Imaging the Electrical Activity Of Organelles in living cells

Eukaryotic cells are complex systems compartmentalized in membrane-bound organelles. Visualization of organellar electrical activity in living cells requires both a suitable reporter and non-invasive imaging at high spatiotemporal resolution. Here we present hVoS org , an optical method to monitor changes in the membrane potential of subcellular membranes. This method takes advantage of a FRET pair consisting of a membrane-bound voltage-insensitive fluorescent donor and a colorless voltage-dependent acceptor that rapidly moves across the membrane in response to changes in polarity. Compared to the currently available techniques, hVoS org has advantages including simple and precise subcellular targeting, the ability to record from individual organelles, and the potential for optical multiplexing. Summary By adapting a hybrid-FRET voltage sensor we report here the resting membrane potential of different organelles in living cells.