Live-Cell Imaging of Peroxisomal Calcium Levels and Dynamics.

Calcium (Ca) is an intracellular messenger that plays an essential role in a variety of cellular processes ranging from early embryonic events to muscle contraction and neuron excitability. Measurement of cytosolic, endoplasmic reticulum (ER), and mitochondrial Ca has contributed immensely to our understanding of cellular physiology. Here we describe the measurement of peroxisomal Ca using ratiometric Ca sensors, enabling measurement of absolute Ca concentration and its dynamics in living cells.