Kang, Bok Eum Lee, Sungmoo Baker, Bradley J. 2024-01-19T19:30:29Z 2024-01-19T19:30:29Z 2021-09-05 2019-09 0168-0102 https://pubs.kist.re.kr/handle/201004/119618 Genetically-Encoded Voltage Indicators (GEVIs) are capable of converting changes in membrane potential into an optical signal. Here, we focus on recent insights into the mechanism of ArcLight-type probes and the consequences of utilizing a pH-dependent Fluorescent Protein (FP). A negative charge on the exterior of the beta-can of the FP combined with a pH-sensitive FP enables voltage-dependent conformational changes to affect the fluorescence of the probe. This hypothesis implies that interaction/dimerization of the FP creates a microenvironment for the probe that is altered via conformational changes. This mechanism explains why a pH sensitive FP with a negative charge on the outside of the beta-can is needed, but also suggests that pH could affect the optical signal as well. To better understand the effects of pH on the voltage-dependent signal of ArcLight, the intracellular pH (pHi) was tested at pH 6.8, 7.2, or 7.8. The resting fluorescence of ArcLight gets brighter as the pHi increases, yet only pH 7.8 significantly affected the Delta F/F. ArcLight could also simultaneously report voltage and pH changes during the acidification of a neuron firing multiple action potentials revealing different buffering capacities of the soma versus the processes of the cell. (C) 2018 The Authors. Published by Elsevier B.V. English ELSEVIER IRELAND LTD STIMULUS-EVOKED CHANGES CENTRAL-NERVOUS-SYSTEM ACTION-POTENTIALS INTRACELLULAR PH SENSING DOMAIN SENSORS NEURONS TRANSMISSION INHIBITION MECHANISMS Optical consequences of a genetically-encoded voltage indicator with a pH sensitive fluorescent protein Article 10.1016/j.neures.2018.10.006 1 NEUROSCIENCE RESEARCH, v.146, pp.13 - 21 NEUROSCIENCE RESEARCH 146 13 21 scie scopus 000476999200002 2-s2.0-85055632438 Neurosciences Neurosciences & Neurology Review STIMULUS-EVOKED CHANGES CENTRAL-NERVOUS-SYSTEM ACTION-POTENTIALS INTRACELLULAR PH SENSING DOMAIN SENSORS NEURONS TRANSMISSION INHIBITION MECHANISMS GEVI Voltage imaging pH imaging ArcLight Super ecliptic pHluorin