Green fluorescent proteins (GFPs) for measuring voltage.
Measuring signal transduction in large numbers of cells, with high spatial and temporal resolution, is a fundamental problem for studying information processing in the nervous system. To address this problem, a family of detectors that are chimeras between signal transduction proteins and fluorescent proteins has been designed. The prototype sensor is a genetically encoded probe that can be used to measure transmembrane voltage in single cells. This article describes a modified green fluorescent protein (GFP), fused to a voltage-sensitive K(+) channel, so that voltage-dependent rearrangements in the K(+) channel induce changes in the fluorescence of GFP. The probe has a maximal fractional fluorescence change of 5.1%, making it comparable to some of the best organic voltage-sensitive dyes. Moreover, the fluorescent signal is expanded in time in a manner that makes the signal 30-fold easier to detect than a traditional linear dye. DNA-encoded sensors have the advantage that they may be introduced into an organism noninvasively and targeted to specific brain regions, cell types, and subcellular compartments.
Siegel
Micah S
MS
Isacoff
Ehud Y
EY
D000818:Animals; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism*; D008564:Membrane Potentials; D009865:Oocytes / Q000502:physiology*; D024642:Potassium Channels, Voltage-Gated / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D056969:Voltage-Sensitive Dye Imaging / Q000379:methods*; D014982:Xenopus laevis
D024642:Potassium Channels, Voltage-Gated; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins