RT Journal Article
SR Electronic
T1 Optical determination of absolute membrane potential
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 519736
DO 10.1101/519736
A1 Julia R. Lazzari-Dean
A1 Anneliese M.M. Gest
A1 Evan W. Miller
YR 2019
UL http://biorxiv.org/content/early/2019/01/14/519736.abstract
AB All cells maintain ionic gradients across their plasma membranes, producing transmembrane potentials (Vmem). Mounting evidence suggests a relationship between resting Vmem and the physiology of non-excitable cells with implications in diverse areas, including cancer, cellular differentiation, and body patterning. A lack of non-invasive methods to record absolute Vmem limits our understanding of this fundamental signal. To address this need, we developed a fluorescence lifetime-based approach (VF-FLIM) to visualize and optically quantify Vmem with single-cell resolution. Using VF-FLIM, we report Vmem distributions over thousands of cells, a 100-fold improvement relative to electrophysiological approaches. In human carcinoma cells, we visualize the voltage response to epidermal growth factor stimulation, stably recording a 10-15 mV hyperpolarization over minutes. Using pharmacological inhibitors, we identify the source of the hyperpolarization as the Ca2+-activated K+ channel Kca3.1. The ability to optically quantify absolute Vmem with cellular resolution will allow a re-examination of its roles as a cellular signal.