix to enhance ATP production. This provides an important mechanism for synchronizing energy production with the energy demands of Ca²⁺-activated processes, such as contraction, allowing important feedback effects to help shape cytosolic Ca²⁺ signals. A rise in mitochondrial Ca²⁺ can convey both apoptotic and necrotic death signals by inducing opening of the mitochondrial permeability transition pore (MPTP). Here, we present a protocol for measuring Ca²⁺ transport and release in isolated mitochondria.