Genetically encoded fluorescent sensors of membrane potential

Baker, Bradley J.; Mutoh, Hiroki; Dimitrov, Dimitar; Akemann, Walther; Perron, Amélie; Iwamoto, Yuka; Liu, Jin; Cohen, Lawrence B.; Isacoff, Ehud Y.; Pieribone, Vincent A.; Hughes, Thomas E.; Knöpfel, Thomas

doi:10.1007/s11068-008-9026-7

Cited by 85 publications

(75 citation statements)

References 50 publications

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“…Although the membrane potential difference between the vacuolar lumen and the cytosol is generally reported to be rather low (#30 mV), it will be important to determine how this physiological parameter is affected in mutants lacking one or both vacuolar H + -pumps. Determination of the tonoplast membrane potential is challenging as it can currently only be measured via impalement with double-barreled microelectrodes (Miller et al, 2001;Wang et al, 2015) and novel tools that allow in vivo imaging of tonoplast membrane potential based on voltagesensitive fluorescent proteins are highly desirable (Baker et al, 2008). …”

Section: (E) To (J) Vacuoles Of Epidermal Cells ([E] To [G]) and Mesomentioning

confidence: 99%

Job Sharing in the Endomembrane System: Vacuolar Acidification Requires the Combined Activity of V-ATPase and V-PPase

et al. 2015

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The presence of a large central vacuole is one of the hallmarks of a prototypical plant cell, and the multiple functions of this compartment require massive fluxes of molecules across its limiting membrane, the tonoplast. Transport is assumed to be energized by the membrane potential and the proton gradient established by the combined activity of two proton pumps, the vacuolar H + -pyrophosphatase (V-PPase) and the vacuolar H + -ATPase (V-ATPase). Exactly how labor is divided between these two enzymes has remained elusive. Here, we provide evidence using gain-and loss-of-function approaches that lack of the V-ATPase cannot be compensated for by increased V-PPase activity. Moreover, we show that increased V-ATPase activity during cold acclimation requires the presence of the V-PPase. Most importantly, we demonstrate that a mutant lacking both of these proton pumps is conditionally viable and retains significant vacuolar acidification, pointing to a so far undetected contribution of the trans-Golgi network/early endosome-localized V-ATPase to vacuolar pH.

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Section: (E) To (J) Vacuoles Of Epidermal Cells ([E] To [G]) and Mesomentioning

confidence: 99%

Job Sharing in the Endomembrane System: Vacuolar Acidification Requires the Combined Activity of V-ATPase and V-PPase

et al. 2015

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“…Furthermore, optical records of single (K ϩ ) channel conformations are possible with direct fluorescence labeling and total internal reflection fluorescence microscopy imaging to infer membrane voltage changes (87,113,116,117). Certain applications of genetics for development of new imaging probes, i.e., genetically encoded calcium and voltage-sensitive proteins, are considered as part of the broader view of optogenetics (5,10,37,95), despite the lack of an actuation component per se. Such genetically encoded sensors offer cell-specific readout and the potential for long-term in vivo monitoring of electrical activity compared with the widely used organic dyes.…”

Section: Introductionmentioning

confidence: 99%

Cardiac optogenetics

Entcheva

2013

American Journal of Physiology-Heart and Circulatory Physiology

114

105

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Optogenetics is an emerging technology for optical interrogation and control of biological function with high specificity and high spatiotemporal resolution. Mammalian cells and tissues can be sensitized to respond to light by a relatively simple and well-tolerated genetic modification using microbial opsins (light-gated ion channels and pumps). These can achieve fast and specific excitatory or inhibitory response, offering distinct advantages over traditional pharmacological or electrical means of perturbation. Since the first demonstrations of utility in mammalian cells (neurons) in 2005, optogenetics has spurred immense research activity and has inspired numerous applications for dissection of neural circuitry and understanding of brain function in health and disease, applications ranging from in vitro to work in behaving animals. Only recently (since 2010), the field has extended to cardiac applications with less than a dozen publications to date. In consideration of the early phase of work on cardiac optogenetics and the impact of the technique in understanding another excitable tissue, the brain, this review is largely a perspective of possibilities in the heart. It covers the basic principles of operation of light-sensitive ion channels and pumps, the available tools and ongoing efforts in optimizing them, overview of neuroscience use, as well as cardiac-specific questions of implementation and ideas for best use of this emerging technology in the heart. channelrhodopsin; light-sensitive ion channels; optical mapping THIS ARTICLE is part of a collection on Physiological Basis of Cardiovascular Cell and Gene Therapies. Other articles appearing in this collection, as well as a full archive of all collections, can be found online at http://ajpheart.physiology.org/. Background

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“…Furthermore, the relaxation of the required intensities to excite GFP, would, in principle, maximize the sample viability given that the ratio of the energy absorbed to the input energy flux determines the possible induced sample damage. Alternative applications in which the laser can be used for targeting GFP are monitoring membrane potential [62], selective NL optical sensing of electrophysiological processes in C. elegans [63], and protein dynamics recording inside living cells through photobleaching experiments [64], just to mention a few.…”

Section: Nonlinear Imaging Testsmentioning

confidence: 99%