Ca(2+) Measurements in Mammalian Cells with Aequorin-based Probes.

Aequorin is a Ca(2+) sensitive photoprotein suitable to measure intracellular Ca(2+) transients in mammalian cells. Thanks to recombinant cDNAs expression, aequorin can be specifically targeted to various subcellular compartments, thus allowing an accurate measurement of Ca(2+) uptake and release of different intracellular organelles. Here, we describe how to use this probe to measure cytosolic Ca(2+) levels and mitochondrial Ca(2+) uptake in mammalian cells.