Exploiting cameleon probes to investigate organelles Ca2+ handling

Calcium ion (Ca2+) is a ubiquitous intracellular messenger able to generate versatile intracellular signals that modulate a large variety of functions in virtually every cell type. Chemical and genetic biosensors, targeted to different subcellular compartments, have been developed and continuously improved to monitor Ca2+ dynamics in living cells. Here we describe the usage of Förster resonance energy transfer (FRET)-based Cameleon probes to investigate Ca2+ influx across the plasma membrane (PM) or Ca2+ release from the main intracellular Ca2+ store, the endoplasmic reticulum (ER)