Synthetic bioelectrical systems: electrophysiology of minimal spiking cells
Neurons and cardiomyocytes use a complex panoply of ion channels to achieve precisely regulated firing patterns and responses to external stimuli. We asked, what is the simplest cellular system that can generate electrical spikes? Electrically inert HEK cells can be rendered electrically active through expression of just two ion channels: an inward-rectifier potassium channel and a voltage-gated sodium channel. We have been using spiking HEK cells to study fundamental aspects of cellular computation, and as a tool for discovering and probing electrically responsive transmembrane proteins.
Spiking HEK cells generate spontaneous electrical waves |
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Development of improved fluorescent voltage indicators is a key challenge in neuroscience, but progress has been hampered by the low throughput of patch-clamp characterization. We introduce a line of non-fluorescent HEK cells that stably express NaV 1.3 and KIR 2.1 and generate spontaneous electrical action potentials. These cells enable rapid, electrode-free screening of speed and sensitivity of voltage sensitive dyes or fluorescent proteins on a standard fluorescence microscope. We screened a small library of mutants of Archaerhodopsin 3 (Arch) in spiking HEK cells and identified two mutants with greater voltage-sensitivity than found in previously published Arch voltage indicators.
See: J. Park , C.A. Werley, V. Venkatachalam, J.M. Kralj, S.D. Dib-Hajj, S.G. Waxman, A.E. Cohen, Screening fluorescent voltage indicators with spontaneously spiking HEK cells, PLoS ONE, 8, e85221, 2013. |
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